NBME 9 COMPREHENSIVE CLINICAL SCIENCE
SELF-ASSESSMENT 2026/2027 | Updated Edition | Complete
Solutions | USMLE Step Prep | Pass Guaranteed - A+ Graded
Block 1 (Questions 1-50)
Q1: A 58-year-old man with a 40-pack-year smoking history presents to his primary care
physician for a routine follow-up. He reports a chronic cough that has been present for
years but notes that over the past 3 months, it has become more frequent and is now
associated with small amounts of blood-tinged sputum on three occasions. He has also
lost 8 pounds unintentionally. Vital signs are normal. Chest examination reveals mild
expiratory wheezing in the right upper lobe. Chest radiograph shows a 3 cm hilar mass
on the right. Which of the following is the most appropriate next step in management?
A. CT scan of the chest
B. PET-CT scan
C. Sputum cytology
D. Bronchoscopy with biopsy
E. Referral for radiation therapy
Correct Answer: D. Bronchoscopy with biopsy. [CORRECT]
Rationale: This patient presents with hemoptysis, weight loss, chronic cough, and a hilar
mass on chest radiograph, highly suspicious for lung cancer. After an abnormal chest
x-ray showing a suspicious mass, the next step is tissue diagnosis. Bronchoscopy with
biopsy is the most appropriate next step as it allows direct visualization and tissue
,sampling of the central/hilar mass. CT scan (A) would be appropriate for further
characterization but does not provide tissue diagnosis. PET-CT (B) is useful for staging
after diagnosis but is not the next step. Sputum cytology (C) has low sensitivity and is
not the preferred initial diagnostic approach for a visible mass. Referral for radiation
therapy (E) without tissue diagnosis is inappropriate and would delay definitive
diagnosis and treatment. Test-taking insight: NBME questions frequently test the
principle that imaging characterizes, but biopsy diagnoses. For visible central lesions,
bronchoscopy is the preferred biopsy approach.
Q2: A 62-year-old woman with type 2 diabetes mellitus and hypertension presents with
progressive dyspnea on exertion over 6 months. She denies chest pain. Physical
examination reveals a blood pressure of 145/92 mmHg, heart rate of 88/min, and
bilateral basal crackles. Cardiac examination shows an S4 gallop and a soft systolic
murmur at the apex. ECG shows left ventricular hypertrophy. Echocardiography reveals
concentric left ventricular hypertrophy with preserved ejection fraction and an E/e' ratio
of 15. Which of the following is the most appropriate initial pharmacologic therapy?
A. Digoxin
B. Furosemide
C. Lisinopril
D. Metoprolol
E. Hydralazine-isosorbide dinitrate
Correct Answer: C. Lisinopril. [CORRECT]
Rationale: This patient has heart failure with preserved ejection fraction (HFpEF),
evidenced by concentric LVH, preserved EF, and elevated E/e' ratio indicating diastolic
,dysfunction. The cornerstone of HFpEF management is treatment of underlying
comorbidities, particularly hypertension. ACE inhibitors (lisinopril) are first-line for both
hypertension and HFpEF as they reduce afterload, promote regression of LVH, and
improve diastolic filling. Digoxin (A) is not indicated in HFpEF without atrial fibrillation.
Furosemide (B) is used for volume overload symptoms but is not initial monotherapy.
Metoprolol (D) may be used but is not first-line in the absence of compelling indications
like CAD or arrhythmia. Hydralazine-isosorbide (E) is reserved for HFrEF or when ACE
inhibitors are contraindicated. Trap: Students may confuse HFpEF with HFrEF treatment
algorithms. NBME 9 emphasizes that ACE inhibitors remain foundational for HFpEF with
hypertension.
Q3: A 28-year-old woman at 32 weeks gestation presents with severe headache and
visual disturbances for 2 hours. Blood pressure is 168/110 mmHg. Urinalysis shows 3+
protein. She is started on magnesium sulfate for seizure prophylaxis. Four hours later,
she develops absent deep tendon reflexes and a respiratory rate of 10/min. Serum
magnesium level is 9.2 mg/dL. Which of the following is the most appropriate next step
in management?
A. Increase magnesium sulfate infusion
B. Administer calcium gluconate
C. Perform emergent dialysis
D. Administer naloxone
E. Intubate and hyperventilate
Correct Answer: B. Administer calcium gluconate. [CORRECT]
, Rationale: This patient has severe preeclampsia treated with magnesium sulfate who
now shows signs of magnesium toxicity: absent reflexes, respiratory depression (RR
<12), and serum magnesium >9 mg/dL (therapeutic range 4-7 mg/dL). Calcium
gluconate is the specific antidote for magnesium toxicity, competitively antagonizing
magnesium's effects at the neuromuscular junction. Increasing magnesium (A) would
worsen toxicity. Dialysis (C) is unnecessary as magnesium is renally excreted and
toxicity is reversible. Naloxone (D) is for opioid overdose. Intubation (E) may eventually
be needed but the immediate antidote is calcium gluconate. Test-taking insight: NBME
frequently tests magnesium toxicity thresholds: loss of reflexes at >9-10 mg/dL,
respiratory paralysis at >12-15 mg/dL, cardiac arrest at >15 mg/dL. The antidote is
always calcium.
Q4: A 45-year-old man with a history of alcohol use disorder presents with confusion
and ataxia. On examination, he is disoriented, has nystagmus, and bilateral sixth nerve
palsies. He is given thiamine and his condition stabilizes. Two weeks later, he develops
confusion, confabulation, and anterograde amnesia. Which of the following brain
regions is most likely affected?
