Rhabdomyolysis featuring muscular dystrophies

Background Rhabdomyolysis is a potentially life threatening condition of various etiology. The association between rhabdomyolysis and muscular dystrophies is under-recognized in clinical practice. Objective To identify muscular dystrophies presenting with rhabdomyolysis at onset or as predominant feature. Methods We retrospectively reviewed clinical and laboratory data of patients with a genetically confirmed muscular dystrophy in whom rhabdomyolysis was the presenting or main clinical manifestation. Results Thirteen unrelated patients (males = 6; females = 7) were identified. Median age at time of rhabdomyolysis was 18 years (range, 2-47) and median duration between the first episode of rhabdomyolysis and molecular diagnosis was 2 years. Fukutin-related protein (FKRP) muscular dystrophy (n = 6) was the most common diagnosis, followed by anoctaminopathy-5 (n = 3), calpainopathy-3 (n = 2) and dystrophinopathy (n = 2). Four patients experienced recurrent rhabdomyolysis. Eight patients were asymptomatic and 3 reported myalgia and exercise intolerance prior to the rhabdomyolysis. Exercise (n = 6) and fever (n = 4) were common triggers; rhabdomyolysis was unprovoked in 3 patients. Twelve patients required hospitalization. Baseline CK levels were elevated in all patients (median 1200 IU/L; range, 600-3600). Conclusion Muscular dystrophies can present with rhabdomyolysis; FKRP mutations are particularly frequent in causing such complication. A persistently elevated CK level in patients with rhabdomyolysis warrants consideration for underlying muscular dystrophy.