COMSAE PHASE 1 FORM 113
CLINICAL SCIENCES & MEDICAL
KNOWLEDGE EXAM QUESTIONS
WITH CORRECT ANSWERS PLUS
RATIONALES 2026/2027 EDITION
WITH INSTANT PDF DOWNLOAD
Question 1
A 24-year-old woman presents with fatigue, weight loss, heat
intolerance, palpitations, and a fine tremor. Examination reveals a
diffusely enlarged thyroid and bilateral exophthalmos. Laboratory
studies show decreased TSH and increased free T4. Which
mechanism best explains her condition?
A. Destruction of thyroid follicles by cytotoxic T cells
B. Activation of the TSH receptor by stimulating
immunoglobulins
C. Autonomous secretion of TSH by a pituitary adenoma
D. Inhibition of thyroid peroxidase by circulating antibodies
Rationale: Graves disease is caused by thyroid-stimulating
immunoglobulins that bind and activate the TSH receptor,
resulting in increased thyroid hormone synthesis and diffuse
thyroid enlargement. Ophthalmopathy is also characteristic.
Question 2
,A 67-year-old man with hypertension develops sudden right-sided
weakness and difficulty speaking. He is found to have atrial
fibrillation. MRI demonstrates an acute infarction involving the left
middle cerebral artery territory. Which vascular structure is most
likely occluded?
A. Left anterior cerebral artery
B. Left posterior cerebral artery
C. Left middle cerebral artery
D. Basilar artery
Rationale: The middle cerebral artery supplies much of the
lateral cerebral hemisphere. A dominant-hemisphere MCA
infarction commonly produces contralateral weakness,
sensory deficits, and aphasia. Atrial fibrillation increases the
risk of embolic ischemic stroke.
Question 3
A 5-year-old child presents with fever, sore throat, tender anterior
cervical lymphadenopathy, and tonsillar exudates without cough.
Which organism is the most likely cause?
A. Corynebacterium diphtheriae
B. Epstein-Barr virus
C. Streptococcus pyogenes
D. Haemophilus influenzae
Rationale: Streptococcus pyogenes causes group A
streptococcal pharyngitis, which classically presents with
fever, tonsillar exudates, tender anterior cervical nodes, and
absence of cough.
,Question 4
A 58-year-old man experiences 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
Rationale: ST-segment elevation in leads II, III, and aVF
indicates an inferior myocardial infarction. The right coronary
artery is the most common culprit vessel in inferior STEMI.
Question 5
A patient with chronic obstructive pulmonary disease develops
worsening dyspnea and increased sputum production. Which
pulmonary finding is most consistent with emphysema?
A. Decreased total lung capacity
B. Decreased residual volume
C. Increased lung compliance
D. Increased elastic recoil
Rationale: Emphysema involves destruction of alveolar walls
and elastic tissue, causing increased lung compliance and
decreased elastic recoil. Air trapping leads to increased
residual volume and total lung capacity.
Question 6
, A 32-year-old woman develops painful swelling of the left calf 1
week after surgery. Doppler ultrasonography confirms a deep
venous thrombosis. Which component of Virchow triad most
directly explains her postoperative risk?
A. Hypercalcemia
B. Venous stasis
C. Increased arterial flow
D. Thrombocytopenia
Rationale: Virchow triad consists of endothelial injury,
abnormal blood flow such as stasis, and hypercoagulability.
Immobilization after surgery promotes venous stasis and
increases the risk of DVT.
Question 7
A 3-year-old child presents with barking cough, inspiratory stridor,
and hoarseness. Symptoms are worse at night. Which pathogen is
most commonly responsible?
A. Respiratory syncytial virus
B. Influenza B virus
C. Parainfluenza virus
D. Adenovirus
Rationale: Croup is most commonly caused by parainfluenza
virus. It produces inflammation and narrowing of the
subglottic airway, resulting in the characteristic barking cough
and inspiratory stridor.
