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Iran Medical Residency Entrance Exam study materials
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Iran Medical Residency Entrance Exam practice questions

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Question 1Internal Medicine

A 24-year-old man has recurrent episodes of severe abdominal pain, dark urine, and photosensitive skin blisters since childhood. Urine turns black on standing. Which enzyme deficiency is most likely responsible?

  1. Ferrochelatase
  2. Uroporphyrinogen decarboxylase
  3. Porphobilinogen deaminase Correct answer.
  4. Glucose-6-phosphate dehydrogenase

Explanation

This is acute intermittent porphyria, caused by deficiency of porphobilinogen deaminase (hydroxymethylbilane synthase). The classic triad is abdominal pain, neuropsychiatric symptoms, and dark urine from porphobilinogen oxidation; skin blisters are not typical of AIP but the neurovisceral attacks and black urine point here. Ferrochelatase causes protoporphyria with photosensitivity but not the acute attacks.

Question 2Internal Medicine

Which finding best distinguishes diabetic ketoacidosis from hyperosmolar hyperglycemic state at presentation?

  1. Serum glucose above 600 mg/dL
  2. Significant ketonemia with high anion gap acidosis Correct answer.
  3. Serum osmolality above 320 mOsm/kg
  4. Profound dehydration with altered consciousness

Explanation

DKA is defined by ketoacidosis: elevated beta-hydroxybutyrate and a high anion gap metabolic acidosis, with glucose often only moderately elevated. HHS shows extreme hyperglycemia and hyperosmolality but minimal ketosis because residual insulin suppresses lipolysis. Dehydration and altered sensorium occur in both.

Question 3Internal Medicine

A 45-year-old woman has a serum calcium of 11.2 mg/dL, phosphate 2.0 mg/dL, and an inappropriately normal PTH. Twenty-four-hour urine calcium is 380 mg. Which is the most appropriate next step?

  1. Parathyroidectomy Correct answer.
  2. Start hydrochlorothiazide
  3. Start cinacalcet
  4. Observation with repeat calcium in six months

Explanation

Symptomatic or guideline-defined primary hyperparathyroidism with age under 50, urine calcium over 400 mg/day (borderline here), or serum calcium above 1 mg/dL over normal warrants parathyroidectomy. This patient is 45, meeting the age criterion for surgery. Cinacalcet is reserved for patients who cannot undergo surgery.

Question 4Internal Medicine

Which antibody is most specific for systemic lupus erythematosus and associated with a lower risk of lupus nephritis?

  1. Anti-histone
  2. Anti-Smith Correct answer.
  3. Anti-dsDNA
  4. Anti-SSA/Ro

Explanation

Anti-Smith antibody is highly specific for SLE though less sensitive, and its presence is associated with a lower risk of nephritis. Anti-dsDNA, by contrast, correlates with renal flares. Anti-histone suggests drug-induced lupus, and anti-SSA is linked to neonatal lupus and subacute cutaneous disease.

Question 5Internal Medicine

A 60-year-old man with cirrhosis presents with fever, abdominal pain, and a neutrophil count of 400/mm3 in ascitic fluid. Which antibiotic is the first-line empiric choice?

  1. Ceftriaxone Correct answer.
  2. Ciprofloxacin
  3. Vancomycin
  4. Metronidazole alone

Explanation

Spontaneous bacterial peritonitis is treated empirically with a third-generation cephalosporin such as ceftriaxone, covering the common Enterobacteriaceae. Albumin infusion is added when creatinine is elevated or bilirubin high to reduce renal failure. Metronidazole alone or vancomycin does not cover the typical gram-negative organisms.

Question 6Internal Medicine

Which pattern on liver enzymes most suggests alcoholic hepatitis?

  1. AST/ALT ratio above 2 with AST usually under 300 Correct answer.
  2. Isolated alkaline phosphatase elevation
  3. AST/ALT ratio below 1 with marked ALT elevation
  4. Predominantly isolated hyperbilirubinemia

Explanation

Alcoholic hepatitis classically produces an AST/ALT ratio greater than 2, with AST usually below 300 IU/L because of pyridoxine deficiency limiting ALT synthesis. Viral hepatitis typically shows ALT exceeding AST. Isolated alkaline phosphatase elevation suggests cholestasis, not hepatocellular injury.

