COMLEX-USA Level 3 ACTUAL EXAM-STYLE QUESTIONS &
ANSWERS
200 High-Yield Clinical Vignettes with Detailed Rationales
Covering Emergency Medicine, Internal Medicine, Pediatrics,
OB/GYN, Psychiatry, Surgery, and Osteopathic Principles
Updated Per Latest NBOME Blueprint | 100% Verified
Solutions | Graded A+
1. A 58-year-old man with a history of heavy alcohol use presents with
confusion, ataxia, and ophthalmoplegia. He is disoriented to time and
place. Which of the following is the most appropriate immediate
intervention?
A) IV dextrose 50%
B) IV thiamine 100 mg
C) IV lorazepam
D) CT scan of the head
Answer: B) IV thiamine 100 mg
Rationale: This presentation is classic for Wernicke's encephalopathy,
caused by thiamine deficiency. Thiamine must be administered before
or simultaneously with glucose to prevent precipitation of Wernicke-
Korsakoff syndrome. Lorazepam is for withdrawal seizures, and a head
CT is not the immediate priority.
,2. A 72-year-old man with a history of smoking and hypertension
presents with sudden-onset severe "tearing" back pain. His blood
pressure is 210/110 mmHg in the right arm and 180/100 mmHg in the
left arm. Which of the following is the most appropriate next step?
A) IV labetalol and emergent CT angiography
B) Immediate surgical consultation only
C) CT angiography alone
D) IV antihypertensives and echocardiogram
Answer: A) IV labetalol and emergent CT angiography
Rationale: This is a classic presentation of aortic dissection. CT
angiography is the diagnostic study of choice, and blood pressure must
be controlled emergently with IV beta-blockers to reduce aortic wall
stress. Surgical consultation should follow imaging confirmation.
3. A 28-year-old woman presents with sudden-onset dyspnea,
pleuritic chest pain, and tachycardia. She recently completed a 14-
hour international flight. Her SpO₂ is 89% on room air. Which of the
following is the most appropriate diagnostic test?
A) D-dimer
B) CT pulmonary angiography
C) V/Q scan
D) Chest X-ray
Answer: B) CT pulmonary angiography
Rationale: This patient has a high pretest probability for pulmonary
embolism. CT pulmonary angiography is the gold standard diagnostic
,test and should be obtained without delay. A D-dimer is useful only for
low-risk patients.
4. A 65-year-old man with a history of hypertension and diabetes
presents with 3 hours of substernal chest pressure radiating to his left
arm, diaphoresis, and nausea. ECG shows ST-segment elevation in
leads V1–V4. He is hemodynamically stable. Which of the following is
the most appropriate immediate management?
A) Aspirin, sublingual nitroglycerin, and emergent PCI
B) Aspirin and thrombolytic therapy
C) Aspirin, oxygen, and morphine
D) Immediate CABG
Answer: A) Aspirin, sublingual nitroglycerin, and emergent PCI
Rationale: This is an anteroseptal STEMI. Primary percutaneous
coronary intervention is the gold standard if available within 90
minutes. Thrombolytics are used if PCI is unavailable, and CABG is not
first-line.
5. A 32-year-old man with no significant medical history presents with
acute-onset, severe headache described as "the worst of his life." He
is photophobic and nauseated. Neurological exam is non-focal. Which
of the following is the most appropriate initial imaging study?
A) Non-contrast CT head
B) CT angiography
C) MRI brain
D) Lumbar puncture
, Answer: A) Non-contrast CT head
Rationale: This is a classic "thunderclap" headache concerning for
subarachnoid hemorrhage. Non-contrast CT is the first-line imaging
study with high sensitivity for acute SAH. Lumbar puncture is indicated
if the CT is negative but suspicion remains high.
6. A 55-year-old woman presents with 2 days of right lower quadrant
abdominal pain. She has a low-grade fever and nausea. On
examination, she has rebound tenderness and guarding in the right
lower quadrant. Which of the following is the most appropriate initial
step?
A) Abdominal CT with contrast
B) Complete blood count and urinalysis
C) Surgery consultation
D) Pelvic ultrasound
Answer: B) Complete blood count and urinalysis
Rationale: In a patient with suspected appendicitis, initial evaluation
should include a CBC to assess for leukocytosis and a urinalysis to rule
out urinary tract pathology. CT imaging may be needed, but basic labs
are the appropriate first step.
7. A 24-year-old male with no significant history presents with acute-
onset, severe scrotal pain. The left testicle is swollen and tender;
cremasteric reflex is absent. Which of the following is the most
appropriate management?
