McArdle disease: a "pediatric" disorder presenting in an adult with acute kidney injury.

Rhabdomyolysis is characterized by the acute breakdown of skeletal muscle, resulting in the release of muscle cell contents, subsequent myoglobinuria, and in severe cases, acute renal failure. A number of etiologies have been identified in acute rhabdomyolysis, in which drugs and trauma account for the majority of cases. One etiological category that is commonly overlooked in the adult population is an underlying genetic defect. This may be challenging to diagnose due to its rarity in the adult demographic and the marked heterogeneity, often requiring a high level of clinical suspicion before investigation is pursued. Once diagnosed, however, appropriate steps can be taken to reduce future episodes of rhabdomyolysis, further renal injury, and other systemic complications. Here, we report a case of an adult patient presenting with acute rhabdomyolysis secondary to McArdle disease, a genetic disease causing defective glycogenolysis. The case highlights the importance of recognizing the potential of undiagnosed "pediatric" disorders in adulthood and particularly for underlying genetic causes of rhabdomyolysis.