Acute Kidney Injury Management

Pathophysiology and Etiology

ATN damages tubular epithelial cells through ischemia or direct toxin exposure, causing necrosis of the tubular structures 1
ATN accounts for approximately 29% of renal biopsies in acute kidney injury 1
AIN involves immune-mediated inflammation of the renal interstitium, typically triggered by medications 1, 3
AIN represents 80-90% of immune-related renal dysfunction, particularly in immunotherapy patients 3, 1
Risk factors for AIN include concomitant PPI and NSAID use 3, 4

ATN diagnosis is suggested by recent hypotension, nephrotoxin exposure, or ischemic events 1
NGAL levels are significantly higher in ATN than AIN, with a cutoff of 220-244 μg/g creatinine for differentiation 1
Renal biopsy is the definitive diagnostic tool for AIN, showing interstitial inflammation with lymphocytic infiltrate 3, 1

The American College of Physicians recommends removing all nephrotoxic agents immediately in ATN management 1
The American Society of Nephrology suggests optimizing fluid management and maintaining renal perfusion in ATN patients 1
For AIN, the European Society of Medical Oncology recommends initiating methylprednisolone 1 mg/kg IV daily for moderate cases 3, 2, 4
The National Kidney Foundation advises transitioning to oral prednisone 1 mg/kg/day after stabilization in AIN patients 2

The American College of Physicians recommends checking creatinine, electrolytes, and mental status daily during the acute phase of AIN 2
The European Society of Medical Oncology suggests monitoring for steroid-related complications in AIN patients 2
Oliguria should prompt inpatient admission for careful fluid balance and planning for potential renal replacement therapy 5, 6

Failing to identify and remove the offending agent in AIN worsens outcomes 2
Using steroids empirically for ATN provides no benefit and adds complications 1
The American Society of Nephrology warns that 20% of patients with immune checkpoint inhibitor-related AIN may have persistently abnormal renal function 5, 7