Question 8
CLINICAL SCIENCES & MEDICAL
KNOWLEDGE EXAM QUESTIONS
WITH CORRECT ANSWERS PLUS
RATIONALES 2026/2027 EDITION
WITH INSTANT PDF DOWNLOAD
Question 1
A 24-year-old woman presents with fatigue, weight loss, heat
intolerance, palpitations, and a fine tremor. Examination reveals a
diffusely enlarged thyroid and bilateral exophthalmos. Laboratory
studies show decreased TSH and increased free T4. Which
mechanism best explains her condition?
A. Destruction of thyroid follicles by cytotoxic T cells
B. Activation of the TSH receptor by stimulating
immunoglobulins
C. Autonomous secretion of TSH by a pituitary adenoma
D. Inhibition of thyroid peroxidase by circulating antibodies
Rationale: Graves disease is caused by thyroid-stimulating
immunoglobulins that bind and activate the TSH receptor,
resulting in increased thyroid hormone synthesis and diffuse
thyroid enlargement. Ophthalmopathy is also characteristic.
Question 2
,A 67-year-old man with hypertension develops sudden right-sided
weakness and difficulty speaking. He is found to have atrial
fibrillation. MRI demonstrates an acute infarction involving the left
middle cerebral artery territory. Which vascular structure is most
likely occluded?
A. Left anterior cerebral artery
B. Left posterior cerebral artery
C. Left middle cerebral artery
D. Basilar artery
Rationale: The middle cerebral artery supplies much of the
lateral cerebral hemisphere. A dominant-hemisphere MCA
infarction commonly produces contralateral weakness,
sensory deficits, and aphasia. Atrial fibrillation increases the
risk of embolic ischemic stroke.
Question 3
A 5-year-old child presents with fever, sore throat, tender anterior
cervical lymphadenopathy, and tonsillar exudates without cough.
Which organism is the most likely cause?
A. Corynebacterium diphtheriae
B. Epstein-Barr virus
C. Streptococcus pyogenes
D. Haemophilus influenzae
Rationale: Streptococcus pyogenes causes group A
streptococcal pharyngitis, which classically presents with
fever, tonsillar exudates, tender anterior cervical nodes, and
absence of cough.
,Question 4
A 58-year-old man experiences 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
Rationale: ST-segment elevation in leads II, III, and aVF
indicates an inferior myocardial infarction. The right coronary
artery is the most common culprit vessel in inferior STEMI.
Question 5
A patient with chronic obstructive pulmonary disease develops
worsening dyspnea and increased sputum production. Which
pulmonary finding is most consistent with emphysema?
A. Decreased total lung capacity
B. Decreased residual volume
C. Increased lung compliance
D. Increased elastic recoil
Rationale: Emphysema involves destruction of alveolar walls
and elastic tissue, causing increased lung compliance and
decreased elastic recoil. Air trapping leads to increased
residual volume and total lung capacity.
Question 6
, A 32-year-old woman develops painful swelling of the left calf 1
week after surgery. Doppler ultrasonography confirms a deep
venous thrombosis. Which component of Virchow triad most
directly explains her postoperative risk?
A. Hypercalcemia
B. Venous stasis
C. Increased arterial flow
D. Thrombocytopenia
Rationale: Virchow triad consists of endothelial injury,
abnormal blood flow such as stasis, and hypercoagulability.
Immobilization after surgery promotes venous stasis and
increases the risk of DVT.
Question 7
A 3-year-old child presents with barking cough, inspiratory stridor,
and hoarseness. Symptoms are worse at night. Which pathogen is
most commonly responsible?
A. Respiratory syncytial virus
B. Influenza B virus
C. Parainfluenza virus
D. Adenovirus
Rationale: Croup is most commonly caused by parainfluenza
virus. It produces inflammation and narrowing of the
subglottic airway, resulting in the characteristic barking cough
and inspiratory stridor.
Question 8
