Expert Rationale:
COMSAE 115 EXAM 2026/2027 MOST DETAILED
TESTED QUESTIONS AND CORRECT
ANSWERS WITH RATIONALES
(VERIFIEDSOLUTIONS) 2026 EDITION
|BEST DOCUMENT FOR EXAM-TESTBANK
A 58-year-old woman with a history of hypertension and hyperlipidemia presents
with sudden onset chest pain radiating to her jaw. ECG shows ST-segment
elevations in leads V2 through V4. Which coronary artery is most likely occluded?
a. Right coronary artery
b. Left anterior descending artery
c. Left circumflex artery
d. Posterior descending artery
e. Right marginal artery
✔️ Correct Answer: B
Rationale:
ST-segment elevations in leads V2 through V4 indicate an anterior wall myocardial
infarction, which is most commonly caused by occlusion of the left anterior descending
(LAD) artery. The LAD supplies the anterior wall of the left ventricle and the
interventricular septum. Option A, the right coronary artery, typically causes inferior wall
MI (leads II, III, aVF). Option C, the left circumflex artery, usually causes lateral wall MI
(leads I, aVL, V5, V6). Option D, the posterior descending artery, affects inferior and
posterior walls. Option E, the right marginal artery, supplies the right ventricle.
A 24-year-old man presents with fever, neck stiffness, and altered mental status.
CSF analysis shows neutrophilic pleocytosis, low glucose, and elevated protein.
What is the most likely causative organism?
a. Streptococcus pneumoniae
b. Neisseria meningitidis
c. Haemophilus influenzae
,Expert Rationale:
d. Listeria monocytogenes
e. Enterovirus
✔️ Correct Answer: A
Rationale:
In adults, the most common cause of bacterial meningitis is Streptococcus pneumoniae,
which presents with neutrophilic CSF pleocytosis, decreased glucose, and elevated
protein. Option B, Neisseria meningitidis, is more common in adolescents and young
adults in outbreaks. Option C, Haemophilus influenzae, is now less common due to
vaccination. Option D, Listeria monocytogenes, affects neonates, the elderly, and
immunocompromised individuals. Option E, Enterovirus, causes viral meningitis with
normal glucose levels.
A 32-year-old woman presents with heat intolerance, weight loss, and palpitations.
Laboratory studies show low TSH and elevated free T4. Which antibody is most
likely present?
a. Anti-thyroid peroxidase
b. Anti-thyroglobulin
c. Thyroid-stimulating immunoglobulin
d. Anti-TSH receptor blocking antibody
e. Anti-TSH receptor IgG blocking type
✔️ Correct Answer: C
Rationale:
Graves disease is caused by thyroid-stimulating immunoglobulins (TSI) that activate the
TSH receptor, leading to increased thyroid hormone production. Options A and B are
seen in Hashimoto thyroiditis. Options D and E describe blocking antibodies that cause
hypothyroidism, not hyperthyroidism.
A 45-year-old man with chronic alcohol use presents with tremors and confusion
that improve after eating. Which hormone is primarily responsible for his
symptoms?
a. Insulin
b. Glucagon
c. Cortisol
,Expert Rationale:
d. Epinephrine
e. Growth hormone
✔️ Correct Answer: B
Rationale:
In hypoglycemia, glucagon is the primary counter-regulatory hormone that increases
blood glucose via glycogenolysis. Insulin (A) lowers glucose. Cortisol (C), epinephrine
(D), and growth hormone (E) contribute to the stress response but glucagon is the
primary acute regulator.
A newborn fails to pass meconium within 48 hours and has a distended abdomen.
A rectal biopsy shows absence of ganglion cells. What is the most likely diagnosis?
a. Meconium ileus
b. Hirschsprung disease
c. Pyloric stenosis
d. Intussusception
e. Necrotizing enterocolitis
✔️ Correct Answer: B
Rationale:
Hirschsprung disease is caused by failure of neural crest cell migration, resulting in
absence of ganglion cells in the distal colon and functional bowel obstruction. Option A,
meconium ileus, is associated with cystic fibrosis. Option C, pyloric stenosis, causes
projectile vomiting. Option D, intussusception, presents with currant jelly stools. Option
E, necrotizing enterocolitis, occurs in premature infants.
