COMSAE Phase 1 Final Comprehensive
Mock Exam — 100-Question Advanced
Practice Test 2026 | Questions &
Answers with Detailed Rationales |
Complete COMSAE Phase 1 Final Mock
Exam Prep & Study Guide
1. A 24-year-old woman presents with fatigue, weight loss, tremor, heat
intolerance, and palpitations. Examination reveals a diffuse, nontender
goiter and bilateral exophthalmos. Laboratory studies show elevated free
T4 and suppressed TSH. Which mechanism most directly explains her
thyroid stimulation?
A. Antibodies against thyroid peroxidase
B. Antibodies against the TSH receptor
C. Antibodies against thyroglobulin
D. Antibodies against the sodium-iodide symporter
E. Immune destruction of thyroid follicular cells
Answer: B. Antibodies against the TSH receptor
Rationale: Graves disease is caused by thyroid-stimulating immunoglobulins
that bind and activate the TSH receptor, increasing thyroid hormone synthesis
and secretion.
, 2. A 67-year-old man with a 60-pack-year smoking history develops
progressive hoarseness, weight loss, and a hilar lung mass. Biopsy
demonstrates small cells with scant cytoplasm and hyperchromatic nuclei.
Laboratory studies reveal hyponatremia with low serum osmolality and
inappropriately concentrated urine. Which substance is most likely being
produced by the tumor?
A. ACTH
B. PTH-related peptide
C. ADH
D. Calcitonin
E. Erythropoietin
Answer: C. ADH
Rationale: Small-cell lung carcinoma commonly causes SIADH through ectopic
ADH production, producing euvolemic hyponatremia with concentrated urine.
3. A 45-year-old woman develops severe watery diarrhea after completing a
course of clindamycin. Colonoscopy demonstrates raised yellow-white
plaques. Which bacterial factor is primarily responsible for colonic epithelial
injury?
A. Shiga toxin
B. Heat-labile toxin
C. Toxin A and toxin B
D. Cholera toxin
E. Pertussis toxin
Answer: C. Toxin A and toxin B
Rationale: Clostridioides difficile produces toxins A and B. Toxin B is a potent
cytotoxin that glucosylates Rho GTPases, disrupting the cytoskeleton and
causing epithelial cell death.
, 4. A patient with chronic kidney disease develops weakness. ECG shows
peaked T waves and progressive QRS widening. Which treatment most
rapidly stabilizes the cardiac membrane?
A. Furosemide
B. Insulin with glucose
C. Sodium polystyrene sulfonate
D. Calcium gluconate
E. Hemodialysis
Answer: D. Calcium gluconate
Rationale: IV calcium rapidly stabilizes the myocardial membrane in severe
hyperkalemia. It does not lower serum potassium but reduces the immediate
risk of fatal arrhythmia.
5. A 6-year-old child develops periorbital edema and frothy urine after an
upper respiratory infection. Urinalysis shows heavy proteinuria without
hematuria. Electron microscopy demonstrates diffuse podocyte foot-
process effacement. Which diagnosis is most likely?
A. Focal segmental glomerulosclerosis
B. Membranous nephropathy
C. Minimal change disease
D. IgA nephropathy
E. Poststreptococcal glomerulonephritis
Answer: C. Minimal change disease
Rationale: Minimal change disease is the most common nephrotic syndrome in
children and classically shows selective albuminuria with diffuse podocyte foot-
process effacement.
6. A 58-year-old man develops sudden right-sided weakness and aphasia.
Imaging reveals an infarct involving the left middle cerebral artery territory.
Which artery supplies the primary motor cortex controlling the
contralateral lower extremity?
, A. Anterior cerebral artery
B. Middle cerebral artery
C. Posterior cerebral artery
D. Anterior communicating artery
E. Posterior communicating artery
Answer: A. Anterior cerebral artery
Rationale: The anterior cerebral artery supplies the medial frontal and parietal
cortex, including the motor and sensory areas representing the contralateral
lower limb.
7. A 19-year-old college student presents with fever, headache, photophobia,
and neck stiffness. CSF demonstrates lymphocytic pleocytosis, elevated
protein, and normal glucose. Which organism is most likely?
A. Neisseria meningitidis
B. Streptococcus pneumoniae
C. HSV-1
D. Listeria monocytogenes
E. Cryptococcus neoformans
Answer: C. HSV-1
Rationale: HSV encephalitis typically produces lymphocytic CSF findings with
elevated protein and normal glucose. Temporal-lobe involvement may cause
seizures and focal neurologic deficits.
8. A 28-year-old woman has recurrent episodes of painful oral ulcers, genital
ulcers, and uveitis. Which pathologic process best explains this condition?
