Is absence epilepsy benign?

What does "benign" epilepsy mean?
What does it mean to say that a type of epilepsy is "benign"? To be truly benign, it should meet three criteria:

1. It should not be caused by anything that will injure the brain.
2. The seizures themselves should not injure the brain or any other part of the body.
3. It should have no significant impact on the person's psychological and social well-being.

Most people also would expect that a benign childhood epilepsy should be outgrown.

Describe what "absence epilepsy" means.
We're talking about what's known as "typical" absence seizures, the most common type. They usually occur in cognitively normal children and are brief, ordinarily lasting less than 30 seconds.

There's another kind called "atypical" absence seizures. These are much less common and often are seen in children with developmental delay. They usually last longer than typical absences and frequently are associated with multiple other seizure types. They are often not benign, so we're not going to say any more about them here.

Typical absence seizures are seen in three epilepsy syndromes:

1. Childhood Absence Epilepsy

   This type of epilepsy usually begins in middle childhood, usually between ages 4 and 10 years, with absence seizures occurring very frequently throughout the day. Most children with this type of epilepsy have no other seizures during childhood, but about one-third of them will develop generalized tonic-clonic (grand mal) seizures later, often in adolescence.



2. Juvenile Absence Epilepsy

   Seizures in this syndrome begin somewhat later, often around puberty. Absences are less frequent and may not occur every day. Approximately 80% of those with this type of epilepsy will develop generalized tonic-clonic seizures, which often occur shortly after awakening. They also may experience myoclonic seizures (brief jerks of the body or limbs).



3. Juvenile Myoclonic Epilepsy

   This disorder usually begins around or shortly after puberty. The most prominent seizure type is myoclonic seizures, which usually affect the arms. These jerks most commonly occur first thing in the morning and can be made worse by sleep deprivation. Most of these young people also have generalized tonic-clonic seizures, which also occur predominantly in the morning and are often preceded by a series of jerks. If absence seizures occur, they are usually infrequent.

So what's the answer? Is typical absence epilepsy benign?
Let's see how it stacks up against our three criteria:

1. Is it caused by something that injures the brain?

   No, absence epilepsy is mostly caused by genetic factors. Brain injuries or lesions do not cause seizures of this type.

2. Do the seizures themselves cause injury?

   Absence seizures themselves, which nearly always are very brief, do not injure the brain. Once in a while, absence seizures can continue for hours to days, a condition known as absence status epilepticus, but the risk of injury from even very prolonged bouts is extremely remote. Absence seizures are not entirely harmless, however. They may lead to learning problems. They also may increase the risk of injury because of the frequent impairment of consciousness and the fact that they occur without any warning. In one study, 27% of children with absence epilepsy reported accidental injury during an absence seizure. Bicycle accidents, being struck by a car, and mild head injury were the greatest risks.¹ For these reasons, children with absence seizures should be treated aggressively enough to stop their seizures, not just decrease them.

3. Does it have negative effects on psychological or social well-being?

   For many years, children with absence epilepsy were felt to do well socially, in school, and at work. Several studies suggest that this is not always the case.^2-5 In one study that compared young adults diagnosed in childhood with absence epilepsy to others who had had childhood arthritis, those with a history of epilepsy were more likely to have had problems involving school, interpersonal relationships, mental health, behavior, and substance abuse. In addition, the young women with a history of absence epilepsy had a strikingly higher rate of unplanned pregnancy than those with arthritis.

   The reasons for these poorer outcomes were less clear. Those who continued to have seizures clearly did worse and had a high risk of ongoing psychological problems, but even those who outgrew their seizures and were no longer taking medication did not always do well socially. No differences in outcome were seen between those who were seizure-free but continued taking medication and those who were seizure-free without medication, suggesting that potential side effects from these medications were not the cause of the problems. The families of children and teens with absence epilepsy should be aware of these potential concerns. Careful follow-up is essential so that any problems that arise can be addressed early.

Is it outgrown?

Although most people would expect a "benign" childhood epilepsy to be outgrown, this is not always the case for absence epilepsy. The chance of remission (being seizure-free without medication) depends on the type. About 65% of children with childhood absence epilepsy do outgrow their seizures and are able to stop taking medication.⁶ The chance that the seizures will be outgrown is lower in those who have:

• learning problems
• a history of absence status epilepticus
• generalized tonic-clonic or myoclonic seizures
• failure to respond to the first seizure medicine tried
• a family history of seizures

About 15% of children first diagnosed with childhood absence epilepsy later will progress to juvenile myoclonic epilepsy. The outcome for juvenile myoclonic epilepsy and juvenile absence epilepsy is less favorable. Seizures in these disorders usually can be controlled by low doses of seizure medicine, but about 90% of these patients will have seizures again if the medicine is stopped, so treatment often must be lifelong.

Is there anything else to worry about?
One other concern is that the seizure medicine of choice for treating absence epilepsy, valproic acid, has a number of potentially problematic side effects, especially in young women. These include weight gain, loss or thinning of hair, and a possible risk of polycystic ovary syndrome (which involves irregular periods, weight gain, infertility, acne, and excessive hair growth on the body or face). There is also an increased risk of a birth defect, spina bifida, in babies conceived while their mothers are taking this medication. Because of these concerns, young women probably should talk with their doctor about trying another medication, such as lamotrigine (Lamictal), before they use valproic acid.

References:

1. Wirrell EC, Camfield PC, Camfield CS, Dooley JM, Gordon KE. Accidental injury is a serious risk in children with typical absence epilepsy. Archives of Neurology 1996;53:929-32.
2. Wirrell EC, Camfield CS, Camfield PC, Dooley JM, Gordon KE, Smith B. Long-term psychosocial outcome in typical absence epilepsy: sometimes a wolf in sheep's clothing. Archives of Pediatric and Adolescent Medicine 1997;151:152-8.
3. Olsson I, Campenhausen G. Social adjustment in young adults with absence epilepsies. Epilepsia 1993;34:846-51. PMID: 8404736
4. Hertoft P. The clinical, electroencephalographic and social prognosis in petit mal epilepsy. Epilepsia 1963;4:298-314.
5. Loiseau P, Pestre M, Dartigues JF, et al. Long term prognosis in two forms of childhood epilepsy: typical absence seizures and epilepsy with rolandic (centrotemporal) EEG foci. Annals of Neurology 1983;13:642-8.
6. Wirrell EC, Camfield CS, Camfield PR, Gordon KE, Dooley JM. Long-term prognosis of typical childhood absence epilepsy: remission or progression to juvenile myoclonic epilepsy. Neurology 1996;47:912-8.

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