A 60-year-old man with COPD presents with worsening shortness of breath. ABG
shows pH 7.32, elevated PaCO₂, and elevated HCO₃⁻. What is the primary acid-base
disorder?
a. Acute respiratory acidosis
b. Chronic respiratory acidosis
c. Metabolic acidosis
d. Metabolic alkalosis
e. Mixed respiratory alkalosis and metabolic acidosis
, Expert Rationale:
✔️ Correct Answer: B
Rationale:
Elevated PaCO₂ with elevated bicarbonate indicates renal compensation, consistent with
chronic respiratory acidosis as seen in COPD. Option A, acute respiratory acidosis, lacks
renal compensation. Options C, D, and E do not match the ABG pattern.
A 19-year-old college student presents with fever, cough, and "walking
pneumonia." Chest X-ray shows diffuse interstitial infiltrates. What is the most
likely organism?
a. Streptococcus pneumoniae
b. Mycoplasma pneumoniae
c. Klebsiella pneumoniae
d. Legionella pneumophila
e. Chlamydia trachomatis
✔️ Correct Answer: B
Rationale:
Mycoplasma pneumoniae causes atypical pneumonia in young adults with mild
symptoms and interstitial infiltrates. Option A, Streptococcus pneumoniae, causes
typical lobar pneumonia. Option C, Klebsiella pneumoniae, produces currant jelly
sputum in alcoholics. Option D, Legionella pneumophila, is associated with
hyponatremia and severe pneumonia. Option E, Chlamydia trachomatis, causes neonatal
conjunctivitis and pneumonia.
A 55-year-old woman presents with progressive dysphagia to both solids and
liquids. Barium swallow shows "bird's beak" narrowing. What is the underlying
pathology?
a. Esophageal cancer
b. Achalasia due to loss of myenteric plexus
c. GERD-induced stricture
d. Diffuse esophageal spasm
e. Scleroderma
✔️ Correct Answer: B
Rationale:
COMSAE 115 EXAM 2026/2027 MOST DETAILED
TESTED QUESTIONS AND CORRECT
ANSWERS WITH RATIONALES
(VERIFIEDSOLUTIONS) 2026 EDITION
|BEST DOCUMENT FOR EXAM-TESTBANK
A 58-year-old woman with a history of hypertension and hyperlipidemia presents
with sudden onset chest pain radiating to her jaw. ECG shows ST-segment
elevations in leads V2 through V4. Which coronary artery is most likely occluded?
a. Right coronary artery
b. Left anterior descending artery
c. Left circumflex artery
d. Posterior descending artery
e. Right marginal artery
✔️ Correct Answer: B
Rationale:
ST-segment elevations in leads V2 through V4 indicate an anterior wall myocardial
infarction, which is most commonly caused by occlusion of the left anterior descending
(LAD) artery. The LAD supplies the anterior wall of the left ventricle and the
interventricular septum. Option A, the right coronary artery, typically causes inferior wall
MI (leads II, III, aVF). Option C, the left circumflex artery, usually causes lateral wall MI
(leads I, aVL, V5, V6). Option D, the posterior descending artery, affects inferior and
posterior walls. Option E, the right marginal artery, supplies the right ventricle.
A 24-year-old man presents with fever, neck stiffness, and altered mental status.
CSF analysis shows neutrophilic pleocytosis, low glucose, and elevated protein.
What is the most likely causative organism?
a. Streptococcus pneumoniae
b. Neisseria meningitidis
c. Haemophilus influenzae
,Expert Rationale:
d. Listeria monocytogenes
e. Enterovirus
✔️ Correct Answer: A
Rationale:
In adults, the most common cause of bacterial meningitis is Streptococcus pneumoniae,
which presents with neutrophilic CSF pleocytosis, decreased glucose, and elevated
protein. Option B, Neisseria meningitidis, is more common in adolescents and young
adults in outbreaks. Option C, Haemophilus influenzae, is now less common due to
vaccination. Option D, Listeria monocytogenes, affects neonates, the elderly, and
immunocompromised individuals. Option E, Enterovirus, causes viral meningitis with
normal glucose levels.
