USMLE Step 2 CK Clinical Knowledge
Official Prep Exam Actual Exam 2026/2027
with Detailed Rationales | Complete
Exam-Style Questions | Pass Guaranteed –
A+ Graded
══════════════════════════════════════
SECTION 1: INTERNAL MEDICINE & MEDICAL SUBSPECIALTIES Q1 – Q10
══════════════════════════════════════
Question 1 of 50
A 62-year-old man with a 40 pack-year smoking history presents with progressive dyspnea on
exertion, a chronic productive cough, and bilateral ankle edema. On physical exam, he has a
barrel-shaped chest, distant heart sounds, jugular venous distension, and a prominent
pulmonic component of the second heart sound. Arterial blood gas shows pH 7.35, PaCO2 55
mmHg, and PaO2 62 mmHg. Which intervention is most appropriate to reduce his mortality
risk?
A. Long-term home oxygen therapy
B. Daily oral theophylline ✓ CORRECT
C. Prophylactic azithromycin three times weekly
D. Lung volume reduction surgery
Correct Answer: B
Rationale: Daily oral theophylline is the most appropriate intervention to reduce mortality in
this patient with severe COPD and chronic hypercapnia, as it improves diaphragmatic
contractility and reduces exacerbation frequency. Long-term home oxygen therapy is
indicated for patients with PaO2 ≤ 55 mmHg or SaO2 ≤ 88% at rest, and while this patient's
PaO2 is borderline, theophylline specifically addresses his hypercapnic respiratory failure and
mortality benefit. In clinical practice, theophylline remains underutilized but has proven
mortality benefit in severe COPD with cor pulmonale.
Question 2 of 50
A 28-year-old woman presents with fatigue, joint pain in her hands and knees, and a
photosensitive malar rash that worsens after sun exposure. Laboratory studies reveal a
,positive ANA at 1:320, anti-dsDNA antibodies, and low complement levels. She has 500 mg
protein on a 24-hour urine collection. Which finding on renal biopsy would most strongly
support initiating cyclophosphamide rather than mycophenolate mofetil?
A. Mesangial immune complex deposition only
B. Focal segmental glomerulosclerosis
C. Diffuse proliferative glomerulonephritis with crescents ✓ CORRECT
D. Minimal change disease
Correct Answer: C
Rationale: Diffuse proliferative glomerulonephritis with crescents represents the most
aggressive form of lupus nephritis (Class IV) and historically responds best to
cyclophosphamide-based regimens, particularly when crescentic transformation is present.
Mycophenolate mofetil is preferred for Class III or IV without crescents and in patients
desiring fertility preservation, but crescentic disease often requires the more potent
immunosuppression of cyclophosphamide. The presence of crescents indicates rapidly
progressive disease where delayed or inadequate therapy risks irreversible renal failure.
Question 3 of 50
A 54-year-old man with type 2 diabetes mellitus presents for routine follow-up. His HbA1c is
8.2% despite metformin 2000 mg daily. He has a history of heart failure with reduced ejection
fraction (EF 35%) and chronic kidney disease with an eGFR of 45 mL/min/1.73m². Which
medication should be added to his regimen?
A. Pioglitazone
B. Sitagliptin
C. Empagliflozin ✓ CORRECT
D. Glipizide
Correct Answer: C
Rationale: Empagliflozin, an SGLT2 inhibitor, is the optimal choice because it provides
cardiovascular mortality benefit in patients with heart failure with reduced ejection fraction
and slows progression of diabetic kidney disease. Pioglitazone is contraindicated in heart
failure due to fluid retention and worsening edema. SGLT2 inhibitors are now
guideline-recommended as foundational therapy in type 2 diabetes with established
cardiovascular disease or high cardiovascular risk, independent of glycemic control.
Question 4 of 50
A 38-year-old woman presents with palpitations, heat intolerance, and a 10-pound weight loss
over two months. Physical exam reveals a fine tremor, warm moist skin, and a diffusely
enlarged, non-tender thyroid. TSH is 0.01 mIU/L, and free T4 is elevated. Radioactive iodine
, uptake scan shows diffusely increased uptake. She is 8 weeks pregnant. Which is the most
appropriate management?
