Upper extremity exertional rhabdomyolysis: MR imaging findings in four cases.

While uncommon, exertional-induced rhabdomyolysis is an important diagnostic consideration when encountering hyperintensity within one or more muscles on fluid sensitive sequences in conjunction with signal abnormality in the overlying superficial fascia and subcutaneous fat. The clinical history of recent extreme exercise helps distinguish this disorder from other possible diagnoses, such as cellulitis, necrotizing fasciitis, compartment syndrome, inflammatory processes and diabetic myonecrosis. Patients diagnosed with severe exertional induced rhabdomyolysis often require hospital admission for intravenous hydration and serial laboratory monitoring due to the potential risk of acute renal failure. While contributory, magnetic resonance imaging findings can be nonspecific, and therefore the clinical history is often essential in making this diagnosis.