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Seizure Disorder - Initial Diagnosis

Overview

When a child presents having experienced a paroxysmal event, the clinician must determine the cause from among seizures and other causes of such events and, if a seizure, classify it by type – provoked or unprovoked, focal (localized) or generalized, etc. – to determine the appropriate diagnostic workup and treatment. The Seizure history & physical form(PDF Document 88 KB) may help guide your seizure history and physical exam.

Diagnostic Criteria

If there is reasonable certainty that the child has had a seizure (see Differential diagnosis of paroxysmal events below), the next questions are why and what kind? A complete description of the event, including age of the patient and descriptions of the seizure (focal vs. generalized) and related events (e.g. sleep deprivation before, a period of profound sleepiness afterward, associated fever, etc.), is needed. The Seizure assessment tool(PDF Document 41 KB) adapted from [Hirtz: 2000]] may be helpful. The official classification of seizure types is in flux; the approach described below is from [Engel: 2006]. Seizure type will guide the search for etiology and treatment choices if antiepileptic drug (AED) therapy is considered.
  • Focal onset seizures (also called localized or partial seizures): symptoms at onset are convincingly localized in the motor, somatosensory, special sensory, autonomic, or limbic systems. Examples of focal onset seizures include: a seizure that starts with limb jerking on one side of the body, with tingling on one side of the body, with a sense of fear, or with vomiting. Focal onset seizures may occur in children of all ages and may be difficult to diagnose and treat. For example, seizures originating in the frontal lobe may manifest only as unusual automatisms. Because focal seizures may be associated with focal brain pathology (e.g., stroke or tumor), imaging is almost always indicated. The exception is in benign Rolandic epilepsy or other known benign epilepsy syndromes. Seizures with focal onset before generalization are classified as focal seizures with secondary generalization and for purposes of evaluation, should be treated as focal seizures. The focal onset may be subtle and must be asked about – for instance, did the child's eyes go to one side before the tonic-clonic activity was noted?
  • Generalized seizures begin with widespread manifestations, caused by widespread electrical dysfunction of the entire cortex. Types of generalized seizures include:
    • Absence seizures (as seen in Absence Epilepsy) Absence seizures appear as a sudden impairment in consciousness, often associated with eye blinking, staring, and other minor facial movements. There is abrupt interruption of preceding activities like talking, eating, or walking, but the child does not fall down or have a convulsion. Absence seizures may last from a few seconds to a minute and typically occur multiple times per day with abrupt onset/termination and minimal, if any, post-ictal manifestations.
    • Atypical absence seizures are most common in Lennox Gastaut syndrome and other epilepsy syndromes. Atypical absence seizures have gradual onset and termination, cyclic frequency, and are more prolonged or pronounced than typical absence seizures.
    • Myoclonic seizures are lightning-quick limb or body jerks, either unilateral or bilateral, usually without impairment of consciousness.
    • Tonic seizures are episodes of increased muscle tone (spasm) of truncal and facial muscles, associated with flexion of upper extremities and extension of lower extremities. They are most common in childhood and may result in falls.
    • Clonic seizures are common in children and may resemble myoclonus, except that there is a loss of consciousness, the repetition rate is slower, and the seizures are usually longer.
    • Tonic-clonic seizures generally involve tonic posturing followed by clonic activity, typically with sudden onset of increased truncal tone that causes the patient to cry out with forced expiration. They are usually accompanied by a marked increase in heart rate and blood pressure. Incontinence after the spells, as sphincter muscles relax, and post-ictal impairment of consciousness are common.
    • Atonic seizures (also called "drop attacks") result in a sudden loss of all muscle tone, causing the patient to fall to the ground, often with injury.

