| Prerenal acute renal failure |
| True intravascular depletion | Sepsis, hemorrhage, overdiuresis, poor fluid intake, vomiting, diarrhea |
| Decreased effective circulating volume to the kidneys | Congestive heart failure, cirrhosis or hepatorenal syndrome, nephrotic syndrome |
| Impaired renal blood flow because of exogenous agents | Angiotensin-converting enzyme inhibitors, nonsteroidal anti-inflammatory drugs |
| Intrinsic acute renal failure |
| Acute tubular necrosis | Ischemia |
| Toxins: drugs (e.g., aminoglycosides), contrast agents, pigments (myoglobin or hemoglobin) |
| Glomerular disease | Rapidly progressive glomerulonephritis: systemic lupus erythematosus, small-vessel vasculitis (Wegener's granulomatosis or polyarteritis nodosa), Henoch-Schönlein purpura (immunoglobulin A nephropathy), Goodpasture's syndrome |
| Acute proliferative glomerulonephritis: endocarditis, poststreptococcal infection, postpneumococcal infection |
| Vascular disease | Microvascular disease: atheroembolic disease (cholesterol-plaque microembolism), thrombotic thrombocytopenic purpura, hemolytic uremic syndrome, HELLP syndrome or postpartum acute renal failure |
| Macrovascular disease: renal artery occlusion, severe abdominal aortic disease (aneurysm) |
| Interstitial disease | Allergic reaction to drugs, autoimmune disease: (systemic lupus erythematosus or mixed connective tissue disease), pyelonephritis, infiltrative disease (lymphoma or leukemia) |
| Postrenal acute renal failure | Benign prostatic hypertrophy or prostate cancer, cervical cancer, retroperitoneal disorders, intratubular obstruction (crystals or myeloma light chains), pelvic mass or invasive pelvic malignancy, intraluminal bladder mass (clot, tumor or fungus ball), neurogenic bladder, urethral strictures |