Basics
Description
Seizures arise from abnormal electrical discharges in the cerebral cortex that lead to alterations of consciousness, behavior, motor activity, sensation, or autonomic function. Epilepsy is defined as 2 or more seizures without acute provocation. Seizures are classified as focal, generalized, and unknown.
- Focal seizure types
- Without impairment of consciousness (either with observable motor or autonomic components or involving subjective sensory or psychic phenomena only)
- With impairment of consciousness (dyscognitive)
- Evolving to a bilateral, convulsive seizure
- Generalized seizure types
- Tonic " clonic, absence, myoclonic, clonic, tonic, atonic
- Unknown seizure types: epileptic spasms
Epidemiology
Incidence
Epilepsy affects 0.5 " 1% of all children (birth through 16 years). 120,000 children seek care annually in the United States for a seizure. Between 20,000 and 45,000 children/year are diagnosed with epilepsy, highest risk is in the 1st year of life.
Prevalence
4 " 10 per 1,000 children in developed countries have epilepsy.
Etiology and Pathophysiology
- Genetic
- Structural/metabolic
- Brain tumor
- Malformations of cortical development
- Neurocutaneous syndromes
- Prior cerebral insult
- Metabolic disorders
- Unknown cause
Genetics
- Epilepsy is both polygenic and multifactorial.
- The risk of epilepsy with an affected primary relative increases from the population risk (1 " 2%) to 2 " 5%.
- Single-gene epilepsy syndromes with defined genetic loci: autosomal dominant nocturnal frontal lobe epilepsy, benign familial neonatal convulsions, severe myoclonic epilepsy of infancy
- Other epilepsy syndromes (benign rolandic, childhood absence, juvenile myoclonic epilepsy) are heterogeneous.
- Epilepsy may also be a feature of other genetic and metabolic disorders such as trisomy 21, Angelman syndrome, and Menkes disease.
Commonly Associated Conditions
- The incidence of childhood-onset epilepsy associated with intellectual disability and cerebral palsy is 15 " 38%.
- Epilepsy occurs in 8 " 28% of children with autism.
- ADHD, depression, and anxiety are more common in children with epilepsy than in the general population.
Diagnosis
History
- Age, family history of seizures, developmental status, birth history
- Health at seizure onset: febrile, ill, sleep deprivation, trauma, toxins, ingestion, head injury
- Current medications and change in antiepileptic medication
- Other neurologic signs: confusion; encephalopathy; weakness; sensory deficits; and change in vision, behavior, balance, or gait
- Detailed history of symptoms during seizure
- Aura: subjective sensations
- Behavior: preceding and during seizure
- Change in consciousness or responsiveness
- Vocal: cry, gasp, speech
- Motor: head or eye turning, jerking, posturing, stiffening, automatisms (purposeless repetitive movements such as picking at clothing, lip smacking)
- Respiration: cyanosis, change in breathing pattern, apnea
- Autonomic: pupillary dilation, drooling, incontinence, pallor, vomiting, tachycardia
- Symptoms after seizure: amnesia, confusion, sleepiness, transient focal weakness (Todd paresis), headache
Physical Exam
- Vital signs: ABCs need to be checked immediately and recurrently, fever, tachycardia, bradycardia, or hypertension
- Signs of head trauma or child abuse: retinal hemorrhages, papilledema, presence of fractures, bruises of different ages
- Head circumference/abnormal head growth
- Signs of systemic infection: meningismus, purpura
- Skin examination: cafe au lait or ash leaf spots, facial hemangioma (suggesting neurocutaneous disorders)
- Neurologic examination: pupillary reactivity, mental status, focal motor weakness
- Seizures: If there is a question of continuing seizures, proceed with recommendations for "Status Epilepticus. "
Alert
- Attention to adequate airway and breathing and need for oxygenation or ventilatory support is the primary focus.
- If the child continues to have a seizure or has recurrent seizures, an abortive benzodiazepine should be administered either rectally or IV.
Diagnostic Tests & Interpretation
Lab
- Testing should be based on clinical history.
- In general, a standard laboratory evaluation (electrolytes, CBC, liver enzymes, calcium, and magnesium) did not show unsuspected abnormalities or contribute to the diagnosis or management in several clinical studies.
