Acute kidney injury: Viva

Branch 1: Definition and staging

The candidate should recognise that this girl has acute kidney injury by the KDIGO criteria. The creatinine has risen to 3.0 times the baseline of 55 micromoles per litre, which places her in stage 3 on the creatinine criterion alone, and the oliguria adds to the staging. A strong candidate states the KDIGO definition precisely: a rise in serum creatinine of 0.3 mg per dL or more within 48 hours, or to 1.5 times baseline or more within seven days, or a urine output below 0.5 mL per kg per hour for six hours. The staging is by the magnitude of the change, and stage 3, which this girl has, is a creatinine of 3.0 times baseline or more, or a rise to 4.0 mg per dL or more, or the initiation of renal replacement therapy, or in a patient under 18 years an estimated GFR below 35 mL per min per 1.73 m2. ^[1]

If the examiner presses on the paediatric pRIFLE classification, the candidate should describe the modification by Akcan-Arikan and colleagues that uses the estimated creatinine clearance: risk is a 25 percent reduction, injury is a 50 percent reduction, and failure is a 75 percent reduction or an estimated clearance below 35 mL per min per 1.73 m2. The candidate should note that the pRIFLE is validated for critically ill children and complements the KDIGO definition in the intensive care setting, and that the PODIUM consensus and the ADQI 26 report endorse KDIGO as the primary definition in children. ^[1]