COMSAE PHASE 2- 114
Questions with Answers &
Rationales 2026 Edition
1.
A 24-year-old woman presents with fatigue, weight gain,
constipation, and cold intolerance. Examination reveals dry
skin and delayed relaxation of deep tendon reflexes.
Laboratory studies show elevated TSH and decreased free T4.
Which mechanism best explains her condition?
A. Increased thyroid hormone synthesis
B. Autoimmune destruction of thyroid follicles
C. Excessive TSH secretion from a pituitary adenoma
D. Increased peripheral conversion of T4 to T3
Answer: B. Autoimmune destruction of thyroid follicles
Hashimoto thyroiditis causes autoimmune destruction of
thyroid tissue, producing primary hypothyroidism with high
TSH and low T4.
2.
A 67-year-old man with a 50-pack-year smoking history
presents with hemoptysis and weight loss. Imaging reveals a
,central hilar lung mass. Biopsy shows sheets of malignant
cells with scant cytoplasm and hyperchromatic nuclei.
Laboratory studies reveal hyponatremia and decreased serum
osmolality. Which substance is most likely being secreted?
A. ACTH
B. ADH
C. PTH-related peptide
D. Calcitonin
Answer: B. ADH
Small cell lung carcinoma commonly produces ectopic ADH,
causing euvolemic hyponatremia through inappropriate
water retention.
3.
A 19-year-old man develops sudden severe scrotal pain while
playing basketball. The affected testis is elevated, and the
cremasteric reflex is absent. Which structure is primarily
involved?
A. Epididymis
B. Spermatic cord
C. Vas deferens
D. Tunica vaginalis
Answer: B. Spermatic cord
Testicular torsion twists the spermatic cord, compromising
venous drainage followed by arterial blood flow. Immediate
surgical detorsion is required.
,4.
A patient with a history of recurrent kidney stones has
hypercalcemia, low serum phosphate, and elevated PTH.
Which renal process is increased by PTH?
A. Phosphate reabsorption in the proximal tubule
B. Calcium reabsorption in the distal nephron
C. Calcium excretion
D. 1α-hydroxylase inhibition
Answer: B. Calcium reabsorption in the distal nephron
PTH increases distal calcium reabsorption, decreases proximal
phosphate reabsorption, and stimulates calcitriol production.
5.
A 35-year-old woman presents with episodic headaches,
palpitations, diaphoresis, and severe hypertension. A
pheochromocytoma is suspected. Which biochemical test is
most appropriate initially?
A. Serum aldosterone
B. Plasma free metanephrines
C. Serum cortisol
D. Urinary VMA alone
Answer: B. Plasma free metanephrines
Plasma free metanephrines are highly sensitive for detecting
catecholamine excess from pheochromocytoma.
, 6.
A 42-year-old man develops progressive proximal muscle
weakness, difficulty climbing stairs, and a heliotrope rash.
Laboratory studies reveal elevated creatine kinase. Which
diagnosis is most likely?
A. Polymyalgia rheumatica
B. Dermatomyositis
C. Myasthenia gravis
D. Guillain-Barré syndrome
Answer: B. Dermatomyositis
Dermatomyositis causes inflammatory proximal muscle
weakness with characteristic cutaneous findings such as a
heliotrope rash.
7.
A 58-year-old man with chronic alcohol use presents with
confusion, ophthalmoplegia, and ataxia. Which treatment
should be given immediately?
A. Glucose before vitamins
B. Thiamine before glucose
C. Folate alone
D. Pyridoxine before glucose
Answer: B. Thiamine before glucose
Questions with Answers &
Rationales 2026 Edition
1.
A 24-year-old woman presents with fatigue, weight gain,
constipation, and cold intolerance. Examination reveals dry
skin and delayed relaxation of deep tendon reflexes.
Laboratory studies show elevated TSH and decreased free T4.
Which mechanism best explains her condition?
A. Increased thyroid hormone synthesis
B. Autoimmune destruction of thyroid follicles
C. Excessive TSH secretion from a pituitary adenoma
D. Increased peripheral conversion of T4 to T3
Answer: B. Autoimmune destruction of thyroid follicles
Hashimoto thyroiditis causes autoimmune destruction of
thyroid tissue, producing primary hypothyroidism with high
TSH and low T4.
2.
A 67-year-old man with a 50-pack-year smoking history
presents with hemoptysis and weight loss. Imaging reveals a
,central hilar lung mass. Biopsy shows sheets of malignant
cells with scant cytoplasm and hyperchromatic nuclei.
Laboratory studies reveal hyponatremia and decreased serum
osmolality. Which substance is most likely being secreted?
A. ACTH
B. ADH
C. PTH-related peptide
D. Calcitonin
Answer: B. ADH
Small cell lung carcinoma commonly produces ectopic ADH,
causing euvolemic hyponatremia through inappropriate
water retention.
3.
A 19-year-old man develops sudden severe scrotal pain while
playing basketball. The affected testis is elevated, and the
cremasteric reflex is absent. Which structure is primarily
involved?
A. Epididymis
B. Spermatic cord
C. Vas deferens
D. Tunica vaginalis
Answer: B. Spermatic cord
Testicular torsion twists the spermatic cord, compromising
venous drainage followed by arterial blood flow. Immediate
surgical detorsion is required.
,4.
A patient with a history of recurrent kidney stones has
hypercalcemia, low serum phosphate, and elevated PTH.
Which renal process is increased by PTH?
A. Phosphate reabsorption in the proximal tubule
B. Calcium reabsorption in the distal nephron
C. Calcium excretion
D. 1α-hydroxylase inhibition
Answer: B. Calcium reabsorption in the distal nephron
PTH increases distal calcium reabsorption, decreases proximal
phosphate reabsorption, and stimulates calcitriol production.
5.
A 35-year-old woman presents with episodic headaches,
palpitations, diaphoresis, and severe hypertension. A
pheochromocytoma is suspected. Which biochemical test is
most appropriate initially?
A. Serum aldosterone
B. Plasma free metanephrines
C. Serum cortisol
D. Urinary VMA alone
Answer: B. Plasma free metanephrines
Plasma free metanephrines are highly sensitive for detecting
catecholamine excess from pheochromocytoma.
, 6.
A 42-year-old man develops progressive proximal muscle
weakness, difficulty climbing stairs, and a heliotrope rash.
Laboratory studies reveal elevated creatine kinase. Which
diagnosis is most likely?
A. Polymyalgia rheumatica
B. Dermatomyositis
C. Myasthenia gravis
D. Guillain-Barré syndrome
Answer: B. Dermatomyositis
Dermatomyositis causes inflammatory proximal muscle
weakness with characteristic cutaneous findings such as a
heliotrope rash.
7.
A 58-year-old man with chronic alcohol use presents with
confusion, ophthalmoplegia, and ataxia. Which treatment
should be given immediately?
A. Glucose before vitamins
B. Thiamine before glucose
C. Folate alone
D. Pyridoxine before glucose
Answer: B. Thiamine before glucose