Question 7Internal Medicine

A 30-year-old woman has a blood pressure of 168/104 mmHg, hypokalemia, and a suppressed renin with elevated aldosterone. Which test best confirms primary aldosteronism?

  1. Renal artery Doppler
  2. Captopril renin stimulation
  3. Plasma metanephrines
  4. Saline suppression test Correct answer.

Explanation

After screening shows elevated aldosterone with suppressed renin, confirmatory testing uses saline loading; failure to suppress aldosterone confirms autonomous secretion. Adrenal vein sampling then distinguishes unilateral adenoma from bilateral hyperplasia. Captopril testing is an alternative confirmatory approach but saline suppression is standard.

Question 8Internal Medicine

Which feature most strongly suggests a nephrotic rather than nephritic syndrome?

  1. Proteinuria above 3.5 g/day with hypoalbuminemia Correct answer.
  2. Elevated anti-streptolysin O titer
  3. Hypertension and oliguria
  4. Red cell casts in urine

Explanation

Nephrotic syndrome is defined by heavy proteinuria (>3.5 g/day), hypoalbuminemia, edema, and hyperlipidemia with a bland urine sediment. Nephritic syndrome shows hematuria, red cell casts, hypertension, and oliguria. Anti-streptolysin O suggests post-streptococcal glomerulonephritis, a nephritic picture.

Question 9Internal Medicine

A patient with chronic kidney disease has a corrected calcium of 8.2 mg/dL, phosphate 6.5 mg/dL, and PTH of 350 pg/mL. Which mechanism best explains the hyperparathyroidism?

  1. Familial hypocalciuric hypercalcemia
  2. Secondary hyperparathyroidism from phosphate retention and low calcitriol Correct answer.
  3. Primary parathyroid adenoma
  4. Tertiary hyperparathyroidism from a parathyroid carcinoma

Explanation

In CKD, reduced phosphate excretion raises phosphate, which lowers ionized calcium and suppresses 1-alpha-hydroxylase, lowering calcitriol. The resulting hypocalcemia and hyperphosphatemia stimulate PTH, producing secondary hyperparathyroidism. Treatment includes phosphate binders and active vitamin D analogs.

Question 10Internal Medicine

Which spirometric pattern is expected in a patient with idiopathic pulmonary fibrosis?

  1. Isolated reduction in diffusion capacity with normal spirometry
  2. Increased residual volume with air trapping
  3. Restrictive pattern with reduced FVC and preserved or increased FEV1/FVC ratio Correct answer.
  4. Obstructive pattern with reduced FEV1/FVC ratio

Explanation

Pulmonary fibrosis causes a restrictive defect: reduced FVC with a normal or elevated FEV1/FVC ratio, and reduced total lung capacity. Diffusion capacity is also reduced. Obstructive disease shows a reduced FEV1/FVC ratio with air trapping and increased residual volume.

Question 11Internal Medicine

A 28-year-old woman has episodic wheezing, a normal chest examination, and symptoms worse at night and after exercise. Which test best supports the diagnosis of asthma?

  1. Chest radiograph showing hyperinflation
  2. Sputum eosinophils above 3%
  3. Elevated serum IgE
  4. Bronchodilator reversibility with FEV1 improvement over 12% and 200 mL Correct answer.

Explanation

Demonstrating reversible airflow obstruction, defined as FEV1 improvement of at least 12% and 200 mL after a bronchodilator, confirms variable airway obstruction typical of asthma. Sputum eosinophilia and elevated IgE support an atopic phenotype but are not diagnostic. A normal chest radiograph is common.

Question 12Internal Medicine

Which organism is the most common cause of community-acquired pneumonia requiring hospitalization in adults?

  1. Mycoplasma pneumoniae
  2. Chlamydia psittaci
  3. Legionella pneumophila
  4. Streptococcus pneumoniae Correct answer.

