MCQ on Pathophysiology of Common Diseases

🫀 Cardiovascular System

1. Which of the following is a primary cause of atherosclerosis?
   A. Bacterial infection
   B. Low blood sugar
   ✅ C. Endothelial injury
   D. Valve stenosis
   Explanation: Endothelial injury initiates the inflammatory cascade that leads to plaque buildup.
2. Myocardial infarction is caused by:
   A. Aortic valve regurgitation
   B. Decreased pulmonary output
   ✅ C. Blockage of coronary arteries
   D. High systemic calcium levels
   Explanation: A blocked coronary artery stops blood flow to heart muscle, causing tissue death.
3. Hypertension increases the risk of which complication?
   A. Hepatitis
   B. Pneumonia
   ✅ C. Stroke
   D. Appendicitis
   Explanation: High blood pressure can lead to hemorrhagic or ischemic strokes.
4. Heart failure leads to:
   A. Hypervolemia
   ✅ B. Decreased cardiac output
   C. Increased blood viscosity
   D. Increased renal filtration
   Explanation: Failing heart pumps less blood, reducing perfusion to organs.
5. In left-sided heart failure, fluid accumulates in the:
   A. Legs
   ✅ B. Lungs
   C. Abdomen
   D. Pericardium
   Explanation: Backflow from the left ventricle causes pulmonary congestion.

🫁 Respiratory System

6. Asthma is characterized by:
   A. Alveolar destruction
   ✅ B. Bronchoconstriction
   C. Pulmonary fibrosis
   D. Pleural effusion
   Explanation: Asthma involves airway narrowing and inflammation.
7. In COPD, airflow limitation is:
   A. Fully reversible
   B. Caused by pulmonary embolism
   ✅ C. Progressive and irreversible
   D. Due to bacterial toxins
   Explanation: COPD causes chronic airway obstruction that cannot be reversed.
8. The main pathophysiological mechanism in emphysema is:
   A. Bronchial infection
   ✅ B. Alveolar wall destruction
   C. Excessive mucus
   D. Pleural scarring
   Explanation: Emphysema damages alveolar walls, reducing gas exchange surface area.
9. Pneumonia primarily affects:
   A. Bronchioles
   ✅ B. Alveoli
   C. Pleura
   D. Trachea
   Explanation: Infection inflames alveoli, filling them with fluid or pus.
10. Pulmonary embolism leads to:
    ✅ A. Impaired gas exchange
    B. Increased surfactant production
    C. Bronchial dilation
    D. Decreased alveolar surface tension
    Explanation: Emboli block blood flow, reducing oxygenation.

🧠 Neurological System

11. Parkinson’s disease is due to deficiency of:
    A. Serotonin
    ✅ B. Dopamine
    C. Acetylcholine
    D. GABA
    Explanation: Dopamine-producing neurons degenerate in the substantia nigra.
12. A common cause of ischemic stroke is:
    A. Brain tumor
    ✅ B. Thromboembolism
    C. Hyperkalemia
    D. Cerebral aneurysm rupture
    Explanation: Clots block cerebral arteries, reducing blood supply.
13. Multiple sclerosis affects the:
    A. Skeletal muscles
    ✅ B. Myelin sheath
    C. Synaptic vesicles
    D. Dendritic spines
    Explanation: Autoimmune attack leads to demyelination in CNS.
14. Alzheimer’s disease involves:
    ✅ A. Amyloid plaque formation
    B. Spinal cord compression
    C. GABA overproduction
    D. Viral encephalitis
    Explanation: Alzheimer’s features beta-amyloid plaques and neurofibrillary tangles.
15. Seizures in epilepsy result from:
    A. Reduced neurotransmission
    ✅ B. Excessive neuronal firing
    C. Myelin degeneration
    D. Spinal nerve impingement
    Explanation: Abnormal electrical discharges lead to seizure activity.

