Endocrine System Disorders Flashcards

A patient with polyuria has dilute urine after water deprivation; urine osmolality rises by 70% after desmopressin. What is the diagnosis?

Answer: Central diabetes insipidus

A marked rise in urine osmolality after desmopressin indicates ADH deficiency with intact renal response.

After a delivery complicated by massive hemorrhage, a woman is unable to breastfeed and later develops amenorrhea and fatigue. What is the most likely cause?

Answer: Sheehan syndrome

Postpartum pituitary ischemic necrosis causes hypopituitarism, with failure of lactation often the first sign.

At what eGFR is metformin contraindicated per FDA labeling?

Answer: Below 30 mL/min/1.73 m2

Metformin is contraindicated below eGFR 30 because of lactic acidosis risk, and initiation is not recommended at 30-45.

A woman at 9 weeks gestation is diagnosed with Graves disease requiring antithyroid therapy. Which drug is preferred during the first trimester?

Answer: Propylthiouracil

PTU is preferred in the first trimester because methimazole is associated with embryopathy such as aplasia cutis.

A 30-year-old has mild asymptomatic hypercalcemia, high-normal PTH, and a calcium-to-creatinine clearance ratio of 0.005; her father has similar labs. What is the best management?

Answer: Reassurance and no surgery

Familial hypocalciuric hypercalcemia is a benign CaSR mutation that does not improve with parathyroidectomy.

A 28-year-old woman with galactorrhea and amenorrhea has a 6-mm pituitary adenoma and prolactin of 150 ng/mL. What is first-line therapy?

Answer: Cabergoline

Dopamine agonists, preferably cabergoline, normalize prolactin and shrink most prolactinomas.

A newborn girl has ambiguous genitalia, and on day 7 develops hyponatremia, hyperkalemia, and hypotension. Which lab is most likely elevated?

Answer: 17-hydroxyprogesterone

21-hydroxylase deficiency blocks cortisol and aldosterone synthesis, causing 17-hydroxyprogesterone accumulation and salt wasting.