USMLE STEP 1 / STEP 2 CK COMPLETE HIGH-YIELD EXAM READY -
VERIFIED QUESTIONS AND ANSWERS - COMPREHENSIVE LATEST
VERSION 2026/2027
Q1. A 65-year-old man presents with crushing chest pain radiating
to the left arm, diaphoresis, and nausea. ECG shows ST elevation in
leads II, III, and aVF. Which coronary artery is most likely occluded?
ANSWER : Right coronary artery (RCA). ST elevation in the inferior
leads (II, III, aVF) indicates an inferior STEMI, which is most commonly
caused by RCA occlusion. The RCA supplies the inferior wall of the left
ventricle, the AV node, and the SA node in most patients.
Q2. A patient presents with wide, fixed splitting of S2 that does not
vary with respiration. What is the most likely diagnosis?
ANSWER : Atrial septal defect (ASD). The wide, fixed splitting of S2 is
pathognomonic for ASD. The fixed splitting occurs because the left-to-
right shunt equalizes pressure between the atria, causing constant delay
in pulmonic valve closure regardless of respiratory phase.
Q3. A 45-year-old woman presents with exertional dyspnea and a
mid-systolic click followed by a late systolic murmur best heard at
the apex. What is the diagnosis?
ANSWER : Mitral valve prolapse (MVP). The mid-systolic click followed
by a late systolic murmur is classic for MVP. The click moves earlier with
decreased preload (standing, Valsalva) and later with increased preload
(squatting, leg elevation).
Q4. Which antihypertensive is the drug of choice for a diabetic
patient with proteinuria and hypertension?
, ANSWER : ACE inhibitors (e.g., lisinopril) or ARBs are first-line. They
provide renoprotection by reducing intraglomerular pressure, decrease
proteinuria, and slow progression of diabetic nephropathy, independent
of their antihypertensive effect.
Q5. A patient has a blood pressure reading of 180/110 mmHg with
no end-organ damage. What is the appropriate management?
ANSWER : This is a hypertensive urgency. Management includes oral
antihypertensive medications (e.g., amlodipine, captopril, clonidine) with
gradual blood pressure reduction over 24-48 hours. Rapid correction
risks ischemic stroke, MI, or renal failure due to impaired autoregulation.
Q6. A 70-year-old man develops atrial fibrillation. His CHADS2-
VASc score is 4. What is the recommended treatment?
ANSWER : Oral anticoagulation (warfarin or a DOAC such as
rivaroxaban or apixaban) is indicated. A CHADS2-VASc score ≥2 in
males (≥3 in females) indicates high stroke risk requiring anticoagulation.
The annual stroke risk at score 4 is approximately 4%.
Q7. What is the mechanism of action of digoxin in heart failure?
ANSWER : Digoxin inhibits the Na/K-ATPase pump, increasing
intracellular sodium which in turn raises intracellular calcium via the
Na/Ca exchanger. The increased intracellular calcium enhances
myocardial contractility (positive inotrope). It also has vagotonic effects
that slow the heart rate.
Q8. A 55-year-old man develops sudden-onset palpitations. ECG
shows delta waves, a short PR interval, and a wide QRS. What is
the diagnosis?
ANSWER : Wolff-Parkinson-White (WPW) syndrome. The classic triad
of delta waves (slurred upstroke of QRS), short PR interval (<0.12 s),
and widened QRS indicates pre-excitation via an accessory pathway
(Bundle of Kent). Avoid AV-nodal blocking agents (digoxin, verapamil) in
WPW with AF.
,Q9. What ECG change is most characteristic of hyperkalemia when
potassium is 6.5 mEq/L?
ANSWER : Peaked (tall, narrow, symmetric) T waves are the earliest
ECG finding in hyperkalemia. Progressive hyperkalemia leads to: peaked
T waves → prolonged PR → widened QRS → sine wave pattern →
ventricular fibrillation.
Q10. A patient post-MI develops a holosystolic murmur at the lower
left sternal border and hemodynamic compromise. What
complication has occurred?