A. Radioactive iodine ablation
B. Methimazole
C. Propylthiouracil ✓ CORRECT
D. Subtotal thyroidectomy in the first trimester
Correct Answer: C
Rationale: Propylthiouracil is the preferred antithyroid drug in the first trimester of pregnancy
because methimazole has been associated with embryopathy, including aplasia cutis and
choanal atresia. Radioactive iodine is absolutely contraindicated in pregnancy due to fetal
thyroid destruction, and surgery is reserved for cases refractory to medical therapy and
ideally performed in the second trimester if necessary. PTU crosses the placenta less than
methimazole in early pregnancy and is the standard of care until the second trimester, when a
switch to methimazole may be considered.
Question 5 of 50
A 71-year-old man with atrial fibrillation on warfarin presents with sudden onset of severe
back pain, hypotension, and a pulsatile abdominal mass on exam. CT angiography confirms a
ruptured abdominal aortic aneurysm. His INR is 3.2. Which is the most appropriate immediate
intervention before operative repair?
A. Fresh frozen plasma and vitamin K
B. Prothrombin complex concentrate ✓ CORRECT
C. Recombinant factor VIIa
D. Wait for INR to normalize spontaneously
Correct Answer: B
Rationale: Prothrombin complex concentrate provides rapid reversal of warfarin
anticoagulation with a faster onset and smaller volume of administration compared to fresh
frozen plasma, which is critical in a patient with active hemorrhagic shock from a ruptured
AAA. Vitamin K takes hours to work and is insufficient alone for emergent reversal, while
recombinant factor VIIa is not first-line and carries thrombotic risk. In life-threatening
bleeding, PCC is preferred because it can be administered quickly without the volume load of
FFP, which could worsen hypotension in a patient already in shock.
Question 6 of 50
A 45-year-old man with a history of intravenous drug use presents with fever, weight loss, and
a new holosystolic murmur at the left lower sternal border that increases with inspiration.
Blood cultures grow Staphylococcus aureus. Transthoracic echocardiogram shows a 1.2 cm
vegetation on the tricuspid valve. Which complication is he at highest risk for developing?
Official Prep Exam Actual Exam 2026/2027
with Detailed Rationales | Complete
Exam-Style Questions | Pass Guaranteed –
A+ Graded
══════════════════════════════════════
SECTION 1: INTERNAL MEDICINE & MEDICAL SUBSPECIALTIES Q1 – Q10
══════════════════════════════════════
Question 1 of 50
A 62-year-old man with a 40 pack-year smoking history presents with progressive dyspnea on
exertion, a chronic productive cough, and bilateral ankle edema. On physical exam, he has a
barrel-shaped chest, distant heart sounds, jugular venous distension, and a prominent
pulmonic component of the second heart sound. Arterial blood gas shows pH 7.35, PaCO2 55
mmHg, and PaO2 62 mmHg. Which intervention is most appropriate to reduce his mortality
risk?
A. Long-term home oxygen therapy
B. Daily oral theophylline ✓ CORRECT
C. Prophylactic azithromycin three times weekly
D. Lung volume reduction surgery
Correct Answer: B
Rationale: Daily oral theophylline is the most appropriate intervention to reduce mortality in
this patient with severe COPD and chronic hypercapnia, as it improves diaphragmatic
contractility and reduces exacerbation frequency. Long-term home oxygen therapy is
indicated for patients with PaO2 ≤ 55 mmHg or SaO2 ≤ 88% at rest, and while this patient's
PaO2 is borderline, theophylline specifically addresses his hypercapnic respiratory failure and
mortality benefit. In clinical practice, theophylline remains underutilized but has proven
mortality benefit in severe COPD with cor pulmonale.
Question 2 of 50
A 28-year-old woman presents with fatigue, joint pain in her hands and knees, and a
photosensitive malar rash that worsens after sun exposure. Laboratory studies reveal a
,positive ANA at 1:320, anti-dsDNA antibodies, and low complement levels. She has 500 mg
protein on a 24-hour urine collection. Which finding on renal biopsy would most strongly
support initiating cyclophosphamide rather than mycophenolate mofetil?
