Acute myositis related to influenza virus

Four cases of acute myositis during influenza epidemic detected at the Asturias Central Hospital are described. They had affection of the muscles of the legs and abnormal CPK levels. Influenza virus was confirmed in two cases. Evolution was benign in every case, with only symptomatic treatment. We describe the clinical and biological findings of this illness. It must be considered as the first possibility for a child with lower leg pain and abnormal CPK levels into an epidemiological setting of influenza and more aggressive studies are not justified. Paediatrician at the Health Centre is fundamental at this role. Incidence of this illness probably is higher than reported in our country because of his transient clinical course. Serological and virological studies are of little conclusiveness. We describe rare complications and differential diagnosis.