ANSWER : Ventricular septal rupture (VSR). This typically occurs 3-5
days post-MI, most commonly with anterior MI (LAD territory). It causes a
left-to-right shunt and is confirmed with step-up in oxygen saturation from
right atrium to pulmonary artery on right heart catheterization.
, PULMONOLOGY (10 Questions)
Q11. A 32-year-old woman presents with dyspnea and wheezing.
PFTs show FEV1/FVC < 0.70, FVC normal, and significant
reversibility after bronchodilator. What is the diagnosis?
ANSWER : Asthma. Obstructive pattern (reduced FEV1/FVC) with
significant reversibility (>12% and >200 mL improvement in FEV1 after
bronchodilator) is diagnostic of asthma. Normal FVC distinguishes it from
COPD with air trapping.
Q12. What is the most common cause of community-acquired
pneumonia (CAP) in a healthy adult?
ANSWER : Streptococcus pneumoniae is the most common cause of
CAP overall. Atypical organisms (Mycoplasma pneumoniae,
Chlamydophila pneumoniae) are common in younger adults. Treatment
is amoxicillin or azithromycin for mild outpatient CAP.
Q13. A 68-year-old smoker presents with progressive dyspnea,
barrel chest, and pursed-lip breathing. Spirometry shows FEV1/FVC
< 0.70 with no reversibility. Chest X-ray shows hyperinflation and
flattened diaphragms. What is the diagnosis?
ANSWER : Chronic Obstructive Pulmonary Disease (COPD),
specifically emphysema. The irreversible obstructive pattern, smoking
history, barrel chest, and hyperinflation on CXR are characteristic.
Emphysematous ('pink puffer') patients maintain oxygenation at rest by
hyperventilating.
Q14. A patient on heparin develops sudden-onset pleuritic chest
pain and hemoptysis. D-dimer is elevated. What is the next best
step in diagnosis?
ANSWER : CT pulmonary angiography (CTPA) is the gold standard for
diagnosing pulmonary embolism. It is fast, accurate, and can also
identify alternative diagnoses. V/Q scan is used when CTPA is
contraindicated (renal insufficiency, contrast allergy).
VERIFIED QUESTIONS AND ANSWERS - COMPREHENSIVE LATEST
VERSION 2026/2027
Q1. A 65-year-old man presents with crushing chest pain radiating
to the left arm, diaphoresis, and nausea. ECG shows ST elevation in
leads II, III, and aVF. Which coronary artery is most likely occluded?
ANSWER : Right coronary artery (RCA). ST elevation in the inferior
leads (II, III, aVF) indicates an inferior STEMI, which is most commonly
caused by RCA occlusion. The RCA supplies the inferior wall of the left
ventricle, the AV node, and the SA node in most patients.
Q2. A patient presents with wide, fixed splitting of S2 that does not
vary with respiration. What is the most likely diagnosis?
ANSWER : Atrial septal defect (ASD). The wide, fixed splitting of S2 is
pathognomonic for ASD. The fixed splitting occurs because the left-to-
right shunt equalizes pressure between the atria, causing constant delay
in pulmonic valve closure regardless of respiratory phase.
Q3. A 45-year-old woman presents with exertional dyspnea and a
mid-systolic click followed by a late systolic murmur best heard at
the apex. What is the diagnosis?
ANSWER : Mitral valve prolapse (MVP). The mid-systolic click followed
by a late systolic murmur is classic for MVP. The click moves earlier with
decreased preload (standing, Valsalva) and later with increased preload
(squatting, leg elevation).
Q4. Which antihypertensive is the drug of choice for a diabetic
patient with proteinuria and hypertension?
, ANSWER : ACE inhibitors (e.g., lisinopril) or ARBs are first-line. They
provide renoprotection by reducing intraglomerular pressure, decrease
proteinuria, and slow progression of diabetic nephropathy, independent
of their antihypertensive effect.
Q5. A patient has a blood pressure reading of 180/110 mmHg with
no end-organ damage. What is the appropriate management?
