[Myalgia during warming-up in a 12-year-old boy].

INTRODUCTION: McArdle disease is a hereditary myopathy caused by muscle phosphorylase deficiency. Patients experience painful muscle cramps after strenuous exercise; the condition is sometimes associated with rhabdomyolysis, myoglobinuria and resulting acute renal failure.

CASE DESCRIPTION: A 12-year-old boy visited the Paediatric and Neurology outpatients' departments with symptoms of leg myalgia, occurring during the warming-up phase of soccer practice, which disappeared after a short rest. Detailed history-taking revealed that he already experienced pain while walking during early childhood. An elevated serum creatine kinase concentration in combination with the typical presentation led to the presumptive diagnosis 'McArdle disease', which was confirmed by molecular genetic analysis.

CONCLUSION: There is no effective gene therapy; a multidisciplinary approach by a neurologist, paediatrician, physiotherapist and nutritionist is advised.