COMSAE PHASE 1 FORM 113 EXAM EDITION COMPREHENSIVE REVIEW QUESTIONS WITH DETAILED EXPLANATIONS Complete Coverage of All Tested Topics with Clinical Correlates and Evidence-Based Rationales

COMSAE PHASE 1 FORM 113 EXAM EDITION COMPREHENSIVE REVIEW QUESTIONS WITH DETAILED EXPLANATIONS Complete Coverage of All Tested Topics with Clinical Correlates and Evidence-Based Rationales 1. A 25-year-old woman presents with episodic palpitations, sweating, and anxiety. During an episode, her blood pressure is 180/100 mmHg and heart rate 120 bpm. Laboratory testing reveals elevated urinary metanephrines. Which imaging modality is most appropriate for initial localization of the suspected tumor? A) CT scan of the abdomen and pelvis B) MRI of the brain C) Ultrasound of the thyroid D) PET scan CORRECT ANSWER: A) CT scan of the abdomen and pelvis is the initial imaging modality of choice for localizing pheochromocytoma. MRI (B) is alternative but CT is preferred first-line. Ultrasound (C) cannot adequately visualize adrenal masses. PET scan (D) is not initial localization study. Rationale: Pheochromocytoma typically arises from adrenal medulla (90%). CT provides excellent anatomic detail. After biochemical confirmation with elevated plasma or urinary metanephrines, imaging localization guides surgical resection. Alpha-blockade must precede any intervention to prevent hypertensive crisis. ________________________________________ 2. A 55-year-old man with chronic kidney disease stage 4 presents with fatigue, bone pain, and muscle weakness. Laboratory studies show calcium 8.9 mg/dL, phosphorus 5.8 mg/dL, PTH 450 pg/mL, and 25-hydroxyvitamin D 15 ng/mL. Which medication is most appropriate to address the underlying pathophysiology? A) Calcitriol B) Calcium carbonate C) Sevelamer D) Cinacalcet CORRECT ANSWER: C) Sevelamer is a phosphate binder that addresses hyperphosphatemia, the primary driver of secondary hyperparathyroidism in CKD. Calcitriol (A) treats low active vitamin D but does not address phosphate. Calcium carbonate (B) can worsen vascular calcification. Cinacalcet (D) treats hyperparathyroidism but phosphate control is first step. Rationale: In CKD, phosphate retention stimulates PTH secretion. Reducing phosphate absorption with non-calcium binders like sevelamer addresses the underlying stimulus. This prevents further bone disease and vascular calcification. ________________________________________ 3. A 72-year-old man presents with progressive dysphagia to both solids and liquids, weight loss of 20 pounds over 3 months, and regurgitation of undigested food. Barium swallow shows a dilated esophagus with a bird-beak appearance at the gastroesophageal junction. What is the most likely diagnosis? A) Esophageal cancer B) Achalasia C) Diffuse esophageal spasm D) Peptic stricture CORRECT ANSWER: B) Achalasia presents with progressive dysphagia to solids and liquids, regurgitation, and bird-beak sign on barium swallow. Esophageal cancer (A) typically shows irregular filling defect. Diffuse esophageal spasm (C) shows corkscrew esophagus. Peptic stricture (D) typically from GERD with solid food dysphagia only. Rationale: Achalasia results from loss of inhibitory neurons in the esophageal myenteric plexus, causing failure of LES relaxation. Manometry shows incomplete LES relaxation and aperistalsis. Treatment options include pneumatic dilation or surgical myotomy. ________________________________________ 4. A 68-year-old woman with hypertension presents with acute-onset severe headache, nausea, and visual disturbances. Her blood pressure is 220/140 mmHg. Fundoscopic exam reveals papilledema and retinal hemorrhages. Which medication should be administered immediately intravenously? A) Labetalol B) Nitroprusside C) Hydralazine D) Enalaprilat CORRECT ANSWER: B) Nitroprusside is preferred for hypertensive emergency with neurologic symptoms due to rapid onset and titratable effect. Labetalol (A) can be used but may have slower onset. Hydralazine (C) can cause reflex tachycardia. Enalaprilat (D) has variable response. Rationale: Hypertensive emergency with end-organ damage requires rapid controlled blood pressure reduction. Nitroprusside is a potent arterial and venous vasodilator with onset within seconds. Blood pressure should be reduced by no more than 25% in the first hour to prevent cerebral ischemia. ________________________________________ 5. A 45-year-old man presents with jaundice, dark urine, and pale stools. He reports a 2-week history of right upper quadrant pain. Laboratory studies show AST 450 U/L, ALT 520 U/L, alkaline phosphatase 380 U/L, total bilirubin 6.5 mg/dL, and direct bilirubin 4.2 mg/dL. Ultrasound reveals a dilated intrahepatic and extrahepatic biliary tree. What is the most likely diagnosis? A) Acute viral hepatitis B) Choledocholithiasis C) Alcoholic liver disease D) Hepatocellular carcinoma CORRECT ANSWER: B) Choledocholithiasis presents with obstructive jaundice (elevated direct bilirubin, dark urine, pale stools) and dilated bile ducts on ultrasound. Acute viral hepatitis (A) shows hepatocellular pattern with lower alkaline phosphatase. Alcoholic liver disease (C) typically ASTALT. Hepatocellular carcinoma (D) requires mass lesion.