, Question 1
A patient with primary hyperaldosteronism is being evaluated for surgical
candidacy. Which diagnostic finding best distinguishes an
aldosterone-producing adenoma from bilateral adrenal hyperplasia?
A. Suppressed plasma renin activity with elevated aldosterone
B. Elevated aldosterone with normal renin and no suppression on saline
infusion
C. Unilateral aldosterone excess on adrenal venous sampling
D. Elevated 24-hour urinary aldosterone with hypokalemia
Correct Answer: C - Unilateral aldosterone excess on adrenal
venous sampling
RATIONALE
Adrenal venous sampling is the gold standard to lateralize aldosterone
secretion, distinguishing a unilateral adenoma from bilateral
hyperplasia. Suppressed renin and elevated aldosterone occur in both,
while saline infusion and urinary aldosterone are nonspecific. Only
lateralization guides surgical vs. medical management.
Question 2
A patient on levothyroxine for hypothyroidism reports palpitations and weight
loss. Labs show TSH 0.02 mIU/L and free T4 at the upper limit of normal.
Which action is most appropriate?
A. Increase levothyroxine dose
B. Add liothyronine
C. Reduce levothyroxine dose
D. Switch to desiccated thyroid
Correct Answer: C - Reduce levothyroxine dose
Page 2
, RATIONALE
The clinical picture and suppressed TSH indicate iatrogenic
thyrotoxicosis from over-replacement. Reducing the levothyroxine
dose is the correct first step. Adding or switching medications would
worsen thyrotoxicosis, and increasing the dose is contraindicated.
Question 3
A patient with type 2 diabetes on metformin and empagliflozin develops a
urinary tract infection and is now confused, hypotensive, and has a blood pH of
7.25 with elevated beta-hydroxybutyrate but normal glucose. Which condition
is most likely?
A. Diabetic ketoacidosis
B. Hyperosmolar hyperglycemic state
C. Euglycemic diabetic ketoacidosis
D. Lactic acidosis
Correct Answer: C - Euglycemic diabetic ketoacidosis
RATIONALE
SGLT2 inhibitors can precipitate euglycemic DKA, characterized by
ketoacidosis with normal or mildly elevated glucose. The presence of
ketones and acidosis with normal glucose rules out HHS and typical
DKA. Lactic acidosis would not typically present with elevated
ketones.
Question 4
A patient with polycystic ovary syndrome (PCOS) is started on combined oral
contraceptives. Which additional medication is most appropriate to manage
insulin resistance and improve ovulatory function?
A. Spironolactone
B. Metformin
C. Clomiphene
Page 3
, D. Pioglitazone
Correct Answer: B - Metformin
RATIONALE
Metformin improves insulin sensitivity and can restore ovulatory
cycles in PCOS, especially in those with insulin resistance.
Spironolactone is antiandrogenic but does not address insulin
resistance; clomiphene is for ovulation induction but not first-line for
metabolic management; pioglitazone is not first-line and has safety
concerns.
Question 5
A postpartum patient presents with fatigue, weight gain, and cold intolerance.
Labs show low free T4 and elevated TSH. Which is the most likely diagnosis?
A. Postpartum thyroiditis, hyperthyroid phase
B. Postpartum thyroiditis, hypothyroid phase
C. Graves' disease
D. Sheehan's syndrome
Correct Answer: B - Postpartum thyroiditis, hypothyroid phase
RATIONALE
Postpartum thyroiditis often presents with a hypothyroid phase
characterized by low free T4 and elevated TSH. The hyperthyroid
phase would show elevated T4 and suppressed TSH. Graves' disease
causes hyperthyroidism, and Sheehan's syndrome typically involves
multiple pituitary hormone deficiencies.
Question 6
A patient with suspected Cushing's syndrome has an elevated late-night
salivary cortisol and a normal 24-hour urinary free cortisol. Which next test is
most appropriate to confirm the diagnosis?
