Infantile myositis: a case diagnosed in the neonatal period

Abstract

Infantile myositis is an inflammatory myopathy occurring in children under one year of age. This condition is extremely rare in the neonatal period and may be confused with other causes of generalized weakness. Creatine kinase activity is usually markedly elevated and electromyography demonstrates low amplitude, polyphasic motor unit activity. Muscle biopsy, necessary for diagnosis, documents characteristic findings of perifascicular atrophy and the presence of perivascular inflammatory cells. The diagnosis should be followed by corticosteroid treatment. The patient presented is the youngest biopsy-proved case of infantile myositis. In this report, his symptoms and clinical course are compared with those of previously described patients. The role of infectious agents and the immune state in the etiology of infantile myositis is considered.