COMSAE Institutional Readiness
Assessment Form IRA 105 Exam Practice
Questions & [Verified Answers], Plus
Explained Rationales|2026 Latest Update|
Instant Download PDF
1. A 67-year-old man presents with progressive fatigue, exertional
dyspnea, and intermittent headaches. Physical examination
reveals plethora and splenomegaly. Laboratory studies show
hemoglobin 20.2 g/dL, hematocrit 61%, platelets 520,000/mm³,
leukocytes 15,000/mm³, and low erythropoietin levels. Which of
the following is the most likely diagnosis?
A. Secondary erythrocytosis due to chronic hypoxia
B. Polycythemia vera
C. Essential thrombocythemia
D. Myelofibrosis
E. Chronic lymphocytic leukemia
Answer: B. Polycythemia vera
Rationale: Polycythemia vera is a myeloproliferative neoplasm
characterized by increased red cell mass, low erythropoietin levels,
splenomegaly, leukocytosis, and thrombocytosis. Secondary
erythrocytosis typically presents with elevated erythropoietin levels.
, 2. A 24-year-old woman develops ptosis and diplopia that worsen
throughout the day. Muscle strength improves after rest. Which
antibody is most commonly associated with this condition?
A. Anti-MuSK
B. Anti-acetylcholine receptor
C. Anti-Jo-1
D. Anti-dsDNA
E. Anti-centromere
Answer: B. Anti-acetylcholine receptor
Rationale: Myasthenia gravis is caused by antibodies directed against
postsynaptic acetylcholine receptors, producing fluctuating muscle
weakness that worsens with activity and improves with rest.
3. A newborn develops bilious vomiting within the first day of life.
Abdominal radiograph demonstrates a double-bubble sign with
minimal distal bowel gas. What is the diagnosis?
A. Jejunal atresia
B. Meconium ileus
C. Duodenal atresia
D. Pyloric stenosis
E. Hirschsprung disease
Answer: C. Duodenal atresia
Rationale: Duodenal atresia classically presents with early bilious
vomiting and the double-bubble sign representing a distended stomach
and proximal duodenum.
, 4. A 56-year-old man presents with chest pain radiating to his back.
Blood pressure is 190/100 mmHg in the right arm and 150/90
mmHg in the left arm. Chest radiograph shows widened
mediastinum. Which is the most likely diagnosis?
A. Pulmonary embolism
B. Acute pericarditis
C. Aortic dissection
D. Myocardial infarction
E. Esophageal rupture
Answer: C. Aortic dissection
Rationale: Tearing chest pain radiating to the back, unequal blood
pressures, and mediastinal widening strongly suggest aortic dissection.
5. A patient with chronic alcoholism develops confusion,
ophthalmoplegia, and gait ataxia. Which vitamin deficiency is
responsible?
A. Vitamin B12
B. Niacin
C. Pyridoxine
D. Thiamine
E. Vitamin C
Answer: D. Thiamine
Rationale: Wernicke encephalopathy consists of confusion,
ophthalmoplegia, and ataxia due to thiamine deficiency.
6. Which nephron segment is impermeable to water and serves as
the primary diluting segment?
, A. Proximal tubule
B. Thin descending limb
C. Thick ascending limb
D. Collecting duct with ADH
E. Cortical collecting tubule
Answer: C. Thick ascending limb
Rationale: The thick ascending limb actively reabsorbs sodium,
potassium, and chloride but is impermeable to water, creating dilute
tubular fluid.
7. A 38-year-old woman has episodic flushing, diarrhea, and
wheezing. Urinary 5-HIAA is elevated. The tumor most likely
originates from:
A. Gastric chief cells
B. Enterochromaffin cells
C. Pancreatic beta cells
D. Hepatocytes
E. Adrenal cortex
Answer: B. Enterochromaffin cells
Rationale: Carcinoid tumors arise from enterochromaffin
neuroendocrine cells and secrete serotonin, causing carcinoid syndrome.
8. A patient has hypercalcemia, kidney stones, abdominal pain, and
psychiatric symptoms. Elevated PTH is present. What is the most
likely diagnosis?