Epilepsy Syndromes If a thorough history and physical exam does not suggest any provoking cause for a seizure, the child might have an epilepsy syndrome. Epilepsy syndromes can be classified using the age of onset and seizure type as follows:
  • Neonatal seizures with onset between birth and 1 month of age - epilepsy syndromes include benign neonatal convulsions, benign myoclonic epilepsy of infancy, and others. Children with seizures occurring in this age group should be urgently evaluated for a provoking cause of the seizures, and if none is found, then seen by a pediatric neurologist.
  • Seizures with onset from 2 months to 3 years of age - in this age group, epilepsy syndromes can range in severity of impact from benign to devastating
    • Febrile seizures - generally benign, and very common. These are often familial, and may be part of the recently described syndrome Generalized Epilepsy with Febrile Seizures Plus (GEFS+) [Scheffer: 2005].
    • Benign myoclonic seizures - generally benign
    • Early infantile epileptic encephalopathy and early myoclonic epilepsy - generally severe and with a very poor prognosis
    • Infantile spasms (See also Infantile Spasms - old) - generally severe and with a very poor prognosis
    • Lennox Gastaut syndrome - generally severe and with a very poor prognosis
  • Seizures with onset between 3 and 10 years of age - the majority of children in this group have genetic epilepsies that carry a good prognosis.
  • Seizures with onset over the age of 10 years - these epilepsy syndromes may also have a genetic origin but usually don't resolve spontaneously. Youths with these epileptic syndromes usually have normal lives but may need to be on medication indefinitely.

Pearls And Alerts

Flashing lights can trigger seizures in approximately 9% of people with epilepsy. This is more common in children and adolescents and becomes less common with age. The frequency of flashing that is most likely to cause seizures varies from person to person but is generally between 15 and 80 Hertz. [Hughes: 2008]

Practice Guidelines

Hirtz D, Ashwal S, Berg A, Bettis D, Camfield C, Camfield P, Crumrine P, Elterman R, Schneider S, Shinnar S.
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):616-23. PubMed abstract / Full Text

Differential Diagnosis

When a patient presents with a paroxysmal event, a first step is to determine if the event was a seizure. There is no reliable test that can differentiate seizures from other events, although creatine kinase ([Fein: 1997]) and prolactin ([Neufeld: 1997]) levels may be helpful. See Differential diagnosis of paroxysmal events. The clinical history of the event(s) is the most useful information in arriving at the diagnosis, but even a detailed history may not be sufficient to distinguish between a seizure or some other type of episode in a normally-developing child. Families can be given a (Seizure diary(PDF Document 75 KB)) to record descriptions of events and to help determine patterns over time. The family can also be asked to videotape an event, which is sometimes very helpful. For a one-time event in a child with a normal clinical evaluation, reassurance and reevaluation of the child if another similar event occurs may be the best approach. Because it is difficult to be certain that a seizure has not occurred, the child should be reevaluated if new events occur. If there is uncertainty, seizure precautions should be recommended (see Activity restrictions in children with seizures) and documented. An EEG may not always help since mildly abnormal EEGs are common in the general population and many children with seizures have normal EEGs. If the child has neurologic abnormalities as a baseline, seizures are much more likely and the threshold for referral to pediatric neurology for further evaluation and management should be lower.

History And Examination

The initial assessment of a child with a history of an event thought to be a seizure (or seizures) should focus on three areas: determining the seizure type, classification of the child developmentally, and the neurologic exam. Some seizures will belong to an obvious, fairly benign class, such as absence seizures in a child who is developing well, and an extensive etiological search will not be necessary. Others may be worrisome because of their type or associated history, e.g., a child with a new seizure and developmental regression. In yet other cases, there may be an obvious remote cause, e.g. new seizures in a child with known hemiplegic cerebral palsy.

Family History

Children may have a heritable epilepsy syndrome – there are now more than 70 gene mutations associated with epilepsy [Noebels: 2003] [Reid: 2009] or an underlying condition that predisposes them to seizures, e.g., tuberous sclerosis.

Pregnancy/Perinatal History

Children who experienced infections in utero, such as toxoplasmosis or CMV, are at greater risk for seizures. Brain injury associated with perinatal asphyxia or significant prematurity also increase the risk.

