Many people in the community have seizures. 1 in 20 children (5%) will have a seizure of some form during childhood. About 1 in 200 children (0.5%) have epilepsy, a neurological condition where children have a predisposition to recurrent, unprovoked seizures.
There are many different types of epilepsy, especially in infancy, childhood and adolescence. Epilepsy can be thought of in terms of either:
- the site of seizure origin in the brain (generalised or focal seizures), or
- the underlying cause
Genetic epilepsies (formerly called idiopathic or primary epilepsies) occur in an otherwise normal person and are due to a genetic predisposition to seizures. Some epilepsies are due to an underlying abnormality of the brain structure or chemistry (formerly called symptomatic or secondary epilepsies). Other epilepsies have no known cause.
Seizures occur when there is a momentary 'imbalance' within electrical and chemical circuits in the brain, such that groups of brain cells act in an excessive fashion. This may create a temporary disturbance in the way the brain controls awareness and responsiveness and may cause unusual sensations or abnormal movements and postures. What happens during a seizure reflects what parts of the brain are involved.
There are many different types of seizures, but the major distinction that doctors try to make is between focal seizures, where the seizure arises in one part of the brain (usually on one side of the brain) and generalised seizures, where epileptic activity begins all over the brain (on both sides of the brain) simultaneously.
Focal seizures occur when the seizure arises in a localised part of the brain, usually on one side. Focal seizures used to be called partial seizures. Consciousness may or may not be impaired. The manifestations of a focal seizure depend on the part of the brain involved with the abnormal brain cell activity. Focal seizures used to be classified according to whether there is impairment of consciousness or not.
Focal seizures without impaired consciousness
Formerly called simple partial seizures, these arise in parts of the brain not responsible for maintaining consciousness, typically the movement or sensory areas. Consciousness is NOT impaired and the effects of the seizure relate to the part of the brain involved. If the site of origin is the motor area of the brain, bodily movements may be abnormal (e.g. limp, stiff, jerking). If sensory areas of the brain are involved the person may report experiences such as tingling or numbness, changes to what they see, hear or smell, or very unusual feelings that may be hard to describe. Young children might have difficulty describing such sensations or may be frightened by these
Focal seizures with impaired consciousness
Formerly called complex partial seizures, these arise in parts of the brain responsible for maintaining awareness, responsiveness and memory, typically parts of the temporal and frontal lobes. Consciousness is lost and the person may appear dazed or unaware of their surroundings. Sometimes the person experiences a warning sensation or 'aura' before they lose awareness , essentially the simple partial phase of the seizure. Behaviour during a complex partial seizure relates to the site of origin and spread of the seizure. Often the person's actions are clumsy and they will not respond normally to questions and commands. Behaviour may be confused and they may exhibit automatic movements and behaviours e.g. picking at clothing, picking up objects, chewing and swallowing, trying to stand or run, appearing afraid and struggling with restraint. Colour change, wetting and vomiting can occur in complex partial seizures.
Following the seizure the person may remain confused for a prolonged period and may not be able to speak, see, or hear if these parts of the brain were involved. The person has no memory of what occurred during the complex partial phase of the seizure and often needs to sleep.
Focal seizures becoming bilaterally convulsive
Focal seizures may progress due to spread of epileptic activity over one or both sides of the brain. Formerly called secondarily generalised seizures, bilaterally convulsive seizures look like generalised tonic-clonic seizures.
The distinction between simple and complex partial seizures is often unclear and the terminology may be confusing. For these reasons those terms are falling out of favour and more descriptive terminology is used for focal seizures.
Generalised seizures occur when epileptic activity begins all over the brain simultaneously. Consciousness is always impaired in generalised seizures.
Tonic-clonic seizures produce sudden loss of consciousness, with the person commonly falling to the ground, followed by stiffening (tonic) and then rhythmic jerking (clonic) of the muscles. Shallow or 'jerky' breathing, bluish tinge of the skin and lips, drooling of saliva and often loss of bladder or bowel control generally occur. The seizures usually last a couple of minutes and normal breathing and consciousness then returns. The person is tired following the seizure and may be confused.
Absence seizures produce a brief cessation of activity and loss of consciousness, usually lasting 5-30 seconds. Often the momentary blank stare is accompanied by subtle eye blinking and mouthing or chewing movements. Awareness returns quickly and the person continues with the previous activity. Falling and jerking do not occur in typical absences.
Myoclonic seizures are sudden and brief muscle contractions that may occur singly, repeatedly or continuously. They may involve the whole body in a massive jerk or spasm, or may only involve individual limbs or muscle groups. If they involve the arms they may cause the person to spill what they were holding. If they involve the legs or body the person may fall.