A. Overnight dexamethasone suppression test
Page 4
A patient with primary hyperaldosteronism is being evaluated for surgical
candidacy. Which diagnostic finding best distinguishes an
aldosterone-producing adenoma from bilateral adrenal hyperplasia?
A. Suppressed plasma renin activity with elevated aldosterone
B. Elevated aldosterone with normal renin and no suppression on saline
infusion
C. Unilateral aldosterone excess on adrenal venous sampling
D. Elevated 24-hour urinary aldosterone with hypokalemia
Correct Answer: C - Unilateral aldosterone excess on adrenal
venous sampling
RATIONALE
Adrenal venous sampling is the gold standard to lateralize aldosterone
secretion, distinguishing a unilateral adenoma from bilateral
hyperplasia. Suppressed renin and elevated aldosterone occur in both,
while saline infusion and urinary aldosterone are nonspecific. Only
lateralization guides surgical vs. medical management.
Question 2
A patient on levothyroxine for hypothyroidism reports palpitations and weight
loss. Labs show TSH 0.02 mIU/L and free T4 at the upper limit of normal.
Which action is most appropriate?
A. Increase levothyroxine dose
B. Add liothyronine
C. Reduce levothyroxine dose
D. Switch to desiccated thyroid
Correct Answer: C - Reduce levothyroxine dose
Page 2
, RATIONALE
The clinical picture and suppressed TSH indicate iatrogenic
thyrotoxicosis from over-replacement. Reducing the levothyroxine
dose is the correct first step. Adding or switching medications would
worsen thyrotoxicosis, and increasing the dose is contraindicated.
Question 3
A patient with type 2 diabetes on metformin and empagliflozin develops a
urinary tract infection and is now confused, hypotensive, and has a blood pH of
7.25 with elevated beta-hydroxybutyrate but normal glucose. Which condition
is most likely?
A. Diabetic ketoacidosis
B. Hyperosmolar hyperglycemic state
C. Euglycemic diabetic ketoacidosis
D. Lactic acidosis
Correct Answer: C - Euglycemic diabetic ketoacidosis
RATIONALE
SGLT2 inhibitors can precipitate euglycemic DKA, characterized by
ketoacidosis with normal or mildly elevated glucose. The presence of
ketones and acidosis with normal glucose rules out HHS and typical
DKA. Lactic acidosis would not typically present with elevated
ketones.
Question 4
A patient with polycystic ovary syndrome (PCOS) is started on combined oral
contraceptives. Which additional medication is most appropriate to manage
insulin resistance and improve ovulatory function?
A. Spironolactone
B. Metformin
C. Clomiphene
Page 3
, D. Pioglitazone
Correct Answer: B - Metformin
RATIONALE
Metformin improves insulin sensitivity and can restore ovulatory
cycles in PCOS, especially in those with insulin resistance.
Spironolactone is antiandrogenic but does not address insulin
resistance; clomiphene is for ovulation induction but not first-line for
metabolic management; pioglitazone is not first-line and has safety
concerns.
Question 5
A postpartum patient presents with fatigue, weight gain, and cold intolerance.
Labs show low free T4 and elevated TSH. Which is the most likely diagnosis?
A. Postpartum thyroiditis, hyperthyroid phase
B. Postpartum thyroiditis, hypothyroid phase
C. Graves' disease
D. Sheehan's syndrome
Correct Answer: B - Postpartum thyroiditis, hypothyroid phase
RATIONALE
Postpartum thyroiditis often presents with a hypothyroid phase
characterized by low free T4 and elevated TSH. The hyperthyroid
phase would show elevated T4 and suppressed TSH. Graves' disease
causes hyperthyroidism, and Sheehan's syndrome typically involves
multiple pituitary hormone deficiencies.
Question 6
A patient with suspected Cushing's syndrome has an elevated late-night
salivary cortisol and a normal 24-hour urinary free cortisol. Which next test is
most appropriate to confirm the diagnosis?
A. Overnight dexamethasone suppression test
Page 4
