2026 EDITION COMSAE Phase 2 Form
117 Exam Original Practice Questions
Verified Answers With Rationales
Question 1
A 67-year-old man with a 50-pack-year smoking history
presents with progressive dyspnea, weight loss, and
weakness. He has been taking hydrochlorothiazide for
hypertension. Laboratory studies show sodium 121 mEq/L,
serum osmolality 255 mOsm/kg, urine osmolality 620
mOsm/kg, and urine sodium 58 mEq/L. He appears
euvolemic. Chest CT reveals a 3-cm hilar mass. Which of the
following is the most likely mechanism responsible for this
patient's electrolyte abnormality?
A. Increased renal sodium reabsorption due to
hyperaldosteronism
B. Reduced distal nephron responsiveness to antidiuretic
hormone
C. Increased secretion of antidiuretic hormone by an ectopic
tumor
D. Increased atrial natriuretic peptide secretion
Rationale: This patient has hypotonic, euvolemic
hyponatremia with inappropriately concentrated urine and
elevated urine sodium, consistent with SIADH. A hilar lung
mass in a heavy smoker strongly suggests small-cell lung
,carcinoma, which can produce ectopic ADH. The high urine
osmolality indicates persistent ADH activity despite low
plasma osmolality.
Question 2
A 24-year-old woman presents with fever, hypotension,
diffuse myalgias, vomiting, and a generalized erythematous
rash that involves the palms and soles. She reports using
tampons during menstruation. Blood cultures are negative.
Which of the following mechanisms best explains her
condition?
A. Endotoxin-mediated activation of complement
B. IgE-mediated mast-cell degranulation
C. Immune-complex deposition in small vessels
D. Superantigen-mediated polyclonal T-cell activation
Rationale: Toxic shock syndrome caused by Staphylococcus
aureus is associated with tampon use and produces fever,
hypotension, diffuse rash, and multiorgan involvement. TSST-
1 acts as a superantigen, cross-linking MHC II molecules on
antigen-presenting cells with T-cell receptors, causing massive
cytokine release.
Question 3
A 71-year-old man develops sudden aphasia and right-sided
weakness. Examination shows impaired repetition, fluent
speech with numerous paraphasic errors, and poor
,comprehension. Which vascular territory is most likely
affected?
A. Left anterior cerebral artery
B. Left posterior cerebral artery
C. Right middle cerebral artery
D. Left middle cerebral artery inferior division
Rationale: Fluent aphasia with impaired comprehension and
repetition is characteristic of Wernicke aphasia, caused by
injury to the dominant posterior superior temporal region.
This area is supplied primarily by the inferior division of the
middle cerebral artery. The dominant hemisphere is usually
the left hemisphere.
Question 4
A 59-year-old woman with rheumatoid arthritis presents with
fatigue and exertional dyspnea. Hemoglobin is 8.7 g/dL, MCV
is 79 fL, serum iron is low, TIBC is low, and ferritin is elevated.
Which of the following best explains these findings?
A. Increased intestinal iron absorption
B. Decreased hepcidin production
C. Hepcidin-mediated sequestration of iron within
macrophages
D. Increased erythropoietin degradation
Rationale: Anemia of chronic inflammation is characterized
by low serum iron, low TIBC, and normal or elevated ferritin.
Inflammatory cytokines stimulate hepatic hepcidin
production, which degrades ferroportin and traps iron in
, macrophages and enterocytes, limiting iron availability for
erythropoiesis.
Question 5
A 36-year-old man develops severe substernal chest pain and
dyspnea 4 days after an inferior myocardial infarction. He has
a new harsh holosystolic murmur best heard at the lower left
sternal border and a palpable thrill. Which complication is
most likely?
A. Papillary muscle rupture
B. Free-wall rupture
C. Left ventricular aneurysm
D. Ventricular septal rupture
Rationale: Ventricular septal rupture typically occurs 3–5 days
after transmural myocardial infarction due to macrophage-
mediated degradation of necrotic myocardium. It causes an
acute left-to-right shunt, producing a harsh holosystolic
murmur with a thrill. Papillary muscle rupture produces acute
severe mitral regurgitation and is classically associated with
an inferior MI.
