2026 Edition Questions with
Correct Answers and Concise
Rationales
Question 1
A 24-year-old woman presents with episodic wheezing, chest
tightness, and shortness of breath after exposure to cat
dander. Pulmonary function testing demonstrates reversible
airflow obstruction. Which mechanism is primarily
responsible for her bronchoconstriction?
A. Increased β₂-adrenergic stimulation
B. Parasympathetic stimulation via the vagus nerve
C. Reduced leukotriene synthesis
D. Inhibition of muscarinic receptors
Answer: B. Parasympathetic stimulation via the vagus nerve
Vagal stimulation activates muscarinic receptors on bronchial
smooth muscle, producing bronchoconstriction. Asthma also
involves inflammatory mediators, including leukotrienes, that
contribute to airway narrowing.
,Question 2
A 67-year-old man with a history of hypertension develops
sudden right-sided weakness and expressive aphasia. Imaging
reveals an infarct involving the dominant frontal lobe. Which
artery is most likely occluded?
A. Right middle cerebral artery
B. Left anterior cerebral artery
C. Left middle cerebral artery
D. Right posterior cerebral artery
Answer: C. Left middle cerebral artery
The dominant middle cerebral artery supplies Broca area and
much of the lateral motor cortex controlling the contralateral
face and upper extremity. A left-sided lesion therefore
produces aphasia with right-sided weakness.
Question 3
A 45-year-old woman presents with fatigue, weight gain,
constipation, and cold intolerance. Laboratory studies reveal
elevated TSH and decreased free T₄. Which finding is most
likely?
A. Increased basal metabolic rate
B. Hyperreflexia
C. Bradycardia
D. Increased lipolysis
Answer: C. Bradycardia
,Primary hypothyroidism reduces metabolic activity and
sympathetic responsiveness, commonly causing fatigue,
weight gain, constipation, cold intolerance, and bradycardia.
Question 4
A 19-year-old college student develops fever, headache, neck
stiffness, and photophobia. Cerebrospinal fluid demonstrates
neutrophilic pleocytosis, elevated protein, and decreased
glucose. Which organism is most likely in this age group?
A. Escherichia coli
B. Listeria monocytogenes
C. Neisseria meningitidis
D. Cryptococcus neoformans
Answer: C. Neisseria meningitidis
Neisseria meningitidis is a major cause of bacterial meningitis
in adolescents and young adults. It is an encapsulated gram-
negative diplococcus that can cause rapidly progressive
meningococcemia.
Question 5
A patient with chronic kidney disease develops metabolic
acidosis. Which renal adaptation normally helps compensate
for this acid-base disturbance?
A. Reduced ammonium excretion
B. Increased bicarbonate excretion
, C. Increased hydrogen ion secretion
D. Decreased glutamine metabolism
Answer: C. Increased hydrogen ion secretion
The kidneys compensate for metabolic acidosis by increasing
hydrogen ion secretion, ammonium production, and
bicarbonate reabsorption. Chronic kidney disease impairs
these mechanisms.
Question 6
A 58-year-old man experiences substernal chest pressure
radiating to his left arm. ECG demonstrates ST-segment
elevation in leads II, III, and aVF. Which coronary artery is
most likely involved?
A. Left anterior descending artery
B. Right coronary artery
C. Left circumflex artery
D. Left main coronary artery
Answer: B. Right coronary artery
Inferior-wall myocardial infarctions most commonly result
from right coronary artery occlusion. The affected leads are II,
III, and aVF.
Question 7
A 32-year-old woman presents with recurrent episodes of
palpitations, diaphoresis, headache, and severe hypertension.