Increased serum creatinine kinase after physical activity is well known and there is currently no cut-off value. We present the systematic diagnosis after rhabdomyolysis in a rare cause.

A 36-year-old soldier developed acute kidney failure due to rhabdomyolysis after intense physical exertion.

Sporty habitus, CK elevation and highly normal kidney values. Massive CK increase after step loading on the bicycle ergometer. We stopped further physical stress and initiated diagnostics.

The genetic diagnosis found a hereditary myopathy of the lipid metabolism (VLCAD deficiency). We used individualized performance analysis to determine the safe load limit. In the ordinary athletic testing of these performance limits, no excessive CK activation could be determined.

Recurrent rhabdomyolyses characterize the late onset of VLCAD, which can occur after intense physical activity, periods of fasting or dehydration. Patients can continue physical exercise safely after determining the individual tolerance.