Question 6
A 42-year-old woman has recurrent episodes of severe
epigastric pain and watery diarrhea. She has a history of
recurrent peptic ulcers despite proton pump inhibitor
117 Exam Original Practice Questions
Verified Answers With Rationales
Question 1
A 67-year-old man with a 50-pack-year smoking history
presents with progressive dyspnea, weight loss, and
weakness. He has been taking hydrochlorothiazide for
hypertension. Laboratory studies show sodium 121 mEq/L,
serum osmolality 255 mOsm/kg, urine osmolality 620
mOsm/kg, and urine sodium 58 mEq/L. He appears
euvolemic. Chest CT reveals a 3-cm hilar mass. Which of the
following is the most likely mechanism responsible for this
patient's electrolyte abnormality?
A. Increased renal sodium reabsorption due to
hyperaldosteronism
B. Reduced distal nephron responsiveness to antidiuretic
hormone
C. Increased secretion of antidiuretic hormone by an ectopic
tumor
D. Increased atrial natriuretic peptide secretion
Rationale: This patient has hypotonic, euvolemic
hyponatremia with inappropriately concentrated urine and
elevated urine sodium, consistent with SIADH. A hilar lung
mass in a heavy smoker strongly suggests small-cell lung
,carcinoma, which can produce ectopic ADH. The high urine
osmolality indicates persistent ADH activity despite low
plasma osmolality.
Question 2
A 24-year-old woman presents with fever, hypotension,
diffuse myalgias, vomiting, and a generalized erythematous
rash that involves the palms and soles. She reports using
tampons during menstruation. Blood cultures are negative.
Which of the following mechanisms best explains her
condition?
A. Endotoxin-mediated activation of complement
B. IgE-mediated mast-cell degranulation
C. Immune-complex deposition in small vessels
D. Superantigen-mediated polyclonal T-cell activation
Rationale: Toxic shock syndrome caused by Staphylococcus
aureus is associated with tampon use and produces fever,
hypotension, diffuse rash, and multiorgan involvement. TSST-
1 acts as a superantigen, cross-linking MHC II molecules on
antigen-presenting cells with T-cell receptors, causing massive
cytokine release.
Question 3
A 71-year-old man develops sudden aphasia and right-sided
weakness. Examination shows impaired repetition, fluent
speech with numerous paraphasic errors, and poor
,comprehension. Which vascular territory is most likely
affected?
A. Left anterior cerebral artery
B. Left posterior cerebral artery
C. Right middle cerebral artery
D. Left middle cerebral artery inferior division
Rationale: Fluent aphasia with impaired comprehension and
repetition is characteristic of Wernicke aphasia, caused by
injury to the dominant posterior superior temporal region.
This area is supplied primarily by the inferior division of the
middle cerebral artery. The dominant hemisphere is usually
the left hemisphere.
Question 4
A 59-year-old woman with rheumatoid arthritis presents with
fatigue and exertional dyspnea. Hemoglobin is 8.7 g/dL, MCV
is 79 fL, serum iron is low, TIBC is low, and ferritin is elevated.
Which of the following best explains these findings?
A. Increased intestinal iron absorption
B. Decreased hepcidin production
C. Hepcidin-mediated sequestration of iron within
macrophages
D. Increased erythropoietin degradation
Rationale: Anemia of chronic inflammation is characterized
by low serum iron, low TIBC, and normal or elevated ferritin.
Inflammatory cytokines stimulate hepatic hepcidin
production, which degrades ferroportin and traps iron in
, macrophages and enterocytes, limiting iron availability for
erythropoiesis.
Question 5
A 36-year-old man develops severe substernal chest pain and
dyspnea 4 days after an inferior myocardial infarction. He has
a new harsh holosystolic murmur best heard at the lower left
sternal border and a palpable thrill. Which complication is
most likely?
A. Papillary muscle rupture
B. Free-wall rupture
C. Left ventricular aneurysm
D. Ventricular septal rupture
Rationale: Ventricular septal rupture typically occurs 3–5 days
after transmural myocardial infarction due to macrophage-
mediated degradation of necrotic myocardium. It causes an
acute left-to-right shunt, producing a harsh holosystolic
murmur with a thrill. Papillary muscle rupture produces acute
severe mitral regurgitation and is classically associated with
an inferior MI.
Question 6
A 42-year-old woman has recurrent episodes of severe
epigastric pain and watery diarrhea. She has a history of
recurrent peptic ulcers despite proton pump inhibitor
