G.P.70 Acute necrotising myopathy induced by strenuous exercise and co-factors

Abstract

Abstract Spinning cycling classes are a popular form of keep-fit exercise in Ireland, and involve upwards of an hour – long session cycling in an upright position with the quadriceps stretched. Myalgia, muscle weakness and abnormalities of muscle enzymes are well – documented in healthy subjects and experimental animals following excessive exercise. Acute muscle necrosis may unmask a subclinical muscle enzyme or basement membrane deficiency, or be triggered by agents including alcohol and drugs. We describe a patient with fulminant necrotising myopathy precipitating renal insufficiency following a long spinning session. Biopsy showed numerous necrotic fibres, all at the same stage of necrosis, suggesting a single triggering event, without an underlying enzyme or basement membrane protein deficiency. Following multidisciplinary review, a history of additional alcohol consumption prior to exercise emerged and Epstein–Barr Virus IgM antibody was positive, suggesting recent sub-clinical infection. EBERpb in situ hybridization was negative in muscle and inflammatory cells indicating direct muscle infection by EBV was unlikely. This case indicates the value of muscle biopsy and discussion in a multidisciplinary setting in clarifying neuromuscular diagnosis in a patient with unexplained myalgia and muscular weakness. The adverse combined effects of alcohol and severe exercise is also highlighted.