ABIM Nephrology 2

Question 1

A patient with a history of recurrent kidney stones has 24-hour urine showing hypercalciuria with normal serum calcium. What is the most likely diagnosis?

Accepted Answer

Idiopathic hypercalciuria

Answer

Idiopathic hypercalciuria (with normal serum calcium) is the most common cause of calcium oxalate nephrolithiasis and is treated with thiazide diuretics.

Question 2

A 50-year-old man with polycystic kidney disease asks about his prognosis. His father died from a ruptured cerebral aneurysm. What screening should be offered?

Accepted Answer

MRA of the cerebral vasculature

Answer

Patients with ADPKD and a family history of intracranial aneurysm should undergo MRA screening for cerebral aneurysms due to the increased familial risk.

Question 3

Which finding best distinguishes acute tubular necrosis (ATN) from prerenal azotemia?

Accepted Answer

Muddy brown granular casts in urine

Answer

Muddy brown granular casts (renal tubular epithelial cell casts) in the urine are pathognomonic of ATN and reflect tubular epithelial cell injury and sloughing.

Question 4

A patient with end-stage renal disease on hemodialysis develops itching, periorbital edema, and a facial rash with hypercalcemia. Serum PTH is very low. What is the diagnosis?

Accepted Answer

Adynamic bone disease

Answer

Adynamic bone disease in ESRD patients is characterized by low PTH, impaired bone turnover, and often results from over-suppression of PTH with calcium or vitamin D therapy.

Question 5

A patient has an anion gap of 22 mEq/L, arterial pH of 7.28, and serum bicarbonate of 14 mEq/L. Which condition is NOT a cause of high anion gap metabolic acidosis?

Accepted Answer

Diarrhea

Answer

Diarrhea causes a non-anion gap (normal anion gap, hyperchloremic) metabolic acidosis due to bicarbonate loss, not accumulation of unmeasured anions.

ABIM - American Board of Internal Medicine Practice Test

ABIM - American Board of Internal Medicine Practice Test

ABIM Nephrology 2