10 USMLE Internal Medicine Questions with Answers and Explanations (Set 2)

These 10 USMLE internal medicine practice questions (Set 2) focus on Step 2 CK management decisions: emergencies such as cauda equina, DKA and pulmonary embolism, preeclampsia with severe features, acute pancreatitis, stroke prevention in atrial fibrillation, latent tuberculosis, peripartum cardiomyopathy, dermatomyositis and acute low back pain. 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 45-year-old man presents with a 2-day history of severe low back pain radiating to both legs. He now reports new-onset urinary retention and decreased sensation in the perianal region. On examination, there is bilateral lower extremity weakness and decreased anal sphincter tone. Which of the following is the most appropriate next step in management?

A- MRI of the lumbosacral spine
B- Plain radiograph of the lumbar spine
C- Outpatient physical therapy referral
D- Oral corticosteroids
E- Lumbar puncture

A- MRI of the lumbosacral spine- Cauda equina syndrome is a surgical emergency caused by compression of the lumbosacral nerve roots, presenting with saddle anesthesia, bowel/bladder dysfunction, and bilateral leg weakness. Urgent MRI is required to confirm the diagnosis and guide emergency surgical decompression, as delay increases the risk of permanent neurologic damage.
The correct answer is A

 

Question 2. A 32-year-old woman at 34 weeks gestation presents with a blood pressure of 168/112 mmHg on two occasions four hours apart and a mild headache. Urinalysis shows 2+ protein. She has no visual changes or epigastric pain. Which of the following is the most appropriate next step in management?

A- Reassurance and follow-up in one week
B- Admit for blood pressure control and fetal monitoring
C- Immediate delivery regardless of gestational age
D- Start oral iron supplementation
E- Outpatient 24-hour urine protein collection only

B- Admit for blood pressure control and fetal monitoring- Severe-range blood pressure with proteinuria meets criteria for preeclampsia with severe features. This patient should be admitted for blood pressure control, fetal monitoring, and magnesium sulfate for seizure prophylaxis. Delivery timing depends on gestational age and disease severity.
The correct answer is B

 

Question 3. A 50-year-old man with a history of chronic alcohol use presents with severe epigastric pain radiating to the back, nausea, and vomiting for the past 12 hours. On examination, he has epigastric tenderness with voluntary guarding. Lipase is 3 times the upper limit of normal. Which of the following is the most appropriate initial step in management?

A- Aggressive intravenous fluid resuscitation
B- Emergency ERCP
C- Immediate surgical debridement
D- Broad-spectrum prophylactic antibiotics
E- NPO with total parenteral nutrition indefinitely

A- Aggressive intravenous fluid resuscitation- The cornerstone of initial management of acute pancreatitis is early, aggressive IV fluid resuscitation to prevent hypovolemia and pancreatic necrosis. ERCP is reserved for gallstone pancreatitis with cholangitis or biliary obstruction. Prophylactic antibiotics and routine TPN are not indicated in most cases; early enteral feeding is preferred once tolerated.
The correct answer is A

 

Question 4. A 22-year-old woman with type 1 diabetes mellitus presents with nausea, vomiting, and abdominal pain for one day. She appears lethargic with deep, labored breathing. Laboratory studies show glucose of 480 mg/dL, pH 7.12, bicarbonate 9 mEq/L, and positive serum ketones. Her potassium is 3.2 mEq/L. Which of the following is the most appropriate initial step in management?

A- Intravenous isotonic saline
B- Intravenous insulin bolus followed by infusion
C- Intravenous potassium repletion before fluids
D- Intravenous sodium bicarbonate
E- Subcutaneous insulin

A- Intravenous isotonic saline- The first step in managing diabetic ketoacidosis is aggressive isotonic fluid resuscitation to restore intravascular volume, which also helps lower glucose and correct electrolyte disturbances. Insulin therapy should be started only after ensuring the potassium level is at least 3.3 mEq/L, since insulin drives potassium intracellularly and can precipitate life-threatening hypokalemia and arrhythmias if given first in a hypokalemic patient.
The correct answer is A

 

Question 5. A 60-year-old woman who underwent hip replacement surgery 5 days ago develops sudden-onset dyspnea and pleuritic chest pain. Her heart rate is 118/min, respiratory rate is 26/min, and oxygen saturation is 89% on room air. She is hemodynamically stable otherwise. Which of the following is the most appropriate next step in management?

A- CT pulmonary angiography
B- D-dimer testing
C- Empiric anticoagulation while awaiting imaging
D- Ventilation-perfusion scan
E- Lower extremity Doppler ultrasound only

C- Empiric anticoagulation while awaiting imaging- In a patient with high pretest probability for pulmonary embolism (recent major surgery, tachycardia, hypoxia, and classic symptoms) who is hemodynamically stable but at risk of clinical deterioration, empiric anticoagulation should be started while confirmatory imaging (CT pulmonary angiography, the gold standard) is arranged, provided there is no contraindication to anticoagulation. D-dimer is not useful in high pretest probability patients since a negative result does not reliably exclude PE.
The correct answer is C

 

Question 6. A 63-year-old man with atrial fibrillation presents for routine follow-up. He has no history of stroke, diabetes, or heart failure. His blood pressure is well controlled. Which of the following is the most appropriate long-term management to reduce stroke risk?

