Nephrology and Kidney Injury Flashcards
7 cards from real Internal Medicine Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Nephrology and Kidney Injury flashcards as text
A 55-year-old woman with type 2 diabetes has a GFR of 28 mL/min/1.73m² and serum phosphorus of 6.1 mg/dL despite dietary restriction. What is the most appropriate next step?
Answer: Start sevelamer (non-calcium binder)
Sevelamer is preferred over calcium-based binders in dialysis-stage CKD to avoid calcium loading and vascular calcification risk.
A 40-year-old man is found to have a serum sodium of 118 mEq/L. He has psychogenic polydipsia and appears euvolemic. Which correction rate is safe to prevent osmotic demyelination syndrome?
Answer: Correct by 8-10 mEq/L in 24 hours
Safe correction of chronic hyponatremia is limited to 8-10 mEq/L per 24 hours to prevent osmotic demyelination syndrome (central pontine myelinolysis).
A 70-year-old man with decompensated heart failure has oliguria, BUN 48 mg/dL, creatinine 2.2 mg/dL, and urine sodium 10 mEq/L. His kidney injury is best classified as:
Answer: Pre-renal AKI from reduced effective circulating volume
Low urine sodium (<20 mEq/L) and elevated BUN:creatinine ratio in heart failure indicate pre-renal AKI from reduced effective arterial blood volume.
A 50-year-old woman with a history of recurrent UTIs presents with flank pain and imaging showing a staghorn calculus filling the right renal pelvis. Urine culture grows Proteus mirabilis. What type of stone is this?
Answer: Struvite (magnesium ammonium phosphate)
Struvite stones form in the setting of urease-producing organisms (Proteus, Klebsiella) that alkalinize urine, causing precipitation of magnesium ammonium phosphate.
A patient with nephrotic syndrome develops sudden flank pain and hematuria. CT shows right renal vein thrombosis. Which underlying condition most predisposes to renal vein thrombosis in nephrotic syndrome?
Answer: Membranous nephropathy
Membranous nephropathy has the highest risk of renal vein thrombosis among nephrotic syndromes due to urinary loss of anticoagulant proteins (antithrombin III, protein C/S).
A 25-year-old man presents with episodic gross hematuria 1-2 days after upper respiratory infections. Renal biopsy shows mesangial IgA deposits. What is the most likely diagnosis?
Answer: IgA nephropathy (Berger disease)
Synpharyngitic hematuria (hematuria concurrent with URI, not 2-3 weeks later) with mesangial IgA deposits is the hallmark of IgA nephropathy.
A 68-year-old woman with osteoporosis takes high-dose vitamin D supplements. She now has polyuria, polydipsia, constipation, confusion, and serum calcium of 13.2 mg/dL. Her PTH is suppressed. The most likely mechanism of hypercalcemia is:
Answer: Vitamin D toxicity causing excess intestinal calcium absorption
Vitamin D toxicity increases intestinal calcium absorption via 1,25(OH)2D, causing hypercalcemia with suppressed PTH.