ABIM MCQ 5 — Questions and Answers
Question 1: A 35-year-old woman presents with recurrent episodes of severe abdominal pain, vomiting, and port-wine colored urine precipitated by fasting and oral contraceptive use. Urine porphobilinogen is markedly elevated during attacks. What is the most appropriate acute treatment?
- IV hemin (heme arginate) and glucose loading (Correct answer)
- IV morphine and ondansetron only
- Plasmapheresis
- Pyridoxine supplementation
Correct answer: IV hemin (heme arginate) and glucose loading
Acute attacks of acute intermittent porphyria are treated with IV hemin, which represses ALA synthase, and high glucose loading to suppress the heme biosynthesis pathway.
Question 2: A 67-year-old man with CLL presents with worsening fatigue and pallor. Hemoglobin is 7.1 g/dL, MCV 92, reticulocyte count 8%. Direct antiglobulin test (DAT) is positive for IgG. LDH is elevated. What is the diagnosis?
- Autoimmune hemolytic anemia (AIHA) (Correct answer)
- Aplastic anemia
- Myelodysplastic syndrome
- Iron deficiency anemia
Correct answer: Autoimmune hemolytic anemia (AIHA)
Warm AIHA is the most common hematologic complication of CLL, presenting with a positive DAT for IgG, elevated LDH, and increased reticulocyte count reflecting hemolysis.
Question 3: A 48-year-old woman with known mitral stenosis and atrial fibrillation presents with acute onset left hemiplegia and facial droop. MRI brain confirms ischemic stroke. She is outside the tPA window. Her INR was 1.4 yesterday. What is the most appropriate anticoagulation strategy going forward?
- Warfarin with goal INR 2.0-3.0 (Correct answer)
- Apixaban 5 mg twice daily
- Aspirin plus clopidogrel
- Low-molecular-weight heparin long-term
Correct answer: Warfarin with goal INR 2.0-3.0
Rheumatic mitral stenosis with atrial fibrillation is an indication for warfarin; DOACs like apixaban are not approved for this indication due to inferior outcomes in valvular AF.
Question 4: A 57-year-old man with HIV on ART (CD4 450 cells/µL, undetectable viral load) presents with progressive vision loss in his right eye. Ophthalmology exam shows a 'pizza pie' fundus appearance with perivascular hemorrhages and exudates. What is the most likely diagnosis?
- CMV retinitis (Correct answer)
- Toxoplasma chorioretinitis
- Syphilitic uveitis
- Cryptococcal choroiditis
Correct answer: CMV retinitis
CMV retinitis presents with the classic 'pizza pie' or 'scrambled eggs and ketchup' fundus appearance and occurs in severe immunosuppression, though can rarely occur at higher CD4 counts.
Question 5: A 73-year-old woman is admitted with decompensated heart failure. She is started on IV furosemide but develops worsening creatinine (1.4 → 2.1 mg/dL) despite improving pulmonary congestion. What is this phenomenon called and what should be done?
- Cardiorenal syndrome — continue diuresis if congestion persists (Correct answer)
- Acute kidney injury — stop diuretics immediately
- Contrast nephropathy — hydrate aggressively
- Prerenal azotemia — give IV fluids
Correct answer: Cardiorenal syndrome — continue diuresis if congestion persists
Cardiorenal syndrome type 1 involves AKI from decompensated HF; continued gentle diuresis is appropriate if the patient remains fluid overloaded, as congestion itself harms the kidneys.
Question 6: A 44-year-old man presents with a 3-month history of dysphagia to solids and liquids, regurgitation of undigested food, and weight loss of 12 lbs. Barium swallow shows a 'bird beak' narrowing at the gastroesophageal junction. Esophageal manometry confirms absent peristalsis. What is the diagnosis?
- Achalasia (Correct answer)
- Diffuse esophageal spasm
- Eosinophilic esophagitis
- Scleroderma esophagus
Correct answer: Achalasia
Achalasia is characterized by absent esophageal peristalsis and failure of the lower esophageal sphincter to relax, confirmed by manometry and showing 'bird beak' sign on barium swallow.
Question 7: A 61-year-old woman with a history of breast cancer treated 10 years ago presents with back pain and hypercalcemia (Ca 12.4 mg/dL). PTH is low (<5 pg/mL) and PTHrP is elevated. Bone scan shows multiple areas of increased uptake. What is the mechanism of her hypercalcemia?
- PTHrP-mediated humoral hypercalcemia of malignancy (Correct answer)
- Osteolytic metastases releasing calcium
- Vitamin D-mediated granulomatous hypercalcemia
- Primary hyperparathyroidism
Correct answer: PTHrP-mediated humoral hypercalcemia of malignancy
Elevated PTHrP with suppressed PTH confirms humoral hypercalcemia of malignancy; PTHrP mimics PTH action on osteoclasts, mobilizing calcium from bone.
ABIM MCQ 5
A 35-year-old woman presents with recurrent episodes of severe abdominal pain, vomiting, and port-wine colored urine precipitated by fasting and oral contraceptive use.
Urine porphobilinogen is markedly elevated during attacks.
What is the most appropriate acute treatment?