Medical History

  • Head trauma is an uncommon cause of seizures, but an important diagnosis – subdural or epidural hemorrhage can be life-threatening. Brain tumors are an even less common cause of seizures and may present also with behavior or personality change and vomiting (particularly early morning).
  • Febrile seizures may be associated with a greater tendency for later epilepsy. [Ahmad: 2010]
  • What is the child's basic state of health? Illness, sleep-deprivation, alcohol and certain medications and illegal substances may lower seizure threshold.
  • Features of an event that are more associated with seizures than with non-seizure events:
    • Precipitating events: head trauma, conditions that cause abrupt electrolyte changes (gastroenteritis, diabetes), febrile illness
    • Pre-ictal symptoms: behavior or mood change or an aura minutes before a seizure may be a symptom to a focal onset
    • Ictal description (appearance during the seizure): vocal – cry or gasp, slurring of words, garbled speech; motor – head or eye turning, eye deviation, posturing, jerking, stiffening, automatisms, generalized or focal movements; respiration – change in breathing pattern, cessation of breathing, cyanosis; autonomic – pupillary dilation, drooling, change in heart or respiratory rate, incontinence, pallor, vomiting; loss of consciousness or inability to understand or speak
    • Postictal symptoms (appearance following the seizure): – amnesia for events, confusion, lethargy, sleepiness, headaches and muscle aches, transient focal weakness (Todd's paralysis), nausea or vomiting, bitten tongue

Developmental and Educational History

Developmental screening should be performed for young children and IQ and school performance assessment should be considered in older children. Developmental delays may be a manifestation of an underlying condition. A decrease in school performance may be due to undiagnosed seizures, especially absence seizures. Mood disorders and attention problems are common in children with epilepsy.

Social and Family History

Seizures and epilepsy can have substantial impact on families including fear of underlying diagnoses, fear of injury/death during seizures, concern about the future, financial problems, etc.

Physical Exam

General

Observe generally the appearance and interaction of the patient. Absence seizures may be obvious to an examiner. Children with autism spectrum disorders have a higher incidence of seizures. [Tuchman: 2011]

Growth Parameters

Check height, weight, and head circumference for decreased growth that may be due to a genetic syndrome

Skin

  • evidence of tuberous sclerosis, such as ash leaf spots (a Wood's lamp may help visualize these in lightly pigmented skin), adenoma sebaceum, forehead plaques, shagreen patches, ungual or subungual fibromas;
  • evidence of neurofibromatosis, such as multiple cafe au lait spots, axillary freckles, neurofibromas;
  • bruises or abrasions that might suggest trauma from falls;
  • rashes that may suggest drug reactions or allergy. It is helpful to point out minor rashes that may be present before starting a new medication so that the already existing rash is not confused with a medication reaction. Medication rashes are usually very obvious.

HEENT

Look for dysmorphic features. Perform visual and fundoscopic exams. Consider referring to pediatric ophthalmology. An unexplained bite mark on the front lateral edge of the tongue might be due to a generalized seizure.

Neurologic Exam

Look for focal abnormalities such as asymmetric or focal weakness or sensation, asymmetric reflexes or impaired coordination that would suggest an intracranial abnormality (tumor, vascular or traumatic injury, abcess)?

Testing

Sensory Testing

Vision or hearing abnormalities may be present in a child with an underlying genetic or neurologic condition. If these are suspected, a referral to ophthalmology and/or audiology may be helpful.

Laboratory Testing

Depending on the presentation, laboratory testing may be helpful to identify a metabolic, electrolyte, or acid-base derangement that could cause seizures or be associated with a seizure-causing diagnosis. Examples include hypo- or hypernatremia, severe acidosis, hyperammonemia, and many others. Baseline labs might include comprehensive metabolic profiles, CBC with differential, serum amino acids, urine organic acids, blood PH, lactate, pyruvate, ammonia, and biotinidase.
Some medications (e.g., valproic acid, carbamazepine) require the child to have baseline comprehensive metabolic profiles and CBCs before they are initiated.