🍽️ Gastrointestinal System

16. Peptic ulcers are most commonly caused by:
    A. High fiber diet
    ✅ B. Helicobacter pylori
    C. Gluten intolerance
    D. Gallstones
    Explanation: H. pylori damages the stomach lining, allowing acid erosion.
17. Hepatitis affects which organ primarily?
    A. Pancreas
    ✅ B. Liver
    C. Gallbladder
    D. Spleen
    Explanation: Hepatitis is liver inflammation caused by viruses, toxins, or drugs.
18. In pancreatitis, inflammation is caused by:
    A. Liver dysfunction
    B. Excess insulin
    ✅ C. Premature enzyme activation
    D. Gastric ulcers
    Explanation: Digestive enzymes activate inside the pancreas, damaging tissue.
19. Cirrhosis results in:
    A. Pancreatic atrophy
    B. Renal obstruction
    ✅ C. Fibrosis of liver tissue
    D. Loss of appetite only
    Explanation: Chronic liver damage leads to scarring and impaired function.
20. Gastroesophageal reflux disease (GERD) involves:
    A. Peptic ulcer formation
    ✅ B. Lower esophageal sphincter weakness
    C. Hiatal hernia rupture
    D. Gastric bleeding
    Explanation: GERD is due to backflow of stomach acid into the esophagus.

💉 Endocrine & Metabolic Disorders

21. Type 1 diabetes is caused by:
    ✅ A. Autoimmune destruction of beta cells
    B. Insulin resistance
    C. Excess glucagon
    D. Genetic mutations only
    Explanation: Type 1 diabetes results from autoimmune attack on pancreatic cells.
22. In hyperthyroidism, metabolic rate is:
    A. Decreased
    ✅ B. Increased
    C. Normal
    D. Absent
    Explanation: Excess thyroid hormone increases cellular metabolism.
23. Cushing’s syndrome results from:
    A. Low cortisol
    B. Adrenalectomy
    ✅ C. Excess cortisol
    D. Hypopituitarism
    Explanation: Cushing’s is caused by chronic exposure to high cortisol levels.
24. Graves’ disease causes:
    A. Hypothyroidism
    ✅ B. Hyperthyroidism
    C. Hyperinsulinemia
    D. Parathyroid disorder
    Explanation: It is an autoimmune condition that overactivates the thyroid gland.
25. Ketoacidosis in diabetes is due to:
    A. Low blood sugar
    B. High protein intake
    ✅ C. Fat breakdown
    D. Increased insulin
    Explanation: Lack of insulin leads to fat breakdown and ketone accumulation.

🦴 Musculoskeletal Disorders

26. Osteoporosis is characterized by:
    A. Muscle wasting
    ✅ B. Decreased bone density
    C. Cartilage inflammation
    D. Tendon rupture
    Explanation: Bones become brittle and prone to fractures.
27. Rheumatoid arthritis is a(n):
    A. Genetic disease
    B. Infectious arthritis
    ✅ C. Autoimmune joint disorder
    D. Degenerative cartilage loss
    Explanation: RA involves immune attack on synovial joints.
28. Osteoarthritis mainly involves:
    A. Immune system activation
    ✅ B. Cartilage degeneration
    C. Bone infection
    D. Spinal compression
    Explanation: OA leads to gradual wear-and-tear of cartilage.
29. Gout is caused by:
    A. Calcium stones
    B. Autoimmune disease
    ✅ C. Uric acid crystal deposition
    D. Vitamin C deficiency
    Explanation: Excess uric acid forms crystals in joints.
30. In muscular dystrophy, muscles:
    A. Become calcified
    ✅ B. Degenerate over time
    C. Retain fluid
    D. Grow abnormally
    Explanation: Muscles progressively weaken and waste away.

🦠 Infectious & Immune Disorders

31. HIV primarily attacks which cells?
    A. Red blood cells
    ✅ B. CD4+ T cells
    C. Neutrophils
    D. B cells
    Explanation: HIV targets immune helper T cells, weakening defense.
32. Sepsis results from:
    A. Autoimmunity
    B. Local infection
    ✅ C. Systemic inflammatory response to infection
    D. Allergic reaction
    Explanation: It’s a life-threatening condition due to widespread infection.
33. Tuberculosis primarily affects the:
    A. Liver
    ✅ B. Lungs
    C. Kidneys
    D. Brain
    Explanation: TB commonly infects and damages lung tissue.
34. Systemic lupus erythematosus (SLE) is a:
    ✅ A. Multisystem autoimmune disease
    B. Bone marrow cancer
    C. Viral illness
    D. Skin infection
    Explanation: SLE affects joints, kidneys, and other organs via immune overactivity.
35. Anaphylaxis involves:
    A. Gradual inflammation
    ✅ B. Rapid systemic allergic reaction
    C. Chronic immune suppression
    D. T-cell suppression
    Explanation: Anaphylaxis causes life-threatening hypersensitivity.

