Childhood Absence Epilepsy

Guidance for primary care clinicians diagnosing and managing children with childhood absence epilepsy
Childhood absence epilepsy (CAE) is a form of genetically determined, generalized epilepsy that is characterized by absence seizures and, in 10% of cases, generalized tonic-clonic seizures. In CAE, absence seizures start between 4–12 years of age, have a peak occurrence at 6–7 years, and occur many times a day. CAE accounts for 10–15% of childhood epilepsy and is one of the genetic generalized epilepsies.
Children with CAE have higher rates of behavioral, social, and educational problems, and a third of the children with CAE present with attention deficit disorder. [Glauser: 2010] In addition to attention deficit disorder, inattentiveness may be due to ongoing absence seizures or to the side effects of antiseizure medications.

Other Names

Generalized nonconvulsive epilepsy
Petit mal epilepsy

Key Points

Daydreaming vs. absence seizures
Since a diagnosis of absence epilepsy generally results in 2 years of treatment with an antiseizure medication, it is important to have the correct diagnosis. Families and teachers of children with absence epilepsy almost always note an interruption of the child’s activity during the event. Children with absence epilepsy don't usually respond to the triad of touch, voice, and eye contact when someone tries to stop the seizure.
Uncontrolled seizures
If the child is not responding to the antiseizure medication, refer to a pediatric neurologist to determine if the child has a different epilepsy syndrome and needs changes in treatment.
Signals for increasing medication
Declining school performance may signal a need for an increased antiseizure medication dose in a child already being treated for absence seizures.
Treating absence seizures
Three antiseizure medications have been well-studied in CAE: ethosuximide, valproate, and lamotrigine. Ethosuximide does not prevent generalized tonic-clonic seizures. If a child with absence seizures also has generalized tonic-clonic seizures, consider valproate instead of ethosuximide. Lamotrigine is considered second-line therapy for absence seizures but may be helpful when there are other seizure types. [Kanner: 2018]
Medications that may increase absence seizures
Carbamazepine and gabapentin may increase absence seizures.
Role of the pediatric clinician
The primary care clinician can diagnose and manage most children with absence seizures who are developing typically and have a normal physical exam without neurologic consultation.

Practice Guidelines

Hirsch E, French J, Scheffer IE, Bogacz A, Alsaadi T, Sperling MR, Abdulla F, Zuberi SM, Trinka E, Specchio N, Somerville E, Samia P, Riney K, Nabbout R, Jain S, Wilmshurst JM, Auvin S, Wiebe S, Perucca E, Moshé SL, Tinuper P, Wirrell EC.
ILAE definition of the Idiopathic Generalized Epilepsy Syndromes: Position statement by the ILAE Task Force on Nosology and Definitions.
Epilepsia. 2022;63(6):1475-1499. PubMed abstract

Diagnosis

Absence seizures may occur in other epileptic syndromes, such as juvenile absence epilepsy (JAE) and juvenile myoclonic epilepsy (JME). In JAE, absence seizures start after age 10 and are the most common seizure type, but they often have a shorter duration and occur less frequently than those seen in CAE. Most patients with JAE develop generalized tonic-clonic seizures. In JME, absence seizures are infrequent; the predominant seizure type is myoclonic seizures of the upper extremities on awakening, but generalized tonic-clonic seizures occur as well.
When the history is suggestive of absence seizures (e.g., a 5-year-old with 10-second spells of inattentiveness that have an abrupt onset and offset), the provider can have the child hyperventilate in clinic by having them blow on a paper towel for 2-3 minutes. If hyperventilation elicits a behavioral arrest lasting about 10 seconds with an abrupt onset and abrupt offset, then the child almost certainly has absence seizures. This kind of seizure is brief and safe to evoke in clinic. An EEG will confirm diagnosis.

Presentations

Characteristics of absence seizures:
  • Staring, sometimes blinking, eyes may begin to roll back
  • Lasts 2–20 seconds but usually about 10 seconds
  • Abruptly interrupts activity (such as drinking from a cup or speaking)
  • Unaware of their surroundings (e.g., not responsive to being called by name)
  • Many a day, sometimes up to 100
  • No warning - seizures begin and end suddenly
  • Often evoked by hyperventilation - this is a good provocative test in the clinic

Diagnostic Criteria

Criteria are available at Childhood Absence Epilepsy (ILAE).

