Differential for acute kidney injury (AKI)

Prerenal

• True volume depletion—poor oral intake, gastrointestinal or renal losses, bleeding
• Low effective circulating volume—congestive heart failure, cirrhosis, nephrotic syndrome, protein losing enteropathy, sepsis
• Impaired vascular perfusion—drugs (NSAIDs, ACE), renal artery thrombus, renal artery stenosis, hypercalcemia, dissection, hypotension

Renal

• Vascular—cholesterol emboli, microangiopathic hemolytic anemia (MAHA), chronic hypertension
• Tubular—obstruction (drugs, light chains, crystals), ATN (toxic or ischemic)
• Interstitial—infection, infiltration (sarcoid), inflammation (Sjogren’s), ingestion (antibiotics, PPIs diuretics, NSAIDs), idiopathic
• Glomerular—nephrotic or nephritic

Postrenal

• Anatomic—obstructing uropathy involving the urethra, prostate, bladder, ureters, extraluminal obstruction
• Etiology—cancer, clots, stones, stricture or stenosis