Explanation

Streptococcus pneumoniae remains the most frequent cause of community-acquired pneumonia across all severity levels, including those requiring admission. Atypical organisms such as Mycoplasma are more common in younger outpatients. Legionella causes severe pneumonia but is less frequent overall.

Question 13Internal Medicine

A 55-year-old smoker has a 4 cm cavitating upper lobe mass and hyponatremia with a serum osmolality of 260 mOsm/kg and urine osmolality of 600 mOsm/kg. Which mechanism explains the sodium disorder?

  1. Primary polydipsia
  2. Ectopic ADH secretion Correct answer.
  3. Diuretic-induced hypovolemia
  4. Adrenal insufficiency

Explanation

Small cell lung cancer commonly secretes ADH ectopically, producing euvolemic hypotonic hyponatremia with inappropriately concentrated urine. Treatment includes fluid restriction and, in some cases, demeclocycline or vasopressin receptor antagonists. Diuretic use and adrenal insufficiency cause hypovolemic hyponatremia with different volume findings.

Question 14Internal Medicine

Which electrocardiographic finding is most characteristic of hyperkalemia?

  1. Peaked T waves with widened QRS Correct answer.
  2. Prominent U waves
  3. Sawtooth flutter waves
  4. Prolonged QT interval

Explanation

Hyperkalemia classically causes tall, peaked T waves followed by QRS widening and eventual sine wave morphology as potassium rises. U waves suggest hypokalemia, prolonged QT suggests hypocalcemia or drug effect, and sawtooth waves indicate atrial flutter.

Question 15Internal Medicine

A 70-year-old man has fatigue and a hemoglobin of 9 g/dL with an MCV of 105 fL and a normal reticulocyte count. Which is the most appropriate initial test?

  1. Serum ferritin
  2. Hemoglobin electrophoresis
  3. Direct antiglobulin test
  4. Serum vitamin B12 and folate Correct answer.

Explanation

Macrocytic anemia with a low reticulocyte count requires evaluation for B12 and folate deficiency, the most common nutritional causes. If these are normal, thyroid disease, liver disease, alcohol, and myelodysplasia are considered. Ferritin evaluates microcytic anemia, and hemoglobin electrophoresis evaluates hemolysis or thalassemia.

Question 16Internal Medicine

Which finding is most consistent with iron deficiency anemia rather than anemia of chronic disease?

  1. Normal ferritin with low transferrin saturation
  2. Elevated ferritin with low total iron-binding capacity
  3. Low ferritin with high total iron-binding capacity Correct answer.
  4. Elevated ferritin with normal soluble transferrin receptor

Explanation

Iron deficiency shows low ferritin, low serum iron, high total iron-binding capacity, and low transferrin saturation. Anemia of chronic disease shows normal or high ferritin with low TIBC because inflammation sequesters iron. Soluble transferrin receptor rises in iron deficiency but is normal in inflammatory anemia.

Question 17Internal Medicine

A 32-year-old woman presents with symmetric proximal muscle weakness, a heliotrope rash, and Gottron papules. Which antibody is most associated with this condition and with interstitial lung disease?

  1. Anti-centromere
  2. Anti-topoisomerase I
  3. Anti-Jo-1 Correct answer.
  4. Anti-U1 RNP

Explanation

Dermatomyositis with antisynthetase antibodies such as anti-Jo-1 is associated with myositis, interstitial lung disease, mechanic's hands, and arthritis. Anti-topoisomerase I (Scl-70) is linked to diffuse systemic sclerosis, anti-centromere to limited scleroderma, and anti-U1 RNP to mixed connective tissue disease.

Question 18Internal Medicine

Which feature best distinguishes gout from pseudogout in an acutely inflamed joint?

  1. Positively birefringent rhomboid crystals
  2. Elevated serum uric acid
  3. Negatively birefringent needle-shaped crystals Correct answer.
  4. Radiographic chondrocalcinosis

Explanation

Gout is confirmed by needle-shaped monosodium urate crystals that are negatively birefringent under polarized light. Pseudogout shows rhomboid calcium pyrophosphate crystals that are positively birefringent. Serum uric acid can be normal during an acute attack, and chondrocalcinosis supports but does not confirm pseudogout.

