Understanding Juvenile Myoclonic Epilepsy

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Epilepsy syndromes are conditions characterized by patterns of seizures and possibly other associated symptoms. If you experience recurrent seizures, it is useful for your medical team to know if you have one of the epilepsy syndromes because there are specific treatment approaches that are useful for each of them.

Juvenile myoclonic epilepsy is one of the recognized epilepsy syndromes and is among the most common.

If you or your child has been diagnosed with it, your symptoms may be frightening, frustrating, and may seem unrelated to each other—but many of the experiences you are having are part of this condition and there is effective medical treatment.

Symptoms

Juvenile myoclonic epilepsy is characterized by three types of seizures that begin in childhood, usually between the ages of 5 to 15. One of the features of the syndrome is that the seizure types evolve as children reach adolescence and adulthood.

Absence seizures

Children with juvenile myoclonic epilepsy may start having absence seizures, also often referred to as petit mal seizures, in early childhood. These seizures are seen as episodes of "zoning out" during which the child is unaware of surroundings and unable to respond for a few seconds.

Absence seizures are brief and are not accompanied by abnormal or erratic physical movements, so they may go unnoticed.

If a child repeatedly has absence seizures, parents and teachers may recognize that these episodes are not simple day-dreaming and that they are involuntary changes in consciousness.

Myoclonic seizures

These seizures generally begin to occur several years after the absence seizures. They consist of sudden jerking movements of the arms, legs, or body, as well as a decreased level of consciousness.

 Sometimes they occur during periods of sleepiness, either when falling asleep or when waking from sleep.

Generalized tonic clonic seizures

A few months to a few years after the myoclonic seizures start, young people with juvenile myoclonic epilepsy begin to experience generalized tonic clonic seizures, or what are often referred to as  grand mal seizures. These seizures are more intense, involving involuntary movements and stiffness of the body, accompanied by decreased awareness or passing out.

People with juvenile myoclonic epilepsy may have episodes in which more than one of the seizure types occur sequentially within a few minutes.

Diagnosis

The diagnosis of juvenile myoclonic epilepsy is based on a number of factors that typify this syndrome. The factors that your doctor will take into consideration when determining whether you have juvenile myoclonic epilepsy include:

  • The types of seizures and the combination of seizure types that you experience
  • The age at which the seizures manifest
  • EEG patterns during waking and sleep
  • Family history of seizures

The myoclonic seizure type is a trademark sign of juvenile myoclonic epilepsy, but myoclonic seizures can occur with other epilepsy syndromes as well.

Additionally, more than half of people who have juvenile myoclonic epilepsy have abnormal patterns of brain wave activity, which are seen on electroencephalogram (EEG.)

These EEG patterns are a normal background activity with accompanying generalized spike-wave discharges, multiple spike-wave complexes, and/or focal discharges while awake. Sleep EEG studies may show a pattern of multiple spike-wave complexes or three to four Hz spike-wave complexes.

The brain MRI of a person with juvenile myoclonic epilepsy does not necessarily show any specific patterns that point to the diagnosis. Newer modes of sophisticated brain imaging studies may show certain features in juvenile myoclonic epilepsy, but the research into these trends is still fairly new, and therefore there aren't definitive criteria for juvenile myoclonic epilepsy based on brain imaging studies.

The Role of Genetics

Overall, there is a hereditary tendency for juvenile myoclonic epilepsy. People who have it have a higher than average chance of having family members with any type of epilepsy.

Specific genes or inheritance patterns have not been definitively identified as responsible for juvenile myoclonic epilepsy, but there have been three genetic abnormalities that may be associated with juvenile myoclonic epilepsy: rs2029461 SNP in GRM4; rs3743123 in CX36, and rs3918149 in BRD2.

Treatment

There are several treatment approaches that come into play.

Medications

There are effective anti-seizure medications. These include valproic acid, levetiracetam, topiramate, zonisamide, lamotrigine, and clonazepam.

Most people who have juvenile myoclonic epilepsy only need to take one anti-seizure medication, which is described as monotherapy. If you experience side effects, your doctor will switch you to another medication. If you do not experience adequate improvement of your seizures, your doctor may either switch your prescription to another medication or prescribe a combination of more than one medication for optimal seizure control.

Lifestyle management

In general, as with many people who have epilepsy, there are some lifestyle factors that can exacerbate seizures. The most common triggers for seizures in juvenile myoclonic epilepsy include sleep deprivation, alcohol use, taking medications known to increase the risk of seizures, and exposure to flickering lights and severe stress. Avoidance of these lifestyle triggers is an important component of seizure prevention.

Medications to avoid

Interestingly, a few anti-seizure medications are known to worsen the seizures of juvenile myoclonic epilepsy. Carbamazepine, oxcarbazepine, and phenytoin can worsen the absence seizures and myoclonus. Gabapentin, pregabalin, tiagabine, and vigabatrin can also worsen seizures, including the generalized seizures, and therefore are not usually prescribed for this condition.

Surgery

In general, epilepsy surgery is not the usual treatment approach for juvenile myoclonic epilepsy. However, in some instances, it is an option if the seizures do not improve with medication.

Prognosis

The seizures of juvenile myoclonic epilepsy are usually self-limited, which means that they end on their own without becoming excessively prolonged or dangerous. Of course, having a seizure at all, even for a brief time, is something to be taken seriously. Therefore, if you have juvenile myoclonic epilepsy, you need to take your medication to reduce the severity and frequency of your seizures.

Over time, many young adults who are diagnosed with juvenile myoclonic epilepsy experience some improvement of seizures, and about 10 to 30 percent improve enough that medication may no longer be needed throughout adulthood.

Traits Associated With Juvenile Myoclonic Epilepsy 

Personality

Some research studies have noted that children and young adults with juvenile myoclonic epilepsy may have some degree of decreased social awareness or problems with interpersonal relationships. However, these traits are not consistent for everyone who has the syndrome, and it does not appear that there are associated inborn behavioral deficits. Some medical researchers have suggested that the psychological impact of living with seizures as a young adult may be the reason for some of the observed psychosocial issues.

Intelligence

The cognitive abilities and intelligence measures of people with juvenile myoclonic epilepsy is, on average, the same as that of peers who do not have epilepsy.

Sleep disturbances

There are sleep disturbances associated with juvenile myoclonic epilepsy. These disturbances may result in less efficient sleep, which manifests as tiredness. The medications used for seizure control seem to have a positive impact on these sleep problems.

A Word From Verywell

Epilepsy causes stress, uncertainty, and worry for those who have the condition and for their parents. The fact that juvenile myoclonic epilepsy is a recognized epilepsy syndrome with a known treatment and prognosis can ease some of that uncertainty.

Living with epilepsy requires some lifestyle adjustments, including the avoidance of epilepsy triggers, consistently taking medications as prescribed, being on the lookout for side effects when starting new medications, and awareness of safety precautions that affect driving and fall hazards. The vast majority of people living with juvenile myoclonic epilepsy experience good seizure control with medication and are able to live healthy and productive lives without significant restrictions.

Sources:

Koepp MJ, Thomas RH, Wandschneider B, Berkovic SF, Schmidt D. Concepts and controversies of juvenile myoclonic epilepsy: still an enigmatic epilepsy. Expert Rev Neurother. 2014;14(7):819-31.

Santos BPD, Marinho CRM, Marques TEBS, et al. Genetic susceptibility in Juvenile Myoclonic Epilepsy: Systematic review of genetic association studies. PLoS ONE. 2017;12(6):e0179629.