Epileptic seizures in children occur in a variety of forms. While it may be difficult to classify some attacks, most seizures may be broadly divided into five groups: major motor (grand mal), petit mal, psychomotor (temporal lobe), myoclonic and autonomic. This writing is devoted to a discussion of the clinical manifestations, EEC findings, etiology, prognosis and treatment of myoclonic epilepsy of childhood. The data presented are based on approximately 1,500 children with myoclonic seizures who have been studied at The Johns Hopkins Hospital Epilepsy Clinic. In 1,150 patients, myoclonic seizures appeared during the first two years of life, most commonly between 3 and 9 months of age; and in the remaining 350 children, after the first two years of life, usually between 3 and 7 years of age. We classify myoclonic epilepsy into two types on this basis of age at onset.
1. Myoclonic epilepsy of infancy. In previous writings, we referred to this form of epilepsy as "minor motor epilepsy." Other terms currently in usage are "infantile spasms," "hypsarrhythmia" and "massive myoclonic seizures."
2. Myoclonic epilepsy of older children. This form of epilepsy is designated by many physicians as "petit mal variant," "head-dropping spells," "headbobbing spells," "akinetic seizures," "Lennox syndrome" and "Lennox-Gastaut syndrome."
The predominant clinical feature of myoclonic epilepsy is a sudden flexor spasm of the body musculature, although extensor spasms are sometimes observed. The clinical manifestations vary, depending upon the posture of the patient.
Although this spell in the recumbent patient varies somewhat in clinical manifestations, it most commonly consists of a sudden flexion of the head with a simultaneous outward thrust of the upper extremities and flexion of the thighs on the abdomen. It is sometimes preceded by a short cry, laugh or giggle.