Question 19Internal Medicine

A 40-year-old man has a blood pressure of 180/110 mmHg, a creatinine of 3.5 mg/dL, and a urinalysis showing red cell casts. Which diagnosis is most likely?

  1. Primary hyperaldosteronism
  2. Essential hypertension without target organ damage
  3. Renovascular hypertension from fibromuscular dysplasia
  4. Hypertensive emergency with malignant nephrosclerosis Correct answer.

Explanation

Severe hypertension with acute kidney injury and active urine sediment indicates malignant hypertension with target organ damage, requiring controlled blood pressure reduction. Red cell casts reflect glomerular injury from fibrinoid necrosis. Essential hypertension lacks acute target organ injury, and fibromuscular dysplasia usually presents in younger women without active sediment.

Question 20Internal Medicine

Which finding is most specific for infective endocarditis in a patient with fever and a new murmur?

  1. Splinter hemorrhages
  2. Elevated erythrocyte sedimentation rate
  3. New conduction abnormality
  4. Positive blood cultures in two separate sets Correct answer.

Explanation

Persistent bacteremia with the same organism in multiple blood culture sets is a major Duke criterion for infective endocarditis. Splinter hemorrhages are nonspecific and common in many conditions. An elevated sedimentation rate is a nonspecific inflammatory marker, and conduction abnormalities suggest perivalvular extension but are not diagnostic.

Question 21Internal Medicine

A patient with atrial fibrillation has a CHA2DS2-VASc score of 3. Which anticoagulation strategy is most appropriate?

  1. Aspirin alone
  2. Oral anticoagulation with a direct oral anticoagulant or warfarin Correct answer.
  3. Dual antiplatelet therapy
  4. No anticoagulation because the score is low

Explanation

A CHA2DS2-VASc score of 2 or more in men or 3 or more in women warrants oral anticoagulation to reduce stroke risk. Direct oral anticoagulants are preferred over warfarin in most non-valvular cases. Aspirin and dual antiplatelet therapy provide inadequate stroke prophylaxis and increase bleeding risk.

Question 22Internal Medicine

Which laboratory pattern is most consistent with acute pancreatitis?

  1. Normal lipase with elevated alkaline phosphatase
  2. Elevated lipase with normal amylase and normal imaging
  3. Lipase elevated three times the upper limit of normal Correct answer.
  4. Amylase elevated once with normal lipase

Explanation

Acute pancreatitis is diagnosed when at least two of three criteria are met: characteristic pain, lipase or amylase above three times the upper limit of normal, or imaging findings. Lipase is more specific and remains elevated longer than amylase. A single borderline amylase elevation lacks diagnostic value.

Question 23Internal Medicine

A 25-year-old man has bloody diarrhea, tenesmus, and continuous mucosal inflammation extending from the rectum. Which feature most favors ulcerative colitis over Crohn disease?

  1. Continuous mucosal disease starting in the rectum Correct answer.
  2. Granulomas on biopsy
  3. Transmural inflammation with skip lesions
  4. Fistulae and perianal disease

Explanation

Ulcerative colitis involves continuous mucosal inflammation beginning in the rectum and extending proximally without skip lesions. Crohn disease is transmural, patchy, and may involve any part of the gastrointestinal tract with fistulae and granulomas. These features guide diagnosis and management.

Question 24Internal Medicine

A 65-year-old man has a serum creatinine of 2.4 mg/dL, a urine sodium of 10 mEq/L, and a fractional excretion of urea of 20% after diuretic use. Which cause of acute kidney injury is most likely?

  1. Prerenal azotemia Correct answer.
  2. Obstructive uropathy
  3. Acute tubular necrosis
  4. Acute interstitial nephritis

Explanation

A low urine sodium and fractional excretion of urea below 35% in a patient on diuretics suggest prerenal azotemia with intact tubular sodium reabsorption. Acute tubular necrosis typically shows a high urine sodium and muddy brown casts. Interstitial nephritis shows eosinophiluria, and obstruction shows hydronephrosis.

