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For further information, see CMDT Part 24-04: 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 over 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/d
20% of all hospitalized patients and 65% of ICU admissions have acute kidney injury (AKI)
The 2012 Kidney Disease Improving Global Outcomes (KDIGO) Clinical Practice Guidelines for Acute Kidney Injury describes three progressive stages based on the degree of 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-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 kidney replacement therapy
Serum creatinine concentration can typically increase by 1.0–1.5 mg/dL daily, although in certain conditions such as rhabdomyolysis serum creatinine can increase more rapidly
Patients with AKI from any cause are at higher risk for all-cause mortality even if there is substantial renal recovery
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Can be asymptomatic
Uremia: Nausea, vomiting, malaise, altered sensorium
Hypertension
Pericardial friction rub, effusions, and cardiac tamponade
Hyperkalemia: Heart block and ventricular tachycardia
Prolonged bleeding time due to platelet dysfunction
Asterixis, encephalopathy, seizures
Oliguria
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Differential Diagnosis
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