Internal Medicine Exam Acute Kidney Injury 2

Question 1

A 68-year-old man with chronic heart failure presents with worsening dyspnea and oliguria. Creatinine has risen from 1.2 to 2.8 mg/dL after aggressive diuresis. Urine sodium is 8 mEq/L and BUN/Cr ratio is 28. What is the most likely mechanism of AKI?

Accepted Answer

Cardiorenal syndrome type 1

Answer

Cardiorenal syndrome type 1 occurs when acute cardiac decompensation causes AKI, with low urine sodium reflecting avid sodium retention due to reduced renal perfusion.

Question 2

Which of the following urine microscopy findings is most specific for acute tubular necrosis?

Accepted Answer

Muddy brown granular casts

Answer

Muddy brown granular casts (composed of sloughed tubular epithelial cells) are the hallmark finding of acute tubular necrosis.

Question 3

A patient develops AKI after receiving vancomycin. Urinalysis shows eosinophiluria and white blood cell casts. Serum creatinine peaks at 3.1 mg/dL on day 10. What is the primary pathophysiology?

Accepted Answer

Acute interstitial nephritis

Answer

Vancomycin-induced AKI commonly causes acute interstitial nephritis, characterized by eosinophiluria, WBC casts, and a delayed onset after drug exposure.

Question 4

In the AKIN staging system, Stage 2 AKI is defined as:

Accepted Answer

Creatinine increase ≥2× baseline or urine output <0.5 mL/kg/h for 12 hours

Answer

AKIN Stage 2 is defined as serum creatinine increase ≥2× but <3× baseline, or urine output <0.5 mL/kg/h for ≥12 hours.

Question 5

A 55-year-old woman with lupus presents with AKI, RBC casts, proteinuria >2 g/day, and hypertension. Which diagnosis best fits this presentation?

Accepted Answer

Lupus nephritis causing rapidly progressive glomerulonephritis

Answer

RBC casts, nephrotic-range proteinuria, and hypertension in a lupus patient indicate lupus nephritis with rapidly progressive glomerulonephritis as the cause of AKI.

Internal Medicine Exam Practice Test

Internal Medicine Exam Practice Test

Internal Medicine Exam Acute Kidney Injury 2