Question 25Internal Medicine

Which finding is most characteristic of myasthenia gravis?

  1. Proximal muscle pain with elevated creatine kinase
  2. Hyperreflexia with spasticity
  3. Ascending symmetric weakness after gastroenteritis
  4. Fatigable weakness worsening with repetitive use Correct answer.

Explanation

Myasthenia gravis causes fatigable weakness that worsens with activity and improves with rest, often affecting extraocular and bulbar muscles. Ascending weakness after infection suggests Guillain-Barré syndrome, and painful proximal weakness with elevated creatine kinase suggests myositis. Hyperreflexia and spasticity indicate upper motor neuron disease.

Question 26Internal Medicine

A 45-year-old man with type 2 diabetes and a BMI of 34 kg/m² has an HbA1c of 8.9% despite metformin 1000 mg twice daily and lifestyle modification. Which next step is most appropriate according to current guidelines?

  1. Add a DPP-4 inhibitor
  2. Add a GLP-1 receptor agonist or SGLT2 inhibitor with proven cardiovascular benefit Correct answer.
  3. Switch to insulin
  4. Add a sulfonylurea

Explanation

In patients with type 2 diabetes and established or high risk of cardiovascular disease, guidelines recommend adding an agent with proven cardiovascular benefit, such as a GLP-1 receptor agonist or SGLT2 inhibitor, when glycemic targets are not met with metformin. These agents also promote weight loss, which is beneficial in obesity.

Question 27Internal Medicine

A 60-year-old woman with a history of hypertension presents with sudden-onset severe headache and a blood pressure of 220/120 mmHg. Funduscopy reveals papilledema and retinal hemorrhages. Which diagnosis is most likely?

  1. Primary aldosteronism
  2. Pheochromocytoma
  3. Hypertensive emergency Correct answer.
  4. Hypertensive urgency

Explanation

Hypertensive emergency is defined by severe blood pressure elevation with acute target organ damage, such as papilledema, retinal hemorrhages, or neurologic deficits. The presence of papilledema and retinal hemorrhages indicates end-organ damage and requires immediate controlled blood pressure reduction.

Question 28Internal Medicine

A 55-year-old man with a history of alcohol use disorder presents with confusion, ataxia, and ophthalmoplegia. MRI shows symmetric lesions in the medial thalami and periaqueductal gray matter. Which treatment is most appropriate?

  1. Intravenous thiamine Correct answer.
  2. Intravenous glucose
  3. Intravenous methylprednisolone
  4. Oral lorazepam

Explanation

The clinical triad of confusion, ataxia, and ophthalmoplegia, along with MRI findings of symmetric medial thalamic and periaqueductal lesions, is characteristic of Wernicke encephalopathy. Immediate intravenous thiamine is the treatment of choice to prevent progression to Korsakoff syndrome.

Question 29Internal Medicine

A 30-year-old woman presents with fatigue, weight gain, cold intolerance, and constipation. Physical examination reveals dry skin, bradycardia, and delayed relaxation of deep tendon reflexes. Which laboratory finding is most consistent with primary hypothyroidism?

  1. Low TSH and low free T4
  2. Low TSH and elevated free T4
  3. Elevated TSH and low free T4 Correct answer.
  4. Elevated TSH and elevated free T4

Explanation

Primary hypothyroidism is characterized by an elevated TSH due to loss of negative feedback from thyroid hormones, along with a low free T4. The clinical features of fatigue, weight gain, cold intolerance, and delayed reflex relaxation support this diagnosis.

Question 30Internal Medicine

A 25-year-old man is brought to the emergency department after a motor vehicle accident. He is unconscious and has a blood pressure of 80/50 mmHg and a heart rate of 130 bpm. He has distended neck veins and muffled heart sounds. Which is the most appropriate immediate management?