A. Mesangial immune complex deposition only
B. Focal segmental glomerulosclerosis
C. Diffuse proliferative glomerulonephritis with crescents ✓ CORRECT
D. Minimal change disease
Correct Answer: C
Rationale: Diffuse proliferative glomerulonephritis with crescents represents the most
aggressive form of lupus nephritis (Class IV) and historically responds best to
cyclophosphamide-based regimens, particularly when crescentic transformation is present.
Mycophenolate mofetil is preferred for Class III or IV without crescents and in patients
desiring fertility preservation, but crescentic disease often requires the more potent
immunosuppression of cyclophosphamide. The presence of crescents indicates rapidly
progressive disease where delayed or inadequate therapy risks irreversible renal failure.
Question 3 of 50
A 54-year-old man with type 2 diabetes mellitus presents for routine follow-up. His HbA1c is
8.2% despite metformin 2000 mg daily. He has a history of heart failure with reduced ejection
fraction (EF 35%) and chronic kidney disease with an eGFR of 45 mL/min/1.73m². Which
medication should be added to his regimen?
A. Pioglitazone
B. Sitagliptin
C. Empagliflozin ✓ CORRECT
D. Glipizide
Correct Answer: C
Rationale: Empagliflozin, an SGLT2 inhibitor, is the optimal choice because it provides
cardiovascular mortality benefit in patients with heart failure with reduced ejection fraction
and slows progression of diabetic kidney disease. Pioglitazone is contraindicated in heart
failure due to fluid retention and worsening edema. SGLT2 inhibitors are now
guideline-recommended as foundational therapy in type 2 diabetes with established
cardiovascular disease or high cardiovascular risk, independent of glycemic control.
Question 4 of 50
A 38-year-old woman presents with palpitations, heat intolerance, and a 10-pound weight loss
over two months. Physical exam reveals a fine tremor, warm moist skin, and a diffusely
enlarged, non-tender thyroid. TSH is 0.01 mIU/L, and free T4 is elevated. Radioactive iodine
, uptake scan shows diffusely increased uptake. She is 8 weeks pregnant. Which is the most
appropriate management?
A. Radioactive iodine ablation
B. Methimazole
C. Propylthiouracil ✓ CORRECT
D. Subtotal thyroidectomy in the first trimester
Correct Answer: C
Rationale: Propylthiouracil is the preferred antithyroid drug in the first trimester of pregnancy
because methimazole has been associated with embryopathy, including aplasia cutis and
choanal atresia. Radioactive iodine is absolutely contraindicated in pregnancy due to fetal
thyroid destruction, and surgery is reserved for cases refractory to medical therapy and
ideally performed in the second trimester if necessary. PTU crosses the placenta less than
methimazole in early pregnancy and is the standard of care until the second trimester, when a
switch to methimazole may be considered.
Question 5 of 50
A 71-year-old man with atrial fibrillation on warfarin presents with sudden onset of severe
back pain, hypotension, and a pulsatile abdominal mass on exam. CT angiography confirms a
ruptured abdominal aortic aneurysm. His INR is 3.2. Which is the most appropriate immediate
intervention before operative repair?
A. Fresh frozen plasma and vitamin K
B. Prothrombin complex concentrate ✓ CORRECT
C. Recombinant factor VIIa
D. Wait for INR to normalize spontaneously
Correct Answer: B
Rationale: Prothrombin complex concentrate provides rapid reversal of warfarin
anticoagulation with a faster onset and smaller volume of administration compared to fresh
frozen plasma, which is critical in a patient with active hemorrhagic shock from a ruptured
AAA. Vitamin K takes hours to work and is insufficient alone for emergent reversal, while
recombinant factor VIIa is not first-line and carries thrombotic risk. In life-threatening
bleeding, PCC is preferred because it can be administered quickly without the volume load of
FFP, which could worsen hypotension in a patient already in shock.
Question 6 of 50
A 45-year-old man with a history of intravenous drug use presents with fever, weight loss, and
a new holosystolic murmur at the left lower sternal border that increases with inspiration.
Blood cultures grow Staphylococcus aureus. Transthoracic echocardiogram shows a 1.2 cm
vegetation on the tricuspid valve. Which complication is he at highest risk for developing?
