Juvenile myasthenia: diagnosis and treatment.

Myasthenia in children can be juvenile (autoimmune) or congenital. Juvenile myasthenia (JM) is an autoimmune disorder characterised by fluctuating weakness and fatigue in the ocular, facial, bulbar or limb muscles. Diagnosis is confirmed by electromyography (EMG), single fibre EMG and the patient's clinical response to anticholinesterase medication. Serology is less helpful in children because acetylcholine receptor antibodies, usually positive in adults, are frequently absent in patients with prepubertal onset of the disease. Treatment methods in JM include anticholinesterase drugs, thymectomy and immunomodulatory agents. Plasmapheresis and intravenous immunoglobulin are used in myasthenic crisis. The prognosis of patients with JM is usually good, clinical remission being achieved in the majority of patients with the current treatment methods.