title: Myopathic causes of exercise intolerance with rhabdomyolysis.
abstract: We review the muscular dystrophies and metabolic myopathies associated with myalgia and rhabdomyolysis together with some less well-recognized associations based upon the personal practice of the authors. A careful history and clinical examination will direct investigation towards an accurate molecular diagnosis. Non-specific exercise-induced myalgia in the presence of muscle hypertrophy and a high creatine kinase will point towards a muscular dystrophy. Symptoms occurring within minutes of exercise and with isometric contraction, especially with a history of a 'second wind' phenomenon, suggest a disorder of glycogen metabolism. In those patients in whom symptoms occur after prolonged exercise, infections, fasting, stress, and cold, a disorder of fatty acid oxidation should be considered. Heat-induced rhabdomyolysis caused by exercising in hot and humid climates should lead the clinician to suspect a mutation in RYR1. Serum creatine kinase level should be a checked in all children presenting with leg pains. A careful history and examination and laboratory confirmation of myoglobinuria will target investigations leading to a correct molecular diagnosis.
authors.affiliation: MRC Centre for Neuromuscular Diseases, Institute of Neurology, National Hospital, London, UK.
authors.forename: Ros
authors.initials: R
authors.lastname: Quinlivan
authors.forename: Heinz
authors.initials: H
authors.lastname: Jungbluth
mesh_terms: D000465:Algorithms; D002648:Child; D003937:Diagnosis, Differential; D005080:Exercise Test; D017079:Exercise Tolerance; D006801:Humans; D008661:Metabolism, Inborn Errors / Q000175:diagnosis* / Q000235:genetics / Q000628:therapy; D025202:Molecular Diagnostic Techniques; D009120:Muscle Cramp / Q000175:diagnosis* / Q000235:genetics / Q000628:therapy; D009136:Muscular Dystrophies / Q000175:diagnosis* / Q000235:genetics / Q000628:therapy; D012206:Rhabdomyolysis / Q000175:diagnosis* / Q000235:genetics / Q000628:therapy