A. Immune-complex deposition
B. Neutrophilic inflammation with vasculitis
C. Granulomatous inflammation caused by mycobacteria
D. Antibody-mediated destruction of basement membrane
E. Eosinophilic infiltration
Mock Exam — 100-Question Advanced
Practice Test 2026 | Questions &
Answers with Detailed Rationales |
Complete COMSAE Phase 1 Final Mock
Exam Prep & Study Guide
1. A 24-year-old woman presents with fatigue, weight loss, tremor, heat
intolerance, and palpitations. Examination reveals a diffuse, nontender
goiter and bilateral exophthalmos. Laboratory studies show elevated free
T4 and suppressed TSH. Which mechanism most directly explains her
thyroid stimulation?
A. Antibodies against thyroid peroxidase
B. Antibodies against the TSH receptor
C. Antibodies against thyroglobulin
D. Antibodies against the sodium-iodide symporter
E. Immune destruction of thyroid follicular cells
Answer: B. Antibodies against the TSH receptor
Rationale: Graves disease is caused by thyroid-stimulating immunoglobulins
that bind and activate the TSH receptor, increasing thyroid hormone synthesis
and secretion.
, 2. A 67-year-old man with a 60-pack-year smoking history develops
progressive hoarseness, weight loss, and a hilar lung mass. Biopsy
demonstrates small cells with scant cytoplasm and hyperchromatic nuclei.
Laboratory studies reveal hyponatremia with low serum osmolality and
inappropriately concentrated urine. Which substance is most likely being
produced by the tumor?
A. ACTH
B. PTH-related peptide
C. ADH
D. Calcitonin
E. Erythropoietin
Answer: C. ADH
Rationale: Small-cell lung carcinoma commonly causes SIADH through ectopic
ADH production, producing euvolemic hyponatremia with concentrated urine.
3. A 45-year-old woman develops severe watery diarrhea after completing a
course of clindamycin. Colonoscopy demonstrates raised yellow-white
plaques. Which bacterial factor is primarily responsible for colonic epithelial
injury?
A. Shiga toxin
B. Heat-labile toxin
C. Toxin A and toxin B
D. Cholera toxin
E. Pertussis toxin
Answer: C. Toxin A and toxin B
Rationale: Clostridioides difficile produces toxins A and B. Toxin B is a potent
cytotoxin that glucosylates Rho GTPases, disrupting the cytoskeleton and
causing epithelial cell death.
, 4. A patient with chronic kidney disease develops weakness. ECG shows
peaked T waves and progressive QRS widening. Which treatment most
rapidly stabilizes the cardiac membrane?
A. Furosemide
B. Insulin with glucose
C. Sodium polystyrene sulfonate
D. Calcium gluconate
E. Hemodialysis
Answer: D. Calcium gluconate
Rationale: IV calcium rapidly stabilizes the myocardial membrane in severe
hyperkalemia. It does not lower serum potassium but reduces the immediate
risk of fatal arrhythmia.
5. A 6-year-old child develops periorbital edema and frothy urine after an
upper respiratory infection. Urinalysis shows heavy proteinuria without
hematuria. Electron microscopy demonstrates diffuse podocyte foot-
process effacement. Which diagnosis is most likely?
A. Focal segmental glomerulosclerosis
B. Membranous nephropathy
C. Minimal change disease
D. IgA nephropathy
E. Poststreptococcal glomerulonephritis
Answer: C. Minimal change disease
Rationale: Minimal change disease is the most common nephrotic syndrome in
children and classically shows selective albuminuria with diffuse podocyte foot-
process effacement.
6. A 58-year-old man develops sudden right-sided weakness and aphasia.
Imaging reveals an infarct involving the left middle cerebral artery territory.
Which artery supplies the primary motor cortex controlling the
contralateral lower extremity?
, A. Anterior cerebral artery
B. Middle cerebral artery
C. Posterior cerebral artery
D. Anterior communicating artery
E. Posterior communicating artery
Answer: A. Anterior cerebral artery
Rationale: The anterior cerebral artery supplies the medial frontal and parietal
cortex, including the motor and sensory areas representing the contralateral
lower limb.
7. A 19-year-old college student presents with fever, headache, photophobia,
and neck stiffness. CSF demonstrates lymphocytic pleocytosis, elevated
protein, and normal glucose. Which organism is most likely?
A. Neisseria meningitidis
B. Streptococcus pneumoniae
C. HSV-1
D. Listeria monocytogenes
E. Cryptococcus neoformans
Answer: C. HSV-1
Rationale: HSV encephalitis typically produces lymphocytic CSF findings with
elevated protein and normal glucose. Temporal-lobe involvement may cause
seizures and focal neurologic deficits.
8. A 28-year-old woman has recurrent episodes of painful oral ulcers, genital
ulcers, and uveitis. Which pathologic process best explains this condition?
A. Immune-complex deposition
B. Neutrophilic inflammation with vasculitis
C. Granulomatous inflammation caused by mycobacteria
D. Antibody-mediated destruction of basement membrane
E. Eosinophilic infiltration