A. Familial hypocalciuric hypercalcemia
B. Primary hyperparathyroidism
Assessment Form IRA 105 Exam Practice
Questions & [Verified Answers], Plus
Explained Rationales|2026 Latest Update|
Instant Download PDF
1. A 67-year-old man presents with progressive fatigue, exertional
dyspnea, and intermittent headaches. Physical examination
reveals plethora and splenomegaly. Laboratory studies show
hemoglobin 20.2 g/dL, hematocrit 61%, platelets 520,000/mm³,
leukocytes 15,000/mm³, and low erythropoietin levels. Which of
the following is the most likely diagnosis?
A. Secondary erythrocytosis due to chronic hypoxia
B. Polycythemia vera
C. Essential thrombocythemia
D. Myelofibrosis
E. Chronic lymphocytic leukemia
Answer: B. Polycythemia vera
Rationale: Polycythemia vera is a myeloproliferative neoplasm
characterized by increased red cell mass, low erythropoietin levels,
splenomegaly, leukocytosis, and thrombocytosis. Secondary
erythrocytosis typically presents with elevated erythropoietin levels.
, 2. A 24-year-old woman develops ptosis and diplopia that worsen
throughout the day. Muscle strength improves after rest. Which
antibody is most commonly associated with this condition?
A. Anti-MuSK
B. Anti-acetylcholine receptor
C. Anti-Jo-1
D. Anti-dsDNA
E. Anti-centromere
Answer: B. Anti-acetylcholine receptor
Rationale: Myasthenia gravis is caused by antibodies directed against
postsynaptic acetylcholine receptors, producing fluctuating muscle
weakness that worsens with activity and improves with rest.
3. A newborn develops bilious vomiting within the first day of life.
Abdominal radiograph demonstrates a double-bubble sign with
minimal distal bowel gas. What is the diagnosis?
A. Jejunal atresia
B. Meconium ileus
C. Duodenal atresia
D. Pyloric stenosis
E. Hirschsprung disease
Answer: C. Duodenal atresia
Rationale: Duodenal atresia classically presents with early bilious
vomiting and the double-bubble sign representing a distended stomach
and proximal duodenum.
, 4. A 56-year-old man presents with chest pain radiating to his back.
Blood pressure is 190/100 mmHg in the right arm and 150/90
mmHg in the left arm. Chest radiograph shows widened
mediastinum. Which is the most likely diagnosis?
A. Pulmonary embolism
B. Acute pericarditis
C. Aortic dissection
D. Myocardial infarction
E. Esophageal rupture
Answer: C. Aortic dissection
Rationale: Tearing chest pain radiating to the back, unequal blood
pressures, and mediastinal widening strongly suggest aortic dissection.
5. A patient with chronic alcoholism develops confusion,
ophthalmoplegia, and gait ataxia. Which vitamin deficiency is
responsible?
A. Vitamin B12
B. Niacin
C. Pyridoxine
D. Thiamine
E. Vitamin C
Answer: D. Thiamine
Rationale: Wernicke encephalopathy consists of confusion,
ophthalmoplegia, and ataxia due to thiamine deficiency.
6. Which nephron segment is impermeable to water and serves as
the primary diluting segment?
, A. Proximal tubule
B. Thin descending limb
C. Thick ascending limb
D. Collecting duct with ADH
E. Cortical collecting tubule
Answer: C. Thick ascending limb
Rationale: The thick ascending limb actively reabsorbs sodium,
potassium, and chloride but is impermeable to water, creating dilute
tubular fluid.
7. A 38-year-old woman has episodic flushing, diarrhea, and
wheezing. Urinary 5-HIAA is elevated. The tumor most likely
originates from:
A. Gastric chief cells
B. Enterochromaffin cells
C. Pancreatic beta cells
D. Hepatocytes
E. Adrenal cortex
Answer: B. Enterochromaffin cells
Rationale: Carcinoid tumors arise from enterochromaffin
neuroendocrine cells and secrete serotonin, causing carcinoid syndrome.
8. A patient has hypercalcemia, kidney stones, abdominal pain, and
psychiatric symptoms. Elevated PTH is present. What is the most
likely diagnosis?
A. Familial hypocalciuric hypercalcemia
B. Primary hyperparathyroidism
