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High Protein Creatinine Rise vs True AKI — ESENeph MCQ

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ModerateAcute Kidney InjuryHigh Protein Creatinine Rise vs True AKIESENeph

A 40-year-old man with CKD G3a develops acute kidney injury after taking a high-protein supplement (120 g protein/day) for bodybuilding. His creatinine rises from 100 to 145 umol/L. Urine is normal. Is this true AKI?

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Correct answer: C — High protein intake increases creatinine production (from increased muscle protein metabolism) and may also cause a haemodynamic GFR increase followed by decline; the creatinine rise likely reflects increased production rather than true nephron injury; measured GFR would distinguish these

Very high protein intake (>1.5-2 g/kg/day) increases creatinine production from muscle metabolism, raising serum creatinine independent of GFR change. Additionally, high protein causes renal vasodilation and hyperfiltration acutely, followed by haemodynamic adjustment. In CKD, this hyperfiltration is potentially harmful long-term (the basis for KDIGO 2024 recommending protein 0.8 g/kg/day). Distinguishing production-related creatinine rise from true GFR decline requires either cystatin C-based eGFR (unaffected by protein intake) or measured GFR. Protein supplements should be limited in CKD.

Reference: KDIGO 2024 – CKD; Poortmans and Dellalieux 2000