11 USMLE Step 2 CK Clinical Review Questions with Answers (Set 6)

These 11 USMLE Step 2 CK clinical review questions are short clinical cases on diagnosis and next-step management, including Azithromycin, Courvoisier sign, Antiphospholipid antibody syndrome, NADPH oxidase, Polymyositis, Anti-TSH receptor antibodies, Type IV collagen, Plasma exchange. Each question includes the correct answer and an explanation.

Written by Dr. Ray Makar, MD, author of the Repeated USMLE Questions eBook series.

Prefer video? Watch daily USMLE case questions on MedFocus by Dr. Ray on YouTube.

How to use this page: read the question, pick your answer, then tap Show Answer and Explanation.

Questions

Question 1. A 67-year-old man with a history of chronic kidney disease presents with progressive shortness of breath and lower extremity edema. Echocardiography shows concentric left ventricular hypertrophy with normal ejection fraction. BNP is elevated. Which of the following pathophysiologic mechanisms is most responsible for this patient’s condition?

A- Decreased myocardial contractility
B- Impaired ventricular relaxation
C- Increased preload due to valvular regurgitation
D- Reduced coronary perfusion

B- Impaired ventricular relaxation- This patient has heart failure with preserved ejection fraction (HFpEF), caused by diastolic dysfunction due to impaired ventricular relaxation, commonly from hypertension or CKD-related myocardial stiffness.
The correct answer is B

 

Question 2. A 58-year-old woman presents with progressive proximal muscle weakness and dysphagia. She also reports a photosensitive rash over her upper chest and shoulders. Laboratory studies show elevated creatine kinase levels. Which of the following additional findings is most likely present?

A- Anti–acetylcholine receptor antibodies
B- Anti–Jo-1 antibodies
C- Malignancy on age-appropriate screening
D- Thymoma on chest imaging

C- Malignancy on age-appropriate screening- Dermatomyositis presents with proximal muscle weakness and characteristic skin findings (e.g., shawl sign). It is strongly associated with underlying malignancy, making cancer screening essential.
The correct answer is C

 

Question 3. A 45-year-old man presents with recurrent episodes of palpitations and syncope. ECG shows polymorphic ventricular tachycardia with prolonged QT interval. He recently started an antibiotic for pneumonia. Which of the following medications most likely precipitated this arrhythmia?

A- Azithromycin
B- Ceftriaxone
C- Doxycycline
D- Penicillin

A- Azithromycin- QT prolongation leading to torsades de pointes can be caused by macrolides, including azithromycin, especially in susceptible patients.
The correct answer is A

 

Question 4. A 72-year-old woman presents with painless jaundice, weight loss, and pruritus. Labs show elevated alkaline phosphatase and direct bilirubin. CT scan reveals a mass in the head of the pancreas. Which additional finding is most likely present?

A- Courvoisier sign
B- Grey Turner sign
C- Kehr sign
D- Murphy sign

A- Courvoisier sign- Pancreatic head carcinoma causes painless obstructive jaundice and a palpable, nontender gallbladder (Courvoisier sign), due to bile duct obstruction.
The correct answer is A

 

Question 5. A 34-year-old woman presents with recurrent miscarriages and a history of deep vein thrombosis. Laboratory testing shows prolonged aPTT that does not correct with mixing studies. What is the most likely underlying condition?

A- Factor V Leiden mutation
B- Protein C deficiency
C- Protein S deficiency
D- Antiphospholipid antibody syndrome

D- Antiphospholipid antibody syndrome- Antiphospholipid antibody syndrome causes hypercoagulability, recurrent pregnancy loss, and paradoxical prolonged aPTT that does not correct due to inhibitor antibodies.
The correct answer is D

 

Question 6. A 2-year-old child has recurrent infections with catalase-positive organisms. Neutrophils show absent oxidative burst on flow cytometry. Which enzyme is defective?