A. Hippocampus
B. Mammillary bodies
C. Caudate nucleus
D. Substantia nigra
E. Frontal cortex
Correct Answer: B. Mammillary bodies. [CORRECT]
SELF-ASSESSMENT 2026/2027 | Updated Edition | Complete
Solutions | USMLE Step Prep | Pass Guaranteed - A+ Graded
Block 1 (Questions 1-50)
Q1: A 58-year-old man with a 40-pack-year smoking history presents to his primary care
physician for a routine follow-up. He reports a chronic cough that has been present for
years but notes that over the past 3 months, it has become more frequent and is now
associated with small amounts of blood-tinged sputum on three occasions. He has also
lost 8 pounds unintentionally. Vital signs are normal. Chest examination reveals mild
expiratory wheezing in the right upper lobe. Chest radiograph shows a 3 cm hilar mass
on the right. Which of the following is the most appropriate next step in management?
A. CT scan of the chest
B. PET-CT scan
C. Sputum cytology
D. Bronchoscopy with biopsy
E. Referral for radiation therapy
Correct Answer: D. Bronchoscopy with biopsy. [CORRECT]
Rationale: This patient presents with hemoptysis, weight loss, chronic cough, and a hilar
mass on chest radiograph, highly suspicious for lung cancer. After an abnormal chest
x-ray showing a suspicious mass, the next step is tissue diagnosis. Bronchoscopy with
biopsy is the most appropriate next step as it allows direct visualization and tissue
,sampling of the central/hilar mass. CT scan (A) would be appropriate for further
characterization but does not provide tissue diagnosis. PET-CT (B) is useful for staging
after diagnosis but is not the next step. Sputum cytology (C) has low sensitivity and is
not the preferred initial diagnostic approach for a visible mass. Referral for radiation
therapy (E) without tissue diagnosis is inappropriate and would delay definitive
diagnosis and treatment. Test-taking insight: NBME questions frequently test the
principle that imaging characterizes, but biopsy diagnoses. For visible central lesions,
bronchoscopy is the preferred biopsy approach.
Q2: A 62-year-old woman with type 2 diabetes mellitus and hypertension presents with
progressive dyspnea on exertion over 6 months. She denies chest pain. Physical
examination reveals a blood pressure of 145/92 mmHg, heart rate of 88/min, and
bilateral basal crackles. Cardiac examination shows an S4 gallop and a soft systolic
murmur at the apex. ECG shows left ventricular hypertrophy. Echocardiography reveals
concentric left ventricular hypertrophy with preserved ejection fraction and an E/e' ratio
of 15. Which of the following is the most appropriate initial pharmacologic therapy?
A. Digoxin
B. Furosemide
C. Lisinopril
D. Metoprolol
E. Hydralazine-isosorbide dinitrate
Correct Answer: C. Lisinopril. [CORRECT]
Rationale: This patient has heart failure with preserved ejection fraction (HFpEF),
evidenced by concentric LVH, preserved EF, and elevated E/e' ratio indicating diastolic
,dysfunction. The cornerstone of HFpEF management is treatment of underlying
comorbidities, particularly hypertension. ACE inhibitors (lisinopril) are first-line for both
hypertension and HFpEF as they reduce afterload, promote regression of LVH, and
improve diastolic filling. Digoxin (A) is not indicated in HFpEF without atrial fibrillation.
Furosemide (B) is used for volume overload symptoms but is not initial monotherapy.
Metoprolol (D) may be used but is not first-line in the absence of compelling indications
like CAD or arrhythmia. Hydralazine-isosorbide (E) is reserved for HFrEF or when ACE
inhibitors are contraindicated. Trap: Students may confuse HFpEF with HFrEF treatment
algorithms. NBME 9 emphasizes that ACE inhibitors remain foundational for HFpEF with
hypertension.
Q3: A 28-year-old woman at 32 weeks gestation presents with severe headache and
visual disturbances for 2 hours. Blood pressure is 168/110 mmHg. Urinalysis shows 3+
protein. She is started on magnesium sulfate for seizure prophylaxis. Four hours later,
she develops absent deep tendon reflexes and a respiratory rate of 10/min. Serum
magnesium level is 9.2 mg/dL. Which of the following is the most appropriate next step
in management?
A. Increase magnesium sulfate infusion
B. Administer calcium gluconate
C. Perform emergent dialysis
D. Administer naloxone
E. Intubate and hyperventilate
Correct Answer: B. Administer calcium gluconate. [CORRECT]
, Rationale: This patient has severe preeclampsia treated with magnesium sulfate who
now shows signs of magnesium toxicity: absent reflexes, respiratory depression (RR
<12), and serum magnesium >9 mg/dL (therapeutic range 4-7 mg/dL). Calcium
gluconate is the specific antidote for magnesium toxicity, competitively antagonizing
magnesium's effects at the neuromuscular junction. Increasing magnesium (A) would
worsen toxicity. Dialysis (C) is unnecessary as magnesium is renally excreted and
toxicity is reversible. Naloxone (D) is for opioid overdose. Intubation (E) may eventually
be needed but the immediate antidote is calcium gluconate. Test-taking insight: NBME
frequently tests magnesium toxicity thresholds: loss of reflexes at >9-10 mg/dL,
respiratory paralysis at >12-15 mg/dL, cardiac arrest at >15 mg/dL. The antidote is
always calcium.
Q4: A 45-year-old man with a history of alcohol use disorder presents with confusion
and ataxia. On examination, he is disoriented, has nystagmus, and bilateral sixth nerve
palsies. He is given thiamine and his condition stabilizes. Two weeks later, he develops
confusion, confabulation, and anterograde amnesia. Which of the following brain
regions is most likely affected?
A. Hippocampus
B. Mammillary bodies
C. Caudate nucleus
D. Substantia nigra
E. Frontal cortex
Correct Answer: B. Mammillary bodies. [CORRECT]
