Pathology of the Respiratory System
Standard Answer:
1. Write an essay on Lobar pneumonia Lobar pneumonia is an acute bacterial infection of the lung that affects an entire lobe or a large portion of a lobe. It is most commonly caused by Streptococcus pneumoniae (pneumococcus) but can also be caused by Klebsiella pneumoniae, Staphylococcus aureus, and other organisms. Pathogenesis: · Inhalation of bacteria or aspiration from the oropharynx · Organisms reach the alveoli where they multiply · Inflammatory response: Neutrophils accumulate in the alveoli, filling them with exudate · Spread of infection through the pores of Kohn and canals of Lambert to involve the entire lobe Pathological Stages (Classical Four Stages): 1. Congestion Stage (First 24 Hours): · Vascular congestion and engorgement of capillaries · Intra-alveolar fluid with small numbers of neutrophils · Numerous bacteria · Gross: Heavy, red, boggy lung 2. Red Hepatization Stage (Days 2-3): · Massive exudation of neutrophils, red blood cells, and fibrin into alveoli · Alveoli are filled with a fibrin-rich exudate · Gross: Red, firm, airless (liver-like consistency) · Microscopic: Alveoli filled with neutrophils, fibrin, red cells 3. Gray Hepatization Stage (Days 4-6): · Fibrinous exudate with leukocytes; red cells degrade · Fibrin strands become prominent · Gross: Grayish-brown, firm, airless · Microscopic: Alveoli filled with fibrin and neutrophils; fewer red cells 4. Resolution Stage (Day 8 onwards): · Fibrin is lysed by proteolytic enzymes · Macrophages remove debris · Alveolar architecture is restored · Gross: Lung returns to normal appearance Complications: · Delayed resolution · Abscess formation (especially with Klebsiella or Staphylococcus) · Empyema (pus in pleural space) · Pleuritis · Bacteremia and sepsis · Meningitis · Organizing pneumonia (fibrosis) 2. a. Outline risk factors of lung cancer b. Outline common clinical features and histologic types of lung cancer a. Risk Factors of Lung Cancer: 1. Tobacco Smoking: Most important risk factor (accounts for 85% of cases); cigarette smoke contains over 60 carcinogens 2. Secondhand Smoke: Passive smoking increases risk 3. Occupational Exposures: Asbestos (mesothelioma), radon, arsenic, chromium, nickel, uranium, vinyl chloride, silica 4. Air Pollution: Particulate matter, industrial emissions 5. Family History: Genetic predisposition 6. Chronic Lung Disease: COPD, pulmonary fibrosis, tuberculosis 7. Radiation Exposure: Therapeutic radiation, radon gas 8. Diet: Low intake of fruits and vegetables; high fat diet 9. Immunosuppression: HIV, organ transplant recipients 10. Previous Lung Cancer: Increased risk of second primary lung cancer b. Common Clinical Features and Histologic Types of Lung Cancer: Clinical Features: · Pulmonary Symptoms: Chronic cough, hemoptysis, dyspnea, chest pain, wheezing, recurrent pneumonia · Systemic Symptoms: Weight loss, anorexia, fatigue, fever · Extrapulmonary Symptoms: Hoarseness (recurrent laryngeal nerve), Horner syndrome (pancoast tumor), SVC syndrome, pleural effusion · Paraneoplastic Syndromes: Cushing syndrome (ACTH), SIADH, hypercalcemia (PTHrP), clubbing, hypertrophic pulmonary osteoarthropathy Histologic Types: Small Cell Lung Carcinoma (SCLC): · Accounts for 15% of lung cancers · Highly aggressive, rapid growth, early metastasis · Strongly associated with smoking · Microscopic: Small, round cells with scant cytoplasm, "oat cell" appearance · Immunohistochemistry: TTF-1+, neuroendocrine markers (chromogranin, synaptophysin) · Paraneoplastic: SIADH, Cushing syndrome, Lambert-Eaton myasthenic syndrome Non-Small Cell Lung Carcinoma (NSCLC): a. Squamous Cell Carcinoma: · Accounts for 25-30% · Strongly associated with smoking · Arises from bronchial epithelium, often central · Microscopic: Keratin pearls, intercellular bridges · Can cavitate b. Adenocarcinoma: · Accounts for 40% (most common) · Less strongly associated with smoking; most common in non-smokers · Arises from peripheral lung (bronchioloalveolar origin) · Microscopic: Glandular differentiation, mucin production · Subtypes: Acinar, papillary, solid, lepidic · Associated with EGFR, ALK, KRAS mutations c. Large Cell Carcinoma: · Accounts for 5-10% · Undifferentiated, no glandular or squamous features · Poor prognosis · Microscopic: Large cells with prominent nucleoli, abundant cytoplasm Other Types: · Carcinoid Tumors: Low-grade neuroendocrine tumors (typical/atypical) · Mesothelioma: Associated with asbestos · Salivary Gland Type Tumors: Adenoid cystic carcinoma, mucoepidermoid carcinoma 3. Define chronic obstructive pulmonary disease. Describe the mechanism of obstruction in each of the component diseases Definition of COPD: Chronic Obstructive Pulmonary Disease is a preventable and treatable disease characterized by persistent, progressive airflow limitation that is not fully reversible. It is caused by chronic inflammation of the airways and lung parenchyma in response to noxious particles or gases, most commonly tobacco smoke. Component Diseases and Mechanisms of Obstruction: 1. Chronic Bronchitis: · Definition: Chronic productive cough for at least 3 months in 2 consecutive years · Mechanism of Obstruction: · Hypertrophy and hyperplasia of mucus-secreting glands (goblet cells) → excessive mucus production · Inflammation and edema of bronchial mucosa → narrowing of airways · Smooth muscle hypertrophy → bronchoconstriction · Mucus plugging of small airways → obstruction 2. Emphysema: · Definition: Abnormal permanent enlargement of airspaces distal to terminal bronchioles with destruction of alveolar walls without fibrosis · Mechanism of Obstruction: · Loss of elastic recoil of lung due to destruction of elastin (protease-antiprotease imbalance) · Destruction of alveolar septa → reduced surface area for gas exchange · Airway collapse during expiration (dynamic airway compression) → air trapping · Loss of tethering support of small airways → premature closure 3. Bronchiectasis: · Definition: Permanent abnormal dilatation of bronchi and bronchioles due to destruction of bronchial wall · Mechanism of Obstruction: · Chronic inflammation and infection → destruction of bronchial wall (muscle, cartilage) · Dilatation of bronchi → pooling of secretions · Mucus plugging → obstruction · Recurrent infections → further damage Asthma (Often included in COPD): · Mechanism of Obstruction: · Bronchospasm (smooth muscle contraction) · Mucosal edema (increased vascular permeability) · Mucus hypersecretion (goblet cell hyperplasia) · Airway remodeling (in chronic asthma) 4. Write an essay on adult respiratory distress syndrome Adult Respiratory Distress Syndrome (ARDS), also known as Acute Respiratory Distress Syndrome, is a life-threatening form of respiratory failure characterized by acute onset of severe hypoxemia, bilateral pulmonary infiltrates, and diffuse alveolar damage in the absence of cardiogenic pulmonary edema. Etiology: · Direct Lung Injury: Pneumonia, aspiration, pulmonary contusion, near-drowning, inhalation injury · Indirect Lung Injury: Sepsis (most common cause), severe trauma, acute pancreatitis, massive blood transfusion, burns, drug overdose Pathogenesis: 1. Initial Injury: Injury to alveolar epithelium and pulmonary vascular endothelium 2. Inflammatory Response: Activation of neutrophils and macrophages → release of pro-inflammatory cytokines (TNF, IL-1, IL-6, IL-8) and reactive oxygen species 3. Endothelial Damage: Increased vascular permeability → leakage of protein-rich fluid into alveoli and interstitium 4. Alveolar Damage: Damage to type I pneumocytes → loss of epithelial barrier; damage to type II pneumocytes → surfactant deficiency 5. Hyaline Membrane Formation: Protein-rich exudate and cellular debris form hyaline membranes lining alveolar walls 6. Impaired Gas Exchange: Ventilation-perfusion mismatch, shunt, diffusion impairment → severe hypoxemia Pathological Stages: 1. Exudative Phase (Days 0-7): · Gross: Heavy, edematous, congested lungs · Microscopic: Alveolar edema, capillary congestion, neutrophil infiltration, hyaline membranes, alveolar hemorrhage 2. Proliferative Phase (Days 7-21): · Gross: Lungs appear more solid · Microscopic: Organization of exudate; type II pneumocyte proliferation; interstitial and intra-alveolar fibrosis; early fibroblast proliferation 3. Fibrotic Phase (After 3 Weeks): · Gross: Firm, fibrotic lungs · Microscopic: Extensive fibrosis, alveolar septal thickening, honeycombing, vascular obliteration Clinical Features: · Acute onset of severe dyspnea and respiratory distress · Severe hypoxemia (PaO2/FiO2 < 300) · Bilateral infiltrates on chest X-ray · No evidence of cardiogenic pulmonary edema · Tachypnea, tachycardia, use of accessory muscles Complications: · Respiratory failure · Multiple organ dysfunction syndrome (MODS) · Ventilator-associated pneumonia · Barotrauma (pneumothorax, pneumomediastinum) · Pulmonary fibrosis · Death (mortality ~30-50%) 5. List the morphologic features of bronchial asthma Gross Features: · Hyperinflation of lungs (air trapping) · Mucous plugs in airways · Edema of bronchial mucosa Microscopic Features: · Airway Inflammation: Infiltration of bronchial wall by eosinophils, mast cells, lymphocytes, and neutrophils · Mucosal Edema: Swelling of bronchial mucosa · Goblet Cell Hyperplasia: Increased mucus-secreting cells · Mucus Plugging: Airways filled with mucus containing Curschmann spirals (coiled mucus casts) and Charcot-Leyden crystals (eosinophil-derived) · Basement Membrane Thickening: Subepithelial fibrosis (collagen deposition beneath epithelial basement membrane) · Smooth Muscle Hypertrophy: Thickening of bronchial smooth muscle · Epithelial Desquamation: Loss of surface epithelium 6. Complications of bronchial asthma 1. Respiratory Failure: Hypoxemic and hypercapnic respiratory failure 2. Pneumothorax: Rupture of overdistended alveoli causing air in pleural space (barotrauma) 3. Pneumomediastinum: Air in mediastinum 4. Atelectasis: Collapse of lung due to mucus plugging 5. Pneumonia: Secondary bacterial infection 6. Chronic Asthma: Airway remodeling leading to irreversible airflow obstruction 7. Status Asthmaticus: Severe, prolonged asthma attack unresponsive to treatment 8. Respiratory Arrest: Life-threatening complication 9. Growth Retardation: In children (due to chronic hypoxia and steroid therapy) 10. Corticosteroid Side Effects: Osteoporosis, diabetes, immunosuppression 7. Short note on Pulmonary tuberculosis Pulmonary tuberculosis is a chronic granulomatous infection caused by Mycobacterium tuberculosis. Pathogenesis: 1. Inhalation of Bacteria: Droplet nuclei containing M. tuberculosis are inhaled into alveoli 2. Primary Infection: Alveolar macrophages engulf bacteria but may fail to kill them; bacteria multiply intracellularly 3. Granuloma Formation: Cell-mediated immune response (Th1) → formation of granulomas (tubercles) with central caseous necrosis 4. Primary Complex (Ghon Complex): Subpleural granuloma in lower lobe + hilar lymph node involvement 5. Healing: Granulomas may heal by fibrosis and calcification 6. Reactivation (Secondary TB): Occurs in immunocompromised or elderly; usually in apical areas (high oxygen tension) Pathological Features: · Primary TB: Ghon focus (subpleural granuloma in lower/mid lobe) + hilar lymphadenopathy (Ghon complex) · Secondary TB: Apical cavitary lesions, caseous necrosis, fibrosis, calcification · Microscopic: Granulomas with central caseous necrosis, epithelioid macrophages, Langhans giant cells, peripheral lymphocytes Clinical Features: · Chronic cough, hemoptysis, fever, night sweats, weight loss, malaise Complications: · Miliary TB (disseminated) · Meningitis · Pleural effusion, empyema · Bronchiectasis · Lung cavitation (mycetoma) · Hemoptysis (Rasmussen aneurysm) · Fibrosis → respiratory failure 8. Write an essay on bronchial asthma Bronchial asthma is a chronic inflammatory disease of the airways characterized by episodic, reversible bronchoconstriction, airway hyperresponsiveness, and airway inflammation. Pathogenesis: 1. Immunologic (Type I Hypersensitivity): · Atopic Asthma: IgE-mediated; sensitization to allergens (pollens, dust mites, animal dander) · Allergen cross-links IgE on mast cells → mast cell degranulation → release of histamine, leukotrienes, prostaglandins · Eosinophilic inflammation (Th2 response; IL-4, IL-5, IL-13) 2. Non-Immunologic: · Exercise, cold air, stress, respiratory infections, drugs (aspirin, NSAIDs) · Direct stimulation of airway smooth muscle Pathological Features: · Acute: Bronchoconstriction, mucosal edema, mucus plugging, eosinophilic inflammation · Chronic: Airway remodeling – basement membrane thickening, goblet cell hyperplasia, smooth muscle hypertrophy, subepithelial fibrosis Clinical Features: · Symptoms: Episodic wheezing, cough, chest tightness, dyspnea (often at night or early morning) · Signs: Tachypnea, use of accessory muscles, prolonged expiration, wheezing on auscultation Complications: · Status asthmaticus · Respiratory failure · Pneumothorax · Atelectasis · Pneumonia 9. What are the possible morphological findings in the lung in bronchial asthma 1. Hyperinflation: Overdistended lungs due to air trapping 2. Mucous Plugs: Airways filled with thick, tenacious mucus 3. Mucosal Edema: Swelling of bronchial mucosa 4. Eosinophilic Infiltration: Infiltration of bronchial wall by eosinophils 5. Goblet Cell Hyperplasia: Increased number of mucus-secreting cells 6. Basement Membrane Thickening: Subepithelial fibrosis 7. Smooth Muscle Hypertrophy: Thickening of bronchial smooth muscle 8. Curschmann Spirals: Coiled mucus casts in airways 9. Charcot-Leyden Crystals: Eosinophil-derived crystals in mucus 10. What is neonatal respiratory distress syndrome Neonatal Respiratory Distress Syndrome (NRDS), also known as Hyaline Membrane Disease, is a respiratory disorder of premature infants caused by deficiency of pulmonary surfactant. Pathogenesis: · Premature birth → inadequate production of surfactant by type II pneumocytes · Surfactant deficiency → increased surface tension → alveolar collapse (atelectasis) · Difficulty expanding lungs → hypoxia, hypercapnia, respiratory acidosis · Alveolar damage → leakage of protein-rich fluid → hyaline membrane formation Risk Factors: · Prematurity (most important) · Maternal diabetes · C-section without labor · Male gender · Second-born twin · Family history Pathological Features: · Gross: Solid, airless, liver-like lungs · Microscopic: Alveolar collapse, hyaline membranes lining alveolar walls, pulmonary congestion Clinical Features: · Tachypnea, grunting, nasal flaring, intercostal retractions, cyanosis · Onset within minutes to hours of birth · Chest X-ray: Ground-glass appearance, air bronchograms Complications: · Pneumothorax · Pulmonary hemorrhage · Bronchopulmonary dysplasia (chronic lung disease) · Patent ductus arteriosus · Intraventricular hemorrhage · Death 11. Classify pneumonia. b. Briefly discuss pathological stages of lobar pneumonia a. Classification of Pneumonia: By Etiology: · Bacterial: Streptococcus pneumoniae (most common), Haemophilus influenzae, Staphylococcus aureus, Klebsiella pneumoniae, Mycoplasma pneumoniae (atypical) · Viral: Influenza, RSV, adenovirus, SARS-CoV-2 · Fungal: Histoplasma, Coccidioides, Aspergillus · Parasitic: Pneumocystis jirovecii (immunocompromised) · Aspiration: Chemical (gastric contents) or foreign body By Anatomical Distribution: · Lobar Pneumonia: Affects entire lobe · Bronchopneumonia: Patchy, multifocal involvement (bronchi and surrounding alveoli) · Interstitial Pneumonia: Involvement of alveolar walls and interstitium (viral, atypical) By Clinical Setting: · Community-Acquired Pneumonia (CAP) · Hospital-Acquired Pneumonia (HAP) · Ventilator-Associated Pneumonia (VAP) · Aspiration Pneumonia · Pneumonia in Immunocompromised Host b. Pathological Stages of Lobar Pneumonia: 1. Congestion Stage (First 24 Hours): Vascular congestion, intra-alveolar fluid, small numbers of neutrophils 2. Red Hepatization Stage (Days 2-3): Alveoli filled with neutrophils, red blood cells, and fibrin; lung becomes red, firm, airless (liver-like) 3. Gray Hepatization Stage (Days 4-6): Fibrinous exudate with leukocytes; fewer red cells; lung becomes grayish-brown, firm 4. Resolution Stage (Day 8 onwards): Fibrin is lysed; macrophages remove debris; alveolar architecture is restored 12. A young man with poor socioeconomic background is admitted to hospital with a history of weight loss, night sweats and chronic cough. He had been diagnosed as HIV positive. List the possible morphological changes in the following organ/systems in a patient suffering from HIV/AIDS i. What lung disease does this clinical presentation denote? ii. List the histologic feature for the diagnosis. iii. What immunologic test would you like to carry out to suspect this disease? iv. What other laboratory test would be necessary to confirm the disease? v. Should radiology be necessary, what would you expect to see? i. What lung disease does this clinical presentation denote? This clinical presentation (weight loss, night sweats, chronic cough, HIV positive, poor socioeconomic background) is highly suggestive of Pulmonary Tuberculosis (TB) in an HIV-positive patient. ii. List the histologic features for the diagnosis · Granulomas with Caseous Necrosis: Focal collections of epithelioid macrophages with central caseous necrosis · Langhans Giant Cells: Multinucleated giant cells with nuclei arranged at the periphery · Acid-Fast Bacilli (AFB): Seen with Ziehl-Neelsen stain (red, rod-shaped organisms) · In HIV-positive patients: Granulomas may be poorly formed or absent (due to immunosuppression); numerous AFB may be present; tuberculous pneumonia may occur iii. What immunologic test would you like to carry out to suspect this disease? · Tuberculin Skin Test (TST/PPD): May be false-negative in HIV-positive patients (anergy) · Interferon-Gamma Release Assays (IGRAs): QuantiFERON-TB Gold, T-SPOT.TB – more specific and less affected by BCG vaccination iv. What other laboratory test would be necessary to confirm the disease? · Sputum Smear for AFB: Ziehl-Neelsen staining (acid-fast bacilli) · Sputum Culture: For Mycobacterium tuberculosis (gold standard, but takes weeks) · GeneXpert MTB/RIF: Molecular test for TB and rifampicin resistance (rapid, highly sensitive) · HIV Viral Load and CD4 Count: To assess immune status v. Should radiology be necessary, what would you expect to see? Chest X-ray findings in HIV-associated TB: · In early HIV (higher CD4): Apical infiltrates, cavitation (typical reactivation TB) · In advanced HIV (low CD4): Diffuse, lower lobe or miliary infiltrates; less cavitation; hilar/mediastinal lymphadenopathy; patchy hazy shadows; pleural effusion · Other: Miliary pattern (fine nodular opacities), tuberculomas, cavities Possible Morphological Changes in Other Organs in HIV/AIDS: Lungs: Pneumocystis jirovecii pneumonia (PCP), Kaposi sarcoma, lymphocytic interstitial pneumonitis Lymph Nodes: Generalized lymphadenopathy, lymphoma Brain: Toxoplasmosis, cryptococcosis, progressive multifocal leukoencephalopathy, HIV encephalopathy Gastrointestinal Tract: Candidiasis, CMV, cryptosporidiosis Skin: Kaposi sarcoma, herpes zoster, molluscum contagiosum Kidneys: HIV-associated nephropathy (collapsing glomerulopathy) Heart: Myocarditis, pericarditis
GIT Pathology
Standard Answer:
1. Write short note on appendicitis Acute appendicitis is an acute inflammation of the vermiform appendix, most commonly caused by obstruction of the appendiceal lumen. Etiology and Pathogenesis: · Obstruction: Fecalith, lymphoid hyperplasia, foreign body, tumor · Obstruction → increased intraluminal pressure → impaired venous drainage → ischemia → bacterial overgrowth → inflammation Pathological Features: · Gross: Swollen, edematous, erythematous appendix; fibrinous exudate on serosal surface; may be perforated · Microscopic: Neutrophilic infiltration of the muscular wall; mucosal ulceration; congestion and edema; luminal pus Clinical Features: · Classic Presentation: Periumbilical pain migrating to the right lower quadrant (McBurney's point) · Signs: Rebound tenderness, guarding, fever, nausea, vomiting · Laboratory: Leukocytosis with neutrophilia Complications: · Perforation (with peritonitis or abscess) · Periappendiceal abscess · Peritonitis · Sepsis · Pylephlebitis (rare) 2. Define Peptic Ulcer A peptic ulcer is a breach in the mucosal lining of the stomach (gastric ulcer) or duodenum (duodenal ulcer) that extends through the muscularis mucosa into the submucosa or deeper. a. List the predisposing factors in Peptic Ulcer: 1. H. pylori Infection: Most important cause (colonization of gastric mucosa) 2. NSAIDs: Inhibit prostaglandin synthesis → reduced mucus and bicarbonate secretion 3. Excessive Gastric Acid: Zollinger-Ellison syndrome (gastrinoma), hypergastrinemia 4. Stress: Physiological stress (trauma, burns, surgery), psychological stress 5. Smoking: Increases acid secretion, reduces mucosal blood flow 6. Alcohol: Direct mucosal irritation 7. Corticosteroids: Increase risk when used with NSAIDs 8. Genetic Factors: Family history 9. Diet: Spicy foods, caffeine (controversial) b. List the complications of peptic ulcer: 1. Bleeding (Hemorrhage): Most common complication; can be life-threatening (hematemesis, melena) 2. Perforation: Ulcer penetrates through all layers; causes acute peritonitis (surgical emergency) 3. Obstruction: Due to scarring and edema (gastric outlet obstruction, pyloric stenosis) 4. Penetration: Ulcer penetrates into adjacent organs (pancreas, liver, omentum) 5. Malignant Transformation: Gastric ulcers (adenocarcinoma); duodenal ulcers rarely malignant c. State the Histologic appearance of a Peptic Ulcer: · Ulcer Base: Four zones from lumen outward: 1. Fibrinous Exudate: Layer of fibrin, neutrophils, and necrotic debris (slough) 2. Necrotic Zone: Necrotic tissue 3. Granulation Tissue: Proliferating capillaries, fibroblasts, inflammatory cells 4. Fibrous Scar: Dense collagen at the base · Edges: Smooth, punched-out; perpendicular in acute ulcers; sloping in chronic ulcers · Adjacent Mucosa: Chronic gastritis/duodenitis; H. pylori organisms may be seen
