USMLE Step 3 2026-Style Exam
Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant
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1. Acute Coronary Syndrome
A 64-year-old man presents with 45 minutes of substernal chest
pressure radiating to his left arm. ECG shows ST-segment elevations
in leads II, III, and aVF. Blood pressure is 88/58 mm Hg. Which
coronary artery is most likely occluded?
A. Left anterior descending
B. Left circumflex
C. Right coronary artery
D. Left main coronary artery
E. Posterior descending artery
Answer: C. Right coronary artery
Inferior STEMI involving leads II, III, and aVF is most commonly
caused by right coronary artery occlusion.
2. Septic Shock
A 71-year-old woman with pyelonephritis remains hypotensive after
receiving adequate IV crystalloid. Which medication should be
started first?
,A. Dopamine
B. Norepinephrine
C. Dobutamine
D. Phenylephrine
E. Vasopressin alone
Answer: B. Norepinephrine
Norepinephrine is the preferred first-line vasopressor for septic shock
after adequate fluid resuscitation.
3. Diabetic Ketoacidosis
A 24-year-old woman with type 1 diabetes has glucose 480 mg/dL,
pH 7.18, bicarbonate 11 mEq/L, and positive serum ketones.
Potassium is 2.9 mEq/L. What is the next step?
A. IV insulin immediately
B. Sodium bicarbonate
C. IV potassium replacement
D. Subcutaneous insulin
E. Hemodialysis
Answer: C. IV potassium replacement
Insulin drives potassium intracellularly and can precipitate life-
threatening hypokalemia. Insulin should be delayed until potassium is
at least 3.3 mEq/L.
4. Hyperkalemia
A patient with chronic kidney disease has potassium of 7.1 mEq/L
and peaked T waves on ECG. Which intervention should be given
immediately?
,A. IV furosemide
B. Sodium zirconium cyclosilicate
C. IV calcium gluconate
D. Insulin only
E. Hemodialysis only
Answer: C. IV calcium gluconate
IV calcium stabilizes the cardiac membrane and is the immediate
treatment for hyperkalemia with ECG changes.
5. Acute Ischemic Stroke
A 68-year-old man develops sudden right-sided weakness and
aphasia. CT head shows no hemorrhage. Symptoms began 90
minutes ago. Which treatment is appropriate if there are no
contraindications?
A. Aspirin only
B. IV alteplase
C. Warfarin
D. Heparin infusion
E. Dexamethasone
Answer: B. IV alteplase
Eligible patients with acute ischemic stroke presenting within the
appropriate treatment window should receive IV thrombolysis after
intracranial hemorrhage is excluded.
6. Pulmonary Embolism
A 42-year-old woman develops sudden dyspnea after surgery. CT
angiography demonstrates bilateral pulmonary emboli. Blood
pressure is 78/44 mm Hg despite fluids. What is the most
appropriate treatment?
, A. Oral apixaban
B. Observation
C. Systemic thrombolysis
D. Aspirin
E. Compression stockings
Answer: C. Systemic thrombolysis
Hemodynamically unstable pulmonary embolism is high-risk PE and
generally requires urgent reperfusion therapy unless contraindicated.
7. Asthma Exacerbation
A patient with severe asthma remains wheezing after repeated
albuterol treatments. Which additional medication should be
administered?
A. Propranolol
B. IV corticosteroid
C. Montelukast only
D. Theophylline only
E. Antibiotics routinely
Answer: B. IV corticosteroid
Systemic corticosteroids reduce airway inflammation and should be
given early in moderate-to-severe asthma exacerbations.
8. COPD Exacerbation
A 69-year-old man with COPD presents with increased dyspnea,
sputum volume, and purulent sputum. Which treatment is
appropriate?
A. Long-term oxygen only
B. Bronchodilators and systemic corticosteroids
Practice Questions And Correct
Answers (Verified Answers) Plus
Rationale 2026 Q&A| Instant
Download Pdf
1. Acute Coronary Syndrome
A 64-year-old man presents with 45 minutes of substernal chest
pressure radiating to his left arm. ECG shows ST-segment elevations
in leads II, III, and aVF. Blood pressure is 88/58 mm Hg. Which
coronary artery is most likely occluded?
A. Left anterior descending
B. Left circumflex
C. Right coronary artery
D. Left main coronary artery
E. Posterior descending artery
Answer: C. Right coronary artery
Inferior STEMI involving leads II, III, and aVF is most commonly
caused by right coronary artery occlusion.
2. Septic Shock
A 71-year-old woman with pyelonephritis remains hypotensive after
receiving adequate IV crystalloid. Which medication should be
started first?
,A. Dopamine
B. Norepinephrine
C. Dobutamine
D. Phenylephrine
E. Vasopressin alone
Answer: B. Norepinephrine
Norepinephrine is the preferred first-line vasopressor for septic shock
after adequate fluid resuscitation.
3. Diabetic Ketoacidosis
A 24-year-old woman with type 1 diabetes has glucose 480 mg/dL,
pH 7.18, bicarbonate 11 mEq/L, and positive serum ketones.
Potassium is 2.9 mEq/L. What is the next step?
A. IV insulin immediately
B. Sodium bicarbonate
C. IV potassium replacement
D. Subcutaneous insulin
E. Hemodialysis
Answer: C. IV potassium replacement
Insulin drives potassium intracellularly and can precipitate life-
threatening hypokalemia. Insulin should be delayed until potassium is
at least 3.3 mEq/L.
4. Hyperkalemia
A patient with chronic kidney disease has potassium of 7.1 mEq/L
and peaked T waves on ECG. Which intervention should be given
immediately?
,A. IV furosemide
B. Sodium zirconium cyclosilicate
C. IV calcium gluconate
D. Insulin only
E. Hemodialysis only
Answer: C. IV calcium gluconate
IV calcium stabilizes the cardiac membrane and is the immediate
treatment for hyperkalemia with ECG changes.
5. Acute Ischemic Stroke
A 68-year-old man develops sudden right-sided weakness and
aphasia. CT head shows no hemorrhage. Symptoms began 90
minutes ago. Which treatment is appropriate if there are no
contraindications?
A. Aspirin only
B. IV alteplase
C. Warfarin
D. Heparin infusion
E. Dexamethasone
Answer: B. IV alteplase
Eligible patients with acute ischemic stroke presenting within the
appropriate treatment window should receive IV thrombolysis after
intracranial hemorrhage is excluded.
6. Pulmonary Embolism
A 42-year-old woman develops sudden dyspnea after surgery. CT
angiography demonstrates bilateral pulmonary emboli. Blood
pressure is 78/44 mm Hg despite fluids. What is the most
appropriate treatment?
, A. Oral apixaban
B. Observation
C. Systemic thrombolysis
D. Aspirin
E. Compression stockings
Answer: C. Systemic thrombolysis
Hemodynamically unstable pulmonary embolism is high-risk PE and
generally requires urgent reperfusion therapy unless contraindicated.
7. Asthma Exacerbation
A patient with severe asthma remains wheezing after repeated
albuterol treatments. Which additional medication should be
administered?
A. Propranolol
B. IV corticosteroid
C. Montelukast only
D. Theophylline only
E. Antibiotics routinely
Answer: B. IV corticosteroid
Systemic corticosteroids reduce airway inflammation and should be
given early in moderate-to-severe asthma exacerbations.
8. COPD Exacerbation
A 69-year-old man with COPD presents with increased dyspnea,
sputum volume, and purulent sputum. Which treatment is
appropriate?
A. Long-term oxygen only
B. Bronchodilators and systemic corticosteroids