Tonic seizures are characterised by generalised muscle stiffening, lasting 1-10 seconds. Associated features include brief cessation of breathing, colour change and drooling. Tonic seizures often occur during sleep. When tonic seizures occur suddenly with the child awake they may fall violently to the ground and injure themselves. Fortunately, tonic seizures are rare and usually only occur in severe forms of epilepsy.
Atonic seizures produce a sudden loss of muscle tone which, if brief, may only involve the head dropping forward ('head nods'), but may cause sudden collapse and falling ('drop attacks').
From these descriptions, it can be appreciated that the exact type of seizure may be difficult for a witness to determine. For example, a seizure with stopping and staring could be a complex partial (focal) seizure or an absence (generalised) seizure. A convulsive seizure may be a generalised tonic-clonic seizure or focal seizure which became bilaterally convulsive. A sudden fall to the ground ('drop attack') can occur with myoclonic, tonic or atonic seizures or a focal seizure involving the movement areas. Determination of the exact type of seizure is important and is obtained from patient and observer descriptions, home video recordings, EEG testing and sometimes video EEG monitoring.
It is also important to remember that many episodic behaviours and disorders in children can mimic epilepsy, including breath holding spells, sleep movements, day dreaming, fainting, migraine, heart and gastrointestinal problems, and psychological problems.
Clinical assessment of seizures
The most important aspect of the evaluation of a child or adolescent with a suspected seizure disorder is the clinical assessment by a specialist paediatrician or child neurologist. This clinical assessment typically involves obtaining a detailed description of the child's episodes, medical history, development, learning and behaviour. Crucial outcomes of the assessment are to determine:
- if a child's episodes of altered behaviour, movement, consciousness etc. are epileptic or non-epileptic in origin
- the type of epileptic seizures that a child is having, most importantly whether the seizures are focal or generalised
- the type of epilepsy that a child has and its underlying cause (genetic, brain abnormality or unknown)
- any associated medical, physical, learning, behavioural and psychosocial problems that may accompany seizures in a child with epilepsy
Paediatricians are often the most accessible and experienced child health specialists when it comes to assessing a child with a suspected seizure disorder. The Neurology Department provides a consultative service to general practitioners and paediatricians for children with uncertain, poorly characterised or uncontrolled epilepsy.
Special tests are performed in many children with epilepsy. The need for tests is determined following the detailed clinical assessment by a paediatric specialist experienced in seizure disorders.
Tests are generally performed to:
- confirm a clinical suspicion,
- determine the type of seizure or epilepsy,
- determine the underlying cause of a child's epilepsy,
- assess the severity or monitor treatment of a child's epilepsy,
- assess associated medical or psychological problems,
- or determine the most appropriate treatment of a child's condition.
Tests are not performed to determine if a child has epilepsy or not. This is a clinical judgement made by a specialist.
Children who present to their doctor or an emergency department with a first major seizure will usually have a blood test to check the sugar, calcium, magnesium and salt levels, as abnormalities of body chemistry can lead to seizures.
In a child with epileptic seizures, a recording of brainwave activity (
EEG) and a picture of the brain (
MRI) may be obtained, where necessary. In special circumstances, some children with seizures may have an examination of the spinal fluid (lumbar puncture), metabolic testing of the blood or urine, or genetic tests. Children with uncontrolled epilepsy sometimes undergo detailed EEG (
video EEG monitoring) and more specialised imaging studies (
SPECT and/or PET), to accurately localise the source and determine the cause of their seizures, with a view to specialised treatments.
Children with seizures do not always need treatment. In many instances, explanation and reassurance by the doctor and advice about safety precautions and first aid management for possible future seizures is all that is required. Many children with epilepsy have only a single seizure and do not require medication.
For children with recurrent seizures, the decision to prescribe medication depends on the type of epilepsy and seizure, the age of the child, the presence of associated developmental and behavioural problems, and the attitudes and lifestyle of the child and family. Medical treatment usually means prescription of antiepileptic medication to prevent further seizures, but occasionally medication is prescribed to treat seizures only when they occur.
General treatment options for children with epilepsy include:
For children with uncontrolled epilepsy, that is epilepsy in which seizures are not adequately controlled by medication, other treatments are available, including:
A national umbrella body of state-based epilepsy organisations including EFV
Epilepsy resource centre Hospital for Sick Kids, Toronto
A comprehensive educational resource with descriptions of many distinct epilepsy syndromes
Information about sudden unexpected death in epilepsy (SUDEP)