Inclusion Criteria:
  1. Age at onset is between 4-12 years, with a peak at 6-7 years
  2. Normal neurologic state and development
  3. Absence seizures are brief (4-20 seconds, rarely longer) and frequent (tens per day) with abrupt and severe impairment (loss) of consciousness. Automatisms are frequent, but they have no significance in the diagnosis.
  4. An EEG shows 3 Hz spike and wave or polyspike and wave discharges during a clinical absence seizure. The EEG background is usually normal; interictal brief generalized spike and wave discharges can be seen, especially during sleep.
Exclusion criteria:
  1. Seizures other than typical absence seizures, such as generalized tonic-clonic seizures or myoclonic jerks
  2. Eyelid myoclonia, perioral myoclonia, rhythmic massive limb jerking, and single or arrhythmic myoclonic jerks of the head, trunk, or limbs; however, mild myoclonic elements of the eyes, eyebrows, and eyelids may be featured, particularly in the first 3 seconds of the absence seizure
  3. Mild or no impairment of consciousness during the interictal 3- to 4-Hz discharges
  4. Visual (photic) and other sensory precipitation of clinical seizures
Many children who almost meet these criteria or meet these criteria but have 1 of the exclusion criteria are treated in the same way as those meeting the criteria, but they have a more guarded prognosis for being seizure-free. [Valentin: 2007]

Screening & Diagnostic Testing

Laboratory Testing

If the child is to be started on valproic acid or ethosuximide, include liver function tests (LFTs) and complete blood count (CBC) with differential to establish baseline levels for later comparison.

Imaging

In a child with typical absence epilepsy (characteristic EEG, clinical history, and normal development and exam), neuroimaging is usually not necessary. [Gaillard: 2009]

Other Testing

During an absence seizure, the EEG shows 3-Hz spike and wave discharges (often frontally dominant) that have an abrupt beginning and ending. Background activity is usually normal in children with CAE. Two minutes of hyperventilation, usually performed during a routine EEG, often induces an absence seizure. After the child has been seizure free on an antiseizure medication for 2 years, an EEG may guide decisions about tapering off the dose.

Genetics & Inheritance

The etiology of CAE is genetic with complex multifactorial inheritance. Monozygotic twins have a 75% concordance rate, and 15–45% of children with CAE have a positive family history. Affected family members may have other forms of idiopathic or generalized epilepsy, such as febrile convulsions and generalized tonic-clonic seizures. Absence epilepsy is linked to the GABA receptor gamma 2 subunit and the voltage-gated calcium channel alpha 1A subunit. [Weber: 2008]

Prevalence

Prevalence is 1:3,571. [Posner: 2008]

Differential Diagnosis

It can be difficult to differentiate among absence seizures, daydreaming, focal seizures, and attention disorders, but understanding the common characteristics of each may help.

Daydreaming has no clear start or stop, can be interrupted, has varying durations, occurs less frequently than absence seizures, and occurs in predictable situations (e.g., the classroom).

Focal seizures usually infrequently occur (a few times a week, or a day, compared to many a day) and end with the child feeling confused. Focal seizures are often longer than 20 seconds and may be accompanied by automatisms (lip smacking, teeth grinding, finger movements). Attention deficit disorder does not have discrete episodes of inattentiveness.
Absence seizures presenting in children <4 years old may be due to SLCA2 mutation (glucose transporter deficiency). The child should be referred to a neurologist or medical geneticist for further diagnostic testing. The ketogenic diet is the treatment for seizures, including absence seizures, due to glucose transporter deficiency.
Atypical absence seizures may be seen in children with developmental delays or intellectual disability. Atypical absence seizures are characterized by loss of consciousness (similar to an absence seizure but with more gradual onset and resolution), and they can have more motor abnormalities, such as brief body stiffening or jerking. An EEG would show 1.5–2.5 Hz sharp-slow complexes.
Since absence seizures occur frequently, they are often diagnosed on a routine EEG. They also often can be elicited by hyperventilation. If investigating whether an event such as staring off or a brief alteration in consciousness is a seizure and a routine EEG is non-diagnostic, then a prolonged EEG in the hospital or at home may be considered. In these cases, the parents or other observers would have a pushbutton to record an event of concern when they see it, which then would allow the EEG reader to look for epileptiform activity during the identified time.

Co-occurring Conditions

Children with absence epilepsy are at increased risk for learning and attention problems, depression, anxiety, and other mood disorders. [Cerminara: 2013] [Tenney: 2013] For assessment information, see:

Prognosis

Without treatment, children can have hundreds of absence seizures a day, which can significantly impair learning and participation in school and family life. Absence seizures can also interrupt normal motor activity and cause injury. For instance, if a child has an absence seizure while walking on a sidewalk, they might not stop at the curb and instead step into traffic.
Remission during adolescence occurs in 65-70% of children with CAE. A lower chance of resolution may be indicated by the presence of generalized seizures, onset of seizures in children <4 years (some may have glucose transporter deficiency caused by a mutation in the SLC2A1 Gene (ILAE), children >8 years, and lack of response to initial therapy. [Tenney: 2013] Recurrence risk after antiepileptic treatment withdrawal in children who have been seizure free for 2 years is 16%. [Ramos-Lizana: 2010]

Treatment & Management

If the primary care clinician elicits an absence seizure in clinic with hyperventilation, educate the parents about the diagnosis and prognosis. You can start ethosuximide as described below. Most children with absence seizures who are typically developing and have a normal neurologic exam can be managed in the medical home. After the patient has been seizure free for 2 years, an optional consultation with a pediatric neurologist may be helpful when an antiseizure medication taper is being considered.

Neurology

If the primary care clinician elicits an absence seizure in clinic with hyperventilation, educate the parents about the diagnosis and prognosis. You can start ethosuximide as described below. Most children with absence seizures who are typically developing and have a normal neurologic exam can be managed in the medical home. After the patient has been seizure free for 2 years, an optional consultation with a pediatric neurologist may be helpful when an antiseizure medication taper is being considered.

Medications

Three antiseizure medications have been well-studied in CAE: ethosuximide, valproate, and lamotrigine. [Hirsch: 2022]
Ethosuximide is only effective for absence seizures - not the generalized convulsive seizures sometimes associated with this diagnosis. Ethosuximide and valproate have the highest efficacy (~45% seizure free at 1 year) for absence seizures, but of the 2, valproate has significantly more side effects. Both valproic acid and ethosuximide are associated with weight gain, and children on these medications may need active weight management.
Lamotrigine has lower efficacy and is considered inferior to valproate (~20% seizure free at 1 year) but has low side effects. At onset of absence seizures, ethosuximide is a reasonable first choice. [Kanner: 2018] [Rosati: 2018] [Glauser: 2013]
Other medications, including topiramate, levetiracetam, zonisamide, and clobazam, may also be used if there are specific contraindications to the preferred medications or if the seizures are resistant to treatment.

Ethosuximide (Zarontin)
Childhood absence seizures are the only indication for ethosuximide. It is hepatically metabolized; the dose should be adjusted if there is hepatic dysfunction. There are case reports of agranulocytosis and fatal pancytopenia associated with ethosuximide. Check LFTs and CBC with differential before starting and periodically thereafter. Ethosuximide comes in 250 mg capsules and 250mg/5ml syrup.

Valproic acid (Depakote)
Although quite rare in typically developing children over 2 years old, fatal pancreatitis and hepatic failure have been associated with valproate. The incidence of valproate-induced hepatic failure in children <2 years old taking multiple antiseizure medications is 1:500 to 1:800. The risk is lower in older children and adults who are on valproate monotherapy. The risk of hepatic failure is greatest in the first 6 months of use. Valproate is a known teratogen and should be avoided in girls and women of childbearing age, if possible. Check LFTs and CBC with differential before starting and periodically thereafter. Many providers obtain a valproate trough level when the patient is stabilized and repeat labs every 3–6 months throughout treatment. Valproic acid comes in liquid, sprinkle capsules, and tablets (regular and extended-release forms).

Lamotrigine (Lamictal)
Titrate the dose very slowly due to the risk of severe skin reactions (Stevens-Johnson syndrome). If the child is already taking valproic acid, the starting dose is lower and the titration is slower. Adding lamotrigine to valproate, and vice versa, should be done only with the recommendation of a pediatric neurologist. Lamotrigine comes in chewable, dispersible, and regular tablets.

Tapering antiepileptic drugs:
A seizure-free interval of 2 years is recommended before tapering off the antiseizure medication. Some clinicians choose to do an EEG first. If it is normal, consider tapering; if abnormal, consider continuing antiseizure medication therapy for another year.

Learning / Education / Schools

Absence seizures, which can occur many times a day, may be first noted in school when the child is trying to pay attention. It is not uncommon for development (particularly in speech and language) or educational achievement to be mildly impaired. Antiseizure medications may also cause difficulty concentrating. After the child has been diagnosed, developmental and educational progress should be monitored closely.
Children with CAE may have educational difficulties for many reasons including:
  • Neurocognitive defects [Kernan: 2012]
  • Loss of learning time due to frequent seizures before treatment
  • Poor seizure control even with treatment
  • Side effects of antiseizure medications
  • Mood disorders

Services & Referrals

Pediatric Neurology (see ID providers [1])
Refer for help diagnosing absence seizures that started <4 years old and managing absence seizures that are refractory to ethosuximide, occur in the setting of developmental delay or intellectual disability, or are atypical. Depending on the comfort of the medical home provider and family, a referral may be helpful to confirm the diagnosis, suggest management, and guide decisions about tapering off an antiepileptic drug.
Electroencephalography (EEG) (see ID providers [0])
A characteristic EEG is part of the diagnostic criteria for CAE.

ICD-10 Coding

G40.A, Absence epileptic syndrome
Additional digits indicating the details of diagnosis are needed for billable coding. They can be found at ICD-10 for Absence Epileptic Syndrome (icd10data.com).

Resources

Information & Support

Related Portal Content
Attention-Deficit/Hyperactivity Disorder (ADHD)
Diagnosis and treatment information for primary care clinicians caring for the child with ADHD.

Depression
Diagnosis and treatment information for primary care clinicians caring for the child with depression.

Anxiety Disorders
Diagnosis and treatment information for primary care clinicians caring for the child with anxiety.

Childhood Absence Epilepsy (FAQ)
Answers to questions families often have about caring for their child with childhood epilepsy.

Attention Deficit Hyperactivity Disorder (ADHD) (FAQ)
Answers to questions families often have about caring for their child with ADHD

Depression (FAQ)
Answers to questions families often have about caring for their child with depression.

Anxiety Disorders (FAQ)
Answers to questions families often have about caring for their child with anxiety.

For Professionals

International League Against Epilepsy
Up-to-date diagnostic criteria, genetics, testing, and differential diagnosis of absence seizures and childhood absence epilepsy.

Childhood Absence Epilepsy (OMIM)
Information about clinical features, diagnosis, management, and molecular and population genetics; Online Mendelian Inheritance in Man, authored and edited at the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine

For Parents and Patients

Support

Childhood Absence Epilepsy (Epilepsy Foundation)
National organization with local chapters that provides information and support.

Absence Seizure (Mayo Clinic)
Information about tests, treatments, coping, complications, and support for absence seizures.

Patient Education

Let's Talk About... EEG (Spanish & English)
Fact sheet about electroencephalographs that measure brain activity; Intermountain Healthcare.

Services for Patients & Families in Idaho (ID)

For services not listed above, browse our Services categories or search our database.

* number of provider listings may vary by how states categorize services, whether providers are listed by organization or individual, how services are organized in the state, and other factors; Nationwide (NW) providers are generally limited to web-based services, provider locator services, and organizations that serve children from across the nation.

Studies

Childhood Absence Epilepsy (ClinicalTrials.gov)
Studies looking at better understanding, diagnosing, and treating this condition; from the National Library of Medicine.

Helpful Articles

PubMed search for absence epilepsy in children, last 2 years.

Caraballo RH, Dalla Bernardina B.
Idiopathic generalized epilepsies.
Handb Clin Neurol. 2013;111:579-89. PubMed abstract

Gaillard WD, Chiron C, Helen Cross J, Simon Harvey A, Kuzniecky R, Hertz-Pannier L, Gilbert Vezina L.
Guidelines for imaging infants and children with recent-onset epilepsy.
Epilepsia. 2009. PubMed abstract

Glauser T, Ben-Menachem E, Bourgeois B, Cnaan A, Guerreiro C, Kälviäinen R, Mattson R, French JA, Perucca E, Tomson T.
Updated ILAE evidence review of antiepileptic drug efficacy and effectiveness as initial monotherapy for epileptic seizures and syndromes.
Epilepsia. 2013;54(3):551-63. PubMed abstract

Glauser TA, Cnaan A, Shinnar S, Hirtz DG, Dlugos D, Masur D, Clark PO, Adamson PC.
Ethosuximide, valproic acid, and lamotrigine in childhood absence epilepsy: initial monotherapy outcomes at 12 months.
Epilepsia. 2013;54(1):141-55. PubMed abstract / Full Text

Mula M, Kanner AM, Schmitz B, Schachter S.
Antiepileptic drugs and suicidality: an expert consensus statement from the Task Force on Therapeutic Strategies of the ILAE Commission on Neuropsychobiology.
Epilepsia. 2013;54(1):199-203. PubMed abstract

Sidhu R, Velayudam K, Barnes G.
Pediatric seizures.
Pediatr Rev. 2013;34(8):333-41; 342. PubMed abstract

Wheless JW, Clarke DF, Carpenter D.
Treatment of pediatric epilepsy: expert opinion, 2005.
J Child Neurol. 2005;20 Suppl 1:S1-56; quiz S59-60. PubMed abstract

Authors & Reviewers

Initial publication: June 2013; last update/revision: November 2022
Current Authors and Reviewers:
Author: Lynne M. Kerr, MD, PhD
Reviewer: Denise Morita, MD
Authoring history
2019: update: Lynne M. Kerr, MD, PhDA; Denise Morita, MDR
2015: update: Denise Morita, MDR
2013: first version: Lynne M. Kerr, MD, PhDA
AAuthor; CAContributing Author; SASenior Author; RReviewer

Page Bibliography

Cerminara C, D'Agati E, Casarelli L, Kaunzinger I, Lange KW, Pitzianti M, Parisi P, Tucha O, Curatolo P.
Attention impairment in childhood absence epilepsy: an impulsivity problem?.
Epilepsy Behav. 2013;27(2):337-41. PubMed abstract

Gaillard WD, Chiron C, Helen Cross J, Simon Harvey A, Kuzniecky R, Hertz-Pannier L, Gilbert Vezina L.
Guidelines for imaging infants and children with recent-onset epilepsy.
Epilepsia. 2009. PubMed abstract

Glauser TA, Cnaan A, Shinnar S, Hirtz DG, Dlugos D, Masur D, Clark PO, Adamson PC.
Ethosuximide, valproic acid, and lamotrigine in childhood absence epilepsy: initial monotherapy outcomes at 12 months.
Epilepsia. 2013;54(1):141-55. PubMed abstract / Full Text

Glauser TA, Cnaan A, Shinnar S, Hirtz DG, Dlugos D, Masur D, Clark PO, Capparelli EV, Adamson PC.
Ethosuximide, valproic acid, and lamotrigine in childhood absence epilepsy.
N Engl J Med. 2010;362(9):790-9. PubMed abstract / Full Text

Hirsch E, French J, Scheffer IE, Bogacz A, Alsaadi T, Sperling MR, Abdulla F, Zuberi SM, Trinka E, Specchio N, Somerville E, Samia P, Riney K, Nabbout R, Jain S, Wilmshurst JM, Auvin S, Wiebe S, Perucca E, Moshé SL, Tinuper P, Wirrell EC.
ILAE definition of the Idiopathic Generalized Epilepsy Syndromes: Position statement by the ILAE Task Force on Nosology and Definitions.
Epilepsia. 2022;63(6):1475-1499. PubMed abstract

Kanner AM, Ashman E, Gloss D, Harden C, Bourgeois B, Bautista JF, Abou-Khalil B, Burakgazi-Dalkilic E, Park EL, Stern J, Hirtz D, Nespeca M, Gidal B, Faught E, French J.
Practice guideline update summary: Efficacy and tolerability of the new antiepileptic drugs I: Treatment of new-onset epilepsy: Report of the American Epilepsy Society and the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology.
Epilepsy Curr. 2018;18(4):260-268. PubMed abstract / Full Text

Kernan CL, Asarnow R, Siddarth P, Gurbani S, Lanphier EK, Sankar R, Caplan R.
Neurocognitive profiles in children with epilepsy.
Epilepsia. 2012;53(12):2156-63. PubMed abstract

Posner E.
Absence seizures in children.
BMJ Clin Evid. 2008;2008. PubMed abstract / Full Text

Ramos-Lizana J, Aguirre-Rodríguez J, Aguilera-López P, Cassinello-García E.
Recurrence risk after withdrawal of antiepileptic drugs in children with epilepsy: a prospective study.
Eur J Paediatr Neurol. 2010;14(2):116-24. PubMed abstract

Rosati A, Ilvento L, Lucenteforte E, Pugi A, Crescioli G, McGreevy KS, Virgili G, Mugelli A, De Masi S, Guerrini R.
Comparative efficacy of antiepileptic drugs in children and adolescents: A network meta-analysis.
Epilepsia. 2018;59(2):297-314. PubMed abstract

Tenney JR, Glauser TA.
The current state of absence epilepsy: can we have your attention?.
Epilepsy Curr. 2013;13(3):135-40. PubMed abstract / Full Text

Valentin A, Hindocha N, Osei-Lah A, Fisniku L, McCormick D, Asherson P, Moran N, Makoff A, Nashef L.
Idiopathic generalized epilepsy with absences: syndrome classification.
Epilepsia. 2007;48(11):2187-90. PubMed abstract

Weber YG, Lerche H.
Genetic mechanisms in idiopathic epilepsies.
Dev Med Child Neurol. 2008;50(9):648-54. PubMed abstract