- An exception was hyponatremia (<125 mEq/L) found to be associated with seizures in 70% of infants younger than 6 months of age in one clinical study.
- Toxicology screening should be considered in any child in whom there is a question of drug exposure or substance abuse.
- Blood glucose (fingerstick can be obtained quickly)
- Antiepileptic drug (AED) levels if indicated; few of the newer AEDs have relevant or rapidly available serum levels but may be useful for documenting adherence to a medication regimen.
Imaging
- Neuroimaging: Evidence-based reviews showed low yields of acute CT or MRI in children presenting with seizures without focal signs or deficits. Current recommendations are as follows:
- MRI is generally the preferred modality.
- Emergent neuroimaging should be performed in any child with focal deficit not returning to baseline within several hours.
- Nonurgent MRI is recommended based on clinical scenario and EEG findings.
Diagnostic Procedures/Other
- EEG
- Indicated urgently if there is concern that child may be continuing to seize
- Nonurgent EEGs are indicated for first afebrile seizure.
- Lumbar puncture
- Not routinely recommended
- Should be considered for meningeal signs, infants <6 months of age, or persistent alteration of consciousness
- If intracranial hypertension, mass lesion, or hydrocephalus is suspected, defer lumbar puncture until after neuroimaging.
Differential Diagnosis
- Nonepileptic events
- Syncope
- Breath-holding spells
- Hyperventilation
- Nonepileptic events
- Movements related to gastroesophageal reflux (Sandifer syndrome)
- Sleep disorders: benign sleep myoclonus, night terrors, somnambulism, narcolepsy " cataplexy
- Migraine/headache syndromes, especially complicated migraine
- Nonepileptic movements: startle disease, shuddering spells, paroxysmal dyskinesias, tics, drug-induced dystonia
- Behavioral: stereotypies, self-stimulatory behaviors, inattention/ADHD
Treatment
Medication
- The choice of AED for long-term management of epilepsy depends on the specific seizure type and epilepsy syndrome. Monotherapy is always preferred.
- Many formulations (liquid, sprinkle caps, and extended-release) are available and should be individualized to the patient. For teenagers, extended-release forms may be recommended for compliance.
- Focal seizures (any type)
- Oxcarbazepine 20 " 40 mg/kg/24 h
- Levetiracetam 20 " 60 mg/kg/24 h
- Lamotrigine: dosing varies with valproate
- Topiramate 4 " 10 mg/kg/24 h
- Valproate: 15 " 50 mg/kg/24 h
- Zonisamide 2 " 10 mg/kg/24 h
- Genetic generalized epilepsies
- Ethosuximide 15 " 40 mg/kg/24 h: initial AED for absence seizures
- Levetiracetam
- Topiramate
- Acute treatment of seizures
- Benzodiazepines should be given for prolonged seizures (>5 minutes) or acute repetitive seizures.
- Rectal diazepam (0.3 " 0.5 mg/kg/dose), intranasal/buccal midazolam (0.2 mg/kg/dose), or oral/buccal lorazepam (Intensol, 0.05 " 0.1 mg/kg/dose, needs refrigeration) can be administered by parents/caregivers.
- Fosphenytoin 20 mEq/kg IM/IV
- Phenobarbital 10 " 20 mg/kg IV
- Levetiracetam 20 mg/kg IV
- Patients refractory to AED treatment: other options " ketogenic diet, vagus nerve stimulator, surgical resection
Alert
- Hyponatremic seizures: serum sodium <120 mEq/dL in infants with gastroenteritis; slow sodium correction indicated
- Apnea and hypoventilation from excessive administration of benzodiazepines, phenobarbital for seizures. Monitor ventilation and oxygenation; avoid large doses.
Additional Treatment
General Measures
- Chronic AED therapy is not indicated after acute symptomatic seizures or after a single unprovoked seizure in a child with normal neurologic examination and EEG.
- Chronic AED therapy may be considered after 1st seizure symptomatic of an acute, structural brain lesion (i.e., brain tumor).
Issues for Referral
In general, patients who have not responded to 2 seizure medications should be evaluated by a neurologist who specializes in epilepsy.
Alert
A 2-fold risk of increased suicidality has been associated with AED use, with an FDA black box warning on product labeling. Monitoring for suicidal ideation and mood changes is warranted in all patients taking AEDs.
