Chapter 70 Benign myoclonic epilepsy in infancy

Abstract

Benign myoclonic epilepsy in infants (BMEI) is a rare epileptic syndrome characterized by myoclonic seizures. The clinical picture is also characterized by mild developmental delay, learning disability, and behavior problems. Early treatment may improve the neuro psychological outcome. The children are in sound health at the beginning of the seizures. The clinical picture is characterized by generalized myoclonic seizures, usually in bursts, and may occur several times a day, irregularly and unpredictably. The attacks involve the upper limbs with the arms extending up and out, eyes might be deviated upward. In babies, it may be limited to a head nod. The myoclonias may be followed by atonia and sometimes a muscle contraction after the attack. In general, no other type of seizure is observed in infancy. State of consciousness is difficult to assess; impairment of consciousness might be seen in prolonged attacks. Usually, the myoclonus does not interrupt the activities in which the child is involved. The electroencephalogram (EEG) is normal between the attacks and consistently abnormal during the crisis. Generalized spike and wave discharges, with no clinical concomitant, can be seen during the nonREM as well as during the REM sleep. Myoclonias are associated with fast generalized spike-wave and polyspike and wave discharges. The myoclonias increase in frequency during drowsiness and tend to be suppressed during sleep. Photic stimulation may activate the discharges in some cases. This chapter discusses the treatments involved. Treatment with valproic acid and/or benzodiazepines is effective in controlling the seizures and might have an effect on the long-term prognosis; but it is not clear for how long it is necessary to treat these children. Also, there are notes on EEG studies and differential diagnosis of benign myoclonic epilepsy in infancy (BMEI).