A 32-year-old woman presents with heat intolerance, weight loss, and palpitations.
Laboratory studies show low TSH and elevated free T4. Which antibody is most
likely present?
a. Anti-thyroid peroxidase
b. Anti-thyroglobulin
c. Thyroid-stimulating immunoglobulin
d. Anti-TSH receptor blocking antibody
e. Anti-TSH receptor IgG blocking type
✔️ Correct Answer: C
Rationale:
Graves disease is caused by thyroid-stimulating immunoglobulins (TSI) that activate the
TSH receptor, leading to increased thyroid hormone production. Options A and B are
seen in Hashimoto thyroiditis. Options D and E describe blocking antibodies that cause
hypothyroidism, not hyperthyroidism.
A 45-year-old man with chronic alcohol use presents with tremors and confusion
that improve after eating. Which hormone is primarily responsible for his
symptoms?
a. Insulin
b. Glucagon
c. Cortisol
,Expert Rationale:
d. Epinephrine
e. Growth hormone
✔️ Correct Answer: B
Rationale:
In hypoglycemia, glucagon is the primary counter-regulatory hormone that increases
blood glucose via glycogenolysis. Insulin (A) lowers glucose. Cortisol (C), epinephrine
(D), and growth hormone (E) contribute to the stress response but glucagon is the
primary acute regulator.
A newborn fails to pass meconium within 48 hours and has a distended abdomen.
A rectal biopsy shows absence of ganglion cells. What is the most likely diagnosis?
a. Meconium ileus
b. Hirschsprung disease
c. Pyloric stenosis
d. Intussusception
e. Necrotizing enterocolitis
✔️ Correct Answer: B
Rationale:
Hirschsprung disease is caused by failure of neural crest cell migration, resulting in
absence of ganglion cells in the distal colon and functional bowel obstruction. Option A,
meconium ileus, is associated with cystic fibrosis. Option C, pyloric stenosis, causes
projectile vomiting. Option D, intussusception, presents with currant jelly stools. Option
E, necrotizing enterocolitis, occurs in premature infants.
A 60-year-old man with COPD presents with worsening shortness of breath. ABG
shows pH 7.32, elevated PaCO₂, and elevated HCO₃⁻. What is the primary acid-base
disorder?
a. Acute respiratory acidosis
b. Chronic respiratory acidosis
c. Metabolic acidosis
d. Metabolic alkalosis
e. Mixed respiratory alkalosis and metabolic acidosis
, Expert Rationale:
✔️ Correct Answer: B
Rationale:
Elevated PaCO₂ with elevated bicarbonate indicates renal compensation, consistent with
chronic respiratory acidosis as seen in COPD. Option A, acute respiratory acidosis, lacks
renal compensation. Options C, D, and E do not match the ABG pattern.
A 19-year-old college student presents with fever, cough, and "walking
pneumonia." Chest X-ray shows diffuse interstitial infiltrates. What is the most
likely organism?
a. Streptococcus pneumoniae
b. Mycoplasma pneumoniae
c. Klebsiella pneumoniae
d. Legionella pneumophila
e. Chlamydia trachomatis
✔️ Correct Answer: B
Rationale:
Mycoplasma pneumoniae causes atypical pneumonia in young adults with mild
symptoms and interstitial infiltrates. Option A, Streptococcus pneumoniae, causes
typical lobar pneumonia. Option C, Klebsiella pneumoniae, produces currant jelly
sputum in alcoholics. Option D, Legionella pneumophila, is associated with
hyponatremia and severe pneumonia. Option E, Chlamydia trachomatis, causes neonatal
conjunctivitis and pneumonia.
A 55-year-old woman presents with progressive dysphagia to both solids and
liquids. Barium swallow shows "bird's beak" narrowing. What is the underlying
pathology?
a. Esophageal cancer
b. Achalasia due to loss of myenteric plexus
c. GERD-induced stricture
d. Diffuse esophageal spasm
e. Scleroderma
✔️ Correct Answer: B
Rationale:
