Childhood absence epilepsy

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Childhood absence epilepsy is a condition characterized by recurrent seizures (epilepsy). This condition begins in childhood, usually between ages 3 and 8. Affected children have absence seizures (also known as petit mal seizures), which are brief episodes of impaired consciousness that look like staring spells. During seizures, children are not aware of and do not respond to people or activities around them. The seizures usually last several seconds and they occur often, up to 200 times each day.

Some affected individuals have febrile seizures before they develop childhood absence epilepsy. Febrile seizures are involuntary muscle contractions (convulsions) brought on by a high body temperature (fever).

In most people with childhood absence epilepsy, the absence seizures disappear in adolescence. However, some affected individuals continue to have absence seizures into adulthood, or they may develop generalized tonic-clonic seizures, which cause muscle rigidity, convulsions, and loss of consciousness, or myoclonic seizures, which are characterized by rapid, uncontrolled muscle jerks.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

The genetics of childhood absence epilepsy are complex and not completely understood. It is thought that multiple genetic changes or a combination of genetic and environmental factors contribute to development of the condition. Most genetic changes associated with childhood absence epilepsy are rare, having been found in only a small number of affected individuals. Each genetic change appears to play a role in some populations but not others.

Several genes associated with childhood absence epilepsy provide instructions for making pieces (subunits) of the GABAA receptor protein. The GABAA receptor acts as a channel that allows negatively charged chlorine atoms (chloride ions) to cross the cell membrane. The influx of chloride ions in nerve cells (neurons) in developed brains creates an environment that blocks (inhibits) signaling between neurons and prevents the brain from being overloaded with too many signals. Mutations in GABAA receptor subunit genes lead to production of altered subunit proteins that cannot form functional receptors, so fewer GABAA receptors are available. As a result, neurons become overloaded with signals. Researchers believe that the overstimulation of certain neurons in the brain triggers the abnormal brain activity associated with seizures.

Problems with another type of ion channel, called a calcium channel, are also associated with childhood absence epilepsy. Calcium channels transport positively charged calcium atoms (calcium ions) into cells. These channels help control the release of neurotransmitters, which are chemicals that relay signals from one neuron to another. Mutations that result in overactive calcium channels cause certain neurons to become overstimulated, triggering seizures.

Mutations in other genes that do not provide instructions for making ion channels have also been associated with childhood absence epilepsy. It is not clear how these changes are involved in the development of absence seizures.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

Because childhood absence epilepsy appears to be a complex disease without a single genetic cause, it does not have a straightforward pattern of inheritance. When associated with mutations in GABAA receptor or calcium channel genes, it seems to follow an autosomal dominant inheritance pattern, which means one copy of the altered gene in each cell is sufficient to increase the likelihood of the disorder. Some people who have the altered gene never develop the condition, a situation known as reduced penetrance.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Childhood absence epilepsy affects 2 to 8 in 100,000 children under age 15 each year. The condition is more common in girls than in boys.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

EEG with spike-wave complexes (2.5-3.5 Hz) · Very frequent (99-80%)

The presence of complexes of spikes and waves (2.5-3.5 Hz) in electroencephalography (EEG).

Typical absence seizure · Very frequent (99-80%)

A typical absence seizure is a type of generalized non-motor (absence) seizure characterized by its sudden onset, interruption of ongoing activities, a blank stare, possibly a brief upward deviation of the eyes. Usually the patient will be unresponsive when spoken to. Duration is a few seconds to half a minute with very rapid recovery. Although not always available, an EEG would usually show 3 Hz generalized epileptiform discharges during the event.

Attention deficit hyperactivity disorder · Frequent (79-30%)

Attention deficit hyperactivity disorder (ADHD) manifests at age 2-3 years or by first grade at the latest. The main symptoms are distractibility, impulsivity, hyperactivity, and often trouble organizing tasks and projects, difficulty going to sleep, and social problems from being aggressive, loud, or impatient.

Pallor · Frequent (79-30%)

Abnormally pale skin.

Abnormal social behavior · Occasional (29-5%)

An abnormality of actions or reactions of a person exhibited during social interactions with other individuals.

Anxiety · Occasional (29-5%)

Intense feelings of nervousness, tension, or panic often arise in response to interpersonal stresses. There is worry about the negative effects of past unpleasant experiences and future negative possibilities. Individuals may feel fearful, apprehensive, or threatened by uncertainty, and they may also have fears of falling apart or losing control.

Bilateral tonic-clonic seizure · Occasional (29-5%)

A bilateral tonic-clonic seizure is a seizure defined by a tonic (bilateral increased tone, lasting seconds to minutes) and then a clonic (bilateral sustained rhythmic jerking) phase.

Depression · Occasional (29-5%)

Frequently experiencing feelings of being down, miserable, and/or hopeless; struggling to recover from these moods; having a pessimistic outlook on the future; feeling a pervasive sense of shame; having a low self-worth; experiencing thoughts of suicide and engaging in suicidal behavior.

Other findings in the same source

From: Orphanet

Additional reported features include Dyslexia (Occasional (29-5%)); Febrile seizure (within the age range of 3 months to 6 years) (Occasional (29-5%)); Hyperventilation (Occasional (29-5%)); Impaired visuospatial constructive cognition (Occasional (29-5%)); Intellectual disability (Occasional (29-5%)); Low self esteem (Occasional (29-5%)); Myoclonic absence (Occasional (29-5%)); Punding (Occasional (29-5%)); Specific learning disability (Occasional (29-5%)); Uncontrolled eye movements (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing Childhood absence epilepsy is Neurology, with a neurologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which nervous-system findings help explain the symptoms?
• Would an assessment of walking, communication or daily function be helpful?
• Are rehabilitation or other specialist services relevant?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Childhood absence epilepsy. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.