Epidemiology, Clinical Features, and Diagnostic Studies for Major Causes of Acute Renal Failure

Etiology	Epidemiology	Clinical Features	Serum Studies	Urine Studies	Other Testing
Prerenal ARF	Most common cause of community-acquired ARF; history of poor fluid intake, treatment with NSAIDs/ACE inhibitors/ARBs, worsening heart failure	Volume depletion (absolute/postural hypotension, low jugular venous pressure, dry mucus membranes) or decreased effective circulatory volume (e.g., heart failure or liver disease)	High BUN/CR ratio (20) is suggestive but not diagnostic	Hyaline casts FENa <1% UNa <10 mmol/ LSG >1.018
Intrinsic ARF
Diseases of large renal vessels
Renal artery thrombosis	More common in those with atrial fibrillation or arterial thrombosis	Flank or abdominal pain	Elevated LDH	Mild proteinuriaOccasional hematuria	Renal angiogram or MR angiogram are diagnostic
Atheroembolic disease	Vascular disease; classically occurs within days–weeks of manipulation of the aorta or other large vessels, often in the setting of anticoagulation	Retinal plaques, palpable purpura, livedo reticularis	EosinophiliaHypocomplementemia	Eosinophiluria	Skin or renal biopsy
Renal vein thrombosis	History of nephrotic syndrome or pulmonary embolism	Flank pain		Mild proteinuriaOccasional hematuria	Renal venogram or MR venogram are diagnostic
Diseases of small vessels and glomeruli
Glomerulonephritis/vasculitis	Associated with recent infection (postinfectious or endocarditis), systemic lupus erythematosus, liver disease (hepatitis B or C)Anti-GBM disease: Typically men in their 20s–40sANCA disease: Two peaks: 20s–30s and 50s–60s	New cardiac murmur (postinfectious)Skin rash/ulcers, arthralgias (lupus)Sinusitis (anti-GBM disease)Lung hemorrhage (anti-GBM, ANCA, lupus)	ANA, ANCA, anti-GBM antibody, hepatitis serologies, cryoglobulins, blood cultures, ASO, complements (positive tests depend on etiology)	Hematuria with red cell casts/dysmorphic red blood cellsGranular castsProteinuria (usually <1 g/d)	Renal biopsy
Hemolytic-uremic syndrome/thrombotic thrombocytopenic	Recent GI infection (E. coli) or use of calcineurin inhibitors (FK506 and cyclosporine)	Fever, neurologic abnormalities	Schistocytes on peripheral blood smear, elevated LDH, anemia, thrombocytopenia	HematuriaMild proteinuriaRed cell casts (rare)	Renal biopsy
Malignant hypertension	Severe/uncontrolled hypertension	Evidence of damage to other organs: headache, papilledema, heart failure with LVH by echocardiography/ECG		Hematuria with red cell casts/proteinuria
		Typically resolves with blood pressure control
Acute tubular necrosis
Ischemia	Recent hemorrhage or severe hypotension			Muddy brown granular or tubular epithelial cell casts FENa >1% UNa >20 mmol/ LSG <1.015
Exogenous toxins	Recent exposure to nephrotoxic antibiotics or chemotherapy, often in association with sepsis, or volume depletion			Muddy brown granular or tubular epithelial cell castsFENa >1%UNa >20 mmol/LSG <1.015
	Recent exposure to radiocontrast, often in association with volume depletion, diabetes or CKD			Muddy brown granular or tubular epithelial cell castsUrinalysis may be normalFENa often <1%UNa often <20 mmol/L
Endogenous toxins	Rhabdomyolysis	Post ictal state (seizures), evidence of trauma or prolonged immobilization	Increased myoglobin, creatine kinase	U/A positive for heme but no hematuria
	Hemolysis: recent blood transfusion	Fever, other evidence of transfusion reaction	Pink plasma, increased LDH	Pink, heme-positive urine without hematuria	Transfusion reaction workup
	Tumor lysis: recent chemotherapy		Hyperuricemia, increased LDH	Urate crystals
	Multiple myeloma	Individuals >60 years of age, ongoing constitutional symptoms (fatigue, malaise)	Circulating monoclonal spike, anemia	Dipstick-negative proteinuria, monoclonal spike on electrophoresis	Bone marrow or renal biopsy
	Ethylene glycol ingestion	History of alcohol abuse, altered mental status	Metabolic gap acidosis with osmolal gap, positive toxicology	Oxalate crystals
Diseases of the tubulointerstitium
Allergic interstitial nephritis	Recent medication exposure	Fever, rash, arthralgias	Eosinophilia	White cell casts, eosinophiluria	Renal biopsy
Acute bilateral pyelonephritis		Fever, flank pain and tenderness	Positive blood cultures	Leukocytes, proteinuria, positive urine culture
Postrenal ARF	History of renal stones or prostatic disease	Palpable bladder, flank or abdominal pain		Usually normal; hematuria if due to stones	Imaging to assess obstruction: CT scan and/or ultrasound