23rd June 2023

A 54-year-old woman is admitted to hospital with diarrhoea and vomiting for one week, and she is unable to tolerate any oral intake.

A 54-year-old woman is admitted to hospital with diarrhoea and vomiting for one week, and she is unable to tolerate any oral intake. Her observations on admission are heart rate 110 bpm, BP 90/60, RR 19, temperature 37.9 degrees, and oxygen saturation 96% on room air. Admission bloods show raised inflammatory markers and an acute kidney injury – with a serum creatinine of 210μmol/L from a baseline of 80μmol/L (normal range 60-100μmol/L).

Which of the factors below would point towards a diagnosis of acute tubular necrosis rather than a pre-renal acute kidney injury?