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Question 1. Which of the following best describes the inheritance pattern of autosomal dominant polycystic kidney disease (ADPKD)? A) X-linked recessive B) Mitochondrial inheritance C) Autosomal recessive D) Autosomal dominant Answer: D Explanation: ADPKD is transmitted in an autosomal dominant manner; a single mutant allele in PKD1 or PKD2 is sufficient to cause disease. Question 2. A 45-year-old man presents with sudden onset chest pain radiating to the back. Which laboratory test is most specific for diagnosing aortic dissection? A) Troponin I B) D-dimer C) BNP D) Creatine kinase-MB Answer: B Explanation: Elevated D-dimer is sensitive for aortic dissection and, when markedly elevated, supports the diagnosis; it is more specific than cardiac enzymes in this context. Question 3. Which of the following antibiotics is a bacteriostatic inhibitor of protein synthesis that binds the 30S ribosomal subunit? A) Vancomycin B) Ciprofloxacin C) Gentamicin D) Tetracycline Answer: D Explanation: Tetracyclines bind the 30S subunit and prevent tRNA attachment, resulting in bacteriostatic inhibition of protein synthesis. Question 4. In the context of pharmacokinetics, what does the term “first-order elimination” imply? A) A constant amount of drug is eliminated per unit time.
B) Elimination rate is independent of drug concentration. C) A constant fraction of the drug is eliminated per unit time. D) Drug elimination stops once plasma concentration falls below a threshold. Answer: C Explanation: First-order kinetics means the rate of elimination is proportional to the drug concentration; a constant percentage is cleared per unit time. Question 5. Which of the following is the most common cause of iron-deficiency anemia worldwide? A) Chronic renal failure B) Menorrhagia C) Sickle cell disease D) Vitamin B12 deficiency Answer: B Explanation: Heavy menstrual bleeding (menorrhagia) is a leading cause of iron-deficiency anemia in women of reproductive age globally. Question 6. A 68-year-old woman with a history of rheumatoid arthritis develops a new, painless swelling of the distal interphalangeal joint. Which diagnosis is most likely? A) Osteoarthritis B) Gout C) Psoriatic arthritis D) Septic arthritis Answer: A Explanation: Osteoarthritis commonly affects DIP joints, producing painless, bony enlargements (Heberden nodes), distinct from inflammatory arthritides. Question 7. Which of the following neurotransmitters is most directly implicated in the pathophysiology of Parkinson disease? A) Dopamine B serotonin C) Acetylcholine D) GABA
Question 11. Which vitamin deficiency is most commonly associated with beriberi and Wernicke-Korsakoff syndrome? A) Vitamin B B) Vitamin B1 (thiamine) C) Vitamin B D) Vitamin B9 (folate) Answer: B Explanation: Thiamine deficiency leads to beriberi (cardiovascular) and Wernicke-Korsakoff (neurologic) syndromes. Question 12. In the context of heart failure, what does the acronym “HFpEF” stand for? A) Heart failure with preserved ejection fraction B) Heart failure with progressive ejection failure C) Hyperdynamic failure with premature ejection fraction D) Hypertrophic failure with peripheral edema factor Answer: A Explanation: HFpEF denotes heart failure where left-ventricular ejection fraction is ≥50% but diastolic dysfunction limits filling. Question 13. Which of the following is the most sensitive non-invasive test for detecting early diabetic retinopathy? A) Direct ophthalmoscopy B) Fluorescein angiography C) Fundus photography with optical coherence tomography (OCT) D) Visual acuity chart Answer: C Explanation: OCT provides high-resolution cross-sectional imaging of retinal layers, detecting early microvascular changes before they appear on ophthalmoscopy. Question 14. A patient with a known history of chronic hepatitis C presents with elevated ALT/AST, jaundice, and a prolonged PT. Which complication is most likely? A) Acute cholangitis
B) Hepatic encephalopathy C) Acute liver failure D) Portal vein thrombosis Answer: C Explanation: Acute decompensation of chronic hepatitis C can lead to acute liver failure, reflected by transaminase surge, jaundice, and coagulopathy. Question 15. Which of the following statements about the pharmacodynamics of beta-blockers is correct? A) They increase intracellular cyclic AMP in cardiac myocytes. B) They antagonize alpha-1 receptors causing vasodilation. C) They decrease heart rate by blocking sympathetic stimulation of the SA node. D) They act as partial agonists at beta-2 receptors in the bronchial smooth muscle. Answer: C Explanation: Beta-blockers competitively inhibit β1 receptors, reducing sympathetic tone, slowing SA node firing, and decreasing heart rate. Question 16. Which organism is the most common cause of community-acquired pneumonia in adults? A) Streptococcus pneumoniae B) Haemophilus influenzae C) Mycoplasma pneumoniae D) Legionella pneumophila Answer: A Explanation: Streptococcus pneumoniae remains the leading bacterial pathogen in community-acquired pneumonia. Question 17. In a patient with suspected pulmonary embolism, which imaging modality provides the highest sensitivity? A) Chest X-ray B) Ventilation-perfusion (V/Q) scan C) CT pulmonary angiography (CTPA) D) Doppler ultrasound of the lower extremities
