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For further information, see CMDT Part 22-05: Acute Kidney Injury
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Essentials of Diagnosis
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General Considerations
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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 Acute Kidney Injury (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 for 6–12 hours
Stage 2: 2.0–2.9-fold increase in serum creatinine or a decline in urinary output to 0.5 mL/kg/h for > 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
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Nausea, vomiting
Malaise
Hypertension
Pericardial friction rub, effusions, and cardiac tamponade
Arrhythmias
Rales
Abdominal pain and ileus
Platelet dysfunction with bleeding and clotting disorders
Encephalopathy, altered sensorium, asterixis, seizures
Oliguria, defined as urinary output < 500 mL/day or < 20 mL/h
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Differential Diagnosis
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Dehydration
Hemorrhage (eg, gastrointestinal bleeding)
Heart failure
Renal artery stenosis, including fibromuscular dysplasia
Nonsteroidal anti-inflammatory drugs (NSAIDs), angiotensin-converting enzyme inhibitors
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INTRINSIC RENAL DISEASE
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