Imaging and EEG

EEG - After the child is clinically diagnosed with one or more seizures, EEG is performed to obtain additional information, usually on an outpatient basis and not emergently. EEG can show the specific area of onset in a focal onset seizure, and can confirm the diagnosis of an epilepsy syndrome, for example.
EEGs should not be used in the diagnosis of seizures because non-specific abnormalities in background activity can be seen in 10% of children without seizures, and 2-3% of healthy children may have epileptiform patterns on EEG (e.g.spikes or sharp waves) but never have a seizure. Conversely, normal EEGs do not rule out seizure.

The American Academy of Neurology recommends that all children with a first afebrile seizure undergo EEG [Hirtz: 2000], but others argue that this approach is too costly.

Imaging is often performed as part of the seizure workup unless there is a clear clinical diagnosis of a benign or genetic etiology (e.g. absence epilepsy or benign Rolandic epilepsy). [Berg: 2000] [Gaillard: 2009] Findings that are likely to increase the yield of an imaging study include: [Sharma: 2003]
  • Seizure with focal onset
  • Seizures in a newborn or young infant
  • Status epilepticus at any age
  • Focal abnormality on EEG
In children with new onset seizures that had these localizing features, approximately 50% of imaging studies were reported to be abnormal. [Gaillard: 2009]

Brain MRI is preferred over a head CT when looking for cause of seizure or epilepsy. Exceptions are if the child is too unstable to undergo MRI or the sedation it would require. When a particular etiology for seizures is suspected, e.g., prenatal stroke, an MRI is useful to confirm the diagnosis and rule out other possibilities such as a developmental brain malformation, e.g., schizencephaly, or a new condition such as an abscess or tumor.

Genetic Testing

Referral to a geneticist may be indicated if there is a genetic condition such as tuberous sclerosis or a metabolic condition causing seizures. Some epilepsy syndromes are known to be genetic and specific testing is available. Currently, diagnostic testing is available for 16 major epilepsy syndromes. A number of others are diagnosed clinically. See Genetic epilepsy syndromes diagnostic testing. Genetic testing is generally directed by neurology and/or genetics with genetic counseling available for the family.

Subspecialist Collaborations and Other Resources

Pediatric Neurology (see Services below for relevant providers)

Depending on the comfort of the Medical Home clinician, a visit to pediatric neurology to confirm the diagnosis and for further evaluation may be helpful. Depending on the seizure type, the spectrum of involvement with neurology may range from a one-time visit to concurrent care.

Pediatric Genetics (see Services below for relevant providers)

A consult with genetics may be helpful if a genetic or metabolic basis for the seizures is being considered.

Resources

Information & Support

For Professionals

Epilepsy guidelines (NICE)
Guidance documents for the diagnosis and managment of epilepsy in children from the National Institute for Health and Clinical Excellence (National Health Service, UK).

For Parents and Patients

Support

Epilepsy & My Child
Sponsored by the Epilepsy Foundation, this site is for parents to help them learn about epilepsy, talk with other parents, deal with the diagnosis, and get connected to local and national resources.

General

Epilepsy (MedlinePlus)
Offers numerous links to patient/consumer information about epilepsy; from the National Library of Medicine.

Epilepsy Foundation
The Epilepsy Foundation, a national voluntary organization, provides: information about epilepsy; programs to improve epilepsy treatment; materials to assist in helping people with epilepsy find jobs; activities in schools to educate the public; activities to educate policy makers; funds for research; and news about conferences and other items of interest.

Seizures, convulsions, and epilepsy (healthychildren.org)
General information about convulsions, seizures, and epilepsy from Healthychildren.org.

Epilepsy (ninds.nih.gov)
Detailed information about epilepsy and treatment from the NIH.