ANSWER : This is a hypertensive urgency. Management includes oral
antihypertensive medications (e.g., amlodipine, captopril, clonidine) with
gradual blood pressure reduction over 24-48 hours. Rapid correction
risks ischemic stroke, MI, or renal failure due to impaired autoregulation.
Q6. A 70-year-old man develops atrial fibrillation. His CHADS2-
VASc score is 4. What is the recommended treatment?
ANSWER : Oral anticoagulation (warfarin or a DOAC such as
rivaroxaban or apixaban) is indicated. A CHADS2-VASc score ≥2 in
males (≥3 in females) indicates high stroke risk requiring anticoagulation.
The annual stroke risk at score 4 is approximately 4%.
Q7. What is the mechanism of action of digoxin in heart failure?
ANSWER : Digoxin inhibits the Na/K-ATPase pump, increasing
intracellular sodium which in turn raises intracellular calcium via the
Na/Ca exchanger. The increased intracellular calcium enhances
myocardial contractility (positive inotrope). It also has vagotonic effects
that slow the heart rate.
Q8. A 55-year-old man develops sudden-onset palpitations. ECG
shows delta waves, a short PR interval, and a wide QRS. What is
the diagnosis?
ANSWER : Wolff-Parkinson-White (WPW) syndrome. The classic triad
of delta waves (slurred upstroke of QRS), short PR interval (<0.12 s),
and widened QRS indicates pre-excitation via an accessory pathway
(Bundle of Kent). Avoid AV-nodal blocking agents (digoxin, verapamil) in
WPW with AF.
,Q9. What ECG change is most characteristic of hyperkalemia when
potassium is 6.5 mEq/L?
ANSWER : Peaked (tall, narrow, symmetric) T waves are the earliest
ECG finding in hyperkalemia. Progressive hyperkalemia leads to: peaked
T waves → prolonged PR → widened QRS → sine wave pattern →
ventricular fibrillation.
Q10. A patient post-MI develops a holosystolic murmur at the lower
left sternal border and hemodynamic compromise. What
complication has occurred?
ANSWER : Ventricular septal rupture (VSR). This typically occurs 3-5
days post-MI, most commonly with anterior MI (LAD territory). It causes a
left-to-right shunt and is confirmed with step-up in oxygen saturation from
right atrium to pulmonary artery on right heart catheterization.
, PULMONOLOGY (10 Questions)
Q11. A 32-year-old woman presents with dyspnea and wheezing.
PFTs show FEV1/FVC < 0.70, FVC normal, and significant
reversibility after bronchodilator. What is the diagnosis?
ANSWER : Asthma. Obstructive pattern (reduced FEV1/FVC) with
significant reversibility (>12% and >200 mL improvement in FEV1 after
bronchodilator) is diagnostic of asthma. Normal FVC distinguishes it from
COPD with air trapping.
Q12. What is the most common cause of community-acquired
pneumonia (CAP) in a healthy adult?
ANSWER : Streptococcus pneumoniae is the most common cause of
CAP overall. Atypical organisms (Mycoplasma pneumoniae,
Chlamydophila pneumoniae) are common in younger adults. Treatment
is amoxicillin or azithromycin for mild outpatient CAP.
Q13. A 68-year-old smoker presents with progressive dyspnea,
barrel chest, and pursed-lip breathing. Spirometry shows FEV1/FVC
< 0.70 with no reversibility. Chest X-ray shows hyperinflation and
flattened diaphragms. What is the diagnosis?
ANSWER : Chronic Obstructive Pulmonary Disease (COPD),
specifically emphysema. The irreversible obstructive pattern, smoking
history, barrel chest, and hyperinflation on CXR are characteristic.
Emphysematous ('pink puffer') patients maintain oxygenation at rest by
hyperventilating.
Q14. A patient on heparin develops sudden-onset pleuritic chest
pain and hemoptysis. D-dimer is elevated. What is the next best
step in diagnosis?
ANSWER : CT pulmonary angiography (CTPA) is the gold standard for
diagnosing pulmonary embolism. It is fast, accurate, and can also
identify alternative diagnoses. V/Q scan is used when CTPA is
contraindicated (renal insufficiency, contrast allergy).