Question 21. Which of the following statements regarding the “Rule of Nines” is true? A) It is used to estimate burn surface area in children. B) Each arm accounts for 9% of total body surface area in adults. C) The perineum is assigned 9% of body surface area. D) It is applicable only to second-degree burns. Answer: B Explanation: In adults, each upper limb (including the hand) represents 9% of total body surface area according to the Rule of Nines. Question 22. In a patient with suspected acute coronary syndrome, which ECG change is most specific for transmural myocardial infarction? A) ST-segment depression in leads V1-V B) T-wave inversion in leads II, III, aVF C) Pathological Q waves in contiguous leads D) Tall, peaked T waves in precordial leads Answer: C Explanation: Pathological Q waves reflect necrosis of the full thickness of the ventricular wall and are specific for transmural infarction. Question 23. Which of the following cytokines is primarily responsible for mediating the fever response during infection? A) Interleukin-2 (IL-2) B) Interleukin-1 (IL-1) C) Interferon-γ (IFN-γ) D) Tumor necrosis factor-α (TNF-α) Answer: B Explanation: IL-1 acts on the hypothalamic thermoregulatory center, inducing prostaglandin E2 synthesis and resulting in fever. Question 24. A 22-year-old man presents with a painless ulcer on the genitalia, followed by a maculopapular rash on the palms and soles. Which organism is the most likely cause? A) Treponema pallidum
B) Haemophilus ducreyi C) Chlamydia trachomatis (L1-L3) D) Neisseria gonorrhoeae Answer: A Explanation: Primary syphilis (Treponema pallidum) presents with a chancre and secondary stage rash involving palms and soles. Question 25. Which of the following is the most appropriate initial management for a patient with suspected anaphylaxis? A) Intravenous diphenhydramine B) Subcutaneous epinephrine 0.3 mg C) Intramuscular epinephrine 0.3 mg (1:1000) D) Oral corticosteroids Answer: C Explanation: Intramuscular epinephrine in the mid-anterolateral thigh is the first-line treatment for anaphylaxis. Question 26. In the context of renal physiology, what does the term “autoregulation” refer to? A) The kidney’s ability to concentrate urine independent of ADH. B) The intrinsic adjustment of glomerular filtration rate (GFR) despite changes in systemic blood pressure. C) The regulation of sodium excretion by aldosterone. D) The feedback inhibition of renin release by angiotensin II. Answer: B Explanation: Autoregulation maintains a relatively constant GFR over a range of mean arterial pressures via afferent arteriolar tone adjustments. Question 27. Which of the following is the most common cause of primary adrenal insufficiency (Addison disease) in developed countries? A) Tuberculosis B) Autoimmune adrenalitis C) Metastatic cancer D) Waterhouse-Friderichsen syndrome
Question 31. Which of the following is the most common cause of secondary hypertension? A) Primary aldosteronism B) Renovascular disease (renal artery stenosis) C) Coarctation of the aorta D) Pheochromocytoma Answer: B Explanation: Renovascular hypertension due to renal artery stenosis accounts for a significant proportion of secondary hypertension, especially in older adults. Question 32. A 60-year-old man with chronic obstructive pulmonary disease (COPD) presents with acute dyspnea, wheezing, and a prolonged expiratory phase. Which medication class provides the most immediate bronchodilation? A) Inhaled corticosteroids B) Long-acting β 2 - agonists (LABA) C) Short-acting muscarinic antagonists (SAMA) D) Short-acting β 2 - agonists (SABA) Answer: D Explanation: SABAs (e.g., albuterol) act rapidly on β2 receptors to relieve bronchospasm, making them the first choice for acute exacerbations. Question 33. Which of the following laboratory findings is most characteristic of a patient with Cushing syndrome? A) Decreased cortisol, increased ACTH B) Elevated cortisol, decreased ACTH C) Elevated cortisol, elevated ACTH D) Decreased cortisol, decreased ACTH Answer: C Explanation: In most cases of Cushing syndrome (e.g., ACTH-producing pituitary adenoma), both cortisol and ACTH are elevated; cortisol-producing adrenal tumors would have low ACTH. Question 34. In the management of acute ischemic stroke, which therapeutic window is recommended for intravenous alteplase administration? A) Within 1 hour of symptom onset