Pathology of Liver, Biliary Tract and Pancreas
Standard Answer:
1. List the hepatotrophic DNA viruses 1. Hepatitis B Virus (HBV) – DNA virus, causes acute and chronic hepatitis, cirrhosis, hepatocellular carcinoma 2. Hepatitis C Virus (HCV) – RNA virus (not DNA) 3. Hepatitis D Virus (HDV) – RNA virus, requires HBV for replication 4. Hepatitis A Virus (HAV) – RNA virus 5. Hepatitis E Virus (HEV) – RNA virus (Note: Hepatotrophic viruses are those that primarily infect hepatocytes. HBV is a DNA virus; HCV, HDV, HAV, and HEV are RNA viruses.) 2. Write an essay on cirrhosis of the liver Cirrhosis is the final common pathway of chronic liver disease, characterized by diffuse fibrosis and the conversion of normal liver architecture into structurally abnormal nodules. Etiology: 1. Alcohol-related Liver Disease: Chronic alcohol abuse (most common cause in Western countries) 2. Chronic Viral Hepatitis: HBV, HCV 3. Non-Alcoholic Fatty Liver Disease (NAFLD)/Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): Obesity, diabetes, metabolic syndrome 4. Biliary Disease: Primary biliary cholangitis, secondary biliary cirrhosis 5. Autoimmune Hepatitis 6. Metabolic Disorders: Wilson's disease, hemochromatosis, alpha-1 antitrypsin deficiency 7. Cardiac Cirrhosis: Chronic right-sided heart failure 8. Drugs and Toxins: Methotrexate, amiodarone, isoniazid 9. Cryptogenic: Unknown cause Pathogenesis: 1. Chronic Liver Injury: Persistent injury to hepatocytes (alcohol, viruses, toxins) 2. Necroinflammation: Hepatocyte necrosis and inflammatory response 3. Fibrogenesis: Activation of hepatic stellate cells → production of collagen and extracellular matrix 4. Nodular Regeneration: Hepatocytes regenerate in nodules surrounded by fibrous septa 5. Architectural Distortion: Disruption of normal lobular architecture; loss of portal tracts and central veins Morphological Features: · Gross: Firm, nodular liver; reduced size (or enlarged in early stages); yellow-brown color · Micronodular: Nodules < 3 mm (alcohol) · Macronodular: Nodules > 3 mm (viral hepatitis) · Mixed: Both types · Microscopic: Fibrous septa; regenerative nodules; loss of normal architecture; inflammation Complications: 1. Portal Hypertension: Ascites, varices (esophageal, gastric, rectal), splenomegaly 2. Hepatic Failure: Jaundice, coagulopathy, encephalopathy 3. Hepatocellular Carcinoma: Increased risk (annual incidence > 1%) 4. Hepatorenal Syndrome: Renal failure 5. Hepatopulmonary Syndrome: Hypoxemia due to pulmonary vascular dilation 6. Infections: Spontaneous bacterial peritonitis 7. Malnutrition 8. Death (from variceal bleeding, hepatic failure, HCC) 3. List the complications of liver cirrhosis 1. Portal Hypertension: · Esophageal varices (bleeding) · Gastric varices · Ascites (with spontaneous bacterial peritonitis) · Splenomegaly (with hypersplenism) · Caput medusae (abdominal wall varices) 2. Hepatic Failure: · Jaundice (hyperbilirubinemia) · Coagulopathy (decreased synthesis of clotting factors) · Hepatic encephalopathy (ammonia toxicity) · Hypoalbuminemia (edema, ascites) 3. Hepatocellular Carcinoma (HCC) 4. Hepatorenal Syndrome (acute kidney injury) 5. Hepatopulmonary Syndrome (intrapulmonary vascular dilation, hypoxemia) 6. Spontaneous Bacterial Peritonitis (infection of ascitic fluid) 7. Portal Vein Thrombosis 8. Malnutrition and Muscle Wasting 4. Enumerate the common tumours of the liver Benign Tumors: 1. Hemangioma: Most common benign liver tumor; cavernous blood vessels 2. Hepatocellular Adenoma: Benign epithelial tumor; associated with oral contraceptives 3. Focal Nodular Hyperplasia: Hyperplastic nodule with central scar 4. Bile Duct Adenoma: Small, benign bile duct proliferation 5. Lipoma: Benign fat tumor Malignant Tumors: 1. Hepatocellular Carcinoma (HCC): Most common primary liver cancer 2. Cholangiocarcinoma (Bile Duct Cancer): Arises from bile duct epithelium 3. Hepatoblastoma: Embryonal tumor in children 4. Angiosarcoma: Rare, associated with vinyl chloride, Thorotrast 5. Metastatic Tumors: More common than primary tumors (colon, lung, breast, pancreas) 5. Discuss nut-meg appearance of the liver The "nutmeg" appearance of the liver is a characteristic gross finding in chronic passive congestion of the liver, most commonly due to right-sided heart failure. Gross Appearance: · The liver is enlarged and firm · The cut surface shows a mottled, red-brown and yellow appearance resembling a nutmeg · Red-brown areas: Represent congested centrilobular zones (central veins and sinusoids are dilated and filled with red blood cells) · Pale/yellow areas: Represent periportal zones with fatty change (hepatocytes show fatty degeneration) Pathogenesis: 1. Right-sided heart failure → increased venous pressure → passive congestion of the liver 2. Centrilobular sinusoids become congested and dilated 3. Centrilobular hepatocytes undergo ischemic necrosis and atrophy 4. Periportal hepatocytes (better oxygenated) develop fatty change 5. The alternating pattern of congested and fatty areas creates the nutmeg appearance Microscopic Features: · Dilated central veins and sinusoids with red blood cells · Centrilobular hepatocyte atrophy and necrosis · Periportal hepatocytes with fatty vacuolation · Hemosiderin-laden macrophages (heart failure cells) Clinical Significance: · Indicates chronic passive congestion (usually cardiac in origin) · May progress to cardiac cirrhosis (fibrosis) if chronic 6. The common causes of liver cirrhosis 1. Chronic Alcohol Abuse (most common in Western countries) 2. Chronic Viral Hepatitis B and C (most common worldwide) 3. Non-Alcoholic Fatty Liver Disease (NAFLD)/Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) (associated with obesity, diabetes, metabolic syndrome) 4. Primary Biliary Cholangitis (autoimmune, chronic cholestasis) 5. Secondary Biliary Cirrhosis (due to bile duct obstruction) 6. Autoimmune Hepatitis 7. Metabolic Disorders: Wilson's disease (copper accumulation), hemochromatosis (iron accumulation), alpha-1 antitrypsin deficiency 8. Cardiac Cirrhosis (chronic right-sided heart failure) 9. Drugs and Toxins: Methotrexate, amiodarone, isoniazid 10. Cryptogenic Cirrhosis (unknown cause) 7. Consequences of portal hypertension 1. Esophageal and Gastric Varices: Dilated collateral veins in the esophagus and stomach → risk of life-threatening hemorrhage 2. Ascites: Accumulation of fluid in the peritoneal cavity 3. Splenomegaly: Enlarged spleen → hypersplenism (pancytopenia) 4. Caput Medusae: Dilated periumbilical veins (abdominal wall varices) 5. Hemorrhoids: Dilated rectal veins (internal hemorrhoids) 6. Hepatorenal Syndrome: Functional renal failure 7. Hepatopulmonary Syndrome: Intrapulmonary vascular dilation → hypoxemia 8. Portosystemic Encephalopathy: Shunting of blood from portal to systemic circulation bypassing liver → ammonia and toxins reach brain → encephalopathy 8. Pathogenesis of liver cirrhosis 1. Chronic Liver Injury: Persistent injury to hepatocytes (alcohol, viruses, toxins, metabolic) → hepatocyte necrosis and apoptosis 2. Necroinflammation: Inflammatory response (macrophages, lymphocytes, neutrophils) → release of pro-inflammatory cytokines (TNF, IL-6, TGF-β) 3. Hepatic Stellate Cell Activation: Cytokines (especially TGF-β) activate hepatic stellate cells (Ito cells) → transformation into myofibroblast-like cells 4. Collagen Deposition: Activated stellate cells produce extracellular matrix (collagen type I and III) → progressive fibrosis 5. Architectural Distortion: Fibrous septa form, isolating regenerating hepatocytes into nodules → disruption of normal lobular architecture 6. Portal Hypertension: Fibrosis and nodule formation increase resistance to portal blood flow → elevated portal pressure 7. Hepatocyte Dysfunction: Progressive loss of functional hepatocytes → impaired synthetic and metabolic functions (hypoalbuminemia, coagulopathy, jaundice, encephalopathy) 9. Hepatocellular Carcinoma Etiological factors implicated in the genesis of HCC: 1. Chronic Viral Hepatitis: HBV (most important), HCV 2. Cirrhosis: Any cause of cirrhosis increases risk (annual incidence > 1%) 3. Aflatoxin B1: Fungal contaminant of food (peanuts, corn) → DNA adduct formation 4. Alcohol: Chronic alcohol abuse (cirrhosis) 5. Non-Alcoholic Fatty Liver Disease (NAFLD): (metabolic syndrome) 6. Metabolic Disorders: Hemochromatosis, alpha-1 antitrypsin deficiency, Wilson's disease 7. Toxins: Vinyl chloride, Thorotrast 8. Diabetes and Obesity: (increased risk) Morphologic Features of HCC: Gross: · Massive Type: Large solitary mass · Multinodular Type: Multiple nodules throughout the liver · Diffuse (Infiltrative) Type: Diffuse infiltration, may be difficult to distinguish from cirrhosis · Color: Pale, yellow, greenish (bile staining), or hemorrhagic · Cut Surface: Soft, fleshy, may show necrosis, hemorrhage, or fibrosis · Satellite Nodules: Small nodules around the main tumor Microscopic: · Trabecular Pattern: Thick cell plates (trabeculae) separated by sinusoids · Acinar/Pseudoglandular Pattern: Gland-like structures · Solid/Compact Pattern: Sheets of tumor cells · Scirrhous Pattern: Abundant fibrous stroma · Cytological Features: Pleomorphic cells; large, hyperchromatic nuclei; prominent nucleoli; mitotic figures; bile production (some cells); cytoplasmic eosinophilia Possible Causes of Death in HCC: 1. Liver Failure: Progressive hepatic dysfunction (jaundice, coagulopathy, encephalopathy) 2. Variceal Hemorrhage: Due to portal hypertension 3. Tumor Rupture: Spontaneous rupture with intraperitoneal hemorrhage 4. Cachexia: Severe weight loss, muscle wasting 5. Metastasis: Spread to lungs, bones, adrenal glands, brain 6. Infection: Sepsis (often due to immunosuppression) 7. Portal Vein Thrombosis: Extension of tumor into portal vein → acute liver failure
Pathology of Renal System
Standard Answer:
1. Discuss the mechanism of renal glomerular injury and the general reactions of the glomeruli to such injuries Mechanisms of Glomerular Injury: 1. Immune-Mediated Injury (Most Common): a. Antibody-Mediated (Type II): · Anti-GBM Antibody: Antibodies directed against glomerular basement membrane (Goodpasture syndrome) · In Situ Immune Complex Formation: Antibodies bind to antigens planted in glomerulus (e.g., DNA in SLE, drugs) · Circulating Immune Complex Deposition: Immune complexes deposit in glomerular capillaries → complement activation → inflammation (e.g., post-streptococcal GN, SLE) b. Cell-Mediated (Type IV): · T cell-mediated injury (e.g., in some forms of glomerulonephritis) 2. Non-Immune Mechanisms: · Hemodynamic Factors: Glomerular hypertension, hyperfiltration → endothelial injury · Metabolic Factors: Diabetes mellitus → hyperglycemia → advanced glycation end-products (AGEs) → mesangial expansion · Toxins: Drugs, heavy metals · Ischemia: Reduced renal perfusion · Podocyte Injury: Genetic (nephrin mutations), toxins, infections General Reactions of Glomeruli to Injury: 1. Hypercellularity: · Increased number of cells in glomerular tuft (mesangial, endothelial, epithelial) · Inflammatory cell infiltration (neutrophils, monocytes, lymphocytes) 2. Basement Membrane Changes: · Thickening (diabetes, membranous nephropathy) · Thinning (thin basement membrane disease) · Splitting (Alport syndrome) 3. Mesangial Changes: · Mesangial cell proliferation · Mesangial matrix expansion (diabetes, IgA nephropathy) 4. Crescent Formation: · Proliferation of parietal epithelial cells and macrophages in Bowman's space · Indicates severe glomerular injury (crescentic GN) 5. Sclerosis: · Glomerulosclerosis: Replacement of glomerular tuft by extracellular matrix · Focal (some glomeruli) or global (entire glomerulus); segmental (part of glomerulus) 6. Hyalinosis: · Hyaline material (protein) accumulation in glomeruli 2. Write short notes on histologic manifestations of glomerular diseases 1. Proliferative Glomerulonephritis: · Increased number of cells in the glomerulus · Endocapillary Proliferation: Proliferation of endothelial and mesangial cells · Extracapillary Proliferation: Crescent formation (proliferation of parietal epithelial cells and macrophages in Bowman's space) 2. Membranous Glomerulopathy: · Thickening of glomerular basement membrane (GBM) due to immune complex deposition · "Spike and dome" pattern on silver stain · Subepithelial deposits (electron microscopy) 3. Minimal Change Disease: · Normal light microscopy · Electron Microscopy: Effacement of podocyte foot processes (fusion) · No immune deposits 4. Focal Segmental Glomerulosclerosis (FSGS): · Sclerosis affecting some glomeruli (focal) and part of the glomerular tuft (segmental) · Hyalinosis may be present 5. Membranoproliferative Glomerulonephritis (MPGN): · GBM thickening and mesangial proliferation · Type I: Subendothelial deposits ("tram-track" appearance) · Type II: Dense deposit disease (intramembranous deposits) 6. IgA Nephropathy: · Mesangial proliferation with IgA deposits · Mesangial expansion 7. Crescentic Glomerulonephritis: · Crescents (extracapillary proliferation) in Bowman's space · Indicates rapidly progressive GN 3. Short note on Acute pyelonephritis Acute pyelonephritis is an acute bacterial infection of the renal pelvis and kidney parenchyma, most commonly caused by ascending infection from the lower urinary tract. Etiology: · Most common: Escherichia coli (70-80%) · Others: Proteus, Klebsiella, Enterococcus, Pseudomonas (hospital-acquired) Pathogenesis: · Ascending infection from bladder → ureters → renal pelvis → renal parenchyma · Hematogenous spread (less common): Staphylococcus aureus · Predisposing factors: Urinary tract obstruction, vesicoureteral reflux, instrumentation, pregnancy, diabetes, immunosuppression, neurogenic bladder Pathological Features: · Gross: Swollen kidney; abscesses (yellow-white, suppurative foci) on cut surface; pelvic congestion · Microscopic: Neutrophilic infiltration of tubules and interstitium; tubular necrosis; abscess formation; bacteria in tubules Clinical Features: · Fever, chills, flank pain, costovertebral angle tenderness · Urinary symptoms: Dysuria, frequency, urgency · Laboratory: Pyuria, bacteriuria, leukocytosis Complications: · Renal abscess · Pyonephrosis (pus-filled kidney) · Perinephric abscess · Sepsis · Chronic pyelonephritis (recurrent) → renal scarring, hypertension, renal failure 4. Outline clinical manifestations of glomerular diseases 1. Nephrotic Syndrome: · Massive Proteinuria (> 3.5 g/day) · Hypoalbuminemia (< 3 g/dL) · Edema (generalized, periorbital, dependent) · Hyperlipidemia and lipiduria 2. Nephritic Syndrome: · Hematuria (microscopic or macroscopic) · Proteinuria (mild to moderate, < 3.5 g/day) · Hypertension · Azotemia (impaired renal function) · Oliguria · Red Blood Cell Casts in urine 3. Asymptomatic Urinary Abnormalities: · Isolated hematuria and/or proteinuria · No symptoms; found incidentally on urinalysis 4. Rapidly Progressive Glomerulonephritis: · Rapid decline in renal function (weeks to months) · Hematuria, proteinuria, hypertension, oliguria, azotemia · Crescents on biopsy 5. Chronic Glomerulonephritis: · Progressive renal failure (months to years) · Hypertension, proteinuria, hematuria, edema, anemia · End-stage renal disease 6. Acute Kidney Injury: · Sudden decline in renal function; oliguria or anuria 5. List primary nephrotic types of glomerular disease with common clinicopathologic features 1. Minimal Change Disease (Lipoid Nephrosis): · Most common in children · Clinical: Nephrotic syndrome · Pathology: Normal light microscopy; podocyte foot process effacement (electron microscopy); no immune deposits · Prognosis: Excellent, responds to steroids 2. Focal Segmental Glomerulosclerosis (FSGS): · Most common in adults and African Americans · Clinical: Nephrotic syndrome (may be steroid-resistant) · Pathology: Sclerosis of some glomeruli (focal) and part of tuft (segmental); hyalinosis · Prognosis: Variable, often progressive to ESRD 3. Membranous Nephropathy: · Most common in adults (primary: idiopathic; secondary: SLE, hepatitis B, drugs) · Clinical: Nephrotic syndrome (often with hypertension, hematuria) · Pathology: GBM thickening; subepithelial immune deposits ("spike and dome"); C3, IgG deposits · Prognosis: Variable (1/3 remit, 1/3 persist, 1/3 progress to ESRD) 4. Membranoproliferative Glomerulonephritis (MPGN): · Less common · Clinical: Nephrotic or nephritic syndrome · Pathology: GBM thickening and mesangial proliferation ("tram-track" appearance); subendothelial deposits · Prognosis: Often progressive to ESRD 6. Briefly discuss aetiopathogenesis of hydronephrosis Hydronephrosis is the dilation of the renal pelvis and calyces due to obstruction of urine flow. Etiology (Causes of Urinary Obstruction): Congenital: · Ureteropelvic junction obstruction · Ureterovesical junction obstruction · Posterior urethral valves (males) · Ureterocele Acquired: · Intraluminal: Urolithiasis (kidney stones), blood clots, sloughed papilla, tumor · Intramural: Stricture, tumor of ureter or bladder, neurogenic bladder · Extramural: Pelvic tumors, retroperitoneal fibrosis, pregnancy, benign prostatic hyperplasia, prostate cancer, cervical cancer Pathogenesis: 1. Obstruction to Urine Flow: Prevents normal drainage of urine from kidney 2. Increased Intrapelvic Pressure: Urine accumulates in renal pelvis, increasing pressure 3. Dilatation: Renal pelvis and calyces become dilated (hydronephrosis) 4. Compression: Dilatation compresses renal parenchyma, causing ischemia and atrophy 5. Progressive Loss of Function: Renal parenchyma is replaced by fibrous tissue → loss of renal function 6. Infection: Stasis predisposes to infection (pyonephrosis) Morphological Features: · Early: Mild dilation of pelvis and calyces; renal cortex is normal · Late: Marked dilation; thinning of renal parenchyma; papillary atrophy; hydronephrotic sac (kidney may be reduced to a thin-walled sac) Complications: · Renal failure (obstructive uropathy) · Infection (pyonephritis, pyonephrosis) · Hypertension · Urolithiasis (secondary to stasis and infection)
Male and Female Genital Tract
