Internal Medicine Exam Nephrology and Kidney Injury 5

Question 1

A 42-year-old woman with a history of nephrolithiasis has urine pH persistently above 6.5, serum bicarbonate of 18 mEq/L, and normal anion gap metabolic acidosis. Urine anion gap is positive. What is the diagnosis?

Accepted Answer

Distal (Type I) renal tubular acidosis

Answer

Distal RTA is characterized by inability to acidify urine below pH 5.5, positive urine anion gap, normal anion gap acidosis, and predisposition to calcium phosphate nephrolithiasis.

Question 2

A 55-year-old man on hemodialysis three times weekly complains of pruritus, bone pain, and a palpable neck mass. His PTH is 1,200 pg/mL and calcium is 10.8 mg/dL. What is the best treatment?

Accepted Answer

Parathyroidectomy

Answer

Tertiary hyperparathyroidism with autonomous PTH secretion, hypercalcemia, and PTH >800 pg/mL refractory to medical therapy requires parathyroidectomy.

Question 3

A 33-year-old woman presents with bilateral renal masses on ultrasound and a family history of early-onset renal cell carcinoma, pheochromocytoma, and retinal hemangioblastomas. Which genetic syndrome is most likely?

Accepted Answer

Von Hippel-Lindau disease

Answer

Von Hippel-Lindau disease (VHL mutation) causes clear cell RCC, pheochromocytoma, hemangioblastomas, and pancreatic cysts with autosomal dominant inheritance.

Question 4

A 70-year-old man with BPH undergoes bilateral hydronephrosis relief by Foley catheter insertion. Over the next 24 hours he produces 8 liters of urine and his creatinine falls from 8.2 to 3.1 mg/dL. What electrolyte abnormality requires monitoring?

Accepted Answer

Hypokalemia and hyponatremia from post-obstructive diuresis

Answer

Post-obstructive diuresis causes massive urinary losses of sodium, potassium, and water; close monitoring and replacement are required to prevent dangerous electrolyte depletion.

Question 5

A 48-year-old man with cirrhosis develops AKI with creatinine rising to 3.4 mg/dL. Urine sodium is 8 mEq/L and urinalysis is bland. He does not respond to 1.5 L albumin infusion. What is the next step?

Accepted Answer

Start terlipressin and albumin

Answer

Hepatorenal syndrome type 1 (HRS-AKI) is treated with vasoconstrictors (terlipressin preferred in US; norepinephrine as alternative) plus albumin to restore effective circulating volume.

Internal Medicine Exam Practice Test

Internal Medicine Exam Practice Test

Internal Medicine Exam Nephrology and Kidney Injury 5