Ongoing Care
Patient Education
- Injuries: Rarely, serious injury occurs with brief seizures from loss of consciousness and resultant falls.
- Daily precautions: Few restrictions are needed with the exceptions of driving (see state laws) and dangerous sports.
- Supervision around water is strongly advised; showering is generally safer than bathing.
- Helmets should be worn with all wheeled toys; avoid top bunk beds or locked bedrooms and unprotected heights.
- Sudden unexplained death in epilepsy patients (SUDEP) should be mentioned to all patients at appropriate times.
- Families should be instructed in seizure first aid: roll patient on the side, place nothing in the mouth, ensure safe environment.
Prognosis
- In a child who is neurologically normal with an unprovoked seizure, the risk of recurrence is 24% in 1 year and 45% in 14 years.
- If there is evidence of prior neurologic insult, the risk is 37% in 1 year.
- If the patient has 2 seizures separated by >24 hours, risk is 70% in 1 year.
- The EEG is the most significant predictor of recurrence: 15% risk in 1 year in a child with a normal EEG and 41% with an abnormal EEG.
Complications
- Brain damage
- From brief seizures: no convincing evidence
- From prolonged seizures (>30 minutes): Brain injury may occur secondary to hypoxia.
- Untreated or poorly controlled epilepsy: increased risk of intractable epilepsy and SUDEP
- Status epilepticus
- Incidence of 18 " 20/100,000/year in childhood
- Mortality in children between 3 and 6%
- Recurrence risk for status epilepticus is approximately 16% within the first year.
- Patient monitoring: depends on treatment and as mentioned earlier
Additional Reading
- Arthur TM, deGrauw TJ, Johnson CS, et al. Seizure recurrence risk following a first seizure in neurologically normal children. Epilepsia. 2008;49(11):1950 " 1954. [View Abstract]
- Epilepsy Foundation. Answer place: parent information on the Internet. http://www.epilepsyfoundation.org/answerplace. Accessed February 2, 2015.
- Glauser TA, Cnaan A, Shinnar S, et al. Ethosuximide, valproic acid, and lamotrigine in childhood absence epilepsy. N Engl J Med. 2010;362(9):790. [View Abstract]
- Hamiwka LD, Wirrell ED. Comorbidities in pediatric epilepsy: beyond "just " treating the seizures. J Child Neurol. 2009;24(6):734 " 742. [View Abstract]
- Hirtz D, Ashwal S, Berg A, et al. Practice parameter: evaluating a first nonfebrile seizure in children: report of the quality standards subcommittee of the American Academy of Neurology, the Child Neurology Society, and the American Epilepsy Society. Neurology. 2000;55(5):616 " 623. [View Abstract]
Codes
ICD09
- 780.39 Other convulsions
- 345.50 Localization-related (focal) (partial) epilepsy and epileptic syndromes with simple partial seizures, without mention of intractable epilepsy
- 345.90 Epilepsy, unspecified, without mention of intractable epilepsy
- 345.10 Generalized convulsive epilepsy, without mention of intractable epilepsy
ICD10
- R56.9 Unspecified convulsions
- G40.209 Local-rel symptc epi w cmplx prt seiz,not ntrct,w/o stat epi
- G40.309 Gen idiopathic epilepsy, not intractable, w/o stat epi
- G40.409 Other generalized epilepsy and epileptic syndromes, not intractable, without status epilepticus
SNOMED
- 128613002 seizure disorder (disorder)
- 29753000 Partial seizure (disorder)
- 19598007 Generalized epilepsy (disorder)
- 352818000 tonic-clonic epilepsy (disorder)
FAQ
- Q: How do I know my child has epilepsy?
- A: The term "epilepsy " is applied to children with 2 or more seizures without an acute cause.
- Q: Will my child always have epilepsy?
- A: The likelihood of outgrowing epilepsy depends on the syndrome. In many cases, anticonvulsants can be discontinued if the child has been seizure free for 2 years.
- Q: Why does my child have epilepsy?
- A: There are many different reasons to have epilepsy, including genetic, trauma, and other abnormalities of the brain. About 40% of people with epilepsy never have an identified etiology.