COMSAE Phase 9–Style Practice
Examination 2026 Edition Questions
with Verified Answers and Clinical
Rationales
Question 1
A 64-year-old man with a 45-pack-year smoking history
presents with progressive dyspnea, chronic cough, and
increased sputum production. Pulmonary function testing
shows an FEV₁/FVC ratio of 0.58 with minimal reversibility
after inhaled albuterol. Which pathophysiologic change is
most likely responsible for his condition?
A. Increased surfactant production
B. Destruction of alveolar septa
C. Thickening of the alveolar basement membrane
D. Increased pulmonary vascular resistance due to left heart
failure
Answer: B. Destruction of alveolar septa
Chronic obstructive pulmonary disease with emphysematous
changes involves destruction of alveolar walls, reducing
elastic recoil and increasing lung compliance. Smoking is the
major risk factor.
,Question 2
A 23-year-old woman presents with fatigue, weight loss, heat
intolerance, tremor, and palpitations. Examination reveals
diffuse thyroid enlargement and bilateral exophthalmos.
Laboratory studies show suppressed TSH and elevated free
T₄. Which antibody is most likely present?
A. Anti-thyroid peroxidase antibody
B. Anti-thyroglobulin antibody
C. Thyroid-stimulating immunoglobulin
D. Anti-dsDNA antibody
Answer: C. Thyroid-stimulating immunoglobulin
Graves disease results from antibodies that activate the TSH
receptor, causing increased thyroid hormone production and
diffuse gland hyperplasia. Ophthalmopathy is characteristic.
Question 3
A 58-year-old man develops crushing substernal chest pain
radiating to his left arm. ECG demonstrates ST-segment
elevation in leads II, III, and aVF. Which coronary artery is
most likely occluded?
A. Left anterior descending artery
B. Left circumflex artery
C. Right coronary artery
D. Left main coronary artery
Answer: C. Right coronary artery
,Inferior-wall myocardial infarction is classically caused by
right coronary artery occlusion, although the left circumflex
artery can occasionally supply the inferior wall.
Question 4
A 7-year-old child presents with fever, migratory polyarthritis,
and a new cardiac murmur 3 weeks after untreated
pharyngitis. Which organism is most likely responsible?
A. Staphylococcus aureus
B. Streptococcus pyogenes
C. Streptococcus pneumoniae
D. Corynebacterium diphtheriae
Answer: B. Streptococcus pyogenes
Acute rheumatic fever is an autoimmune complication of
group A Streptococcus pharyngitis. Carditis, migratory
polyarthritis, chorea, erythema marginatum, and
subcutaneous nodules are major manifestations.
Question 5
A 45-year-old woman presents with fatigue, paresthesias, and
difficulty walking. Laboratory testing reveals macrocytic
anemia and elevated methylmalonic acid and homocysteine
levels. Which deficiency is most likely?
A. Folate
B. Vitamin B₆
, C. Vitamin B₁₂
D. Iron
Answer: C. Vitamin B₁₂
Vitamin B₁₂ deficiency causes megaloblastic anemia and
neurologic dysfunction. Both methylmalonic acid and
homocysteine increase, distinguishing it from folate
deficiency.
Question 6
A 72-year-old woman with atrial fibrillation suddenly
develops right-sided weakness and expressive aphasia.
Imaging confirms an ischemic stroke involving the dominant
cerebral hemisphere. Which artery is most likely affected?
A. Right middle cerebral artery
B. Left middle cerebral artery
C. Left posterior cerebral artery
D. Basilar artery
Answer: B. Left middle cerebral artery
The dominant middle cerebral artery supplies Broca and
Wernicke language areas. Occlusion produces contralateral
face and upper-extremity weakness with aphasia.
Question 7
A 35-year-old man develops severe watery diarrhea after
returning from a region with poor sanitation. He has
Examination 2026 Edition Questions
with Verified Answers and Clinical
Rationales
Question 1
A 64-year-old man with a 45-pack-year smoking history
presents with progressive dyspnea, chronic cough, and
increased sputum production. Pulmonary function testing
shows an FEV₁/FVC ratio of 0.58 with minimal reversibility
after inhaled albuterol. Which pathophysiologic change is
most likely responsible for his condition?
A. Increased surfactant production
B. Destruction of alveolar septa
C. Thickening of the alveolar basement membrane
D. Increased pulmonary vascular resistance due to left heart
failure
Answer: B. Destruction of alveolar septa
Chronic obstructive pulmonary disease with emphysematous
changes involves destruction of alveolar walls, reducing
elastic recoil and increasing lung compliance. Smoking is the
major risk factor.
,Question 2
A 23-year-old woman presents with fatigue, weight loss, heat
intolerance, tremor, and palpitations. Examination reveals
diffuse thyroid enlargement and bilateral exophthalmos.
Laboratory studies show suppressed TSH and elevated free
T₄. Which antibody is most likely present?
A. Anti-thyroid peroxidase antibody
B. Anti-thyroglobulin antibody
C. Thyroid-stimulating immunoglobulin
D. Anti-dsDNA antibody
Answer: C. Thyroid-stimulating immunoglobulin
Graves disease results from antibodies that activate the TSH
receptor, causing increased thyroid hormone production and
diffuse gland hyperplasia. Ophthalmopathy is characteristic.
Question 3
A 58-year-old man develops crushing substernal chest pain
radiating to his left arm. ECG demonstrates ST-segment
elevation in leads II, III, and aVF. Which coronary artery is
most likely occluded?
A. Left anterior descending artery
B. Left circumflex artery
C. Right coronary artery
D. Left main coronary artery
Answer: C. Right coronary artery
,Inferior-wall myocardial infarction is classically caused by
right coronary artery occlusion, although the left circumflex
artery can occasionally supply the inferior wall.
Question 4
A 7-year-old child presents with fever, migratory polyarthritis,
and a new cardiac murmur 3 weeks after untreated
pharyngitis. Which organism is most likely responsible?
A. Staphylococcus aureus
B. Streptococcus pyogenes
C. Streptococcus pneumoniae
D. Corynebacterium diphtheriae
Answer: B. Streptococcus pyogenes
Acute rheumatic fever is an autoimmune complication of
group A Streptococcus pharyngitis. Carditis, migratory
polyarthritis, chorea, erythema marginatum, and
subcutaneous nodules are major manifestations.
Question 5
A 45-year-old woman presents with fatigue, paresthesias, and
difficulty walking. Laboratory testing reveals macrocytic
anemia and elevated methylmalonic acid and homocysteine
levels. Which deficiency is most likely?
A. Folate
B. Vitamin B₆
, C. Vitamin B₁₂
D. Iron
Answer: C. Vitamin B₁₂
Vitamin B₁₂ deficiency causes megaloblastic anemia and
neurologic dysfunction. Both methylmalonic acid and
homocysteine increase, distinguishing it from folate
deficiency.
Question 6
A 72-year-old woman with atrial fibrillation suddenly
develops right-sided weakness and expressive aphasia.
Imaging confirms an ischemic stroke involving the dominant
cerebral hemisphere. Which artery is most likely affected?
A. Right middle cerebral artery
B. Left middle cerebral artery
C. Left posterior cerebral artery
D. Basilar artery
Answer: B. Left middle cerebral artery
The dominant middle cerebral artery supplies Broca and
Wernicke language areas. Occlusion produces contralateral
face and upper-extremity weakness with aphasia.
Question 7
A 35-year-old man develops severe watery diarrhea after
returning from a region with poor sanitation. He has