  1. Administration of intravenous furosemide
  2. Rapid infusion of intravenous fluids
  3. Emergent pericardiocentesis Correct answer.
  4. Urgent pericardiectomy

Explanation

The combination of hypotension, distended neck veins, and muffled heart sounds (Beck triad) suggests cardiac tamponade, likely due to hemopericardium from trauma. Immediate pericardiocentesis is life-saving and should be performed without delay.

Question 31Internal Medicine

A 65-year-old man with chronic obstructive pulmonary disease presents with worsening dyspnea and increased sputum purulence. He is alert and has an oxygen saturation of 88% on room air. Which is the most appropriate initial oxygen therapy?

  1. Titrate oxygen to a target saturation of 88–92% Correct answer.
  2. Withhold oxygen unless saturation falls below 80%
  3. Start noninvasive positive pressure ventilation immediately
  4. Administer high-flow oxygen to maintain saturation above 98%

Explanation

In patients with COPD and chronic hypercapnia, oxygen should be titrated to a target saturation of 88–92% to avoid worsening hypercapnia and respiratory acidosis. High-flow oxygen can be harmful in this population.

Question 32Internal Medicine

A 40-year-old woman presents with a 2-week history of progressive weakness and areflexia after a diarrheal illness. She reports difficulty swallowing and double vision. Which is the most likely diagnosis?

  1. Botulism
  2. Guillain-Barré syndrome Correct answer.
  3. Myasthenia gravis
  4. Transverse myelitis

Explanation

Guillain-Barré syndrome often presents with ascending symmetric weakness and areflexia following a gastrointestinal infection, commonly Campylobacter jejuni. Cranial nerve involvement can occur, causing bulbar symptoms and diplopia.

Question 33Internal Medicine

A 70-year-old man with atrial fibrillation is started on warfarin. His INR is 6.5 and he has no bleeding. Which is the most appropriate management?

  1. Continue warfarin and recheck INR in 1 week
  2. Hold warfarin and transfuse fresh frozen plasma
  3. Give intravenous heparin
  4. Hold warfarin and give oral vitamin K Correct answer.

Explanation

For an INR above 4.5 without bleeding, warfarin should be withheld and low-dose oral vitamin K considered, especially if the INR is >10 or there is high bleeding risk. In this case, INR 6.5 without bleeding can be managed with holding warfarin and possibly oral vitamin K.

Question 34Internal Medicine

A 50-year-old woman presents with a 6-month history of episodic flushing, diarrhea, and wheezing. Physical examination reveals a pansystolic murmur at the left lower sternal border. Which is the most likely diagnosis?

  1. Carcinoid syndrome Correct answer.
  2. Medullary thyroid carcinoma
  3. VIPoma
  4. Pheochromocytoma

Explanation

Carcinoid syndrome is characterized by flushing, diarrhea, and bronchospasm due to serotonin and other vasoactive substances released by a neuroendocrine tumor. Right-sided cardiac involvement, such as tricuspid regurgitation, can cause a pansystolic murmur.

Question 35Internal Medicine

A 35-year-old man presents with acute severe abdominal pain radiating to the back, and a serum lipase level three times the upper limit of normal. Which is the most appropriate initial fluid resuscitation strategy?

  1. Restricted fluid intake
  2. Diuretics to maintain urine output
  3. Aggressive intravenous crystalloid therapy Correct answer.
  4. Hypertonic saline

Explanation

Aggressive intravenous crystalloid resuscitation is a cornerstone of early management of acute pancreatitis to maintain pancreatic microcirculation and prevent necrosis. Fluid should be titrated to urine output and clinical response.

Question 36Internal Medicine

A 60-year-old man with cirrhosis presents with confusion and asterixis. He has a serum ammonia level of 120 μmol/L. Which is the most appropriate initial treatment?

  1. Flumazenil
  2. Neomycin
  3. Rifaximin
  4. Lactulose Correct answer.

Explanation

Lactulose is the first-line treatment for hepatic encephalopathy; it acidifies the colon and traps ammonia, reducing absorption. Rifaximin is typically added for secondary prophylaxis after a second episode.

