COMSAE Phase 1 Form C Questions With
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. A 62-year-old man presents with exertional dyspnea, orthopnea,
and bilateral lower extremity edema. Physical exam reveals an S3
heart sound. Which of the following is the most likely diagnosis?
A. Chronic obstructive pulmonary disease
B. Acute pericarditis
C. Congestive heart failure
D. Pulmonary embolism
Answer: C. Congestive heart failure
Rationale: An S3 heart sound in an older adult is strongly associated
with volume overload states such as systolic heart failure. The
presence of dyspnea, orthopnea, and peripheral edema further
supports congestive heart failure rather than pulmonary or
inflammatory causes.
2. A 24-year-old woman presents with episodic palpitations, tremor,
and weight loss. Lab tests show decreased TSH and elevated
, T3/T4. What is the most likely diagnosis?
A. Hypothyroidism
B. Graves disease
C. Hashimoto thyroiditis
D. Subacute thyroiditis
Answer: B. Graves disease
Rationale: Suppressed TSH with elevated thyroid hormones indicates
primary hyperthyroidism. Graves disease is the most common cause in
young adults and is characterized by autoimmune stimulation of TSH
receptors.
3. A patient with COPD is given high-flow oxygen and subsequently
becomes drowsy. What is the most likely mechanism?
A. Oxygen-induced hypoglycemia
B. Loss of hypoxic respiratory drive
C. Pulmonary edema
D. Respiratory alkalosis
Answer: B. Loss of hypoxic respiratory drive
Rationale: In COPD patients with chronic CO2 retention, respiratory
drive becomes dependent on hypoxia. High oxygen administration can
reduce respiratory drive, leading to CO2 narcosis and drowsiness.
, 4. A 45-year-old man has chest pain that improves when leaning
forward. ECG shows diffuse ST elevation. What is the diagnosis?
A. Myocardial infarction
B. Pericarditis
C. Aortic dissection
D. Stable angina
Answer: B. Pericarditis
Rationale: Pleuritic chest pain relieved by leaning forward plus diffuse
ST elevations is classic for acute pericarditis due to inflammation of
the pericardial sac.
5. A child presents with a “slapped cheek” rash and mild fever. What
is the causative agent?
A. Rubella virus
B. Parvovirus B19
C. Measles virus
D. Coxsackie virus
Answer: B. Parvovirus B19
Rationale: Erythema infectiosum (fifth disease) caused by parvovirus
B19 produces a characteristic slapped-cheek rash in children.
6. A patient has severe flank pain radiating to the groin and
hematuria. What is the most likely diagnosis?
, A. Pyelonephritis
B. Kidney stone
C. Appendicitis
D. Diverticulitis
Answer: B. Kidney stone
Rationale: Renal colic with hematuria is classic for nephrolithiasis
caused by obstruction of the ureter.
7. Which electrolyte abnormality is most associated with peaked T
waves on ECG?
A. Hypokalemia
B. Hyperkalemia
C. Hypocalcemia
D. Hypernatremia
Answer: B. Hyperkalemia
Rationale: Elevated potassium causes characteristic ECG changes
including peaked T waves, widened QRS, and eventual sine wave
pattern.
8. A 30-year-old woman presents with heat intolerance, tachycardia,
and exophthalmos. What antibody is most likely present?
A. Anti-TPO
B. Anti-TSH receptor antibody
Correct Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant Download Pdf
1. A 62-year-old man presents with exertional dyspnea, orthopnea,
and bilateral lower extremity edema. Physical exam reveals an S3
heart sound. Which of the following is the most likely diagnosis?
A. Chronic obstructive pulmonary disease
B. Acute pericarditis
C. Congestive heart failure
D. Pulmonary embolism
Answer: C. Congestive heart failure
Rationale: An S3 heart sound in an older adult is strongly associated
with volume overload states such as systolic heart failure. The
presence of dyspnea, orthopnea, and peripheral edema further
supports congestive heart failure rather than pulmonary or
inflammatory causes.
2. A 24-year-old woman presents with episodic palpitations, tremor,
and weight loss. Lab tests show decreased TSH and elevated
, T3/T4. What is the most likely diagnosis?
A. Hypothyroidism
B. Graves disease
C. Hashimoto thyroiditis
D. Subacute thyroiditis
Answer: B. Graves disease
Rationale: Suppressed TSH with elevated thyroid hormones indicates
primary hyperthyroidism. Graves disease is the most common cause in
young adults and is characterized by autoimmune stimulation of TSH
receptors.
3. A patient with COPD is given high-flow oxygen and subsequently
becomes drowsy. What is the most likely mechanism?
A. Oxygen-induced hypoglycemia
B. Loss of hypoxic respiratory drive
C. Pulmonary edema
D. Respiratory alkalosis
Answer: B. Loss of hypoxic respiratory drive
Rationale: In COPD patients with chronic CO2 retention, respiratory
drive becomes dependent on hypoxia. High oxygen administration can
reduce respiratory drive, leading to CO2 narcosis and drowsiness.
, 4. A 45-year-old man has chest pain that improves when leaning
forward. ECG shows diffuse ST elevation. What is the diagnosis?
A. Myocardial infarction
B. Pericarditis
C. Aortic dissection
D. Stable angina
Answer: B. Pericarditis
Rationale: Pleuritic chest pain relieved by leaning forward plus diffuse
ST elevations is classic for acute pericarditis due to inflammation of
the pericardial sac.
5. A child presents with a “slapped cheek” rash and mild fever. What
is the causative agent?
A. Rubella virus
B. Parvovirus B19
C. Measles virus
D. Coxsackie virus
Answer: B. Parvovirus B19
Rationale: Erythema infectiosum (fifth disease) caused by parvovirus
B19 produces a characteristic slapped-cheek rash in children.
6. A patient has severe flank pain radiating to the groin and
hematuria. What is the most likely diagnosis?
, A. Pyelonephritis
B. Kidney stone
C. Appendicitis
D. Diverticulitis
Answer: B. Kidney stone
Rationale: Renal colic with hematuria is classic for nephrolithiasis
caused by obstruction of the ureter.
7. Which electrolyte abnormality is most associated with peaked T
waves on ECG?
A. Hypokalemia
B. Hyperkalemia
C. Hypocalcemia
D. Hypernatremia
Answer: B. Hyperkalemia
Rationale: Elevated potassium causes characteristic ECG changes
including peaked T waves, widened QRS, and eventual sine wave
pattern.
8. A 30-year-old woman presents with heat intolerance, tachycardia,
and exophthalmos. What antibody is most likely present?
A. Anti-TPO
B. Anti-TSH receptor antibody