A- Aspirin only
B- Dual antiplatelet therapy
C- Oral anticoagulation

C- Oral anticoagulation- Patients with atrial fibrillation and a CHA₂DS₂-VASc score ≥2 require oral anticoagulation to reduce the risk of thromboembolic stroke.
The correct answer is C

 

Question 7. A 19-year-old man is referred to the clinic for a positive purified protein derivative (PPD) test for tuberculosis. He moved to the United States from Egypt 2 years ago and has been in good health. He has no history of fever, cough, weight loss, or night sweats. He has no family history or contacts with tuberculosis. His physical examination is normal. His chest x-ray shows no cavitation or hilar adenopathy. What is the best next step in management for this patient?

A- Repeat the PPD test and x-ray after 6 months
B- Start treatment with isoniazid for 9 months
C- Start treatment with multiple-drug antituberculosis therapy
D- Isolation and full anti-tuberculosis therapy for 6 months

B- Start treatment with isoniazid for 9 months- This man has a previous exposure to TB, which caused subclinical infection. His history, physical examination, and chest x-ray exclude current active TB. He does not need multiple drug treatment at this time, but he should take prophylactic treatment in case there is any dormant infection in his body. The best treatment for this case is isoniazid for 9 months.
Note: shorter rifamycin-based regimens (such as 3 months of weekly isoniazid plus rifapentine, or 4 months of rifampin) are now often preferred, but isoniazid for 6–9 months remains an accepted option.
The correct answer is B

 

Question 8. A 27-year-old woman presents with fatigue and shortness of breath. She recently delivered a baby 3 weeks ago. Echocardiography shows dilated cardiomyopathy with reduced ejection fraction. What is the most likely diagnosis?

A- Peripartum cardiomyopathy
B- Restrictive cardiomyopathy
C- Takotsubo cardiomyopathy
D- Viral myocarditis

A- Peripartum cardiomyopathy- Peripartum cardiomyopathy occurs in the last month of pregnancy or within 5 months postpartum and presents with heart failure due to dilated cardiomyopathy.
The correct answer is A

 

Question 9. A 52-year-old woman presents with progressive muscle weakness and a heliotrope rash around her eyes. Laboratory testing shows elevated creatine kinase levels. Which of the following conditions is most strongly associated with this disease?

A- Chronic kidney disease
B- Recent vaccination
C- Underlying malignancy
D- Viral infection

C- Underlying malignancy- Dermatomyositis is associated with paraneoplastic syndromes, particularly ovarian, lung, breast, and gastrointestinal cancers.
The correct answer is C

 

Question 10. A 56-year-old man visits his physician complaining of lower back pain for 1 week. He was moving to a new house and carried a lot of furniture during the last 2 weeks. His pain does not radiate, improves with rest and ibuprofen, and worsens with movement. He has no fever, weight loss, history of cancer, bladder or bowel problems, or trauma. On examination, vital signs are normal and there is diffuse tenderness over the lumbar muscles. Neurological examination is normal. What is the most appropriate next step in management?

A- X-ray of the lumbar spine
B- MRI of the lumbar spine
C- Reassurance, NSAIDs and staying active
D- Strict bed rest for 2 weeks
E- Referral to a spine surgeon

C- Reassurance, NSAIDs and staying active- This is acute mechanical (musculoskeletal) low back pain without red flags. Most cases improve within 4 to 6 weeks. Imaging is NOT recommended in the first 6 weeks unless red flags are present: age over 50 with new pain plus cancer history, fever or IV drug use, unexplained weight loss, trauma, progressive neurologic deficit, or bladder/bowel dysfunction or saddle anesthesia (cauda equina).
Bed rest slows recovery; patients should stay active. Surgery referral is only for serious neurologic findings or pain that fails conservative treatment.
The correct answer is C

 

High-yield points from this set

  • Saddle anesthesia, urinary retention and leg weakness = cauda equina: urgent MRI and surgery.
  • BP 160/110 or higher with proteinuria = preeclampsia with severe features: admit.
  • Acute pancreatitis: early aggressive IV fluids.
  • DKA: start with IV isotonic saline; replace potassium before insulin if K+ is below 3.3.
  • High suspicion of PE: start anticoagulation while waiting for CT angiography.
  • AF with CHA2DS2-VASc of 2 or more: oral anticoagulation.
  • Positive PPD with a normal chest x-ray = latent TB: isoniazid or a rifamycin regimen.
  • Heart failure in late pregnancy or months after delivery = peripartum cardiomyopathy.
  • Dermatomyositis is associated with an underlying malignancy.
  • Acute low back pain without red flags: no imaging, NSAIDs and staying active.

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