How is rhabdomyolysis with myoglobinuria treated
What is the approach to evaluation and management of a patient with rhabdomyolysis and myoglobinuria?
There is no agreed-upon definition of the level of CK elevation required for a diagnosis of rhabdomyolysis, but all agree that CK levels rising from normal to >10,000 U/L would meet that criteria. Interestingly, CK levels must rise to 50,000–75,000 U/L before clinical pigmenturia occurs (though myoglobin may be detected in the urine at lower levels than this). After a single episode of exertional rhabdomyolysis, the risk of recurrence is quite low, and further evaluation may not be warranted. However, after a second episode of rhabdomyolysis, evaluation may include serial CK levels, EMG, muscle biopsy, and/or genetic testing. For patients with multiple, recurrent episodes of rhabdomyolysis, the most reasonable first step now, with the availability of large genetic testing panels at relatively low cost, is to order genetic testing covering 30–500 muscle genes (inclusive of the metabolic myopathy genes). If genetic testing fails to return a definitive diagnosis, either negative testing or variant(s) of undetermined significance, then circling back to EMG and muscle biopsy with enzyme analysis will increase the diagnostic yield.