B) Within 3 hours of symptom onset C) Within 6 hours of symptom onset D) Within 12 hours of symptom onset Answer: B Explanation: Intravenous alteplase (tPA) is approved for use within 3 hours of symptom onset (up to 4.5 hours in selected patients). Question 35. Which of the following statements about the pathophysiology of type 1 diabetes mellitus is correct? A) It is caused by insulin resistance in peripheral tissues. B) Autoimmune destruction of pancreatic β-cells leads to absolute insulin deficiency. C) It results from a mutation in the glucokinase gene. D) Chronic hyperglycemia is secondary to excess glucagon secretion. Answer: B Explanation: Type 1 diabetes is an autoimmune disease where T-cell mediated β-cell destruction causes absolute insulin deficiency. Question 36. A 70-year-old woman presents with progressive dysphagia to solids and liquids, weight loss, and a “bird’s beak” appearance on barium swallow. Which diagnosis is most likely? A) Achalasia B) Esophageal carcinoma C) Diffuse esophageal spasm D) Schatzki ring Answer: A Explanation: Achalasia is characterized by failure of LES relaxation, leading to a “bird’s beak” tapering on imaging and dysphagia to both solids and liquids. Question 37. Which of the following is the most specific serologic marker for systemic lupus erythematosus (SLE)? A) Anti-dsDNA antibodies B) Anti-Smith (Sm) antibodies C) Anti-RNP antibodies D) Anti-centromere antibodies
Explanation: A solitary lesion in a chronic hepatitis B patient warrants tissue diagnosis to differentiate hepatocellular carcinoma from benign lesions before definitive therapy. Question 41. Which of the following is the most common cause of community-acquired bacterial meningitis in neonates (≤ 28 days)? A) Streptococcus pneumoniae B) Neisseria meningitidis C) Group B Streptococcus (Streptococcus agalactiae) D) Listeria monocytogenes Answer: C Explanation: Group B Streptococcus is the leading pathogen in early-onset neonatal bacterial meningitis. Question 42. In the context of evidence-based medicine, which level of evidence is assigned to a well-designed randomized controlled trial (RCT) with low risk of bias? A) Level I B) Level II C) Level III D) Level IV Answer: A Explanation: Level I evidence represents high-quality RCTs with proper randomization, blinding, and minimal bias. Question 43. Which of the following best describes the “golden period” for initiating prophylactic antibiotics after a dog bite to prevent infection? A) Within 30 minutes B) Within 1 hour C) Within 3 hours D) Within 24 hours Answer: C Explanation: Initiating antibiotics within 3 hours of a dog bite significantly reduces infection risk; earlier is better but 3 hours is the accepted window.
Question 44. A 28-year-old woman presents with episodic palpitations, sweating, and headache. Her plasma catecholamine levels are markedly elevated. Which tumor is most likely? A) Insulinoma B) Pheochromocytoma C] Parathyroid adenoma D) Medullary thyroid carcinoma Answer: B Explanation: Pheochromocytoma secretes catecholamines, causing episodic hypertension, tachycardia, sweating, and headaches. Question 45. In a patient with suspected acute pancreatitis, which laboratory value is most sensitive for early diagnosis? A) Serum amylase B) Serum lipase C) Serum bilirubin D) Serum calcium Answer: B Explanation: Serum lipase remains elevated longer than amylase and is more specific for pancreatic inflammation, making it the preferred early marker. Question 46. Which of the following is the most common cause of primary (idiopathic) thrombocytopenia in children? A) Bone marrow failure B) Immune thrombocytopenic purpura (ITP) C) Leukemia D) Aplastic anemia Answer: B Explanation: Acute ITP, an immune-mediated destruction of platelets, is the leading cause of isolated thrombocytopenia in pediatric patients. Question 47. A 65-year-old man with a history of atrial fibrillation is prescribed warfarin. Which dietary component most significantly interferes with warfarin’s anticoagulant effect? A) Vitamin C
Explanation: Ultrasound is safe in pregnancy and can visualize the appendix; MRI is a second-line option if ultrasound is nondiagnostic. Question 51. Which of the following is the most common cause of secondary hyperparathyroidism in chronic kidney disease? A) Decreased vitamin D activation B) Increased dietary calcium intake C) Hypermagnesemia D) Primary hyperparathyroidism Answer: A Explanation: CKD reduces 1-α-hydroxylase activity, leading to low active vitamin D, hypocalcemia, and compensatory secondary hyperparathyroidism. Question 52. A 55-year-old woman presents with progressive proximal muscle weakness, a heliotrope rash, and Gottron papules. Which autoantibody is most specific for her condition? A) Anti-centromere B) Anti-Jo- 1 C) Anti-Mi- 2 D) Anti-U1-RNP Answer: C Explanation: Anti-Mi-2 antibodies are highly specific for dermatomyositis, which presents with heliotrope rash and Gottron papules. Question 53. Which of the following best describes the primary physiologic effect of aldosterone on the distal nephron? A) Increases sodium reabsorption and potassium excretion B) Decreases calcium reabsorption C) Inhibits water reabsorption via aquaporin-2 channels D) Stimulates bicarbonate secretion Answer: A Explanation: Aldosterone promotes Na⁺ reabsorption through ENaC and K⁺ secretion via ROMK channels in the principal cells of the distal tubule and collecting duct.