Practice Guidelines

Hirtz D, Ashwal S, Berg A, Bettis D, Camfield C, Camfield P, Crumrine P, Elterman R, Schneider S, Shinnar S.
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):616-23. PubMed abstract / Full Text
Recommendations are based on a three-tiered scheme of classification of evidence found in literature review.

Subcommittee on febrile seizures.
Neurodiagnostic evaluation of the child with a simple febrile seizure.
Pediatrics. 2011;127(2):389-94. PubMed abstract

Tools

Quality improvement in epilepsy-a toolkit for families (NICHQ)
This toolkit provides different resources and tips that can assist families with children with epilepsy to be part of quality improvement projects.

Seizure assessment tool(PDF Document 41 KB)
Questions to ask about signs and symptoms before, during and after a seizure from the American Academy of Neurology (2000).

Seizure diary(PDF Document 75 KB)
A convenient form for families to use to record seizure events, including an example.

Seizure history & physical form(PDF Document 88 KB)
Offers a format and reminders for performing and recording the physical exam for the child with seizures.

Services

Pediatric Genetics

See all Pediatric Genetics services providers (3) in our database.

Pediatric Neurology

See all Pediatric Neurology services providers (5) in our database.

Seizure Clinics

See all Seizure Clinics services providers (1) in our database.

For other services related to this condition, browse our Services categories or search our database.

Authors

Authors: Lynne M Kerr, MD, PhD - 6/2011
Denise Morita, MD - 6/2010
Content Last Updated: 6/2011

Page Bibliography

Ahmad S, Marsh ED.
Febrile status epilepticus: current state of clinical and basic research.
Semin Pediatr Neurol. 2010;17(3):150-4. PubMed abstract

Berg AT, Testa FM, Levy SR, Shinnar S.
Neuroimaging in children with newly diagnosed epilepsy: A community-based study.
Pediatrics. 2000;106(3):527-32. PubMed abstract

Engel, J. Jr.
ILAE classification of epilepsy syndromes. .
Epilepsy Res. 2006;70(suppl 1):5-10.

Fein JA, Lavelle JM, Clancy RR.
Using age-appropriate prolactin levels to diagnose children with seizures in the emergency department.
Acad Emerg Med. 1997;4(3):202-5. 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

Hirtz D, Ashwal S, Berg A, Bettis D, Camfield C, Camfield P, Crumrine P, Elterman R, Schneider S, Shinnar S.
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):616-23. PubMed abstract / Full Text
Recommendations are based on a three-tiered scheme of classification of evidence found in literature review.

Hughes JR.
The photoparoxysmal response: the probable cause of attacks during video games.
Clin EEG Neurosci. 2008;39(1):1-7. PubMed abstract

Neufeld MY, Treves TA, Chistik V, Korczyn AD.
Sequential serum creatine kinase determination differentiates vaso-vagal syncope from generalized tonic-clonic seizures.
Acta Neurol Scand. 1997;95(3):137-9. PubMed abstract

Noebels JL.
The biology of epilepsy genes.
Annu Rev Neurosci. 2003;26:599-625. PubMed abstract

Reid CA, Berkovic SF, Petrou S.
Mechanisms of human inherited epilepsies.
Prog Neurobiol. 2009;87(1):41-57. PubMed abstract

Scheffer IE, Harkin LA, Dibbens LM, et al.
Neonatal epilepsy syndromes and generalized eilepsy with febrile seizures plus (GEFS).
Epilepsia. 2005;46 (sup 10):41-47.
A description of the generalized epilepsy with febrile seizures plus syndrome.

Sharma S, Riviello JJ, Harper MB, Baskin MN.
The role of emergent neuroimaging in children with new-onset afebrile seizures.
Pediatrics. 2003;111(1):1-5. PubMed abstract

Tuchman R, Cuccaro M.
Epilepsy and Autism: Neurodevelopmental Perspective.
Curr Neurol Neurosci Rep. 2011;. PubMed abstract