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1. List the sites of spread of carcinoma of the cervix Local (Direct) Spread: · Vagina · Uterine body (endometrium, myometrium) · Parametrial tissues · Pelvic sidewall · Bladder · Rectum Lymphatic Spread: · Regional lymph nodes: Obturator, internal iliac, external iliac, common iliac, presacral, para-aortic, inguinal (in advanced cases) Hematogenous Spread (Late): · Lungs (most common) · Liver · Bones · Brain (less common) Transcoelomic Spread: · Peritoneal cavity (rare) 2. List the cause of death in cervical carcinoma 1. Uremia: Bilateral ureteral obstruction by tumor → hydronephrosis → renal failure (most common cause) 2. Hemorrhage: Massive vaginal bleeding from tumor erosion into blood vessels 3. Infection: Sepsis from tumor necrosis, pyelonephritis, pelvic infection 4. Cachexia: Severe weight loss and malnutrition 5. Metastasis: Distant metastasis (lungs, liver) → organ failure 6. Fistula Formation: Vesicovaginal or rectovaginal fistulas → sepsis, electrolyte imbalance 3. Outline risk factors of cancer of the cervix 1. HPV Infection: High-risk HPV types (16, 18, 31, 33, 45) – most important risk factor 2. Early Sexual Activity: (< 16 years) 3. Multiple Sexual Partners 4. High-Risk Male Partner: Promiscuous male partners 5. Immunosuppression: HIV/AIDS (increased risk), transplant recipients 6. Smoking: Cigarette smoking (increases risk 2-3 fold) 7. Long-Term Oral Contraceptive Use: (> 5 years) 8. Multiparity: (> 3 full-term pregnancies) 9. Low Socioeconomic Status: Poor access to screening 10. Dietary Factors: Low intake of fruits and vegetables 11. Chlamydia Infection: Chronic infection 4. Outline the common histologic types and clinical features of cancer of the cervix Common Histologic Types: 1. Squamous Cell Carcinoma (70-80%): · Arises from squamous epithelium of ectocervix · Subtypes: Keratinizing, non-keratinizing, basaloid, warty · Associated with HPV 16 and 18 · Precursor: Cervical intraepithelial neoplasia (CIN) 2. Adenocarcinoma (15-20%): · Arises from columnar epithelium of endocervix (glandular) · Subtypes: Endocervical type, endometrioid, mucinous, clear cell · Associated with HPV 18 · Precursor: Adenocarcinoma in situ (AIS) 3. Adenosquamous Carcinoma (3-5%): · Mixed squamous and glandular features 4. Neuroendocrine (Small Cell) Carcinoma: · Rare, aggressive; associated with HPV 18 Clinical Features: Early Stage: · Often asymptomatic (detected by Pap smear) · Abnormal vaginal bleeding (postcoital, intermenstrual, postmenopausal) · Vaginal discharge (may be blood-stained) · Pelvic pain Advanced Stage: · Pelvic pain, back pain (nerve involvement) · Hematuria (bladder invasion) · Hematochezia (rectal invasion) · Leg edema (pelvic sidewall involvement) · Fistula (vesicovaginal, rectovaginal) · Weight loss, cachexia · Uremia (ureteral obstruction) 5. Microscopic features of prostatic cancer Architectural Features: · Glandular Pattern: Small, crowded glands; loss of normal lobular architecture · Infiltrative Growth: Glands infiltrate between benign glands · Perineural Invasion: Tumor cells around nerves (characteristic) · Acinar Pattern: Glands with "back-to-back" arrangement Cytological Features: · Nuclear Changes: Enlarged, hyperchromatic nuclei; prominent nucleoli · Loss of Basal Cell Layer: (absence of basal cells around glands) · Cytoplasmic Changes: Scant cytoplasm; eosinophilic Grading (Gleason System): · Grade 1: Small, uniform, closely packed glands · Grade 2: Glands with more variation in size and shape · Grade 3: Infiltrative glands; cribriform pattern · Grade 4: Fused glands; poorly formed glands; glomeruloid pattern · Grade 5: Solid sheets; cord-like growth; comedocarcinoma Gleason Score: Sum of the two most common patterns (primary + secondary). Score ranges from 6 (3+3) to 10 (5+5). Immunohistochemistry: · Positive: PSA, PSAP, NKX3.1, AMACR (P504S) · Negative: Basal cell markers (p63, CK34βE12, HMWCK) – helpful for distinguishing from benign glands 6. Short note on Teratomas Teratomas are germ cell tumors that contain tissues derived from all three germ layers: ectoderm, endoderm, and mesoderm. Classification: By Maturity: · Mature Teratoma: Well-differentiated tissues (hair, teeth, skin, cartilage, bone, muscle, neural tissue) – benign · Immature Teratoma: Undifferentiated or embryonic tissues – malignant potential By Location: · Sacrococcygeal Teratoma: Most common in newborns · Ovarian Teratoma: Most common ovarian germ cell tumor (dermoid cyst) · Testicular Teratoma: Can be mature or immature · Mediastinal Teratoma: Anterior mediastinum · Retroperitoneal Teratoma · CNS Teratoma Pathological Features: · Gross: Cystic or solid; may contain hair, teeth, sebaceous material, bone, cartilage, neural tissue; well-circumscribed · Microscopic: Tissues from all three germ layers: · Ectoderm: Skin, hair, sebaceous glands, neural tissue · Endoderm: Respiratory epithelium, gastrointestinal epithelium · Mesoderm: Bone, cartilage, fat, smooth muscle, blood vessels Clinical Features: · Often asymptomatic (incidental finding) · May cause mass effect, pain · Ovarian teratoma: May torsion → acute abdomen Malignant Transformation: Occurs in 1-2% of mature teratomas (usually to squamous cell carcinoma or adenocarcinoma) 7. Short note on Hydatidiform mole Hydatidiform mole is a gestational trophoblastic disease characterized by abnormal proliferation of trophoblastic tissue and hydropic degeneration of chorionic villi. Types: Complete Mole: · Karyotype: 46,XX (androgenetic – all chromosomes paternal) · No fetal tissue · Diffuse hydropic change · Trophoblastic proliferation (marked) Partial Mole: · Karyotype: 69,XXY (triploid – two paternal, one maternal) · Fetal tissue may be present · Focal hydropic change · Trophoblastic proliferation (mild to moderate) Pathological Features: · Gross: Grape-like vesicles (hydropic villi); no identifiable fetus (complete mole); may have fetus (partial mole) · Microscopic: Hydropic villi (cystic dilatation); trophoblastic hyperplasia; absence of fetal blood vessels (complete mole); focal hydropic change (partial mole) Clinical Features: · Vaginal bleeding (first trimester) · Hyperemesis gravidarum (severe nausea and vomiting) · Uterus larger than expected for gestational age · Pre-eclampsia (early onset) · Hyperthyroidism (high hCG) · Serum β-hCG markedly elevated Complications: · Malignant Transformation: Persistent gestational trophoblastic disease · Invasive Mole: Invasion into myometrium (10-15%) · Choriocarcinoma: Malignant trophoblastic tumor (2-5%) · Uterine Perforation · Sepsis · Hemorrhage 8. Short note on cancer of the cervix Cervical cancer is a malignant neoplasm of the uterine cervix, most commonly squamous cell carcinoma (70-80%), followed by adenocarcinoma (15-20%). Etiology and Risk Factors: · HPV infection (types 16, 18) – most important cause · Early sexual activity, multiple partners · Smoking, immunosuppression, multiparity, long-term oral contraceptive use Pathogenesis: · HPV infection → integration of viral DNA into host genome → E6 and E7 oncoproteins inactivate p53 and Rb tumor suppressor genes → cell cycle dysregulation → dysplasia → carcinoma in situ → invasive carcinoma Pathological Features: · Gross: Ulcerative, exophytic (cauliflower-like), or infiltrative lesion on cervix; may be friable, bleeding · Microscopic: · Squamous Cell Carcinoma: Invasive nests of squamous cells with keratin pearls; keratinizing or non-keratinizing · Adenocarcinoma: Glandular pattern; mucin production; from endocervical glands · Precursor: Cervical intraepithelial neoplasia (CIN) grades 1-3; CIN 3 = carcinoma in situ Clinical Features: · Abnormal vaginal bleeding (postcoital, intermenstrual, postmenopausal) · Vaginal discharge · Pelvic pain (advanced) · Hematuria, hematochezia (advanced invasion) Staging (FIGO): · Stage I: Confined to cervix · Stage II: Extends beyond cervix but not to pelvic wall or lower third of vagina · Stage III: Extends to pelvic wall or lower third of vagina; hydronephrosis · Stage IV: Extends to bladder/rectum (IVA) or distant metastasis (IVB) Prognosis: Depends on stage; early-stage disease has good prognosis (5-year survival > 90% with treatment). Prevention through HPV vaccination and Pap smear screening.
Breast Pathology
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1. Discuss the morphologic patterns of invasive carcinoma of the breast Invasive Ductal Carcinoma (No Special Type): · Most common type (70-80%) · Gross: Irregular, hard mass (scirrhous); yellowish-white cut surface; may have necrosis, calcification; retraction of skin · Microscopic: Infiltrating cords, nests, and sheets of tumor cells; desmoplastic stroma; glandular differentiation (variable); cytological atypia; mitotic figures Invasive Lobular Carcinoma (5-10%): · Gross: Diffuse thickening; may not form discrete mass; often bilateral/multicentric · Microscopic: Small, uniform cells (signet-ring cells); "Indian file" pattern (single file infiltration); intracytoplasmic mucin Mucinous (Colloid) Carcinoma (1-2%): · Gross: Gelatinous, soft, well-circumscribed · Microscopic: Islands of tumor cells floating in large pools of extracellular mucin Medullary Carcinoma (1-2%): · Gross: Well-circumscribed, fleshy, soft mass · Microscopic: Sheets of undifferentiated, large cells; syncytial growth; prominent lymphocytic infiltrate; pushing border; no glandular differentiation Papillary Carcinoma: · Gross: Cystic, papillary growth · Microscopic: Fibrovascular cores with epithelial proliferation; may be invasive or in situ Tubular Carcinoma (< 1%): · Gross: Small, well-circumscribed · Microscopic: Well-formed tubules (single layer of cells); open lumina; minimal atypia; excellent prognosis Metaplastic Carcinoma: · Microscopic: Squamous, spindle cell, mesenchymal differentiation Inflammatory Carcinoma: · Clinical: Red, swollen, warm breast (skin involvement); no discrete mass; very aggressive 2. Outline risk factors of Breast cancer Non-Modifiable Risk Factors: 1. Female Gender: Most important risk factor 2. Age: Increasing age (peak incidence 50-70 years) 3. Family History: First-degree relative with breast cancer 4. Genetic Mutations: BRCA1, BRCA2, TP53, PTEN, CHEK2, ATM 5. Personal History: Previous breast cancer, atypical hyperplasia, LCIS 6. Menstrual History: Early menarche (< 12 years), late menopause (> 55 years) 7. Breast Density: Dense breast tissue (mammographic density) 8. Race/Ethnicity: Caucasian > African American (higher incidence); African American have more aggressive tumors Modifiable Risk Factors: 1. Reproductive Factors: Nulliparity, late first pregnancy (> 30 years), no breastfeeding 2. Hormone Replacement Therapy: Postmenopausal HRT (combined estrogen + progesterone) 3. Oral Contraceptives: Current use (slightly increased risk) 4. Alcohol Consumption: > 1 drink/day 5. Obesity: Postmenopausal obesity (increased estrogen production) 6. Physical Inactivity: Sedentary lifestyle 7. Radiation Exposure: Chest radiation (e.g., Hodgkin lymphoma treatment) 8. Diet: High fat diet (controversial) 3. Outline common clinical features and prognostic factors of breast cancer Common Clinical Features: Symptoms: · Breast Lump: Painless, hard, irregular, fixed · Skin Changes: Dimpling (peau d'orange), ulceration, redness, warmth · Nipple Changes: Retraction, inversion, discharge (bloody) · Pain: Uncommon (usually painless) · Axillary Mass: Lymphadenopathy (lymph node involvement) Signs: · Palpable mass (firm, irregular, fixed to skin or chest wall) · Skin retraction/dimpling · Nipple retraction · Peau d'orange (lymphatic obstruction) · Axillary lymphadenopathy · Paget's disease of the nipple: Eczematous change, crusting, ulceration Prognostic Factors: Major Prognostic Factors: 1. Lymph Node Status: Most important prognostic factor; number of involved nodes 2. Tumor Size: Larger size → worse prognosis 3. Histologic Grade: Nottingham grade (1-3) – higher grade → worse prognosis 4. Hormone Receptor Status: Estrogen receptor (ER) and progesterone receptor (PR) positivity → better prognosis (responsive to endocrine therapy) 5. HER2/neu Overexpression: HER2 positive → more aggressive (but targeted therapy available) Minor Prognostic Factors: 1. Age: Younger age (< 35) → worse prognosis 2. Lymphovascular Invasion: Worse prognosis 3. Proliferation Markers: Ki-67 (high → worse prognosis) 4. Molecular Subtypes: Luminal A (best prognosis), Luminal B, HER2-enriched, Triple-negative (worst prognosis) 5. Oncotype DX Score: Genomic assay for recurrence risk 4. Breast cancer is one of the leading causes of cancer death among women. List five major and minor prognostic factors of breast cancer Major Prognostic Factors: 1. Axillary Lymph Node Status: Number of positive nodes (most important) 2. Tumor Size: Diameter of primary tumor 3. Histologic Grade: Degree of differentiation (Nottingham grade) 4. Estrogen Receptor (ER) Status: ER positive → better prognosis 5. HER2/neu Status: HER2 positive → more aggressive (but targetable) Minor Prognostic Factors: 1. Age at Diagnosis: Younger age (< 35) → worse prognosis 2. Lymphovascular Invasion: Presence indicates worse prognosis 3. Ki-67 Proliferation Index: High Ki-67 → worse prognosis 4. Molecular Subtype: Luminal A (best), triple-negative (worst) 5. Tumor Budding: Peripheral tumor budding indicates poor prognosis 5. Write an essay on invasive ductal carcinoma Invasive ductal carcinoma (IDC) is the most common type of breast cancer, accounting for approximately 70-80% of all invasive breast cancers. It is also known as "invasive breast carcinoma of no special type" (NST) or "not otherwise specified" (NOS), as it does not have the specific features of other special types such as lobular, mucinous, or tubular carcinoma. Pathogenesis: · Most IDCs arise from ductal carcinoma in situ (DCIS), a preinvasive lesion · Progressive accumulation of genetic alterations (mutations, amplifications, deletions) leads to invasion through the basement membrane · Common genetic alterations: TP53 mutation, HER2 amplification, PI3KCA mutation Morphological Features: Gross: · Irregular, firm, hard mass (scirrhous) due to desmoplastic stromal reaction · Yellowish-white cut surface · May show necrosis, hemorrhage, or calcification · Retraction of skin or nipple (if close to surface) Microscopic: · Architecture: Infiltrating cords, nests, and sheets of tumor cells; desmoplastic stroma (fibrous tissue) · Cytology: Pleomorphic cells; large, hyperchromatic nuclei; prominent nucleoli; mitotic figures · Glandular Differentiation: May form tubules/glands (well-differentiated) or solid sheets (poorly differentiated) · In Situ Component: Often associated with DCIS (ductal carcinoma in situ) · Stromal Changes: Desmoplasia (dense fibrous stroma), lymphocytic infiltration, calcification Grading (Nottingham/Modified Bloom-Richardson): · Grade I (Low): Well-differentiated; tubule formation > 75%; mild atypia; low mitotic count · Grade II (Intermediate): Moderate differentiation; tubule formation 10-75%; moderate atypia; moderate mitotic count · Grade III (High): Poorly differentiated; tubule formation < 10%; severe atypia; high mitotic count Immunohistochemistry: · Cytokeratins: CK7, CK8/18, CK19 positive; CK20 negative · Hormone Receptors: ER and PR expression (variable, 70-80% positive) · HER2: Overexpressed/amplified in 15-20% · E-Cadherin: Positive (differentiates from lobular carcinoma which is negative) · GCDFP-15: May be positive Molecular Subtypes: 1. Luminal A: ER+/PR+, HER2-, low Ki-67 – best prognosis 2. Luminal B: ER+/PR+, HER2±, high Ki-67 – intermediate prognosis 3. HER2-Enriched: ER-, PR-, HER2+ – aggressive but targetable 4. Triple-Negative/Basal-like: ER-, PR-, HER2- – most aggressive, limited targeted therapy Clinical Features: · Painless breast lump (most common presentation) · Skin dimpling (peau d'orange), nipple retraction · Axillary lymphadenopathy · May be detected on mammography (microcalcifications) Prognosis: · Depends on stage (TNM), grade, molecular subtype, and treatment · Early-stage IDC has good prognosis with appropriate treatment (surgery, radiation, endocrine therapy, chemotherapy, targeted therapy) · Triple-negative and HER2-positive have worse prognosis without targeted therapy
CNS Pathology
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1. Discuss the causes and pathological consequences of raised intracranial pressure Causes of Raised Intracranial Pressure (ICP): Space-Occupying Lesions: · Tumors (primary or metastatic) · Abscesses · Hematomas (subdural, epidural, intracerebral) · Hydrocephalus Increased Brain Volume: · Cerebral edema (vasogenic, cytotoxic, interstitial) · Congestion (hyperemia) Increased CSF Volume: · Hydrocephalus (obstructive or communicating) · CSF overproduction (choroid plexus papilloma) Increased Blood Volume: · Venous sinus thrombosis · Hyperemia Others: · Idiopathic intracranial hypertension (pseudotumor cerebri) · Meningitis (inflammation and edema) Pathological Consequences: 1. Brain Herniation (Most Serious Consequence): · Subfalcine (Cingulate) Herniation: Displacement of cingulate gyrus under falx cerebri → compression of anterior cerebral artery · Transtentorial (Uncal) Herniation: Displacement of uncus through tentorium → compression of CN III (pupil dilation, ophthalmoplegia), posterior cerebral artery, midbrain (hemiparesis, coma) · Tonsillar Herniation: Displacement of cerebellar tonsils through foramen magnum → compression of medulla (respiratory arrest, death) · Central (Transforaminal) Herniation: Downward displacement of diencephalon and brainstem 2. Cerebral Ischemia and Infarction: · Compression of blood vessels reduces cerebral blood flow · Leads to hypoxia, ischemia, and infarction 3. Cerebral Edema: · Vasogenic edema (leakage of fluid from damaged vessels) · Cytotoxic edema (cellular swelling due to ATP failure) 4. Hydrocephalus: · Obstruction of CSF flow (e.g., by herniation or tumor) 5. Brain Atrophy: · Chronic increased ICP → compression of brain tissue → atrophy 6. Clinical Manifestations: · Headache (worse in morning, with coughing/straining) · Nausea, vomiting · Papilledema (swelling of optic disc) · Altered consciousness (confusion, drowsiness, coma) · Seizures · Cushing's triad: Hypertension, bradycardia, irregular respiration (late sign) 2. List the causes and complications of space occupying lesions in the brain Causes of Space-Occupying Lesions: Neoplastic: · Primary brain tumors: Glioma, meningioma, medulloblastoma, pituitary adenoma, schwannoma · Metastatic tumors (most common in adults): Lung, breast, colon, renal cell, melanoma Infectious: · Abscess (pyogenic) · Tuberculoma · Toxoplasmosis · Neurocysticercosis Vascular: · Hematoma (subdural, epidural, intracerebral) · Aneurysm · Arteriovenous malformation · Cavernous hemangioma Inflammatory: · Demyelinating lesions (multiple sclerosis) · Sarcoidosis Cysts: · Arachnoid cyst · Epidermoid/dermoid cyst · Colloid cyst Complications: 1. Raised Intracranial Pressure: · Headache, vomiting, papilledema · Herniation (uncal, tonsillar, subfalcine) – life-threatening 2. Neurological Deficits: · Focal deficits depending on location (motor, sensory, visual, speech, cognitive) 3. Seizures: Focal or generalized 4. Hydrocephalus: Obstruction of CSF pathways 5. Hemorrhage: Vascular lesions or tumor bleeding 6. Infection: Risk of meningitis or ventriculitis (especially with surgery) 7. Brain Edema: Vasogenic edema around the lesion 8. Cognitive and Behavioral Changes: Memory impairment, personality changes 9. Cushing's Triad: Hypertension, bradycardia, irregular respirations (sign of increased ICP) 10. Death: Due to herniation or brainstem compression 3. Briefly discuss the causes, morphology and complications of cerebral oedema Causes of Cerebral Edema: Vasogenic Edema: · Disruption of blood-brain barrier (BBB) · Causes: Tumors, abscesses, inflammation, trauma, hypertension Cytotoxic Edema: · Cellular swelling due to ATP depletion (failure of Na+-K+ pump) · Causes: Ischemia, hypoxia, hypoglycemia, toxins, hyponatremia Interstitial Edema: · Increased CSF pressure → transudation of CSF into brain · Causes: Obstructive hydrocephalus Morphology: Gross: · Brain Swelling: Increased brain weight; flattened gyri; narrowed sulci · Compressed Ventricles: Ventricular compression or obliteration · Herniation: May be present (uncal, tonsillar) · Congestion: Dilated surface vessels Microscopic: · Vasogenic: Widening of extracellular spaces; perivascular fluid accumulation · Cytotoxic: Cellular swelling (neurons, astrocytes, endothelial cells); shrinkage of extracellular space · Interstitial: Periventricular fluid accumulation Complications: 1. Increased Intracranial Pressure: · Headache, vomiting, papilledema · Altered consciousness, coma 2. Brain Herniation: · Subfalcine, uncal, tonsillar herniation (life-threatening) 3. Cerebral Ischemia: · Compression of blood vessels → reduced cerebral blood flow → ischemia and infarction 4. Neurological Deficits: · Focal deficits depending on affected area 5. Death: · Due to herniation and brainstem compression 4. Write short notes on increased intracranial pressure Increased intracranial pressure (ICP) is the elevation of pressure within the cranial cavity, normally < 10-15 mmHg in adults. Causes: · Space-occupying lesions (tumors, hematomas, abscesses) · Cerebral edema (vasogenic, cytotoxic, interstitial) · Hydrocephalus (obstructive or communicating) · Increased CSF production (choroid plexus papilloma) · Venous sinus thrombosis (increased venous pressure) · Idiopathic intracranial hypertension (pseudotumor cerebri) Pathophysiology: · The Monroe-Kellie doctrine: The sum of volumes of brain, blood, and CSF is constant within the rigid skull · Increase in one compartment must be compensated by decrease in another · Once compensation is exhausted, ICP rises sharply Clinical Features: · Headache (worse in morning, with coughing/straining) · Nausea, vomiting (projectile) · Papilledema (swelling of optic disc) · Altered consciousness (confusion, drowsiness, coma) · Seizures · Cushing's triad: Hypertension, bradycardia, irregular respiration (late sign) · Pupillary changes (CN III compression) Complications: · Brain herniation (uncal, tonsillar, subfalcine) · Cerebral ischemia and infarction · Death 5. Short note on intracranial haemorrhage Intracranial hemorrhage is bleeding within the cranial cavity, which can occur in various compartments. Types: 1. Intracerebral Hemorrhage: · Bleeding within the brain parenchyma · Causes: Hypertension (most common), trauma, arteriovenous malformation, amyloid angiopathy, bleeding disorders, tumors · Common Sites: Basal ganglia, thalamus, cerebellum, brainstem (hypertensive) · Gross: Well-circumscribed hematoma; surrounding edema; mass effect 2. Subarachnoid Hemorrhage: · Bleeding in the subarachnoid space · Causes: Ruptured cerebral aneurysm (most common), trauma, arteriovenous malformation · Gross: Blood in subarachnoid space (basal cisterns, sulci) 3. Subdural Hemorrhage: · Bleeding between dura and arachnoid · Causes: Trauma (bridging vein rupture), especially in elderly · Gross: Blood clot overlying cerebral convexity 4. Epidural Hemorrhage: · Bleeding between skull and dura · Causes: Trauma (middle meningeal artery rupture) · Gross: Blood clot between skull and dura; lens-shaped on imaging 5. Intraventricular Hemorrhage: · Bleeding into ventricles · Causes: Extension from intracerebral hemorrhage, prematurity Clinical Features: · Sudden severe headache ("thunderclap" – subarachnoid) · Neurological deficits (depending on location) · Altered consciousness · Nausea, vomiting · Seizures · Signs of increased ICP Complications: · Herniation (mass effect) · Hydrocephalus (intraventricular) · Vasospasm (subarachnoid) · Death 6. List the causes of intracranial haemorrhage 1. Hypertension: Most common cause of intracerebral hemorrhage 2. Trauma: Subdural, epidural, intracerebral hemorrhage 3. Ruptured Cerebral Aneurysm: Subarachnoid hemorrhage (most common cause) 4. Arteriovenous Malformation (AVM): Intracerebral or subarachnoid hemorrhage 5. Cerebral Amyloid Angiopathy: Intracerebral hemorrhage in elderly 6. Bleeding Disorders: Hemophilia, thrombocytopenia, anticoagulant therapy 7. Brain Tumors: Hemorrhage into tumor (metastatic melanoma, renal cell carcinoma) 8. Ischemic Stroke: Hemorrhagic transformation 9. Vasculitis: Inflammation of blood vessels 10. Drugs: Cocaine, amphetamines 11. Idiopathic: Unknown cause 7. List the sites of intracranial haemorrhage 1. Intracerebral (Parenchymal): · Basal ganglia (putamen, caudate) – most common in hypertensive hemorrhage · Thalamus · Cerebellum · Brainstem (pons) · Cerebral lobes (lobar hemorrhage) 2. Subarachnoid: · Basal cisterns (circle of Willis) · Cerebral sulci · Sylvian fissures 3. Subdural: · Over cerebral convexities · Along falx cerebri · Tentorium 4. Epidural: · Temporoparietal region (middle meningeal artery) · Frontal region 5. Intraventricular: · Lateral ventricles · Third ventricle · Fourth ventricle 8. Write a comprehensive essay on pathology of meningitis in a Nigerian Introduction: Meningitis is the inflammation of the meninges (pia, arachnoid, and dura mater) and the subarachnoid space. In Nigeria, meningitis remains a significant public health concern, with seasonal outbreaks (particularly in the "meningitis belt" of sub-Saharan Africa) caused predominantly by Neisseria meningitidis. Etiology in Nigeria: Bacterial Meningitis (Most Common and Severe): · Neisseria meningitidis (Meningococcus): Predominant cause of epidemics; serogroups A, C, W135, X are common in Nigeria · Streptococcus pneumoniae (Pneumococcus): Common in children and elderly · Haemophilus influenzae type b: Declining due to Hib vaccination · Mycobacterium tuberculosis: Tuberculous meningitis (increasing with HIV/AIDS) · Staphylococcus aureus: Post-neurosurgical · Listeria monocytogenes: Neonates, elderly, immunocompromised Viral Meningitis (Less Severe): · Enteroviruses, arboviruses, herpes simplex virus, HIV Fungal Meningitis (Immunocompromised): · Cryptococcus neoformans (HIV/AIDS patients) Pathogenesis: 1. Entry and Colonization: Bacteria colonize the nasopharynx (meningococcus, pneumococcus) → invade bloodstream (bacteremia) → cross the blood-brain barrier → enter subarachnoid space 2. Inflammatory Response: Bacterial components (endotoxin, cell wall) trigger release of pro-inflammatory cytokines (TNF, IL-1, IL-6) from macrophages, microglia, and endothelial cells → neutrophil infiltration → increased vascular permeability → cerebral edema 3. Exudate Formation: Neutrophils and fibrin form an exudate in the subarachnoid space, particularly at the base of the brain (basal meningitis) 4. Cerebral Edema: Vasogenic edema (BBB disruption), cytotoxic edema (cellular swelling), interstitial edema (hydrocephalus) → increased ICP 5. Vascular Complications: Vasculitis → thrombosis → ischemia and infarction; venous thrombosis Pathological Features: Gross: · Purulent Meningitis: Thick, yellow-green exudate covering the brain surface (especially over the convexities and at the base) · Congestion: Dilated, engorged meningeal vessels · Cerebral Edema: Brain swelling, flattened gyri, narrowed sulci · Hydrocephalus: Dilated ventricles (if CSF outflow is obstructed) Microscopic: · Neutrophilic Infiltration: In subarachnoid space (acute bacterial meningitis) · Fibrinous Exudate: With inflammatory cells and bacteria · Vasculitis: Inflammatory cell infiltration of vessel walls → thrombosis · Cerebritis: Inflammation extending into brain parenchyma (in severe cases) · Tuberculous Meningitis: Granulomas, caseous necrosis, lymphocytes and plasma cells (chronic) · Cryptococcal Meningitis: Yeast forms with mucinous capsule (India ink stain) Clinical Features (Nigerian Context): · Classic Triad: Fever, headache, neck stiffness (meningism) · Other Signs: Photophobia, vomiting, altered consciousness, seizures, Kernig's sign, Brudzinski's sign · In Infants: Bulging fontanelle, irritability, poor feeding, high-pitched cry · In HIV/AIDS: Atypical presentation; less prominent meningism; tuberculous or cryptococcal meningitis common Complications: 1. Cerebral Edema and Increased ICP: Leading to herniation 2. Hydrocephalus: Obstructive (due to exudate blocking CSF flow) or communicating 3. Vascular Complications: Stroke (ischemic or hemorrhagic) 4. Cranial Nerve Palsies: Especially CN III, VI, VII, VIII (basal meningitis) 5. Subdural Effusion/Empyema: Collection of fluid/pus between dura and arachnoid 6. Brain Abscess 7. Cerebritis 8. Hearing Loss: Most common long-term complication 9. Cognitive Impairment: Learning difficulties, intellectual disability 10. Death: Due to herniation, sepsis, or complications Diagnosis in Nigeria: · Lumbar Puncture: CSF analysis (cell count, protein, glucose, Gram stain, culture, PCR) · CSF Findings: Neutrophilic pleocytosis, elevated protein, low glucose (bacterial) · Blood Culture: To identify organism · Imaging: CT scan (to exclude mass lesion before LP, especially in HIV patients) · Rapid Tests: Lateral flow assays for meningococcal and cryptococcal antigens Prevention: · Vaccination: Meningococcal vaccines (MenAfriVac, quadrivalent), pneumococcal vaccine, Hib vaccine · Public Health Surveillance: During dry season (December-June) when outbreaks occur · Chemoprophylaxis: For close contacts of meningococcal cases 9. Define and state factors that influence intracranial pressure Definition of Intracranial Pressure (ICP): Intracranial pressure is the pressure exerted by the contents of the cranial cavity (brain tissue, blood, and cerebrospinal fluid) within the rigid skull. Normal ICP: < 10-15 mmHg in adults; > 20 mmHg is considered elevated. Factors that Influence ICP (Monroe-Kellie Doctrine): The total volume within the skull is constant: Vbrain + Vblood + VCSF = Constant. An increase in one compartment must be compensated by a decrease in another. 1. Brain Volume: · Cerebral edema (vasogenic, cytotoxic, interstitial) → increased brain volume → increased ICP · Space-occupying lesions (tumors, abscesses, hematomas) → increased brain volume 2. Blood Volume: · Increased cerebral blood volume (hyperemia, venous congestion) → increased ICP · Increased cerebral blood flow (hypercapnia, vasodilation) → increased ICP · Decreased venous drainage (venous sinus thrombosis, neck compression) → increased ICP 3. Cerebrospinal Fluid Volume: · Increased CSF production (choroid plexus papilloma) → increased ICP · Decreased CSF absorption (meningitis, subarachnoid hemorrhage) → increased ICP · Obstructed CSF flow (tumor, herniation, congenital anomalies) → increased ICP 4. Compensation Mechanisms: · CSF displacement into spinal subarachnoid space · Increased CSF absorption · Decreased CSF production · Compression of cerebral veins (reduced blood volume) · Once compensation is exhausted, ICP rises sharply Other Factors: · Posture: Lying flat increases ICP; head elevation decreases ICP · Intrathoracic/Intra-abdominal Pressure: Coughing, straining, Valsalva maneuver increase ICP · Arterial CO2 and O2: Hypercapnia → vasodilation → increased ICP; hypoxia → vasodilation → increased ICP · Body Temperature: Fever increases metabolic demand → increased cerebral blood flow → increased ICP · Seizures: Increased metabolic demand and blood flow → increased ICP 10. Write a short essay on non-traumatic intracranial haemorrhage Non-traumatic intracranial hemorrhage is bleeding within the cranial cavity that occurs spontaneously, without external trauma. Types and Causes: 1. Intracerebral Hemorrhage (ICH): · Bleeding within the brain parenchyma · Most Common Cause: Hypertension (chronic poorly controlled hypertension → rupture of small penetrating arteries) · Other Causes: Cerebral amyloid angiopathy (elderly), arteriovenous malformation, bleeding disorders, anticoagulant therapy, tumors, cocaine use, vasculitis · Common Sites: Basal ganglia (putamen, caudate), thalamus, cerebellum, pons, lobar (cerebral amyloid angiopathy) 2. Subarachnoid Hemorrhage (SAH): · Bleeding in the subarachnoid space · Most Common Cause: Ruptured saccular (berry) aneurysm at the circle of Willis (85%) · Other Causes: Arteriovenous malformation, mycotic aneurysm, bleeding disorders, cocaine use 3. Intraventricular Hemorrhage (IVH): · Bleeding into the ventricles · Causes: Extension from intracerebral hemorrhage, prematurity (germinal matrix hemorrhage) 4. Subdural Hemorrhage (Spontaneous): · Bleeding between dura and arachnoid · Causes: Bleeding disorders, anticoagulant therapy, ruptured cortical vein 5. Epidural Hemorrhage (Spontaneous): · Rare; may occur with dural arteriovenous fistula or bleeding disorders Pathophysiology: · Rupture of a blood vessel → bleeding into brain parenchyma or subarachnoid space · Hematoma formation → mass effect → increased intracranial pressure · Blood breakdown products → vasospasm (especially in SAH), inflammation, and edema Clinical Features: · Intracerebral: Acute onset of focal neurological deficit (hemiparesis, aphasia, sensory loss); headache; vomiting; altered consciousness; seizures · Subarachnoid: Sudden severe ("thunderclap") headache; nausea; vomiting; neck stiffness; photophobia; loss of consciousness · Signs: Hypertension, bradycardia, irregular respiration (Cushing's triad in severe cases); papilledema; pupil changes Diagnosis: · CT Scan: Hyperdense (bright) area indicating fresh blood; location and extent · MRI: For subacute or chronic hemorrhage · Lumbar Puncture: For SAH (if CT negative) – xanthochromia (yellow CSF) · Angiography: To identify aneurysm or AVM Complications: · Increased ICP and herniation · Vasospasm (SAH) → delayed cerebral ischemia · Hydrocephalus (SAH, IVH) → due to obstruction or impaired absorption of CSF · Rebleeding (aneurysm) · Seizures · Cardiopulmonary complications (neurogenic pulmonary edema) · Death Prognosis: Depends on cause, location, extent of hemorrhage, and patient's age and comorbidities. ICH has high mortality (30-50%); SAH has mortality of 30-40% (with high morbidity in survivors). 11. Briefly discuss CEREBRAL OEDEMA under the following sub-headings: a. Etiopathogenetic classification b. The gross appearance of the brain in generalised oedema a. Etiopathogenetic Classification: 1. Vasogenic Edema: · Most common type · Pathogenesis: Disruption of the blood-brain barrier (BBB) → leakage of protein-rich fluid into the extracellular space of the brain · Causes: Tumors, abscesses, inflammation (meningitis, encephalitis), trauma, hypertensive encephalopathy · Characteristics: Accumulation of fluid in the extracellular space (white matter); sparing of gray matter (initially); responsive to corticosteroids 2. Cytotoxic Edema: · Pathogenesis: Cellular swelling due to failure of the Na+-K+ ATPase pump → intracellular accumulation of sodium and water → cell swelling · Causes: Ischemia, hypoxia, hypoglycemia, toxins, hyponatremia, Reye's syndrome · Characteristics: Affects neurons, astrocytes, and endothelial cells; gray and white matter involvement; no response to corticosteroids 3. Interstitial Edema: · Pathogenesis: Increased CSF pressure → transudation of CSF into the brain parenchyma (periventricular) · Causes: Obstructive hydrocephalus, communicating hydrocephalus · Characteristics: Periventricular white matter edema; may resolve with CSF diversion 4. Osmotic Edema: · Pathogenesis: Osmotic gradient causing water to enter the brain · Causes: Rapid correction of hyponatremia, hyperglycemia, hemodialysis · Characteristics: Generalized brain swelling b. Gross Appearance of the Brain in Generalised Oedema: · Increased Brain Weight: The brain is heavier than normal · Flattened Gyri: The surface convolutions are flattened (effaced) · Narrowed Sulci: The grooves between gyri are narrowed or obliterated · Compressed Ventricles: The lateral ventricles are narrowed or obliterated · Congested Vessels: Dilated, engorged surface blood vessels · Soft, Boggy Consistency: The brain feels soft and swollen · Herniation: May be present (uncal, tonsillar, subfalcine) if severe · Cut Surface: The cut surface may show wet, glistening appearance; indistinct gray-white matter junction
Miscellaneous
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1. Write an essay on the processes a surgical biopsy undergoes from the operation table to a histopathologist's microscope Step 1: Surgical Removal (Operation Table): · The biopsy specimen is surgically removed by the surgeon · The specimen is handled gently to avoid crush artifact · The surgeon provides clinical information (patient details, site, clinical history, suspected diagnosis) Step 2: Fixation: · The specimen is placed in fixative solution immediately (usually 10% neutral buffered formalin) · Fixation prevents autolysis and preserves tissue architecture · The specimen must be adequately fixed (small specimens: 4-6 hours; large specimens: 24-48 hours) · The container is labeled with patient details and specimen site Step 3: Gross Examination (Specimen Receipt in Pathology Lab): · The specimen is accessioned (given a unique pathology number) · The specimen is measured, weighed, and examined grossly · Description of size, shape, color, consistency, and any abnormal features · Inking of surgical margins (for tumor specimens) · The specimen is sectioned to examine the cut surface Step 4: Tissue Processing: · Dehydration: Specimen is passed through increasing concentrations of alcohol (70% → 95% → 100%) to remove water · Clearing: Alcohol is replaced with a clearing agent (xylene) to make tissue miscible with paraffin · Infiltration: Tissue is infiltrated with molten paraffin wax · Embedding: Tissue is embedded in a paraffin block (for sectioning) Step 5: Sectioning (Microtomy): · The paraffin block is trimmed and sectioned using a microtome (4-5 µm thick sections) · Sections are floated on a warm water bath to remove wrinkles · Sections are mounted on glass slides Step 6: Staining: · Hematoxylin and Eosin (H&E) Staining: The most common routine stain · Hematoxylin: Stains nuclei blue (basophilic) · Eosin: Stains cytoplasm and extracellular matrix pink (eosinophilic) · Special Stains: For specific structures (PAS, Congo red, Ziehl-Neelsen, Grocott methenamine silver, etc.) · Immunohistochemistry: For specific antigens (ER, PR, HER2, CD20, CK, etc.) · In Situ Hybridization: For specific DNA/RNA sequences (FISH for HER2, MYC) Step 7: Coverslipping: · A coverslip is applied to the slide to protect the section Step 8: Histopathological Examination (Microscope): · The pathologist examines the slide under a microscope · Assessment of tissue architecture, cellular morphology, nuclear features, mitotic figures, invasion, margins, lymphovascular invasion · Diagnosis is rendered based on histological features · Additional studies may be requested (immunohistochemistry, molecular studies) Step 9: Reporting: · A pathology report is generated · Includes patient details, specimen details, gross description, microscopic description, diagnosis, comments · The report is sent to the clinician Step 10: Archiving: · Slides and blocks are archived for future reference 2. How can you differentiate kwashiorkor from marasmus at autopsy Kwashiorkor: Clinical Features: · Edema: Generalized edema (pitting) – hallmark feature · Skin Changes: Depigmentation, peeling, ulceration ("flaky paint" dermatosis) · Hair Changes: Hypopigmentation, thinning, straightening (flag sign) · Moon Facies: Puffy, round face due to edema · Fatty Liver: Hepatomegaly (fatty infiltration) · Growth: Weight may be normal or reduced (but less severe than marasmus) · Appetite: Usually reduced · Serum Albumin: Severely decreased Autopsy Findings: · Edema: Generalized, pitting edema; ascites; pleural effusion; pericardial effusion · Liver: Enlarged, pale, yellow (fatty liver); greasy, soft consistency; microscopically: fatty infiltration of hepatocytes (macrovesicular steatosis) · Skin: Dry, scaly, peeling, depigmented areas; ulceration; microscopically: epidermal thinning, hyperkeratosis · Hair: Hypopigmented, thin, sparse; microscopically: reduced melanin · Pancreas: Atrophy of exocrine pancreas (acinar atrophy) · Gastrointestinal Tract: Mucosal atrophy (small intestine); villous blunting · Lymphoid Organs: Thymus and lymph node atrophy (due to protein deficiency) · Serous Effusions: Ascites, pleural effusion · Muscles: Muscle wasting (less severe than marasmus) · Heart: Small, atrophic (relative) Marasmus: Clinical Features: · Severe Wasting: Marked muscle wasting; "skin and bones" appearance · Loss of Subcutaneous Fat: Complete loss of fat (emaciation) · No Edema: Absence of edema (distinguishing feature) · Hair Changes: Thin, sparse, brittle; but no depigmentation (unlike kwashiorkor) · Skin: Dry, wrinkled, atrophic; no specific skin lesions · Growth: Severe weight loss and stunting · Appetite: Usually preserved · Serum Albumin: May be normal or mildly decreased (better preserved than kwashiorkor) Autopsy Findings: · Severe Wasting: Marked loss of subcutaneous fat and muscle; emaciated appearance · Absence of Edema: No edema (distinguishes from kwashiorkor) · Adipose Tissue: Complete loss of fat (absence of subcutaneous, visceral, and bone marrow fat) · Muscles: Severe muscle wasting; small, atrophic muscles · Liver: Normal or small; no fatty infiltration (unlike kwashiorkor) · Skin: Atrophic, wrinkled, dry; microscopically: epidermal thinning · Hair: Thin, sparse, brittle; no depigmentation · Lymphoid Organs: Thymus and lymph node atrophy · Gastrointestinal Tract: Mucosal atrophy (less severe than kwashiorkor) · Heart: Small, atrophic · Brain: Relative sparing (but may be affected in severe cases) · Serous Effusions: Absent (no edema) Summary of Key Differences at Autopsy: Feature Kwashiork Marasmu or s Edema Present (generaliz Absent ed) Fat Loss Moderate Severe (complete loss) Muscle Wasting Moderate Severe Fatty Liver Present Absent Skin Lesions Flaky paint dermatosi Atrophic, dry s Hair Changes Depigmen (flag sign) Thin, brittle (no depigmen tation tation) Ascites/Pl Effusion Present Absent eural
Cellular Responses To Stress and Toxic Insults
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1. Categorize cells on the basis of their regenerative capacity and give 2 examples each Cells are categorized into three groups based on their proliferative capacity: Labile Cells – These cells continuously divide throughout life to replace cells that are constantly lost. Examples: (1) Surface epithelial cells of the skin, (2) Mucosal epithelial cells of the gastrointestinal tract. Stable Cells – These cells have limited capacity to divide but can undergo rapid division in response to stimuli or injury. Examples: (1) Hepatocytes of the liver, (2) Renal tubular epithelial cells. Permanent Cells – These cells have lost their ability to divide and cannot regenerate after birth. Examples: (1) Neurons, (2) Cardiac muscle cells. 2. What is Cell death? Cell death is the irreversible cessation of cellular functions and the eventual breakdown of cellular structures. It occurs when cells are unable to maintain homeostasis due to severe or persistent injury. Cell death can occur through two main mechanisms: necrosis (accidental, unprogrammed cell death resulting from severe injury) and apoptosis (programmed, controlled cell death that is genetically regulated and occurs as a normal physiological process). 3. Outline cell adaptive changes and mechanisms to injuries with related examples Cellular adaptation refers to reversible changes in cell size, number, phenotype, metabolic activity, or function in response to environmental changes or stress. Hypertrophy – Increase in cell size leading to organ enlargement. Mechanism: Increased synthesis of structural proteins and organelles. Example: Cardiac myocyte hypertrophy in response to hypertension. Hyperplasia – Increase in cell number due to increased cell division. Mechanism: Stimulation by growth factors or hormones. Example: Endometrial hyperplasia during the menstrual cycle. Atrophy – Decrease in cell size and function. Mechanism: Decreased protein synthesis and increased protein degradation via ubiquitin-proteasome pathway. Example: Muscle atrophy following denervation or disuse. Metaplasia – Reversible change from one differentiated cell type to another. Mechanism: Reprogramming of stem cells or undifferentiated mesenchymal cells. Example: Squamous metaplasia of bronchial epithelium in chronic smokers. Dysplasia – Abnormal growth and differentiation characterized by cellular atypia. Mechanism: Disordered maturation of cells. Example: Cervical intraepithelial neoplasia.