A- Adenosine deaminase
B- Glucose-6-phosphate dehydrogenase
C- NADPH oxidase
D- Myeloperoxidase

C- NADPH oxidase- Chronic granulomatous disease is due to NADPH oxidase deficiency → decreased ROS → susceptibility to catalase-positive organisms.
The correct answer is C

 

Question 7. A patient has difficulty rising from a chair and climbing stairs. Biopsy shows endomysial inflammation and CD8+ T-cell infiltration. Which condition is most likely?

A- Becker muscular dystrophy
B- Dermatomyositis
C- Polymyositis
D- Spinal muscular atrophy

C- Polymyositis- Polymyositis causes proximal muscle weakness with endomysial inflammation and CD8+ T cells.
The correct answer is C

 

Question 8. A 35-year-old woman has heat intolerance, weight loss, and palpitations. Lab: ↓TSH, ↑T3/T4. Which finding is most consistent with Graves disease?

A- Anti-thyroid peroxidase antibodies
B- Anti-TSH receptor antibodies
C- Decreased radioactive iodine uptake
D- Non-tender thyroid with fibrosis

B- Anti-TSH receptor antibodies- Graves is caused by stimulating antibodies against the TSH receptor → hyperthyroidism and diffuse uptake.
The correct answer is B

 

Question 9. A patient has episodes of hematuria and hearing loss. Electron microscopy shows splitting of the glomerular basement membrane. Which collagen is defective?

A- Type I collagen
B- Type II collagen
C- Type III collagen
D- Type IV collagen

D- Type IV collagen- Alport syndrome involves defective type IV collagen → GBM abnormalities + hearing loss.
The correct answer is D

 

Question 10. A 64-year-old man presents to the emergency department with severe epigastric pain radiating to the back. He is febrile and tachycardic. Labs show lipase 1,800 U/L. RUQ ultrasound shows gallstones. Despite IV fluids and pain control, he develops hypotension and worsening hypoxemia over the next 12 hours. What is the best next step in management?

A- Administer broad-spectrum antibiotics immediately
B- Endoscopic retrograde cholangiopancreatography (ERCP) now
C- Start oral feeding to reduce catabolism
D- Transfer to ICU for aggressive supportive care

D-Transfer to ICU for aggressive supportive care- This is severe acute pancreatitis with systemic complications (shock/respiratory failure). The next step is ICU-level supportive care (fluids, oxygen/ventilation support, monitoring). Antibiotics are not routine unless infected necrosis is suspected. ERCP is for cholangitis or persistent biliary obstruction.
The correct answer is D

 

Question 11. A 29-year-old woman presents with fatigue and easy bruising. CBC shows Hb 7.6 g/dL, platelets 18,000/mm³. Peripheral smear shows schistocytes. Creatinine is elevated. Coagulation studies are normal. She is confused on exam. What is the most appropriate immediate treatment?

A- Fresh frozen plasma
B- Heparin infusion
C- Platelet transfusion
D- Plasma exchange

D-Plasma exchange- This is classic TTP (thrombocytopenia, microangiopathic hemolytic anemia, neurologic symptoms, renal injury, normal PT/aPTT). Plasma exchange is lifesaving and must be started immediately.
The correct answer is D

 

High-yield points from this set

  • appropriate screening- Dermatomyositis presents with proximal muscle weakness and characteristic skin findings (e.g., shawl sign).
  • QT prolongation leading to torsades de pointes can be caused by macrolides, including azithromycin, especially in susceptible patients.
  • Pancreatic head carcinoma causes painless obstructive jaundice and a palpable, nontender gallbladder (Courvoisier sign), due to bile duct obstruction.
  • Antiphospholipid antibody syndrome causes hypercoagulability, recurrent pregnancy loss, and paradoxical prolonged aPTT that does not correct due to inhibitor antibodies.
  • Chronic granulomatous disease is due to NADPH oxidase deficiency → decreased ROS → susceptibility to catalase-positive organisms.

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