Prerenal azotemia
- Dehydration
- Hemorrhage, e.g., GI bleeding
- Congestive heart failure
- Renal artery stenosis including fibromuscular dysplasia
- NSAIDs, ACE inhibitors
Postrenal azotemia
- Obstruction, e.g., BPH, bladder tumor, pelvic mass
Intrinsic renal disease
Acute tubular necrosis
- Toxins: NSAIDs, antibiotics, contrast, multiple myeloma, rhabdomyolysis, hemolysis, chemotherapy, hyperuricemia, cyclosporine
- Ischemia, e.g., prolonged prerenal azotemia
Acute glomerulonephritis
- Immune complex: IgA nephropathy, endocarditis, SLE, cryoglobulinemia, postinfectious, membranoproliferative, Henoch-Schönlein purpura
- Pauci-immune (ANCA+): Wegener's granulomatosis, Churg-Strauss syndrome, microscopic polyarteritis
- Anti-GBM: Goodpasture's syndrome, anti-GBM glomerulonephritis
- Other: malignant hypertension, TTP, scleroderma renal crisis, preeclampsia-eclampsia
Acute interstitial nephritis
- Drugs: beta-lactams, sulfa, diuretics, NSAIDs, rifampin, phenytoin, allopurinol
- Infections: Streptococcus, leptospirosis, CMV, histoplasmosis, Rocky Mountain spotted fever
- Immune: SLE, Sjögren's syndrome, sarcoidosis, cryoglobulinemia