Necrosis and Cell Death
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4. Define necrosis Necrosis is a form of cell death that results from irreversible cell injury and is characterized by cellular swelling, membrane disruption, organelle breakdown, and leakage of cellular contents into the extracellular space, which typically elicits an inflammatory response. 5. List the different types of necrosis 1. Coagulative necrosis 2. Liquefactive necrosis 3. Caseous necrosis 4. Fat necrosis 5. Fibrinoid necrosis 6. Gangrenous necrosis 6. List the morphological types of necrosis with 2 examples each Coagulative Necrosis – Preservation of tissue architecture with loss of nuclei. Examples: (1) Myocardial infarction, (2) Renal infarction. Liquefactive Necrosis – Tissue becomes liquid due to enzymatic digestion. Examples: (1) Cerebral infarction (brain abscess), (2) Bacterial abscesses. Caseous Necrosis – Soft, friable, cheese-like appearance with loss of tissue architecture. Examples: (1) Tuberculosis, (2) Fungal infections. Fat Necrosis – Necrosis of adipose tissue with chalky-white appearance. Examples: (1) Acute pancreatitis, (2) Traumatic fat necrosis of breast. Fibrinoid Necrosis – Deposition of fibrin-like material in vessel walls. Examples: (1) Malignant hypertension, (2) Polyarteritis nodosa. Gangrenous Necrosis – Coagulative necrosis affecting multiple tissue layers, usually in limbs. Examples: (1) Dry gangrene of lower extremities, (2) Wet gangrene in diabetic foot. 7. Tabulate differences between necrosis and apoptosis Necrosis: · Unprogrammed, accidental cell death · Occurs due to severe injury (hypoxia, toxins, trauma) · Cell swelling and membrane rupture · Inflammation is elicited · Affects groups of contiguous cells · Nuclear changes: pyknosis, karyorrhexis, karyolysis Apoptosis: · Programmed, controlled cell death · Occurs physiologically or in response to mild injury · Cell shrinkage and membrane blebbing · No inflammation (cell fragments are phagocytosed) · Affects individual cells · Nuclear changes: chromatin condensation and fragmentation 8. What is gangrene? Classify gangrene Gangrene is a form of tissue necrosis that occurs when a large mass of tissue undergoes coagulative necrosis, usually affecting a limb or extremity due to loss of blood supply. Classification: Dry Gangrene – Coagulative necrosis with minimal bacterial involvement. The tissue becomes dry, shrunken, and dark brown to black. It spreads slowly and has a clear demarcation line between viable and necrotic tissue. Wet Gangrene – Coagulative necrosis with superimposed bacterial infection and liquefaction. The tissue becomes swollen, moist, putrid, and discolored. It spreads rapidly and is associated with severe systemic symptoms. Gas Gangrene – Caused by Clostridium species producing gas in the tissues. The tissue is swollen, crepitant, and has a foul odor. 9. Tabulate differences between wet and dry gangrene Dry Gangrene: · Coagulative necrosis · Dry, shrunken, mummified appearance · Dark brown to black color · Slow progression · Clear line of demarcation · Minimal systemic symptoms · Common in arteriosclerosis Wet Gangrene: · Coagulative necrosis with liquefaction · Swollen, moist, and putrid · Discolored (greenish-black) · Rapid progression · Poorly defined demarcation · Severe systemic symptoms (sepsis) · Common in diabetic foot, burns 10. List 4 examples of dystrophic calcifications Dystrophic calcification occurs in damaged or necrotic tissues despite normal serum calcium levels. Examples: (1) Caseous necrosis in tuberculosis, (2) Atherosclerotic plaques, (3) Calcified heart valves in rheumatic heart disease, (4) Calcified infarcts. 11. List 4 staining characteristics of Amyloid in organ/tissues 1. Pink with Hematoxylin and Eosin (H&E) staining 2. Apple-green birefringence under polarized light after Congo red staining 3. Metachromasia with crystal violet (red-purple) 4. Positive periodic acid-Schiff (PAS) staining 12. What possible complications may arise in amyloidosis of the following organs: Heart: Restrictive cardiomyopathy, arrhythmias, congestive heart failure, sudden cardiac death. Kidney: Nephrotic syndrome with heavy proteinuria, progressive renal failure, end-stage renal disease. Alimentary tract: Malabsorption, diarrhea, gastrointestinal bleeding, obstruction, perforation. Spleen: Splenomegaly, hypersplenism, impaired immune function. 13. Write short note on necrosis (Essay on tissue necrosis and its complications) Necrosis is the sequence of morphological changes that follow cell death in living tissue. It is a form of irreversible cell injury characterized by cytoplasmic swelling, damage to the plasma membrane, and organelle destruction. The process involves enzymatic digestion of cellular components and denaturation of proteins. Types of Necrosis: Coagulative necrosis (preserved tissue architecture), liquefactive necrosis (tissue liquefaction), caseous necrosis (cheese-like appearance), fat necrosis, fibrinoid necrosis, and gangrenous necrosis. Morphological Features: Nuclear changes include pyknosis (nuclear shrinkage and condensation), karyorrhexis (fragmentation of nucleus), and karyolysis (dissolution of nucleus). Cytoplasmic changes include increased eosinophilia, vacuolation, and loss of cellular detail. Complications of Necrosis: · Inflammatory response with potential for abscess formation · Impaired organ function · Secondary infection and sepsis · Organ failure · Scarring and fibrosis during healing · Calcification (dystrophic calcification) 14. Write an essay on the morphologic changes in reversible cell injury Reversible cell injury occurs when the cell is subjected to mild or brief injury and is able to recover once the injurious stimulus is removed. The morphological changes include: Cellular Swelling – The earliest manifestation of cell injury, characterized by failure of the sodium-potassium pump leading to intracellular accumulation of sodium and water. This results in cytoplasmic vacuolation and increased cell size. Fatty Change – Accumulation of lipid vacuoles in the cytoplasm, particularly in cells involved in fat metabolism such as hepatocytes and myocardial cells. This occurs due to impaired fatty acid oxidation or increased fatty acid synthesis. Plasma Membrane Changes – Blebbing of the plasma membrane, loss of microvilli, and formation of myelin figures. Mitochondrial Changes – Swelling of mitochondria with loss of cristae and increased density of mitochondrial matrix. Endoplasmic Reticulum Changes – Dilatation of the endoplasmic reticulum with detachment of ribosomes. Nuclear Changes – Chromatin clumping and margination. These changes are reversible if the injurious stimulus is removed and cellular ATP production is restored. If the injury persists, the cell undergoes irreversible injury leading to necrosis. 15. Short note on hypertrophy Hypertrophy is an adaptive increase in the size of cells, leading to an increase in organ size. It occurs when cells are unable to divide (such as in permanent cells) or when increased functional demand requires greater cellular output. The mechanism involves increased synthesis of structural proteins and organelles, mediated by growth factors, hormones, and mechanical signals. Examples: (1) Cardiac hypertrophy in hypertension, (2) Skeletal muscle hypertrophy in athletes, (3) Uterine smooth muscle hypertrophy during pregnancy. 16. Short note on pathological calcification Pathological calcification is the abnormal deposition of calcium salts in tissues, classified into two types: Dystrophic Calcification – Deposition of calcium in dead or degenerated tissues despite normal serum calcium levels. Examples: calcification in caseous necrosis, atherosclerotic plaques, and damaged heart valves. Metastatic Calcification – Deposition of calcium in normal tissues due to hypercalcemia. Examples: calcification in lungs, kidneys, and gastric mucosa in conditions such as hyperparathyroidism, vitamin D toxicity, and metastatic bone disease. 17. Short note on metaplasia Metaplasia is a reversible change in which one differentiated cell type is replaced by another differentiated cell type. It represents an adaptive response to chronic irritation or injury, where the new cell type is better suited to withstand the adverse environment. The process involves reprogramming of stem cells or undifferentiated mesenchymal cells. Examples: (1) Squamous metaplasia of bronchial epithelium in chronic smokers, (2) Barrett's esophagus (columnar metaplasia of esophageal squamous epithelium in gastroesophageal reflux disease). 18. Short note on hyperplasia Hyperplasia is an adaptive increase in the number of cells in an organ or tissue. It occurs in tissues containing cells capable of mitotic division (labile and stable cells). Hyperplasia is typically stimulated by hormones or growth factors. Types: · Physiological Hyperplasia: Hormonal (e.g., endometrial hyperplasia during menstrual cycle) or compensatory (e.g., liver regeneration after partial hepatectomy). · Pathological Hyperplasia: Excessive hormonal stimulation (e.g., benign prostatic hyperplasia) or chronic irritation (e.g., epidermal hyperplasia in warts).
Inflammation
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1. Define acute inflammation Acute inflammation is the immediate and early response to tissue injury, characterized by the rapid recruitment of neutrophils, vascular changes (vasodilation and increased permeability), and the formation of exudate. It is of short duration (minutes to days) and typically resolves with elimination of the injurious agent. 2. Outline the morphologic patterns of acute inflammation 1. Serous Inflammation – Thin, watery exudate (e.g., skin blister, pleural effusion) 2. Fibrinous Inflammation – Thick, fibrin-rich exudate (e.g., pericarditis, pleuritis) 3. Suppurative (Purulent) Inflammation – Pus formation with neutrophils (e.g., abscess, cellulitis) 4. Ulcerative Inflammation – Necrosis and sloughing of surface epithelium (e.g., peptic ulcer) 5. Pseudomembranous Inflammation – Necrotic debris and fibrin forming a membrane (e.g., diphtheria) 6. Catarrhal Inflammation – Excessive mucus production (e.g., common cold) 3. Define Inflammation and classify it with reasons Inflammation is the protective response of living tissue to injury, involving vascular, cellular, and humoral responses aimed at eliminating the injurious agent and initiating repair. Classification: Acute Inflammation – Rapid onset, short duration, characterized by neutrophil infiltration, vascular changes, and exudate formation. Occurs in response to acute injury or infection. Chronic Inflammation – Prolonged duration (weeks to years), characterized by lymphocyte and macrophage infiltration, tissue destruction, and repair (fibrosis). Occurs when the injurious agent persists or following repeated episodes of acute inflammation. 4. Enumerate the Sequence of Cellular Events in Acute inflammation 1. Margination and Rolling – Leukocytes move to the periphery of blood vessels and roll along the endothelium. 2. Adhesion – Leukocytes firmly adhere to the endothelial surface via adhesion molecules. 3. Transmigration (Diapedesis) – Leukocytes migrate through the endothelial cell junctions into the tissue. 4. Chemotaxis – Leukocytes move toward the site of injury along a chemical gradient. 5. Phagocytosis – Leukocytes engulf and destroy the injurious agent. 6. Intracellular Killing – Destruction of ingested material through oxidative and non-oxidative mechanisms. 5. Give the Chemical Mediators Involved in each of the above stages Vasodilation and Increased Permeability: · Histamine, serotonin, bradykinin, prostaglandins, leukotrienes C4, D4, E4, complement C3a and C5a Chemotaxis: · Complement C5a, leukotriene B4, bacterial products, chemokines (IL-8) Adhesion: · Selectins, integrins, ICAM-1, VCAM-1 Phagocytosis: · Opsonins (IgG, C3b), complement receptors, Fc receptors Intracellular Killing: · Reactive oxygen species (superoxide, hydrogen peroxide, hydroxyl radical) · Nitric oxide · Lysosomal enzymes (elastase, collagenase, cathepsin G) 6. Write an essay on the vascular event of acute inflammation The vascular events in acute inflammation represent the immediate response to tissue injury and are characterized by changes in the microcirculation that facilitate the delivery of inflammatory cells and plasma proteins to the site of injury. Vasodilation – The first vascular event, caused by the action of mediators such as histamine and nitric oxide on arteriolar smooth muscle. This leads to increased blood flow, manifesting clinically as redness (rubor) and heat (calor). Vasodilation is responsible for the early increased vascular permeability. Increased Vascular Permeability – Occurs in the venules and capillaries, allowing plasma proteins and fluid to escape into the interstitial space. This is mediated by: (1) Endothelial cell contraction (immediate transient response) mediated by histamine, bradykinin, and leukotrienes; (2) Endothelial injury (immediate sustained response) caused by direct damage; (3) Leukocyte-mediated endothelial injury (delayed prolonged response) due to neutrophil adhesion and release of toxic oxygen species. Stasis and Slowing of Blood Flow – As permeability increases, fluid leaves the vessels, increasing blood viscosity and slowing flow. This facilitates leukocyte margination and adhesion. Exudation – The escape of protein-rich fluid from the vessels into the extravascular space, forming inflammatory exudate. This contains immunoglobulins, complement, and fibrinogen. Leukocyte Emigration – Leukocytes leave the vessels through postcapillary venules via diapedesis and migrate to the site of injury. 7. Enumerate the fate of acute inflammation 1. Resolution – Complete restoration of tissue to normal if the injury is mild and tissue is capable of regeneration. 2. Suppuration (Abscess Formation) – When the injurious agent is pyogenic and persists, leading to pus formation. 3. Organization – Replacement of exudate by granulation tissue and eventual fibrosis. 4. Progression to Chronic Inflammation – When the acute inflammatory response fails to eliminate the injurious agent. 5. Healing by Scarring – When tissue destruction is extensive and regeneration is not possible. 8. List the systemic effects of acute inflammation 1. Fever – Caused by pyrogens (IL-1, TNF, IL-6) acting on the hypothalamic thermoregulatory center. 2. Leukocytosis – Increased white blood cell count, with neutrophilia in bacterial infections. 3. Acute-phase Protein Response – Increased synthesis of C-reactive protein, fibrinogen, haptoglobin, and serum amyloid A. 4. Tachycardia and Tachypnoea – Due to increased metabolic demand. 5. Malaise, Fatigue, Anorexia – Due to cytokine effects on the central nervous system. 6. Weight Loss – Due to increased catabolism. 9. List the major mediators of acute inflammation against their effects Histamine and Serotonin: · Vasodilation, increased vascular permeability Prostaglandins (PGE2, PGI2): · Vasodilation, potentiation of edema, pain Leukotrienes (LTB4, LTC4, LTD4, LTE4): · Chemotaxis (LTB4), increased vascular permeability (LTC4, LTD4, LTE4) Complement System (C3a, C5a): · Vasodilation, increased permeability, chemotaxis, opsonization Bradykinin: · Increased vascular permeability, pain, vasodilation Cytokines (IL-1, TNF, IL-6): · Endothelial activation, fever, acute-phase response Platelet Activating Factor (PAF): · Vasodilation, increased permeability, platelet aggregation Reactive Oxygen Species: · Endothelial damage, increased permeability Nitric Oxide: · Vasodilation, antimicrobial activity 10. What is chronic inflammation Chronic inflammation is a prolonged inflammatory response (weeks to years) characterized by the simultaneous presence of ongoing inflammation, tissue destruction, and attempts at repair. It is typically associated with lymphocyte and macrophage infiltration, angiogenesis, and fibrosis. Chronic inflammation can arise from: (1) Persistent infections, (2) Prolonged exposure to toxic agents, (3) Autoimmune diseases, or (4) Progression from acute inflammation. 11. List the causes of chronic inflammation 1. Persistent Infections – Tuberculosis, leprosy, fungal infections, syphilis, viral infections 2. Autoimmune Diseases – Rheumatoid arthritis, systemic lupus erythematosus, inflammatory bowel disease 3. Toxic Agents – Silica, asbestos (silicosis, asbestosis) 4. Foreign Bodies – Surgical sutures, splinters 5. Prolonged Exposure to Irritants – Smoking (chronic bronchitis) 6. Metabolic Disorders – Gout, atherosclerosis 7. Idiopathic Causes – Sarcoidosis, Wegener's granulomatosis 12. List the chemical mediators of chronic nonspecific inflammation, including their effects 1. IL-1 and TNF – Fever, acute-phase response, fibroblast proliferation, endothelial activation 2. TGF-β – Fibroblast proliferation, collagen synthesis, immunosuppression 3. PDGF – Fibroblast proliferation, angiogenesis 4. FGF – Angiogenesis, fibroblast proliferation 5. Prostaglandins – Vasodilation, pain 6. Leukotrienes – Chemotaxis, increased permeability 7. Complement Components – Chemotaxis, opsonization 8. Lysosomal Enzymes – Tissue destruction (elastase, collagenase, cathepsins) 9. Reactive Oxygen Species – Tissue damage 10. Nitric Oxide – Vasodilation, antimicrobial 13. Briefly describe the morphology of chronic inflammation Gross Features: · Thickened, fibrotic tissue · Grayish-white appearance · Adhesions and contractures · Ulceration (if mucosal surfaces are involved) Microscopic Features: · Predominant Cell Types: Mononuclear cells – macrophages, lymphocytes, plasma cells · Tissue Destruction: Necrosis, ulceration, atrophy · Repair: Fibrosis (collagen deposition), angiogenesis · Granulomas: Focal collections of epithelioid macrophages and giant cells in granulomatous inflammation · Lymphoid Follicles: Aggregates of lymphocytes, sometimes with germinal centers 14. Define neoplasia and classify with reasons Neoplasia is abnormal new growth of tissue that is uncoordinated with normal tissue growth and persists after the initiating stimulus is removed. Neoplasms (tumors) are classified as: Benign Neoplasms: · Well-differentiated, resembling tissue of origin · Slow growth · Encapsulated or well-circumscribed · No invasion or metastasis · Examples: lipoma, adenoma Malignant Neoplasms (Cancer): · Poorly differentiated (anaplasia) · Rapid growth · Infiltrative, not encapsulated · Invasion and metastasis · Examples: carcinoma, sarcoma Classification Based on Histogenesis: · Epithelial Tumors: Benign (adenoma, papilloma); Malignant (carcinoma) · Mesenchymal Tumors: Benign (fibroma, lipoma); Malignant (sarcoma) · Hematopoietic Tumors: Leukemias, lymphomas · Germ Cell Tumors: Teratomas, seminomas 15. Short note on the complement system in inflammation The complement system is a cascade of plasma proteins that plays a crucial role in inflammation and host defense. It is activated through three pathways: classical, alternative, and lectin pathways. Functions in Inflammation: · Increased Vascular Permeability: C3a and C5a (anaphylatoxins) stimulate mast cell degranulation, releasing histamine · Chemotaxis: C5a is a potent chemoattractant for neutrophils and monocytes · Opsonization: C3b coats microorganisms, enhancing phagocytosis · Cell Lysis: Membrane attack complex (C5b-C9) causes osmotic lysis of target cells · Inflammation Amplification: Complement activation triggers the release of other inflammatory mediators 16. Short notes on the possible harmful effects of both acute and chronic inflammatory process Harmful Effects of Acute Inflammation: · Tissue Destruction: Release of lysosomal enzymes and reactive oxygen species can damage normal tissues · Abscess Formation: Localized collections of pus that may require surgical drainage · Organ Dysfunction: Inflammatory edema can impair organ function (e.g., laryngeal edema causing airway obstruction) · Systemic Inflammatory Response: Severe acute inflammation can lead to sepsis and septic shock · Pain: Due to mediators such as bradykinin and prostaglandins Harmful Effects of Chronic Inflammation: · Progressive Tissue Destruction: Continued release of inflammatory mediators causes irreversible tissue damage · Fibrosis and Scarring: Excessive collagen deposition leads to organ dysfunction (e.g., liver cirrhosis, pulmonary fibrosis) · Amyloidosis: Chronic inflammation can lead to secondary amyloid deposition · Malignant Transformation: Chronic inflammation increases the risk of cancer (e.g., ulcerative colitis → colorectal cancer, chronic hepatitis → hepatocellular carcinoma) · Autoimmune Disease: Chronic inflammation can lead to autoimmunity · Impaired Function: Loss of organ function due to structural changes 17. Define granuloma A granuloma is a focal aggregate of immune cells that forms in response to a persistent inflammatory stimulus. It characteristically demonstrates the compact organization of mature macrophages, which may or may not be associated with other inflammatory cell types. Granulomas are composed of epithelioid macrophages (activated macrophages with an epithelium-like appearance), often with a peripheral cuff of lymphocytes and plasma cells. Multinucleated giant cells may also be present. 18. Distinguish Between Granuloma and Granulation Tissue Granuloma: · Focal collection of epithelioid macrophages and giant cells · Forms in response to persistent irritants · Not a wound-healing tissue · Contains no significant blood vessels · Associated with granulomatous inflammation · Examples: tuberculous granuloma, foreign body granuloma Granulation Tissue: · Composed of proliferating fibroblasts and endothelial cells · Forms during wound healing and repair · Pink, granular, friable tissue · Rich in blood vessels (angiogenesis) · Associated with tissue repair and regeneration · Examples: healing wound, organizing thrombus 19. Give 5 Clinical Examples of Granulomatous inflammation 1. Tuberculosis – Caseating granulomas with central necrosis 2. Leprosy – Granulomas in skin and nerves 3. Sarcoidosis – Non-caseating granulomas in multiple organs 4. Fungal Infections – Histoplasmosis, coccidioidomycosis 5. Foreign Body Granulomas – Due to surgical sutures, splinters, silica 20. Discuss GRANULOMAS under the following sub-headings: a. Definition b. Pathogenetic classification, with examples c. The possible outcomes a. Definition: A granuloma is a focal aggregate of immune cells that forms in response to a persistent inflammatory stimulus. It characteristically demonstrates the compact organization of mature macrophages, which may or may not be associated with other inflammatory cell types. Granulomas are composed of epithelioid macrophages (activated macrophages with an epithelium-like appearance), often with a peripheral cuff of lymphocyte and plasma cells. b. Pathogenetic classification, with examples: Infectious Granulomas: · Bacterial: Tuberculosis (Mycobacterium tuberculosis), Leprosy (Mycobacterium leprae), Syphilis (Treponema pallidum) · Fungal: Histoplasmosis, Coccidioidomycosis, Blastomycosis · Parasitic: Schistosomiasis Non-Infectious Granulomas: · Immune-mediated: Sarcoidosis, Crohn's disease, Wegener's granulomatosis · Foreign body: Sutures, splinters, silica, talc · Idiopathic: Sarcoidosis (cause unknown) c. The possible outcomes: Resolution: Complete elimination of the inciting agent with restoration of normal tissue structure, leaving minimal or no scarring. Fibrosis and Scarring: The granuloma is replaced by fibrous tissue. This is common in tuberculosis where the granuloma undergoes fibrosis and calcification. Caseous Necrosis: In some infections (e.g., tuberculosis), the center of the granuloma undergoes caseous necrosis, resulting in a cheese-like appearance. Calcification: Dystrophic calcification of the granuloma, often seen in healed tuberculous lesions. Progression: The granulomatous inflammation may spread or persist, causing progressive tissue destruction.