Question 37Internal Medicine

A 28-year-old woman presents with malar rash, photosensitivity, and polyarthritis. Laboratory tests reveal a positive antinuclear antibody and anti-double-stranded DNA. Which is the most appropriate initial pharmacologic therapy for mild disease?

  1. Rituximab
  2. High-dose prednisone
  3. Cyclophosphamide
  4. Hydroxychloroquine Correct answer.

Explanation

Hydroxychloroquine is the cornerstone of therapy for mild systemic lupus erythematosus, including skin and joint involvement. It reduces flares and has beneficial effects on lipid profiles and thrombosis risk.

Question 38Internal Medicine

A 70-year-old man with a history of smoking presents with hemoptysis and a 3 cm mass in the right upper lobe. Biopsy shows small cell lung cancer. Which paraneoplastic syndrome is most commonly associated with this histology?

  1. Syndrome of inappropriate antidiuretic hormone secretion Correct answer.
  2. Cushing syndrome
  3. Hypercalcemia
  4. Carcinoid syndrome

Explanation

Small cell lung cancer is a neuroendocrine tumor that commonly causes paraneoplastic syndromes, most frequently SIADH, leading to euvolemic hyponatremia. Hypercalcemia is more typical of squamous cell carcinoma.

Question 39Internal Medicine

A 55-year-old woman presents with progressive dyspnea on exertion and a new holosystolic murmur at the apex radiating to the axilla. Echocardiography shows severe mitral regurgitation with a flail leaflet. Which is the most appropriate management?

  1. Medical therapy with diuretics alone
  2. Surgical mitral valve repair Correct answer.
  3. Percutaneous balloon valvuloplasty
  4. Anticoagulation with warfarin

Explanation

Severe mitral regurgitation due to a flail leaflet with symptoms is an indication for surgical mitral valve repair, which offers the best long-term outcome. Medical therapy is supportive but not definitive.

Question 40Internal Medicine

A 40-year-old man presents with recurrent kidney stones and a serum calcium of 11.5 mg/dL. Which is the most likely cause?

  1. Primary hyperparathyroidism Correct answer.
  2. Vitamin D toxicity
  3. Sarcoidosis
  4. Hypercalcemia of malignancy

Explanation

Primary hyperparathyroidism is a common cause of hypercalcemia, often presenting with recurrent kidney stones. It is characterized by elevated PTH and hypercalcemia, typically due to a parathyroid adenoma.

Question 41Surgery

A 24-year-old man has a 3 cm clean laceration of the forearm with no tendon, nerve, or vessel injury. Which of the following is the most appropriate initial management?

  1. Skin grafting of the wound
  2. Healing by secondary intention with daily dressing
  3. Primary closure after irrigation and debridement Correct answer.
  4. Delayed primary closure after five days

Explanation

Clean, uncomplicated lacerations presenting early are best treated by irrigation, removal of devitalized tissue, and primary closure, which yields the best scar and fastest healing. Delayed closure is reserved for contaminated or infected wounds, and grafting is unnecessary when wound edges can be approximated.

Question 42Surgery

Which intravenous fluid is most appropriate for initial resuscitation of a young adult with hypovolemic shock from a closed femoral fracture?

  1. 5% dextrose in water
  2. 20% albumin
  3. 0.45% sodium chloride
  4. Isotonic crystalloid such as Ringer lactate Correct answer.

Explanation

Isotonic balanced crystalloid is the first-line fluid for hemorrhagic shock because it expands the extracellular volume effectively. Dextrose solutions distribute into total body water and do not restore intravascular volume, while hypotonic saline worsens hyponatremia and cellular swelling.

Question 43Surgery

A patient develops fever, tachycardia, and a tender erythematous wound with crepitus 48 hours after surgery. Which diagnosis must be suspected first?

  1. Seroma formation
  2. Wound dehiscence
  3. Necrotizing soft tissue infection Correct answer.
  4. Superficial cellulitis

Explanation

Pain out of proportion, systemic toxicity, and crepitus after surgery suggest a necrotizing soft tissue infection, which requires urgent surgical exploration and debridement. Cellulitis alone does not produce crepitus or such rapid systemic deterioration, and seroma or dehiscence do not cause gas in tissues.

