Juvenile myoclonic epilepsy

Fernando Cendes MD PhD (Dr. Cendes of the University of Campinas - UNICAMP has no relevant financial relationships to disclose.)
Jerome Engel Jr MD PhD, editor. (Dr. Engel of the David Geffen School of Medicine at the University of California, Los Angeles, has no relevant financial relationships to disclose.)
Originally released October 18, 1993; last updated December 30, 2016; expires December 30, 2019

This article includes discussion of juvenile myoclonic epilepsy, benign juvenile myoclonic epilepsy, Herpin-Rabot-Janz syndrome, impulsive petit mal, jerk epilepsy, JME, juvenile myoclonic epilepsy of Janz, myoclonic epilepsy of adolescence, and myoclonic petit mal. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.

Overview

In this updated article, the author discusses evidence concerning brain network damage and dysfunction, genetic factors, as well as prognosis and antiepileptic drug treatment in juvenile myoclonic epilepsy.

Key points

 

• Juvenile myoclonic epilepsy is a form of generalized epilepsy with a strong genetic component characterized by (a) myoclonic jerks (cardinal symptom) that are most frequent in the early morning and (b) generalized tonic-clonic seizures. Typical absence seizures may also occur, but these are infrequent and short, and are often ignored by the patient.

 

• The differential diagnosis includes other types of idiopathic generalized epilepsies, juvenile absence epilepsy, and generalized epilepsy with generalized tonic-clonic seizures on awakening.

 

• Although juvenile myoclonic epilepsy has been considered a long-lasting condition, with frequent seizure relapses after withdrawal of medication, studies have shown that a significant proportion of patients become seizure free off medication.

 

• Sodium valproate is the most effective AED; however, the high risk of fetal malformations and other side effects limit its use in young women. Lamotrigine and levetiracetam are good alternatives, but lamotrigine may exacerbate myoclonus. Topiramate and zonisamide are also good alternatives. Benzodiazepines may have an adjunctive role for short periods.

 

• Lifestyle advice is an integral part of the treatment of juvenile myoclonic epilepsy. Patients should avoid sleep deprivation and drinking alcohol.

Historical note and terminology

Juvenile myoclonic epilepsy was first reported in France by Herpin (Herpin 1867). The terminology was variable until Janz and his colleagues in Germany reported 47 cases and proposed the name "impulsive petit mal" as a clinically definable epileptic syndrome (Janz and Matthes 1955; Janz and Christian 1957). The syndrome was later called juvenile myoclonic epilepsy (of Janz) in the English-speaking world (Asconape and Penry 1984; Delgado-Escueta and Enrile-Bacsal 1984). The International League Against Epilepsy suggested the equivalent terms "juvenile myoclonic epilepsy" and "impulsive petit mal" (Commission on Classification and Terminology of the International League Against Epilepsy 1989). A report of the ILAE Commission on Classification and Terminology suggests that juvenile myoclonic epilepsy should be classified as an “electroclinical syndrome” and to avoid the term “idiopathic” (Berg et al 2010).

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