Sections View Full Chapter Figures Tables Videos Full Chapter Figures Tables Videos Supplementary Content ++ Key Features ++ Essentials of Diagnosis ++ Rapid increase in serum creatinine Oliguria may be present Symptoms and signs depend on cause ++ General Considerations ++ Defined as an absolute increase in serum creatinine by ≥ 0.3 mg/dL within 48 hours or relative increase to ≥ 1.5 times baseline that is known or presumed to have occurred within 7 days Characterized as oliguric if urine production is < 400–500 mL/day or < 20 mL/h Clinically, characterized by an inability to maintain acid-base, fluid, and electrolyte balance and to excrete nitrogenous wastes The 2012 KDIGO Clinical Practice Guidelines for AKI describes three progressive stages based on the elevation in serum creatinine or decline in urinary output Stage 1: 1.5- to 1.9-fold increase in serum creatinine or a decline in urinary output to 0.5 mL/kg/h over 6–12 hours Stage 2: 2.0–2.9 increase in serum creatinine or a decline in urinary output to 0.5 mL/kg/h over > 12 hours Stage 3: 3-fold or greater increase in serum creatinine, an increase in serum creatinine to ≥ 4 mg/dL, or a decline in urinary output to < 0.3 mL/kg/h for ≥ 24 hours, anuria for ≥ 12 hours, or initiation of renal replacement therapy Serum creatinine concentration can typically increase by 1.0–1.5 mg/dL daily ++ Demographics ++ 5% of hospital admissions and 30% of ICU admissions have acute kidney injury 25% of hospitalized patients develop acute kidney injury ++ Clinical Findings ++ Symptoms and Signs ++ Nausea, vomiting Malaise Hypertension Pericardial friction rub, effusions, and cardiac tamponade Arrhythmias Rales Abdominal pain and ileus Bleeding secondary to platelet dysfunction Encephalopathy, altered sensorium, asterixis, seizures Oliguria, defined as urinary output < 500 mL/day or < 20 mL/h ++ Differential Diagnosis ++ PRERENAL CAUSES ++ Dehydration Hemorrhage (eg, gastrointestinal bleeding) Heart failure Renal artery stenosis, including fibromuscular dysplasia Nonsteroidal anti-inflammatory drugs (NSAIDs), angiotensin-converting enzyme inhibitors ++ POSTRENAL CAUSES ++ Obstruction (eg, benign prostatic hyperplasia, bladder tumor) ++ INTRINSIC RENAL DISEASE ++ Acute tubular necrosis Toxins NSAIDs Antibiotics Intravenous contrast Plasma cell myeloma (formerly multiple myeloma) Rhabdomyolysis Hemolysis Chemotherapy Hyperuricemia Cyclosporine Ischemia (eg, prolonged prerenal insults) Acute glomerulonephritis Immune complex IgA nephropathy Endocarditis Systemic lupus erythematosus (SLE) Cryoglobulinemia Postinfectious Membranoproliferative Pauci-immune (ANCA-positive) Granulomatosis with polyangiitis (formerly Wegener granulomatosis) Eosinophilic granulomatosis with polyangiitis (formerly Churg-Strauss syndrome) Microscopic polyarteritis Antiglomerular basement membrane (anti-GBM) Goodpasture disease Anti-GBM glomerulonephritis Vascular Malignant hypertension Thrombotic thrombocytopenia purpura Atheroembolism Acute interstitial nephritis Drugs β-Lactams Sulfa Diuretics NSAIDs Rifampin Phenytoin Allopurinol Infections Streptococcus Leptospirosis Cytomegalovirus Histoplasmosis Rocky Mountain spotted fever Immune SLE Sjögren syndrome Sarcoidosis Cryoglobulinemia ++ Diagnosis ++ Laboratory Tests ++ Serum creatinine and BUN elevated BUN–creatinine ratio > 20:1 in prerenal and postrenal causes, and acute glomerulonephritis; < 20:1 in acute tubular necrosis and ... GET ACCESS TO THIS RESOURCE Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth Get Free Access Through Your Institution Contact your institution's library to ask if they subscribe to McGraw-Hill Medical Products. Access My Subscription GET ACCESS TO THIS RESOURCE Subscription Options Pay Per View Timed Access to all of AccessMedicine 24 Hour $34.95 (USD) Buy Now 48 Hour $54.95 (USD) Buy Now Best Value AccessMedicine Full Site: One-Year Individual Subscription $995 USD Buy Now View All Subscription Options