Juvenile Myoclonic Epilepsy (JME)

Guidance for primary care clinicians diagnosing and managing children with juvenile myoclonic epilepsy

Juvenile myoclonic epilepsy (JME) is an idiopathic generalized epilepsy syndrome. It presents in adolescents 12-18 years of age with myoclonic jerks, generalized tonic-clonic seizures, and sometimes absence seizures. Myoclonic jerks, typically but not exclusively upper extremity, often occur for months or more before the seizures begin and must be specifically asked about as patients often think they are normal. Myoclonic jerks typically occur in the morning after awakening and may vary among patients. Some patients describe them as brief tingling sensations, others have myoclonic jerks similar to those the general population experiences upon falling asleep, and others may have them so hard that they throw objects. Leg jerks and sudden falls can also occur. No change in consciousness occurs during the jerks. Seizures may be initiated by light (such as strobe lights), lack of sleep, alcohol, and stress. Treatment usually needs to be lifelong.

Teratogenic effects of anti-epileptic medications
Women of childbearing age should be counseled regarding the possible teratogenic effects of anti-epileptic medications on a fetus. [Hill: 2010] Women on oral contraceptives should understand that anti-epileptic medications can interfere with oral contraceptive serum levels (Antiepileptic Drugs and Contraception (US Pharmacist), [Hill: 2010]).

Seizure activity restrictions
Typical seizure activity restrictions should be discussed and documented for this generalized epilepsy syndrome. Please see Safety Precautions for Children with Seizures.

Juvenile myoclonic epilepsy is a clinical diagnosis based on the myoclonic jerks and the generalized tonic-clonic seizures (sometimes absence) in a normally developing child with a normal exam, sometimes in the setting of a family history of epilepsy. An EEG when the patient is sleep deprived is helpful to confirm the diagnosis. EEG typically shows rapid generalized polyspike waves not only during seizures but interictally. Neuroimaging in the classical clinical setting is not necessarily required.

The JME risk in the general population is approximately 5.6 per 10000 people. It constitutes close to 10% of epilepsy, although this may be a low number as JME is often misdiagnosed unless the myoclonic jerks are specifically sought. [Syvertsen: 2017]

Juvenile myoclonic epilepsy is an idiopathic hereditary form of epilepsy not associated with organic brain pathology. It may be inherited (up to 50% of patients have family members who have experienced seizures). Juvenile myoclonic epilepsy is genetically heterogeneous and, although usually thought of as an autosomal dominant disorder with reduced penetrance, may have autosomal recessive forms as well. Currently, genes on several chromosomes have been implicated in various populations.

Valproic acid is currently the medication of choice and most effective. Newer medications such as lamotrigine and levetiracetam (approved for adjunctive therapy for the treatment of myoclonic seizures by the FDA) are also being used in increasing numbers due to better side effect profiles. Treatment is almost always successful, although generally, the patients will have to continue on antiepileptic therapy long-term. [Crespel: 2013]

Although children and youth with JME will often need to remain indefinitely on medication, seizures are generally well controlled, and intellectual function is not affected.

Pediatric Neurology (see NV providers [5])

G40.B11, Juvenile myoclonic epilepsy, intractable, with status epilepticus