**Question 54. In a patient with suspected pulmonary embolism who has a contraindication to iodinated contrast, which diagnostic test is most appropriate? ** A) Ventilation-perfusion (V/Q) scan B) CT pulmonary angiography (CTPA) with low-dose contrast C) Doppler ultrasound of the lower extremities only D) Plain chest radiograph Answer: A Explanation: A V/Q scan can detect perfusion defects suggestive of PE without the need for iodinated contrast. Question 55. Which of the following is the most common cause of bacterial prostatitis in men under 35 years of age? A) Escherichia coli B) Pseudomonas aeruginosa C) Staphylococcus aureus D) Klebsiella pneumoniae Answer: A Explanation: E. coli accounts for the majority of acute bacterial prostatitis across all age groups, especially younger men. Question 56. A 70-year-old man with a history of smoking presents with hematuria and a 3-cm mass on the left kidney on CT. Which histologic subtype is most common for renal cell carcinoma? A) Clear cell carcinoma B) Papillary carcinoma C) Chromophobe carcinoma D) Oncocytoma Answer: A Explanation: Clear cell RCC represents approximately 70- 80 % of renal cell carcinomas and is strongly associated with smoking. Question 57. Which of the following is the most sensitive screening test for early detection of cervical cancer? A) Visual inspection with acetic acid (VIA)
Answer: C Explanation: Pyoderma gangrenosum often begins as a painful papule or pustule that rapidly ulcerates, commonly on the lower extremities. Question 61. Which of the following is the most common cause of death in patients with cystic fibrosis? A) Liver cirrhosis B) Pancreatic insufficiency C) Respiratory failure due to chronic pulmonary infection D) Renal failure Answer: C Explanation: Progressive lung disease with chronic Pseudomonas infection leads to respiratory failure, the leading cause of mortality in cystic fibrosis. Question 62. Which of the following is the most appropriate first-line treatment for newly diagnosed stage I Hodgkin lymphoma? A) ABVD chemotherapy regimen B) CHOP chemotherapy regimen C) Radiation therapy alone D) Watchful waiting Answer: A Explanation: ABVD (adriamycin, bleomycin, vinblastine, dacarbazine) is the standard first-line regimen for early-stage Hodgkin lymphoma. Question 63. A 22-year-old male presents with fever, sore throat, and a “strawberry” tongue. Which organism is most likely responsible? A) Streptococcus pyogenes B) Corynebacterium diphtheriae C) Epstein-Barr virus D) Mycoplasma pneumoniae Answer: A Explanation: Streptococcal pharyngitis (group A strep) can cause a “strawberry” (punctate) tongue and fever.
Question 64. Which of the following is the most common cause of acute interstitial nephritis (AIN)? A) NSAID use B) Bacterial pyelonephritis C) Hemolytic uremic syndrome D) Acute tubular necrosis Answer: A Explanation: NSAIDs are a frequent culprit for drug-induced AIN, characterized by eosinophilic infiltrates and interstitial inflammation. Question 65. In a patient with a newly diagnosed atrial fibrillation and CHA₂DS₂-VASc score of 3, which antithrombotic strategy is recommended? A) Aspirin 81 mg daily B) No anticoagulation required C) Direct oral anticoagulant (DOAC) D) Warfarin with INR target 2.0-3.0 only if DOAC contraindicated Answer: C Explanation: A CHA₂DS₂-VASc score ≥2 warrants anticoagulation; DOACs are preferred over warfarin for most patients. Question 66. Which of the following is the most common cause of a “ground-glass” opacity on high-resolution CT of the lung in a young adult? A) Pulmonary edema B) Hypersensitivity pneumonitis C) Pulmonary embolism D) Pulmonary fibrosis Answer: B Explanation: Hypersensitivity pneumonitis often presents with diffuse ground-glass opacities in young adults exposed to inhaled antigens. Question 67. A 65-year-old man presents with progressive dysphagia to solids, weight loss, and an ulcerated lesion on the mid-esophagus on endoscopy. Biopsy shows squamous cell carcinoma. Which risk factor is most strongly associated? A) Chronic gastroesophageal reflux disease (GERD) B) Tobacco smoking