A) Scrotal ultrasound
B) Immediate urology consultation
ANSWERS
200 High-Yield Clinical Vignettes with Detailed Rationales
Covering Emergency Medicine, Internal Medicine, Pediatrics,
OB/GYN, Psychiatry, Surgery, and Osteopathic Principles
Updated Per Latest NBOME Blueprint | 100% Verified
Solutions | Graded A+
1. A 58-year-old man with a history of heavy alcohol use presents with
confusion, ataxia, and ophthalmoplegia. He is disoriented to time and
place. Which of the following is the most appropriate immediate
intervention?
A) IV dextrose 50%
B) IV thiamine 100 mg
C) IV lorazepam
D) CT scan of the head
Answer: B) IV thiamine 100 mg
Rationale: This presentation is classic for Wernicke's encephalopathy,
caused by thiamine deficiency. Thiamine must be administered before
or simultaneously with glucose to prevent precipitation of Wernicke-
Korsakoff syndrome. Lorazepam is for withdrawal seizures, and a head
CT is not the immediate priority.
,2. A 72-year-old man with a history of smoking and hypertension
presents with sudden-onset severe "tearing" back pain. His blood
pressure is 210/110 mmHg in the right arm and 180/100 mmHg in the
left arm. Which of the following is the most appropriate next step?
A) IV labetalol and emergent CT angiography
B) Immediate surgical consultation only
C) CT angiography alone
D) IV antihypertensives and echocardiogram
Answer: A) IV labetalol and emergent CT angiography
Rationale: This is a classic presentation of aortic dissection. CT
angiography is the diagnostic study of choice, and blood pressure must
be controlled emergently with IV beta-blockers to reduce aortic wall
stress. Surgical consultation should follow imaging confirmation.
3. A 28-year-old woman presents with sudden-onset dyspnea,
pleuritic chest pain, and tachycardia. She recently completed a 14-
hour international flight. Her SpO₂ is 89% on room air. Which of the
following is the most appropriate diagnostic test?
A) D-dimer
B) CT pulmonary angiography
C) V/Q scan
D) Chest X-ray
Answer: B) CT pulmonary angiography
Rationale: This patient has a high pretest probability for pulmonary
embolism. CT pulmonary angiography is the gold standard diagnostic
,test and should be obtained without delay. A D-dimer is useful only for
low-risk patients.
4. A 65-year-old man with a history of hypertension and diabetes
presents with 3 hours of substernal chest pressure radiating to his left
arm, diaphoresis, and nausea. ECG shows ST-segment elevation in
leads V1–V4. He is hemodynamically stable. Which of the following is
the most appropriate immediate management?
A) Aspirin, sublingual nitroglycerin, and emergent PCI
B) Aspirin and thrombolytic therapy
C) Aspirin, oxygen, and morphine
D) Immediate CABG
Answer: A) Aspirin, sublingual nitroglycerin, and emergent PCI
Rationale: This is an anteroseptal STEMI. Primary percutaneous
coronary intervention is the gold standard if available within 90
minutes. Thrombolytics are used if PCI is unavailable, and CABG is not
first-line.
5. A 32-year-old man with no significant medical history presents with
acute-onset, severe headache described as "the worst of his life." He
is photophobic and nauseated. Neurological exam is non-focal. Which
of the following is the most appropriate initial imaging study?
A) Non-contrast CT head
B) CT angiography
C) MRI brain
D) Lumbar puncture
, Answer: A) Non-contrast CT head
Rationale: This is a classic "thunderclap" headache concerning for
subarachnoid hemorrhage. Non-contrast CT is the first-line imaging
study with high sensitivity for acute SAH. Lumbar puncture is indicated
if the CT is negative but suspicion remains high.
6. A 55-year-old woman presents with 2 days of right lower quadrant
abdominal pain. She has a low-grade fever and nausea. On
examination, she has rebound tenderness and guarding in the right
lower quadrant. Which of the following is the most appropriate initial
step?
A) Abdominal CT with contrast
B) Complete blood count and urinalysis
C) Surgery consultation
D) Pelvic ultrasound
Answer: B) Complete blood count and urinalysis
Rationale: In a patient with suspected appendicitis, initial evaluation
should include a CBC to assess for leukocytosis and a urinalysis to rule
out urinary tract pathology. CT imaging may be needed, but basic labs
are the appropriate first step.
7. A 24-year-old male with no significant history presents with acute-
onset, severe scrotal pain. The left testicle is swollen and tender;
cremasteric reflex is absent. Which of the following is the most
appropriate management?
A) Scrotal ultrasound
B) Immediate urology consultation
