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Related Subjects: |Status Epilepticus (Epilepsy) |Coma management |Lorazepam |Phenytoin |Levetiracetam |Epilepsy - General Management |First Seizure |Epilepsy in Pregnancy |Febrile seizures

Patients diagnosed with JME usually need to remain on AEDs for life due to the high rate of recurrence. JME responds to treatment with Sodium Valproate. Newer broad-spectrum drugs such as topiramate, and possibly Levetiracetam, may also be of benefit.

About

• Often misdiagnosed form of epilepsy
• Can worsen if given wrong anti epileptic medication
• A subtype of idiopathic generalized epilepsy
• Can be worsened with carbamazepine or phenytoin

Aetiology

• Molecular level defect. Genetic. Low fit threshold
• Positive family history in 50% of cases
• Slightly commoner in females

Genetics

• There are some familial forms
• No clear gene cause so far - ongoing research

Epidemiology

• Incidence 1 per 2000. Onset ages of 8 and 26 years
• Onset age 5-16 usual with absence seizures
• Myoclonic jerks come on on 10 years later
• Generalised tonic clonic seizure come on later

3 types of seizures

• Absence seizures: commoner in the mornings. These often happen first. Consciousness may be preserved. Patients may remain standing or sitting.
• Myoclonic seizures: sudden jerks either in the arms, legs, face or whole body. These may happen on awakening.
• Generalised Tonic-clonic seizures: happen in the morning, within an hour or two of waking up. These come on last when the patient is older. They can be preceded by increasing myoclonic jerks just before a GTCS.

Clinical

• It is commoner in the morning - easily remembered as one neurologist called it "cornflake epilepsy" as patients can be imagined having jerky movements whilst eating breakfast or in the morning routine
• Patients may have different types of fits and as well as myoclonic epilepsy patients have generalised tonic-clonic seizures and absence seizures.
• Appears in adolescence that why it's called Juvenile and can be brought on by sleep deprivation, stress, alcohol.
• Photosensitivity means that the myoclonic or tonic-clonic seizures are triggered by flickering or flashing light at certain frequencies.
• JME is non-progressive, and there are no abnormalities on clinical examination or intellectual deficits

Investigations

• Blood tests: normal
• CT/MRI: Brain imaging is typically normal
• EEG: shows a very characteristic pattern called generalized polyspikes, often with generalized 3 Hz spike-wave complexes. Hyperventilation makes the EEG abnormalities more obvious.

Management

• Patients should be advised to avoid sleep deprivation and good compliance and recurrence are seen when drugs stopped. The patient will usually require life long drug therapy. Treatment should not be withdrawn, otherwise, recurrences are frequent. Despite its name, it does not resolve after childhood or adolescence but continues into adult life.
• Excellent seizure control can usually be achieved in JME patients with relatively low doses of appropriate anticonvulsants e.g valproate. However, Valproate often avoided in fertile females. Low serum levels may be adequate to control seizures. Treat patient not serum levels. Alternatives include Lamotrigine, levetiracetam, topiramate, and Zonisamide. Response to valproate supports the diagnosis. Usually resolves seizures in 80%.
• Avoid Phenytoin, Gabapentin, Carbamazepine, or Phenobarbital, Tiagabine, and vigabatrin as these can worsen the condition or be ineffective

References

• JUVENILE MYOCLONIC EPILEPSY