Question 44Surgery

What is the most common cause of mechanical small bowel obstruction in adults who have never had abdominal surgery?

  1. Hernia Correct answer.
  2. Adhesions
  3. Gallstone ileus
  4. Malignant stricture

Explanation

In patients without previous laparotomy, an external hernia is the leading cause of mechanical small bowel obstruction. Adhesions dominate only in patients with prior abdominal surgery, and gallstone ileus and malignant stricture are much less common.

Question 45Surgery

A 30-year-old woman has right lower quadrant pain, fever, and leukocytosis. At laparoscopy the appendix appears normal but the right ovary shows a hemorrhagic cyst. What is the correct next step?

  1. Appendectomy only
  2. Close the abdomen without further intervention
  3. Right salpingo-oophorectomy
  4. Appendectomy and gynecologic evaluation of the cyst Correct answer.

Explanation

When the appendix looks normal at laparoscopy for suspected appendicitis, removing it prevents future diagnostic confusion, and the unexpected adnexal pathology must be assessed and managed appropriately. Salpingo-oophorectomy is not justified for a benign hemorrhagic cyst in a young woman without further indication.

Question 46Surgery

Which finding is most characteristic of acute arterial occlusion of the lower limb?

  1. Sudden severe pain with pallor and absent pulses Correct answer.
  2. Superficial varicosities with ulceration
  3. Pitting edema with a warm limb
  4. Chronic claudication relieved by rest

Explanation

Acute arterial occlusion presents with the classic features of sudden pain, pallor, pulselessness, paresthesia, and paralysis, reflecting abrupt loss of perfusion. Edema and warmth suggest venous obstruction, claudication is a chronic symptom, and varicosities relate to venous disease.

Question 47Surgery

A patient with a stab wound to the left chest is hypotensive with distended neck veins and absent breath sounds on the left. What is the most appropriate immediate intervention?

  1. Chest tube insertion alone
  2. Pericardiocentesis
  3. Needle decompression of the left pleural space Correct answer.
  4. Emergency thoracotomy

Explanation

Hypotension, distended neck veins, and absent unilateral breath sounds after chest trauma indicate tension pneumothorax, which is treated immediately by needle decompression before any imaging. Pericardiocentesis addresses tamponade, which does not abolish breath sounds, and thoracotomy is a last resort.

Question 48Surgery

Which of the following is the most reliable early sign of compartment syndrome in a patient with a tibial fracture?

  1. Pain with passive stretch of the compartment muscles Correct answer.
  2. Pallor of the toes
  3. Absent distal pulse
  4. Decreased capillary refill

Explanation

Pain on passive stretch is the earliest and most reliable clinical sign of compartment syndrome, reflecting ischemic muscle. Pulselessness and pallor are late findings because compartment pressures rarely exceed arterial pressure, so waiting for them delays treatment.

Question 49Surgery

A 55-year-old man has painless gross hematuria. Which initial evaluation is most appropriate after excluding infection?

  1. Cystoscopy with upper urinary tract imaging Correct answer.
  2. Repeat urinalysis in six months
  3. Renal biopsy
  4. Urine cytology alone

Explanation

Painless gross hematuria in an older adult is a red flag for urothelial malignancy and requires direct visualization by cystoscopy plus imaging of the upper tracts. Cytology alone has insufficient sensitivity, and biopsy or simple observation would delay diagnosis.

Question 50Surgery

Which parameter is used to calculate the serum anion gap?

  1. Sodium minus chloride plus bicarbonate
  2. Sodium minus chloride minus bicarbonate Correct answer.
  3. Chloride minus bicarbonate
  4. Potassium plus sodium minus bicarbonate

Explanation

The anion gap is calculated as sodium minus the sum of chloride and bicarbonate, representing unmeasured anions. It helps classify metabolic acidosis into high-gap and normal-gap causes and guide further investigation.