🧬 Genetic & Developmental Disorders

36. Cystic fibrosis affects which system most?
    A. Musculoskeletal
    ✅ B. Respiratory
    C. Circulatory
    D. Immune
    Explanation: Thick mucus blocks airways, leading to frequent lung infections.
37. Sickle cell anemia is caused by:
    ✅ A. Mutation in hemoglobin gene
    B. Iron deficiency
    C. Enzyme disorder
    D. Immune attack on RBCs
    Explanation: A genetic mutation alters hemoglobin shape, reducing oxygen delivery.
38. Phenylketonuria (PKU) results in:
    A. Liver failure
    B. Vitamin D deficiency
    ✅ C. Phenylalanine buildup
    D. Muscle wasting
    Explanation: Enzyme deficiency prevents breakdown of phenylalanine.
39. Down syndrome is caused by:
    A. Gene deletion
    ✅ B. Trisomy 21
    C. Mitochondrial mutation
    D. Sex chromosome loss
    Explanation: It’s due to an extra chromosome 21.
40. Hemophilia results in:
    A. Excess clotting
    B. WBC depletion
    ✅ C. Impaired blood clotting
    D. Platelet overproduction
    Explanation: A deficiency in clotting factors leads to bleeding.

🩺 Miscellaneous/Other Conditions

41. Anemia results in:
    ✅ A. Reduced oxygen-carrying capacity
    B. Increased immunity
    C. Low blood sugar
    D. Clot formation
    Explanation: Less hemoglobin means less oxygen delivered to tissues.
42. Chronic kidney disease leads to:
    A. Decreased blood sugar
    ✅ B. Accumulation of waste products
    C. Hypocalcemia correction
    D. Increased urine concentration
    Explanation: Failing kidneys can’t filter waste efficiently.
43. Hyperkalemia affects the:
    A. Liver
    B. Bone
    ✅ C. Heart
    D. Lungs
    Explanation: High potassium levels can cause life-threatening arrhythmias.
44. Obesity contributes to:
    ✅ A. Insulin resistance
    B. Hypothyroidism
    C. Dehydration
    D. Hypoglycemia
    Explanation: Fat accumulation impairs insulin function.
45. Shock is a state of:
    A. High BP
    B. Enhanced perfusion
    ✅ C. Inadequate tissue perfusion
    D. Strong pulse
    Explanation: Shock reduces oxygen and nutrient delivery to tissues.
46. In hypothyroidism, patients may experience:
    ✅ A. Fatigue and weight gain
    B. Hyperactivity
    C. Heat intolerance
    D. Tachycardia
    Explanation: Low thyroid hormone slows metabolism.
47. Appendicitis is caused by:
    A. Stomach ulcers
    ✅ B. Obstruction and inflammation of the appendix
    C. Bile reflux
    D. Enzyme deficiency
    Explanation: Blocked appendix becomes inflamed and infected.
48. Hernias occur due to:
    A. Cancer
    B. Infection
    ✅ C. Organ protrusion through weak muscle
    D. Hormonal changes
    Explanation: Hernias happen when an organ pushes through muscle wall defects.
49. Varicose veins result from:
    A. Hypertension
    ✅ B. Valve incompetence in veins
    C. Clotting disorder
    D. Fluid overload
    Explanation: Faulty valves cause blood pooling in superficial veins.
50. Psoriasis is a disorder of the:
    A. Bones
    B. Immune cells
    ✅ C. Skin
    D. Glands
    Explanation: It is a chronic autoimmune skin condition causing rapid cell turnover.