Tissue Renewal, Repair and Regeneration
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1. Discuss local and systemic factors that affect wound healing Local Factors: Blood Supply: Adequate vascularity is essential for oxygen and nutrient delivery. Poor vascularity (e.g., in atherosclerotic disease) impairs healing. Infection: Bacterial contamination prolongs inflammation and impairs healing. Foreign Bodies: Sutures, splinters, and debris delay healing. Mechanical Factors: Pressure, torsion, and movement can disrupt the wound. Tissue Type: Well-vascularized tissues (e.g., skin, mucosa) heal faster than poorly vascularized tissues (e.g., cartilage, tendon). Wound Size and Depth: Larger and deeper wounds heal more slowly. Systemic Factors: Age: Healing is slower in the elderly. Nutritional Status: Protein deficiency, vitamin C deficiency (scurvy), and vitamin A deficiency impair healing. Zinc deficiency also delays healing. Hormonal Status: Diabetes mellitus impairs healing due to microvascular disease and impaired immune function. Corticosteroids suppress inflammation and collagen synthesis. Immune Status: Immunosuppression predisposes to infection and impairs healing. Oxygenation: Hypoxia impairs collagen synthesis and angiogenesis. Smoking: Nicotine causes vasoconstriction and reduces oxygen delivery. Alcoholism: Impairs protein synthesis and immune function. 2. List factors that accelerate wound healing and factors that impede wound healing Factors that Accelerate Wound Healing: 1. Optimal nutrition (adequate protein, vitamins A, C, and zinc) 2. Good blood supply 3. Clean, uninfected wound 4. Absence of foreign bodies 5. Proper approximation of wound edges 6. Absence of tension on the wound 7. Adequate oxygenation 8. Young age Factors that Impede Wound Healing: 1. Infection 2. Poor blood supply 3. Foreign bodies 4. Diabetes mellitus 5. Corticosteroid therapy 6. Malnutrition (protein, vitamin C, zinc deficiency) 7. Smoking 8. Advanced age 9. Immunosuppression 10. Mechanical stress on the wound 3. What are the factors affecting wound healing Local Factors: · Blood supply and oxygenation · Infection · Foreign bodies · Mechanical factors (pressure, tension) · Wound size and depth · Type of tissue involved · Presence of necrotic tissue Systemic Factors: · Age · Nutritional status (protein, vitamins, minerals) · Hormonal factors (diabetes, corticosteroids) · Immune status · Systemic diseases (uremia, liver disease) · Medications (steroids, immunosuppressants) · Lifestyle (smoking, alcohol) 4. State 5 Factors Which Adversely affect wound Healing 1. Infection – Delays healing by prolonging inflammation and causing tissue destruction 2. Poor Blood Supply – Reduces oxygen and nutrient delivery to the healing wound 3. Diabetes Mellitus – Impairs microcirculation, immune function, and collagen synthesis 4. Malnutrition – Protein deficiency impairs granulation tissue formation; vitamin C deficiency impairs collagen synthesis 5. Corticosteroid Therapy – Suppresses inflammation and collagen synthesis 5. Briefly describe the steps involved in the healing of an uncomplicated fractured long bone 1. Hematoma Formation – Bleeding from torn vessels forms a hematoma at the fracture site, providing a scaffold for inflammatory cells. 2. Inflammation – Acute inflammatory response with neutrophil and macrophage infiltration to remove debris. 3. Callus Formation: · Procallus Formation (Day 1-3): Fibroblasts and new capillaries form granulation tissue. · Soft Callus Formation (Week 1-2): Fibrocartilaginous callus forms as chondroblasts produce cartilage and fibroblasts produce collagen. · Hard Callus Formation (Week 3-8): The soft callus is replaced by woven bone (endochondral ossification). 4. Bone Remodeling – Woven bone is remodeled into lamellar bone according to mechanical stress. Excess callus is resorbed, and the bone regains its original shape and strength. 5. Healing by Primary Intention (Direct Healing): Occurs when fracture fragments are fixed with compression, with no callus formation. 6. Short note on wound healing Wound healing is the process by which tissue repairs itself after injury, involving a complex cascade of cellular and molecular events. It occurs through two main mechanisms: Healing by First Intention (Primary Union): Occurs in clean, incised wounds with minimal tissue loss and approximated edges. The process involves: (1) Formation of a fibrin clot; (2) Inflammation; (3) Epithelial regeneration; (4) Granulation tissue formation; (5) Scar formation with minimal scar tissue. Healing by Second Intention (Secondary Union): Occurs in wounds with extensive tissue loss, where edges are not approximated. The process involves: (1) Inflammation; (2) Granulation tissue formation from the base; (3) Contraction of the wound; (4) Epithelialization from the margins; (5) Scar formation with larger scar tissue. Complications of Wound Healing: Infection, wound dehiscence, ulceration, excessive scar formation (keloid/hypertrophic scar), and chronic non-healing ulcers. 7. Short note on healing by first intention Healing by first intention (primary union) occurs in clean, incised surgical wounds with minimal tissue loss and approximated edges. Steps: 1. Day 1: A fibrin clot fills the gap, providing a provisional matrix. Neutrophils infiltrate the area. 2. Days 2-3: Macrophages appear and remove debris. Granulation tissue begins to form. Epithelial cells start migrating from the edges. 3. Days 4-5: Granulation tissue fills the wound. Collagen deposition begins. The epithelium covers the surface. 4. Week 1-2: Collagen fibers increase and organize. The wound gains tensile strength. 5. Weeks 2-4: Remodeling of collagen occurs. Scar tissue matures and becomes less cellular and more fibrous. Features: Minimal scar tissue, rapid healing, good cosmetic outcome. 8. A sickle cell patient has a wound on the leg that refused to heal over 5 months. List the local factors that could affect the wound healing 1. Poor Blood Supply – Sickle cell disease causes vaso-occlusion, leading to ischemia and poor oxygen delivery to the wound 2. Infection – Leg ulcers in sickle cell patients are prone to secondary bacterial infection 3. Necrotic Tissue – Presence of necrotic debris delays healing 4. Mechanical Factors – Pressure and friction from walking can disrupt healing 5. Edema – Chronic venous insufficiency may cause edema, impairing circulation 6. Foreign Bodies – Debris in the wound may delay healing 7. Size and Depth – Chronic ulcers are often large and deep, delaying healing
Haemodynamic Disorders
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1. Write a short note on ischaemia Ischemia is the reduction in blood supply to a tissue or organ, resulting in decreased oxygen and nutrient delivery and accumulation of metabolic waste products. It is a common cause of cell injury and necrosis. Causes: · Arterial Obstruction: Atherosclerosis, thrombosis, embolism, vasospasm · Venous Obstruction: Thrombosis, compression · Hypotension: Shock, heart failure Pathological Effects: · Hypoxia: Decreased oxygen supply leading to anaerobic metabolism and ATP depletion · Cell Swelling: Failure of sodium-potassium pump · Necrosis: If ischemia is severe or prolonged, irreversible cell injury occurs (infarction) · Reperfusion Injury: Restoration of blood flow can cause additional damage due to oxidative stress 2. What is an infarct? List the complications An infarct is an area of ischemic necrosis caused by occlusion of the arterial supply or venous drainage to a tissue or organ. Complications of Infarction: 1. Organ Dysfunction – Loss of function of the affected organ (e.g., myocardial infarction → heart failure) 2. Infection – Necrotic tissue provides a medium for bacterial growth, leading to abscess formation 3. Rupture – Infarcted tissue may rupture (e.g., myocardial rupture after MI) 4. Embolism – Mural thrombi over infarcted tissue may embolize 5. Fibrosis and Scarring – Healing by scar formation may lead to contractures 6. Calcification – Dystrophic calcification of the infarct 7. Hemorrhage – Hemorrhagic transformation of infarcts 3. What is edema. Briefly describe the pathogenesis of edema Edema is the accumulation of excess fluid in the interstitial spaces of tissues or body cavities. Pathogenesis of Edema: Increased Capillary Hydrostatic Pressure: · Reduced venous drainage (heart failure, venous obstruction) · Increased venous pressure (pregnancy, portal hypertension) · Mechanism: Forces fluid out of capillaries into the interstitium Decreased Plasma Oncotic Pressure: · Reduced plasma protein synthesis (liver disease, malnutrition) · Increased protein loss (nephrotic syndrome, protein-losing enteropathy) · Mechanism: Reduced osmotic pull of proteins, allowing fluid to leave capillaries Increased Vascular Permeability: · Inflammation (histamine, bradykinin, leukotrienes) · Mechanism: Endothelial cell contraction or damage allows fluid and protein to leak Lymphatic Obstruction: · Filariasis, surgical removal of lymph nodes, tumor infiltration · Mechanism: Failure of lymphatic drainage to remove interstitial fluid Sodium and Water Retention: · Kidney dysfunction, hormonal imbalances (aldosterone, ADH) · Mechanism: Increased total body fluid volume 4. Outline pathophysiologic mechanisms of edema 1. Increased Capillary Hydrostatic Pressure – Forces fluid out of capillaries · Examples: Congestive heart failure (systemic edema), portal hypertension (ascites) 2. Reduced Plasma Oncotic Pressure – Reduced osmotic pull of plasma proteins · Examples: Nephrotic syndrome (hypoalbuminemia), liver cirrhosis (decreased albumin synthesis), malnutrition 3. Increased Vascular Permeability – Allows fluid and protein to escape · Examples: Inflammation (acute edema), allergic reactions 4. Lymphatic Obstruction – Impaired removal of interstitial fluid · Examples: Filariasis (elephantiasis), axillary lymph node dissection (arm edema) 5. Sodium and Water Retention – Increased total body fluid volume · Examples: Renal failure, congestive heart failure, cirrhosis 5. Write a comprehensive essay on edema with clinical examples Edema is the abnormal accumulation of interstitial fluid within tissues. It represents an imbalance between the forces that drive fluid out of the capillaries (hydrostatic pressure) and the forces that keep fluid in the capillaries (plasma oncotic pressure). Pathophysiology: The formation of edema is governed by Starling's forces, which include capillary hydrostatic pressure, plasma oncotic pressure, interstitial hydrostatic pressure, and interstitial oncotic pressure. Edema occurs when: 1. Capillary hydrostatic pressure increases – This forces more fluid out of the capillaries. Clinical example: Congestive heart failure – Reduced cardiac output causes venous congestion, increasing capillary hydrostatic pressure and leading to pedal edema, pulmonary edema, and ascites. 2. Plasma oncotic pressure decreases – Reduced plasma protein concentration (particularly albumin) decreases the osmotic pull of plasma, allowing fluid to escape. Clinical example: Nephrotic syndrome – Massive proteinuria causes hypoalbuminemia, leading to generalized edema (anasarca). 3. Capillary permeability increases – Inflammatory mediators cause endothelial cell contraction, allowing fluid and protein to leak into the interstitium. Clinical example: Acute inflammation – Histamine and bradykinin cause local edema at sites of infection or injury. 4. Lymphatic obstruction occurs – Impaired lymphatic drainage prevents removal of interstitial fluid. Clinical example: Filariasis – Obstruction of lymphatic vessels by Wuchereria bancrofti causes elephantiasis. 5. Sodium and water retention occurs – Renal dysfunction leads to fluid retention. Clinical example: Acute renal failure – Impaired sodium excretion leads to fluid overload and edema. Morphological Features: · Subcutaneous Edema: Pitting edema (pressure leaves an indentation) or non-pitting edema (firm, as in lymphatic obstruction) · Pulmonary Edema: Heavy, wet lungs with frothy fluid in airways · Cerebral Edema: Swollen brain with flattened gyri and narrowed sulci · Ascites: Accumulation of fluid in the peritoneal cavity · Pleural Effusion: Fluid in the pleural space Complications: · Impaired organ function (e.g., pulmonary edema causing respiratory distress) · Impaired wound healing · Tissue necrosis (if severe) · Stasis ulcers (in chronic venous insufficiency) 6. Write short note on pathology of infarction Infarction is the process of ischemic necrosis resulting from occlusion of the arterial supply or venous drainage to a tissue or organ. Types: · White (Anemic) Infarct: Occurs in solid organs with end-arterial circulation (heart, kidney, spleen). Pale, wedge-shaped area of necrosis. · Red (Hemorrhagic) Infarct: Occurs in loose tissues or organs with dual blood supply (lung, intestine). Hemorrhagic due to reperfusion. Gross Appearance: · Wedge-shaped area of necrosis with the apex at the point of occlusion · Pale (white infarct) or dark red (hemorrhagic infarct) · Surrounding hyperemia Microscopic Appearance: · Coagulative necrosis (in most tissues) · Inflammatory cell infiltration · Granulation tissue at the margins · Fibrosis (scarring) in healed infarcts Factors Influencing Infarction: · Nature of vascular supply (end-arterial vs. collateral) · Rate of occlusion (sudden vs. gradual) · Tissue susceptibility to hypoxia (neurons > myocardium > fibroblasts) · Oxygenation (anemia predisposes to infarction) 7. Define shock Shock is a life-threatening clinical syndrome characterized by systemic hypotension and inadequate tissue perfusion, resulting in cellular hypoxia and organ dysfunction. It represents a failure of the cardiovascular system to maintain adequate blood flow to vital organs. 8. Enumerate possible organ changes in a patient who dies of shock Brain: Cerebral edema, ischemic neuronal damage, herniation if intracranial pressure increases. Heart: Subendocardial hemorrhage, myocardial necrosis, contraction band necrosis (in reperfusion). Lungs: Congestion, edema, hyaline membrane formation (shock lung/ARDS), alveolar hemorrhage. Kidneys: Acute tubular necrosis (ATN) with tubular epithelial cell swelling and necrosis; pale, swollen kidneys. Liver: Centrilobular necrosis, congestion, fatty change. Adrenal Glands: Congestion, hemorrhage (particularly in Waterhouse-Friderichsen syndrome in meningococcal sepsis). Gastrointestinal Tract: Mucosal congestion, hemorrhage, ulceration (stress ulcers). Skin: Pallor, cyanosis, petechiae. 9. Short note on septic shock Septic shock is a clinical syndrome that results from the body's disproportionate inflammatory and procoagulation response to infection, leading to life-threatening organ dysfunction. Pathophysiology: · Endothelial Dysfunction: Inflammatory cytokines (TNF, IL-1) cause endothelial activation and damage, leading to increased vascular permeability (capillary leak) · Vasodilation: Nitric oxide causes systemic vasodilation, leading to hypotension · Cardiac Dysfunction: Myocardial depression due to cytokines and nitric oxide · Coagulation: Activation of coagulation cascade, leading to disseminated intravascular coagulation (DIC) · Hypovolemia: Relative or absolute hypovolemia due to fluid loss and vasodilation · Tissue Hypoperfusion: Organ dysfunction due to inadequate oxygen delivery Clinical Features: Fever or hypothermia, tachycardia, tachypnea, hypotension, altered mental status, oliguria, lactic acidosis. Organ Changes: · Lungs: ARDS · Kidneys: Acute tubular necrosis · Liver: Hepatocellular necrosis · Heart: Myocardial dysfunction · Brain: Encephalopathy 10. Short note on Thrombosis Thrombosis is the formation of a solid mass (thrombus) from the components of blood within the vascular system during life. Pathogenesis (Virchow's Triad): 1. Endothelial Injury – Damage to the endothelial lining exposes subendothelial collagen, triggering platelet adhesion and activation. Causes: atherosclerosis, hypertension, trauma, inflammation. 2. Abnormal Blood Flow (Stasis and Turbulence) – Stasis allows platelets and coagulation factors to accumulate; turbulence causes endothelial injury. Causes: immobility, atrial fibrillation, heart failure, aneurysm. 3. Hypercoagulability – Increased tendency of blood to clot. Causes: genetic (factor V Leiden, prothrombin mutation), acquired (pregnancy, oral contraceptives, malignancy, antiphospholipid syndrome). Types of Thrombi: · White (Platelet) Thrombi: Form in arteries, composed mainly of platelets and fibrin · Red (Coagulation) Thrombi: Form in veins, composed mainly of red cells and fibrin · Mixed Thrombi: Have both white and red components 11. Short note on Fate of thrombus 1. Resolution – Complete dissolution by the fibrinolytic system, restoring normal blood flow. 2. Organization – The thrombus is invaded by fibroblasts and endothelial cells, forming granulation tissue that replaces the thrombus. 3. Recanalization – New vascular channels form within the organized thrombus, partially restoring blood flow. 4. Propagation – The thrombus extends proximally or distally, enlarging the obstruction. 5. Embolization – A fragment of the thrombus breaks off and travels through the bloodstream to lodge in a distant vessel (thromboembolism). 6. Calcification – Dystrophic calcification of the thrombus, forming phleboliths in veins. 12. Pathophysiology of edema Edema results from increased movement of fluid from the intravascular to the interstitial space or decreased movement of water from the interstitium into the capillaries or lymphatic vessels. Mechanisms: Increased Capillary Hydrostatic Pressure: · Venous obstruction (deep vein thrombosis, portal hypertension) · Heart failure (congestive heart failure) · Pregnancy (compression of pelvic veins) Decreased Plasma Oncotic Pressure: · Hypoalbuminemia (nephrotic syndrome, liver cirrhosis, malnutrition) Increased Capillary Permeability: · Inflammation (histamine, bradykinin, cytokines) Lymphatic Obstruction: · Filariasis, surgery, tumor infiltration Sodium and Water Retention: · Renal failure, hormonal imbalances (aldosterone, ADH) 13. Define thrombosis b. Pathogenesis of thrombosis a. Definition: Thrombosis is the formation of a solid mass (thrombus) from blood components within the vascular system during life. b. Pathogenesis (Virchow's Triad): 1. Endothelial Injury: · Causes: atherosclerosis, hypertension, inflammation, trauma, radiation, toxins · Effect: Exposure of subendothelial collagen and tissue factor, triggering platelet adhesion and coagulation cascade 2. Abnormal Blood Flow (Stasis and Turbulence): · Causes: immobility, atrial fibrillation, heart failure, aneurysm, venous obstruction · Effect: Stasis allows platelets and coagulation factors to accumulate; turbulence causes endothelial injury 3. Hypercoagulability: · Genetic: Factor V Leiden, prothrombin G20210A mutation, antithrombin deficiency, protein C/S deficiency · Acquired: pregnancy, oral contraceptives, malignancy, antiphospholipid syndrome, smoking, obesity, surgery, trauma 14. List, with 2 clinical examples each, the factors that predispose to Thrombosis Endothelial Injury: · Atherosclerosis (coronary thrombosis) · Hypertension (cerebral thrombosis) Abnormal Blood Flow: · Atrial fibrillation (mural thrombus in atria) · Immobility (deep vein thrombosis in lower limbs) Hypercoagulability: · Pregnancy (venous thrombosis) · Factor V Leiden mutation (recurrent thrombosis) 15. Distinguish between antemortem venous thrombi and postmortem blood clot Antemortem Venous Thrombus: · Forms during life · Attached to vessel wall · Layered appearance (lines of Zahn) · Firm, friable, dull · Dry appearance · May have red and pale layers · Associated with vessel wall inflammation Postmortem Blood Clot: · Forms after death · Not attached to vessel wall (easily removed) · Homogeneous, gelatinous · Soft, elastic, shiny · Wet appearance · Uniform red (red current jelly) or yellow (chicken fat clot) · No vessel wall reaction
Genetic Disorders
Standard Answer:
1. Write on Down's syndrome Down syndrome (Trisomy 21) is the most common chromosomal abnormality, occurring in approximately 1 in 700 live births. Karyotype: 47,XX,+21 (female) or 47,XY,+21 (male) – Trisomy of chromosome 21. Mechanism: Nondisjunction during meiosis (95% of cases), Robertsonian translocation (4%), or mosaicism (1%). The risk increases with maternal age. Phenotypic Characteristics: · Craniofacial: Flat facial profile, small nose, epicanthal folds, protruding tongue, small ears, short neck with excess skin · Limbs: Short stature, short broad hands with single palmar crease, clinodactyly (fifth finger) · Eyes: Upslanting palpebral fissures, Brushfield spots (white spots on iris) · Neurological: Intellectual disability (mild to moderate), hypotonia, delayed development · Other: Congenital heart defects (atrioventricular septal defect, ventricular septal defect), gastrointestinal abnormalities (duodenal atresia, Hirschsprung disease), hearing loss, thyroid disorders Complications: Increased risk of leukemia, Alzheimer's disease, infections, early mortality. 2. Write on Turner's syndrome Turner syndrome is a chromosomal disorder affecting females, caused by complete or partial absence of one X chromosome. Karyotype: 45,X (monosomy X) in about 50% of cases; other variants include 45,X/46,XX mosaicism, 46,X,i(Xq) (isochromosome X), and 46,X,del(Xp) (deletion of short arm of X). Mechanism: Nondisjunction during gametogenesis, resulting in a gamete lacking a sex chromosome. Phenotypic Characteristics: · Craniofacial: Webbed neck (pterygium colli), low posterior hairline, prominent ears, micrognathia · Limbs: Short stature, cubitus valgus (increased carrying angle of elbow), shield chest with widely spaced nipples · Other: Primary amenorrhea, streak ovaries (ovarian dysgenesis), infertility, lymphedema of hands and feet (in neonates) · Cardiovascular: Coarctation of aorta, bicuspid aortic valve · Renal: Horseshoe kidney, duplex collecting system Complications: Hypertension, osteoporosis, hypothyroidism, diabetes mellitus, autoimmune diseases. 3. List the phenotypic characteristics (Turner syndrome) 1. Short stature 2. Webbed neck (pterygium colli) 3. Low posterior hairline 4. Shield chest with widely spaced nipples 5. Cubitus valgus 6. Lymphedema of hands and feet (in neonates) 7. Primary amenorrhea 8. Streak ovaries (ovarian dysgenesis) 9. Infertility 10. Coarctation of aorta 11. Horseshoe kidney 12. Intellectual disability (mild, less common) 4. List the phenotypic characteristics of Down syndrome 1. Flat facial profile 2. Upslanting palpebral fissures 3. Epicanthal folds 4. Protruding tongue 5. Small ears 6. Short neck with excess skin 7. Short stature 8. Short broad hands with single palmar crease 9. Clinodactyly (fifth finger) 10. Brushfield spots on iris 11. Intellectual disability (mild to moderate) 12. Congenital heart defects (atrioventricular septal defect, VSD) 13. Hypotonia 14. Duodenal atresia, Hirschsprung disease 5. What is (are) the associated karyotype(s) for Down syndrome? 1. Standard Trisomy 21: 47,XX,+21 or 47,XY,+21 (95% of cases) 2. Robertsonian Translocation: Translocation of chromosome 21 onto another acrocentric chromosome (usually 14 or 22), resulting in 46 chromosomes 3. Mosaicism: 46,XX/47,XX,+21 or 46,XY/47,XY,+21 (2-4% of cases) 6. Define the following: Aneuploidy, Nondisjunction, Dominant trait, Karyotype, Mosaicism Aneuploidy: Deviation from the normal diploid number of chromosomes, where an individual has an extra chromosome (trisomy) or missing chromosome (monosomy). Nondisjunction: Failure of homologous chromosomes or sister chromatids to separate properly during meiosis or mitosis, resulting in gametes or cells with abnormal chromosome numbers. Dominant Trait: A trait that is expressed in the heterozygous state, where the presence of one copy of the mutant allele is sufficient to produce the phenotype. Karyotype: The chromosomal complement of an individual, typically presented as a organized arrangement of metaphase chromosomes, showing number, size, and shape of chromosomes. Mosaicism: The presence of two or more genetically different cell populations in an individual derived from a single zygote. 7. Define the following with respect to congenital malformations, giving one example each Malformation: A primary structural defect resulting from an intrinsically abnormal developmental process. Example: Cleft lip (failure of fusion of maxillary processes). Deformation: An alteration in shape or structure of a normally formed part, caused by mechanical forces. Example: Clubfoot (due to intrauterine constraint). Disruption: A defect resulting from breakdown of or interference with an originally normal developmental process. Example: Amniotic band syndrome (constriction bands causing limb defects). Sequence: A cascade of abnormalities resulting from a single initial defect. Example: Potter sequence (oligohydramnios → fetal compression → pulmonary hypoplasia, limb deformities, facial abnormalities). Syndrome: A constellation of anomalies that occur together and have a common cause. Example: Down syndrome (multiple anomalies due to trisomy 21). 8. Write short note on the classification of genetic disorders Genetic disorders are classified into the following categories: Chromosomal Disorders: · Numerical abnormalities: Aneuploidy (trisomy 21, monosomy X) · Structural abnormalities: Deletions, translocations, inversions, duplications · Examples: Down syndrome, Turner syndrome, Klinefelter syndrome Single-Gene (Mendelian) Disorders: · Autosomal dominant: Huntington's disease, achondroplasia · Autosomal recessive: Cystic fibrosis, sickle cell disease · X-linked dominant: Fragile X syndrome · X-linked recessive: Hemophilia A, Duchenne muscular dystrophy Multifactorial Disorders: · Caused by interaction of multiple genes and environmental factors · Examples: Diabetes mellitus, hypertension, cleft lip, neural tube defects Mitochondrial Disorders: · Caused by mutations in mitochondrial DNA · Examples: Leber hereditary optic neuropathy, mitochondrial encephalomyopathy
Hypersensitivity Reactions
Standard Answer:
1. What is hypersensitivity reaction and write short note on any of the types Hypersensitivity Reaction: An exaggerated or inappropriate immune response to an antigen that causes tissue damage. Hypersensitivity reactions are classified into four types based on the immunologic mechanism involved. Type I (Immediate) Hypersensitivity: · Mechanism: IgE-mediated reaction. Antigen cross-links IgE on mast cells and basophils, causing degranulation and release of histamine, leukotrienes, prostaglandins, and other mediators. · Pathogenesis: Sensitization phase: First exposure to allergen leads to IgE production and binding to FcεRI on mast cells. Elicitation phase: Subsequent exposure causes mast cell degranulation. · Clinical Examples: Anaphylaxis, allergic rhinitis (hay fever), bronchial asthma, atopic dermatitis, urticaria, food allergies. · Local Effects: Cutaneous (hives, angioedema), respiratory (bronchospasm, rhinitis), gastrointestinal (vomiting, diarrhea) · Systemic Effects: Anaphylactic shock (hypotension, laryngeal edema, respiratory distress) 2. Briefly discuss types I hypersensitivity reactions with related examples Type I hypersensitivity is an immediate, IgE-mediated allergic reaction. Pathogenesis: 1. Sensitization Phase: First exposure to an allergen (e.g., pollen, food, insect venom) is processed by antigen-presenting cells and presented to T helper 2 (Th2) cells. Th2 cells produce IL-4 and IL-13, which stimulate B cells to produce IgE antibodies specific to the allergen. These IgE antibodies bind to high-affinity FcεRI receptors on mast cells and basophils. 2. Elicitation Phase: Subsequent exposure to the same allergen cross-links the IgE molecules on mast cells, triggering degranulation and release of preformed mediators (histamine, tryptase) and newly synthesized mediators (leukotrienes, prostaglandins, platelet-activating factor, cytokines). Mediators and Effects: · Histamine: Vasodilation, increased permeability, bronchoconstriction · Leukotrienes: Bronchospasm, mucus secretion, increased permeability · Prostaglandins: Vasodilation, pain · Cytokines: Recruitment of inflammatory cells (eosinophils, neutrophils, Th2 cells) Clinical Examples: · Systemic: Anaphylaxis (insect stings, drugs, foods) – life-threatening with hypotension and airway obstruction · Respiratory: Allergic rhinitis (hay fever), bronchial asthma · Cutaneous: Urticaria (hives), angioedema, atopic dermatitis · Gastrointestinal: Food allergies (vomiting, diarrhea) 3. Define hypersensitivity reactions Hypersensitivity reactions are exaggerated or inappropriate immune responses to antigens that cause tissue damage. They occur when the immune system reacts to harmless antigens (allergens) or mounts an excessive response to pathogenic antigens. The reactions are classified into four main types based on the immunologic mechanisms involved: Type I (IgE-mediated, immediate), Type II (antibody-mediated cytotoxic), Type III (immune complex-mediated), and Type IV (cell-mediated, delayed). 4. Briefly discuss types of hypersensitivity reactions with related examples Type I (Immediate) Hypersensitivity: · Mechanism: IgE-mediated mast cell degranulation · Examples: Anaphylaxis, asthma, hay fever, food allergies Type II (Antibody-Mediated Cytotoxic) Hypersensitivity: · Mechanism: Antibodies (IgG, IgM) bind to antigens on cell surfaces, leading to cell destruction through complement activation, antibody-dependent cell-mediated cytotoxicity (ADCC), or opsonization · Examples: Autoimmune hemolytic anemia, immune thrombocytopenic purpura, transfusion reactions, erythroblastosis fetalis (hemolytic disease of the newborn), Goodpasture syndrome Type III (Immune Complex-Mediated) Hypersensitivity: · Mechanism: Circulating immune complexes (antigen-antibody) deposit in tissues, activating complement and recruiting neutrophils, causing tissue damage · Examples: Serum sickness, systemic lupus erythematosus, post-streptococcal glomerulonephritis, rheumatoid arthritis, polyarteritis nodosa Type IV (Cell-Mediated, Delayed) Hypersensitivity: · Mechanism: T cell-mediated, no antibody involvement. Sensitized T lymphocytes (Th1, Th17, CD8+) release cytokines that activate macrophages and cause tissue damage · Examples: Contact dermatitis (poison ivy, nickel), tuberculin skin test, granulomatous diseases (tuberculosis, sarcoidosis, leprosy) 5. Briefly discuss aetiopathogenesis, risk factors and morphologic changes in atherosclerosis Aetiopathogenesis (Response-to-Injury Hypothesis): Atherosclerosis is a chronic inflammatory disease of the arteries. The pathogenesis involves: 1. Endothelial Injury: Chronic injury to the endothelium by risk factors (hypertension, smoking, hyperlipidemia) causes endothelial dysfunction 2. Lipid Accumulation: LDL cholesterol enters the intima and becomes oxidized, taken up by macrophages to form foam cells 3. Inflammatory Response: Macrophages and T cells infiltrate the lesion, releasing pro-inflammatory cytokines 4. Smooth Muscle Proliferation: Cytokines (PDGF, FGF) stimulate smooth muscle cell migration and proliferation, contributing to fibrous cap formation 5. Plaque Formation: Accumulation of lipids, foam cells, smooth muscle cells, and extracellular matrix forms an atherosclerotic plaque Risk Factors: · Modifiable: Hyperlipidemia (↑LDL, ↓HDL), smoking, hypertension, diabetes mellitus, obesity, sedentary lifestyle · Non-modifiable: Age, male gender, family history, genetic factors Morphologic Changes: · Fatty Streak: Earliest lesion, yellow linear streaks in intima, composed of lipid-laden foam cells · Fibrous Plaque: Raised white/yellow lesion with a fibrous cap covering a lipid core, smooth muscle cells, and inflammatory cells · Complicated Plaque: Plaque with hemorrhage, thrombosis, ulceration, calcification, or aneurysm formation · Gross: Intimal thickening, yellow-white plaques, calcification, ulceration · Microscopic: Foam cells, cholesterol clefts, extracellular lipid, fibrosis, calcification, neovascularization 6. Discuss the mechanisms responsible for the prevention of autoimmunity 1. Central Tolerance (Thymic and Bone Marrow Selection): · Negative Selection: Self-reactive T cells are eliminated in the thymus (T cells) and bone marrow (B cells) through apoptosis · Positive Selection: T cells that recognize self-MHC molecules survive 2. Peripheral Tolerance: · Anergy: Self-reactive lymphocytes become functionally unresponsive without co-stimulation · Regulatory T Cells (Tregs): Suppress self-reactive T cells through IL-10 and TGF-β · Immune Privilege: Certain sites (eye, brain, testes) have reduced immune surveillance · Clonal Deletion: Self-reactive cells undergo apoptosis 3. Antigen Sequestration: Some self-antigens are hidden from the immune system (e.g., inside cells, in immune-privileged sites) 4. Receptor Editing: B cells may revise their receptors to avoid self-reactivity 5. Apoptosis of Self-Reactive Cells: Fas-FasL pathway eliminates activated self-reactive cells 7. Discuss pathogenesis of anaphylaxis Anaphylaxis is a severe, life-threatening Type I hypersensitivity reaction. Pathogenesis: Sensitization Phase: 1. First exposure to an allergen (e.g., penicillin, insect venom, peanuts, latex) is processed by antigen-presenting cells and presented to Th2 cells 2. Th2 cells produce IL-4 and IL-13, stimulating B cells to produce IgE antibodies specific to the allergen 3. IgE binds to high-affinity FcεRI receptors on mast cells and basophils Elicitation Phase: 1. Subsequent exposure to the same allergen cross-links the IgE molecules on mast cells and basophils 2. Cross-linking triggers signaling cascades leading to mast cell degranulation 3. Release of preformed mediators (histamine, tryptase, proteoglycans) and newly synthesized mediators (leukotrienes, prostaglandins, platelet-activating factor, cytokines) Systemic Effects: · Cardiovascular: Vasodilation → hypotension; increased vascular permeability → edema; myocardial depression · Respiratory: Bronchoconstriction, laryngeal edema, mucus hypersecretion → airway obstruction, respiratory distress · Gastrointestinal: Smooth muscle contraction → vomiting, diarrhea · Cutaneous: Urticaria, angioedema, flushing Contributing Factors: More rapid absorption of allergen (intravenous > intramuscular > subcutaneous), pre-existing sensitization, concurrent medications (β-blockers, ACE inhibitors). 8. Describe the mechanism of metastasis Metastasis is the spread of malignant tumor cells from the primary site to distant organs. The mechanism involves a series of sequential steps: 1. Local Invasion: Tumor cells invade the surrounding extracellular matrix (ECM) and basement membrane. This involves degradation of ECM by proteolytic enzymes (matrix metalloproteinases, cathepsins). 2. Intravasation: Tumor cells enter blood or lymphatic vessels by crossing the endothelial barrier. This involves adhesion to endothelial cells and migration through gaps. 3. Survival in Circulation: Tumor cells must survive mechanical shear stress and immune surveillance in the bloodstream. They may form aggregates with platelets for protection. 4. Arrest in Capillary Bed: Tumor cell emboli become trapped in the microvasculature of distant organs (mechanical trapping or adhesion to endothelium). 5. Extravasation: Tumor cells exit the blood vessels into the target organ by crossing the endothelial barrier, again using proteolytic enzymes. 6. Colonization: Tumor cells must survive and proliferate in the new microenvironment, forming a metastatic tumor. This requires angiogenesis, evasion of immune responses, and adaptation to the new tissue environment. Routes of Spread: · Lymphatic Spread: Via lymphatic vessels to regional lymph nodes · Hematogenous Spread: Via blood vessels to distant organs · Transcoelomic Spread: Via body cavities (peritoneal, pleural, pericardial) Organ Tropism: Certain tumors metastasize to specific organs (e.g., breast cancer to bone, lung cancer to brain, colorectal cancer to liver). 9. Write an essay on chemical carcinogenesis Chemical carcinogenesis is the process by which chemical agents cause cancer. It involves a multistep process of genetic and epigenetic changes that lead to malignant transformation. Types of Chemical Carcinogens: Direct-Acting Carcinogens: · Do not require metabolic activation · React directly with DNA · Examples: Alkylating agents (chemotherapy drugs), nitrogen mustard Indirect-Acting Carcinogens (Procarcinogens): · Require metabolic activation by cytochrome P450 enzymes to become reactive electrophiles (ultimate carcinogens) · Examples: Polycyclic aromatic hydrocarbons (tobacco smoke, soot), aromatic amines (β-naphthylamine), aflatoxin B1, nitrosamines Stages of Chemical Carcinogenesis: Initiation: · Carcinogen causes irreversible DNA damage (mutations) in a single cell · Requires metabolic activation of the carcinogen · The initiated cell has a growth advantage but is not yet malignant · Initiation is rapid and irreversible Promotion: · Promoters (non-carcinogenic agents) stimulate proliferation of initiated cells · Promoters do not cause mutations but enhance tumor growth · Examples: Phorbol esters, hormones, chronic inflammation · Promotion is reversible and requires prolonged exposure Progression: · Accumulation of additional genetic changes (mutations, chromosomal abnormalities) · Tumor becomes malignant with invasion and metastasis · Involves activation of oncogenes, inactivation of tumor suppressor genes, and genomic instability Important Chemical Carcinogens: · Aflatoxin B1 (from Aspergillus flavus): Liver cancer (hepatocellular carcinoma) · Vinyl chloride: Angiosarcoma of the liver · Tobacco smoke: Lung, larynx, bladder, oral cavity cancers · β-Naphthylamine: Bladder cancer · Asbestos: Mesothelioma, lung cancer Mechanisms of Action: · DNA adduct formation · Oxidative DNA damage · Epigenetic changes (DNA methylation, histone modifications) · Activation of oncogenes and inactivation of tumor suppressor genes 10. Short note on Paraneoplastic syndrome Paraneoplastic syndromes are clinical disorders that occur in cancer patients but are not directly caused by the primary tumor or its metastases. They are caused by tumor-derived substances (hormones, cytokines) or immune cross-reactions between tumor antigens and normal tissues. Mechanisms: · Hormone Production: Tumors secrete hormones or hormone-like substances (ectopic hormone production) · Immune-Mediated: Antibodies directed against tumor antigens cross-react with normal tissues · Cytokine-Mediated: Tumor-derived cytokines cause systemic effects Common Paraneoplastic Syndromes: Endocrine: · Cushing syndrome: Ectopic ACTH (small cell lung carcinoma) · SIADH: Ectopic ADH (small cell lung carcinoma) · Hypercalcemia: PTHrP (squamous cell lung carcinoma, breast cancer) Neurological: · Lambert-Eaton myasthenic syndrome (small cell lung carcinoma) · Paraneoplastic cerebellar degeneration (gynecological cancers) · Peripheral neuropathy Hematological: · Polycythemia (renal cell carcinoma, hepatocellular carcinoma) · Thromboembolic events (Trousseau syndrome) Cutaneous: · Acanthosis nigricans (gastric adenocarcinoma) · Dermatomyositis 11. Classify Hypersensitivity reactions, giving salient pathogenetic mechanism and 2 examples in each class Type I (Immediate) Hypersensitivity: · Mechanism: IgE-mediated, mast cell degranulation · Examples: Anaphylaxis, allergic rhinitis Type II (Antibody-Mediated Cytotoxic) Hypersensitivity: · Mechanism: IgG/IgM antibodies bind to cell surface antigens, causing cell destruction via complement, ADCC, or opsonization · Examples: Autoimmune hemolytic anemia, transfusion reactions Type III (Immune Complex-Mediated) Hypersensitivity: · Mechanism: Circulating immune complexes deposit in tissues, activating complement and neutrophils · Examples: Serum sickness, systemic lupus erythematosus Type IV (Cell-Mediated, Delayed) Hypersensitivity: · Mechanism: T cell-mediated, no antibodies involved · Examples: Contact dermatitis, tuberculin skin test
Neoplasia
Standard Answer:
1. Tabulate/Enumerate the differences between benign and malignant tumours Benign Tumours: · Well-differentiated (resemble tissue of origin) · Slow growth · Encapsulated or well-circumscribed · No invasion (expansile growth) · No metastasis · No anaplasia (or minimal) · Rare recurrence after excision · Usually not life-threatening (unless in critical location) · Mitoses: few, normal · Examples: lipoma, adenoma Malignant Tumours: · Poorly differentiated (anaplasia) · Rapid growth · Not encapsulated (infiltrative) · Invasion of adjacent tissues · Metastasis · Anaplasia (loss of differentiation) · Common recurrence after excision · Life-threatening · Mitoses: many, atypical · Examples: carcinoma, sarcoma 2. Compare and contrast benign and malignant neoplasia Similarities: · Both are abnormal growths of tissue · Both arise from genetic alterations (mutations) · Both can cause symptoms (mass effect, pressure on adjacent structures) Differences: Feature Benign Malignant Differentiation Well-differentiate Poorly differentiated (anaplasia) d Growth rate Slow Rapid Encapsulation Usually encapsulated Not encapsulated Invasion No invasion Invades adjacent tissues Metastasis No metastasis Metastasis Recurrence Rare Common Prognosis Excellent Poor (if untreated) 3. Write short notes on Nomenclature of Tumour Tumors are named based on the tissue of origin and whether they are benign or malignant. Benign Tumors: · Named by adding the suffix "-oma" to the cell type of origin · Epithelial: Adenoma (glandular epithelium), Papilloma (surface epithelium) · Mesenchymal: Lipoma (fat), Fibroma (fibrous tissue), Leiomyoma (smooth muscle), Rhabdomyoma (skeletal muscle), Osteoma (bone), Chondroma (cartilage) · Vascular: Hemangioma (blood vessels), Lymphangioma (lymphatic vessels) · Nervous: Neuroma, Ganglioneuroma Malignant Tumors: · Epithelial (Carcinomas): Named by adding "carcinoma" to the cell type · Squamous cell carcinoma · Adenocarcinoma (glandular epithelium) · Transitional cell carcinoma · Basal cell carcinoma · Mesenchymal (Sarcomas): Named by adding "sarcoma" · Liposarcoma (fat) · Fibrosarcoma (fibrous tissue) · Leiomyosarcoma (smooth muscle) · Osteosarcoma (bone) · Chondrosarcoma (cartilage) · Hematopoietic: Leukemias, Lymphomas · Germ Cell: Teratomas, Seminomas, Dysgerminomas Exceptions: Some tumors have traditional names that do not follow the rules (e.g., melanoma, lymphoma, mesothelioma). 4. Spread of malignant tumours Malignant tumors spread through three main routes: 1. Lymphatic Spread: · Tumor cells enter lymphatic vessels and travel to regional lymph nodes · Common in carcinomas · Example: Breast cancer spreads to axillary lymph nodes 2. Hematogenous Spread: · Tumor cells enter blood vessels (intravasation) and travel to distant organs · Common in sarcomas and some carcinomas · Example: Lung cancer spreads to brain, bone, liver 3. Transcoelomic (Direct) Spread: · Tumor cells spread across body cavities (peritoneal, pleural, pericardial) · Example: Ovarian cancer spreads throughout the peritoneal cavity Mechanism of Metastasis: Local invasion → Intravasation → Survival in circulation → Arrest in capillary bed → Extravasation → Colonization 5. List the major Local and Systemic effects of malignant Tumours in general Local Effects: 1. Mass Effect: Compression of adjacent structures (e.g., nerve compression causing pain) 2. Obstruction: Blockage of hollow organs (e.g., intestinal obstruction, airway obstruction) 3. Ulceration: Surface tumors may ulcerate, causing bleeding or infection 4. Invasion: Destruction of adjacent tissues (e.g., bone destruction, nerve invasion) 5. Infection: Necrotic tumors may become infected Systemic Effects: 1. Cachexia: Weight loss, muscle wasting, anorexia (due to cytokines, TNF) 2. Fever: Due to tumor necrosis or infection 3. Paraneoplastic Syndromes: Hormonal, neurological, hematological, cutaneous effects 4. Anemia: Due to chronic blood loss, bone marrow infiltration, or nutritional deficiency 5. Immunosuppression: Impaired immune function 6. Hypercalcemia: Due to bone metastasis or PTHrP production 7. Pain: Due to nerve compression or bone invasion 8. Organ Failure: Due to replacement of normal tissue by tumor 6. What is the basis for nomenclature of neoplasia The nomenclature of neoplasia is based on: 1. Tissue of Origin: The cell type from which the tumor arises determines the prefix (e.g., adeno- for glandular, lipo- for fat, chondro- for cartilage). 2. Behavior (Benign vs. Malignant): The suffix determines whether the tumor is benign (-oma) or malignant (carcinoma for epithelial, sarcoma for mesenchymal). 3. Histological Pattern: The architectural arrangement of cells (e.g., papillary, follicular, solid, mucinous). 4. Cytological Features: The appearance of the cells (e.g., small cell, giant cell, clear cell, signet-ring cell). 5. Grade: The degree of differentiation (well-differentiated, moderately differentiated, poorly differentiated, undifferentiated). 6. Special Characteristics: Pigment (melanoma), vascularity (hemangioma), presence of teratoid elements (teratoma). 7. List the common site of occurrence of Burkitt's lymphoma Burkitt's lymphoma is a highly aggressive B-cell non-Hodgkin lymphoma. The common sites of occurrence are: 1. Jaw (Mandible and Maxilla): Most common in the endemic (African) form 2. Abdominal Organs: Mesentery, ovaries, kidneys, retroperitoneum (sporadic form) 3. Central Nervous System: Meninges, cranial nerves 4. Bone Marrow: May be involved 5. Peripheral Lymph Nodes: Less common 6. Burkitt's lymphoma commonly involves extranodal sites 8. List the microscopic and macroscopic features of Burkitt's lymphoma Macroscopic Features: · Extranodal Involvement: Jaw, abdomen, ovaries, kidneys, CNS · Tumor Masses: Rapidly growing, soft, fleshy, pale gray-white tumors · Cut Surface: Homogeneous, fish-flesh appearance · Hemorrhage and Necrosis: May be present Microscopic Features: · "Starry Sky" Pattern: Uniform population of medium-sized B cells interspersed with tingible-body macrophages (macrophages containing apoptotic tumor cell debris) · Cell Morphology: Medium-sized cells with round nuclei, coarse chromatin, multiple nucleoli, and scant basophilic cytoplasm · High Proliferation Index: Ki-67 > 95% · Mitotic Figures: Numerous · Apoptotic Bodies: Many · Immunophenotype: CD20+, CD10+, BCL6+, BCL2-, surface IgM+, MYC translocation t(8;14) 9. Diagnosis of cancer Clinical Diagnosis: · History and physical examination · Symptom assessment (mass, pain, bleeding, weight loss) Imaging Studies: · X-ray, ultrasound, CT scan, MRI, PET scan, mammography · For tumor localization, staging, and monitoring Laboratory Diagnosis: · Tumor Markers: PSA (prostate cancer), CA-125 (ovarian cancer), AFP (hepatocellular carcinoma), CEA (colorectal cancer), CA 19-9 (pancreatic cancer) · Hematological Tests: Blood counts, LDH, alkaline phosphatase (bone metastasis) Histopathological Diagnosis (Gold Standard): · Biopsy: Incisional, excisional, core needle, fine-needle aspiration (FNAC) · Histological Examination: H&E staining, assessment of architecture, cellular atypia, mitotic figures, invasion · Immunohistochemistry: Specific markers for diagnosis, prognosis, and targeted therapy (e.g., ER/PR, HER2/neu in breast cancer; CD20 in lymphoma) · Molecular Studies: Genetic testing (e.g., EGFR mutations, KRAS, BRAF; FISH for HER2, MYC, BCR-ABL) · Cytogenetics: Karyotyping for chromosomal abnormalities (e.g., Philadelphia chromosome in CML) 10. List the routes of cancer dissemination 1. Lymphatic Spread: · Tumor cells travel through lymphatic vessels to regional lymph nodes · Common in carcinomas · Example: Breast cancer to axillary lymph nodes 2. Hematogenous Spread: · Tumor cells enter blood vessels and travel through the bloodstream · Common in sarcomas and some carcinomas · Example: Lung cancer to brain, bone, liver 3. Transcoelomic (Surface) Spread: · Spread across body cavities (peritoneal, pleural, pericardial) · Example: Ovarian cancer to peritoneal surfaces 4. Local (Direct) Spread: · Invasion into adjacent tissues · Example: Cervical cancer to bladder and rectum 5. Implantation: · Tumor cells shed and implant on surfaces (e.g., surgical wound implantation) 6. Perineural Spread: · Spread along nerves (e.g., head and neck cancers) 11. What is Reed-Sternberg giant cell / short note on Reed-Sternberg giant cell The Reed-Sternberg (RS) cell is the characteristic diagnostic cell of Hodgkin lymphoma (Hodgkin's disease). Morphology: · Large, binucleated or multinucleated cell · Prominent eosinophilic nucleoli (owl-eye appearance) · Abundant cytoplasm · Originates from germinal center B cells Immunophenotype: · CD30+ (strong), CD15+ (variable), CD45-, CD20- (usually) Types: · Classic RS Cell: Binucleated with prominent nucleoli ("owl eye" appearance) · Lacunar Cell: RS cell variant in nodular sclerosis subtype (cytoplasm retracts in formalin-fixed tissue) · Mononuclear Hodgkin Cell: Uninucleated variant · Mummified Cell: RS cell with pyknotic nucleus Diagnostic Significance: The presence of RS cells is essential for the diagnosis of Hodgkin lymphoma. However, they must be identified in the appropriate cellular background (inflammatory cells) for diagnosis. 12. Contrasting features of Hodgkin's and non-Hodgkin's lymphoma Hodgkin's Lymphoma: · Presence of Reed-Sternberg cells (diagnostic) · Unifocal (usually) · Orderly spread (contiguous) · Nodal disease (cervical, mediastinal) · B symptoms common (fever, night sweats, weight loss) · Peak incidence: young adults (15-35 years) and elderly (>55 years) · Types: Nodular sclerosis, mixed cellularity, lymphocyte-rich, lymphocyte-depleted, nodular lymphocyte-predominant · Prognosis: Generally good (curable) Non-Hodgkin's Lymphoma: · No Reed-Sternberg cells · Multifocal (usually) · Non-contiguous spread · Extranodal disease common · B symptoms less common (depending on type) · Incidence increases with age · Types: Many (B-cell, T-cell, NK-cell), categorized by grade (low, intermediate, high) · Prognosis: Variable (depends on type and grade) 13. Short note on Grading and staging of tumours Grading: Assesses the degree of differentiation of tumor cells, indicating the aggressiveness of the tumor. Grading Systems: · Grade I (Well-Differentiated): Cells resemble normal tissue, low mitotic activity, good prognosis · Grade II (Moderately Differentiated): Intermediate features · Grade III (Poorly Differentiated): Cells show significant atypia, high mitotic activity, poor prognosis · Grade IV (Undifferentiated): Cells are anaplastic, no resemblance to tissue of origin, very poor prognosis Examples of Grading Systems: · Gleason score for prostate cancer (2-10) · Nottingham (Bloom-Richardson) grade for breast cancer · Fuhrman grade for renal cell carcinoma Staging: Assesses the extent of spread of the tumor, indicating the clinical stage of the disease. TNM Staging System (Most Common): · T (Tumor): Size and extent of primary tumor (T0-T4) · N (Nodes): Regional lymph node involvement (N0-N3) · M (Metastasis): Presence of distant metastasis (M0-M1) Clinical Staging (Stage Grouping): · Stage 0: Carcinoma in situ · Stage I: Localized tumor, no lymph node involvement · Stage II: Tumor with regional lymph node involvement · Stage III: Extensive regional disease · Stage IV: Distant metastasis Importance: Staging determines prognosis, guides treatment decisions, and allows comparison of treatment outcomes. 14. What is differentiation with respect to neoplasms Differentiation refers to the extent to which neoplastic cells resemble their normal counterparts in terms of morphology and function. Well-Differentiated Tumors: · Cells closely resemble normal tissue of origin · Retain specific functions (e.g., hormone production) · Low mitotic activity · Usually benign or low-grade malignant Poorly Differentiated Tumors: · Cells show minimal resemblance to normal tissue · Loss of specialized functions · High mitotic activity · Usually high-grade malignant Anaplasia (Loss of Differentiation): · Cells show no resemblance to tissue of origin · Pleomorphism (variation in size and shape) · Hyperchromatic nuclei · High nuclear-to-cytoplasmic ratio · Prominent nucleoli · Atypical mitotic figures Importance: Degree of differentiation correlates with aggressiveness and prognosis. Well-differentiated tumors generally have a better prognosis than poorly differentiated tumors. 15. List the Cytological characteristics of malignancy 1. Pleomorphism: Variation in cell size and shape 2. Hyperchromasia: Increased nuclear staining (dark nuclei) 3. High Nuclear-to-Cytoplasmic Ratio: Large nucleus relative to cytoplasm 4. Prominent Nucleoli: Large, multiple nucleoli 5. Atypical Mitotic Figures: Abnormal mitoses (e.g., tripolar, multipolar) 6. Nuclear Irregularities: Irregular nuclear shape, notching, lobulation 7. Chromatin Clumping: Coarse, irregular chromatin pattern 8. Loss of Differentiation: Anaplasia 9. Tumor Giant Cells: Very large cells with multiple nuclei 10. Cytoplasmic Abnormalities: Vacuolation, granularity, loss of specialized features 16. List 5 tumour suppressor genes and the cancer associated with them in each case 1. TP53 (p53): Li-Fraumeni syndrome, most cancers (breast, colon, lung, ovarian) 2. RB1 (Retinoblastoma): Retinoblastoma, osteosarcoma, breast cancer, lung cancer 3. APC: Familial adenomatous polyposis, colorectal cancer 4. BRCA1: Breast cancer, ovarian cancer 5. BRCA2: Breast cancer, ovarian cancer, male breast cancer, pancreatic cancer 17. Classify carcinogens with example Chemical Carcinogens: · Direct-Acting: Alkylating agents (nitrogen mustard, cyclophosphamide) · Indirect-Acting (Procarcinogens): Polycyclic aromatic hydrocarbons (tobacco smoke, soot), aromatic amines (β-naphthylamine), aflatoxin B1, nitrosamines Physical Carcinogens: · Ionizing Radiation: X-rays, gamma rays (leukemia, thyroid cancer) · Ultraviolet (UV) Radiation: Sunlight (skin cancers: basal cell carcinoma, squamous cell carcinoma, melanoma) · Non-Ionizing Radiation: (Less clearly associated) · Asbestos: Mesothelioma, lung cancer Biological Carcinogens: · Viruses: HPV (cervical cancer), EBV (Burkitt's lymphoma, nasopharyngeal carcinoma), HBV/HCV (hepatocellular carcinoma), HIV (Kaposi sarcoma, lymphomas), HTLV-1 (T-cell leukemia) · Bacteria: H. pylori (gastric carcinoma, MALT lymphoma) · Parasites: Schistosoma haematobium (bladder cancer), Clonorchis sinensis (cholangiocarcinoma) Hormonal Carcinogens: · Estrogen (endometrial cancer, breast cancer) Occupational Carcinogens: · Vinyl chloride (angiosarcoma of liver), benzene (leukemia), nickel, chromium (lung cancer), arsenic (skin cancer) 18. Classify the biologic agents involved in carcinogenesis and give examples of the corresponding cancers Oncogenic Viruses: Virus Associate Cancers d HPV (16, 18) Cervical cancer, anal cancer, oropharyn cancer geal EBV Burkitt's lymphoma nasophar carcinoma Hodgkin lymphoma , yngeal , HBV/HCV Hepatocel carcinoma lular HIV Kaposi sarcoma, non-Hodg lymphoma kin HTLV-1 Adult T-cell leukemia/l ymphoma HHV-8 Kaposi sarcoma Oncogenic Bacteria: · H. pylori: Gastric adenocarcinoma, gastric MALT lymphoma · Salmonella typhi: Gallbladder cancer (chronic carriers) Oncogenic Parasites: · Schistosoma haematobium: Bladder cancer · Clonorchis sinensis: Cholangiocarcinoma (bile duct cancer) · Opisthorchis viverrini: Cholangiocarcinoma
CVS Pathology
Standard Answer:
1. What are the organ changes in heart failure Heart (Cardiac Changes): · Left-Sided Failure: Left ventricular hypertrophy (concentric or eccentric), dilatation, myocardial fibrosis · Right-Sided Failure: Right ventricular hypertrophy, dilatation · Morphology: Enlarged, heavy heart; dilated chambers; myocardial thinning or thickening Lungs (Pulmonary Changes): · Left-Sided Failure: Pulmonary congestion, pulmonary edema (heavy, wet lungs), hemosiderin-laden macrophages ("heart failure cells"), pleural effusion · Morphology: Heavy, boggy, red-brown lungs; frothy fluid in airways Liver (Hepatic Changes): · Right-Sided Failure: Congestive hepatomegaly ("nutmeg liver" – alternating pale and dark areas), centrilobular necrosis, fibrosis (cardiac cirrhosis) · Morphology: Enlarged, firm liver; cut surface shows red-brown (congested) and pale (fatty) areas Kidneys (Renal Changes): · Pre-renal Azotemia: Decreased renal perfusion · Cardiorenal Syndrome: Congestion and hypoperfusion · Morphology: Pale, swollen kidneys; acute tubular necrosis (in severe failure) Spleen (Splenic Changes): · Right-Sided Failure: Congestive splenomegaly · Morphology: Enlarged, firm, dark red spleen Peripheral Tissues: · Edema: Dependent edema (pedal edema, sacral edema), ascites, pleural effusion · Skin: Cyanosis, cold extremities 2. Briefly discuss pathophysiology of heart failure. b. List common causes of heart failure a. Pathophysiology of Heart Failure: Heart failure is characterized by the inability of the heart to maintain adequate cardiac output to meet the body's metabolic demands. Mechanisms: 1. Systolic Dysfunction (Heart Failure with Reduced Ejection Fraction): · Impaired myocardial contractility → reduced stroke volume and cardiac output · Causes: Ischemic heart disease, dilated cardiomyopathy, myocarditis 2. Diastolic Dysfunction (Heart Failure with Preserved Ejection Fraction): · Impaired ventricular filling (relaxation) → reduced end-diastolic volume · Causes: Hypertrophic cardiomyopathy, restrictive cardiomyopathy, hypertension 3. Compensatory Mechanisms (Initially beneficial, eventually harmful): · Neurohormonal Activation: Activation of sympathetic nervous system (increased heart rate, contractility) and renin-angiotensin-aldosterone system (vasoconstriction, sodium/water retention) · Frank-Starling Mechanism: Increased preload increases stroke volume (initially) · Ventricular Hypertrophy: Increased wall thickness to maintain wall stress 4. Decompensation: · Progressive decline in cardiac function · Volume overload (edema, pulmonary congestion) · Myocardial remodeling (fibrosis, apoptosis) b. Common Causes of Heart Failure: Coronary Artery Disease: · Ischemic heart disease, myocardial infarction Hypertension: · Systemic hypertension → left ventricular hypertrophy → failure Valvular Heart Disease: · Aortic stenosis, mitral regurgitation, aortic regurgitation Cardiomyopathies: · Dilated cardiomyopathy, hypertrophic cardiomyopathy, restrictive cardiomyopathy Myocarditis: · Viral, bacterial, autoimmune Arrhythmias: · Atrial fibrillation, ventricular tachycardia Congenital Heart Disease: · Ventricular septal defect, patent ductus arteriosus Pericardial Disease: · Constrictive pericarditis, pericardial effusion High-Output States: · Anemia, hyperthyroidism, pregnancy, arteriovenous fistulas 3. Define hypertension- in what different ways can hypertension be classified- Describe the salient organ changes in systemic hypertension-List the possible causes of death in this condition Definition of Hypertension: Hypertension is persistently elevated systemic arterial blood pressure, typically defined as systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg. Classification of Hypertension: By Etiology: · Primary (Essential) Hypertension: No identifiable cause (95% of cases) · Secondary Hypertension: Due to an underlying cause (renal disease, endocrine disorders, coarctation of aorta, sleep apnea, medications) By Severity: · Grade 1 (Mild): Systolic 140-159 mmHg and/or diastolic 90-99 mmHg · Grade 2 (Moderate): Systolic 160-179 mmHg and/or diastolic 100-109 mmHg · Grade 3 (Severe): Systolic ≥ 180 mmHg and/or diastolic ≥ 110 mmHg By Clinical Presentation: · Essential (Primary) · Malignant (Accelerated): Severe hypertension with papilledema, encephalopathy, renal failure Salient Organ Changes in Systemic Hypertension: Heart: · Left ventricular hypertrophy (concentric hypertrophy) · Coronary artery atherosclerosis · Heart failure (hypertensive heart disease) Blood Vessels: · Arteriosclerosis: Thickening of vessel walls, narrowing of lumen · Atherosclerosis: Accelerated · Aneurysms (especially aortic dissection) · Hyaline arteriolosclerosis (benign hypertension): Thickening of arteriolar walls · Hyperplastic arteriolosclerosis (malignant hypertension): "Onion-skin" appearance Kidneys: · Benign nephrosclerosis: Hyaline thickening of arterioles, glomerular sclerosis, focal tubular atrophy · Malignant nephrosclerosis: Fibrinoid necrosis of arterioles, "onion-skin" thickening · Renal failure (chronic kidney disease) Brain: · Lacunar infarcts (small infarcts in basal ganglia, internal capsule) · Hypertensive encephalopathy · Intracerebral hemorrhage · Cerebral atrophy Eyes (Funduscopic Changes): · Arteriolar narrowing · Arteriovenous nicking · Hemorrhages, exudates · Papilledema (malignant hypertension) Possible Causes of Death: 1. Congestive heart failure 2. Myocardial infarction 3. Stroke (cerebral hemorrhage or infarction) 4. Aortic dissection or rupture 5. Renal failure (uremia) 6. Hypertensive encephalopathy 4. Define cardiomyopathy. List the types and discuss any one of them Definition: Cardiomyopathy is a heterogeneous group of diseases of the heart muscle that cause structural and functional abnormalities of the myocardium, not explained by coronary artery disease, hypertension, valvular, or congenital heart disease. Types: 1. Dilated Cardiomyopathy (DCM): · Dilation and impaired systolic function of one or both ventricles · Most common type 2. Hypertrophic Cardiomyopathy (HCM): · Asymmetric septal hypertrophy with diastolic dysfunction · Genetic (autosomal dominant) 3. Restrictive Cardiomyopathy (RCM): · Impaired diastolic filling due to stiff, non-compliant ventricular walls · Least common type 4. Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): · Fibrofatty replacement of right ventricular myocardium · Arrhythmias, sudden death 5. Unclassified: Including Takotsubo (stress-induced) cardiomyopathy Discussion of Dilated Cardiomyopathy (DCM): Pathology: DCM is characterized by dilation and impaired contraction of the left ventricle (or both ventricles), leading to systolic dysfunction. Morphology: · Gross: Enlarged, heavy heart; globular shape; dilated chambers; thin ventricular walls (may be normal thickness) · Microscopic: Myocyte hypertrophy, myocyte degeneration, interstitial fibrosis Etiology: · Idiopathic (most common) · Genetic: Mutations in genes encoding cytoskeletal proteins (titin, desmin, dystrophin), sarcomeric proteins · Infectious: Viral myocarditis (Coxsackie B, HIV) · Toxic: Alcohol, chemotherapy (doxorubicin), cocaine · Metabolic: Diabetes, hypothyroidism, thiamine deficiency · Neuromuscular: Duchenne muscular dystrophy, myotonic dystrophy · Peripartum: Late pregnancy or postpartum period Clinical Features: · Progressive heart failure: Dyspnea, fatigue, edema · Arrhythmias (atrial fibrillation, ventricular tachycardia) · Thromboembolism (mural thrombi) · Sudden cardiac death Prognosis: Poor, with high mortality from heart failure or sudden death. Treatment includes medications (ACE inhibitors, beta-blockers, diuretics), device therapy (ICD, CRT), and heart transplantation. 5. Define hypertension. b. write a short note on hypertensive heart disease a. Definition of Hypertension: Hypertension is persistently elevated systemic arterial blood pressure, defined as systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure ≥ 90 mmHg. b. Hypertensive Heart Disease: Hypertensive heart disease refers to the cardiac changes that occur as a consequence of systemic hypertension. Pathophysiology: · Chronic pressure overload due to hypertension → increased afterload · Ventricular wall stress increases → compensatory concentric hypertrophy (increased wall thickness without chamber dilatation) · Myocyte hypertrophy, increased collagen deposition (interstitial fibrosis) · Increased oxygen demand → relative ischemia → impaired diastolic function Cardiac Changes: · Left Ventricular Hypertrophy (LVH): Concentric hypertrophy; echocardiography shows increased wall thickness · Diastolic Dysfunction: Impaired relaxation, increased filling pressures · Systolic Dysfunction: Progressive decline in contractility → heart failure · Coronary Artery Disease: Accelerated atherosclerosis · Arrhythmias: Atrial fibrillation, ventricular arrhythmias Clinical Features: · May be asymptomatic initially · Chest pain (angina pectoris) · Dyspnea (heart failure) · Arrhythmias · Sudden cardiac death Morphology: · Gross: Enlarged heart (cardiomegaly), increased left ventricular wall thickness; concentric hypertrophy; heart weight > 500 g · Microscopic: Myocyte hypertrophy, interstitial fibrosis, small vessel disease Complications: · Congestive heart failure · Myocardial infarction · Stroke · Sudden cardiac death