Definition: At least 2 unprovoked (or reflex) seizures, occurring more than 24hrs apart; else one unprovoked (or reflex) seizure and probability of further seizures similar to that seen in those who have had 2 unprovoked seizures (ie at least 60%); or recognized epilepsy syndrome. Also part of the definition is that epilepsy is considered “resolved” if age dependent syndrome and past applicable age, or else those who have been seizure free for 10 years and off medication for 5 years. (ILAE 2014)
Note that “seizure” does not have any real medical meaning! Transient signs/symptoms due to excessive or synchronous neuronal activity in brain (ILAE 2017) – but implies you can tell whether caused by abnormal brain activity, which can be hard!
- NICE standard is that patient is seen within 2 weeks by a specialist! NICE guideline just says seen by doctor with training and expertise in epilepsy.
- First assessment should include description of event, age/timing of event, frequency of events.
- Physical examination of neurology, cardiac, mental state and development.
- Presence/absence of developmental, learning or schooling problems.
Despite increasing sophistication, interpreting EEG remains an inexact science! Irregular background activity overlaps with detectable abnormality. Plus, only really picks up activity at surface of brain, and can miss simple partial seizures (but not tonic-clonic generalised). Review in 2000 did not find much evidence base. Requires dialogue between referrer and neurophysiologist. Diagnosis remains principally clinical – eg more than 1 tonic-clonic seizure, or multiple absences! Incidence of epileptiform activity in asymptomatic individuals appears to be about 1%, of which a few percent will develop epilepsy over the subsequent years. Abnormal activity is certainly more likely if structural abnormality, but still many will be and remain asymptomatic.
50% of children with epilepsy have normal EEGs – so not a particularly useful test! Not only that, but in studies, at least 20% of “epileptics” were ultimately given a non-epileptic diagnosis! So request EEG with caution; should be used for confirming clinical opinion, or to guide treatment, not where symptoms are vague. Hence a firm diagnosis of epilepsy and then decisions about treatment may take some time; difficult for families to understand, but it is quite safe to be cautious esp considering the implications of a mistaken diagnosis.
If EEG is negative, then proceed to a sleep EEG (where child is woken by parents at 3am, kept awake then brought to department and allowed to fall asleep during monitoring). This has 80% sensitivity. Failing that, Medilog or Video with continous monitoring. This is good for distinguishing non-epileptic tonic-clonic seizures, but does not rule out co-existing epilepsy.
- status in PICU patients, or non-convulsive status.
- where children too young to describe their symptoms.
- absences – typical absence epilepsy have 3Hz spike and wave with hyperventilation. Highly specific, although absences can be seen in complex partial seizures, which would also be obvious on EEG.
- indicating underlying brain disease (abnormal background)
- specific syndromes
- cognitive impairments that may be seizure related
Beware – an EEG finding of partial epilepsy may not have a surgical lesion! Must be used in conjunction with MRI. A generalized epilepsy may have multiple foci, so if you are unlucky to capture just one you will be misled. Similarly, if secondary generalization occurs rapidly, its partial nature may be missed.
Not usually useful to do after multiple seizures, unless type or frequency changes significantly, in which case a new syndrome/prognosis may have developed.
“The brain is subject to maturation; there are multiple protecting and triggering factors, often unpredictable. Seizures may be rare and easy to treat for months and years, but may become more frequent and difficult to control later on. But in many children a precise syndromic diagnosis can be made, and a good final prognosis can be expected in most cases.”
All children with recurrent seizures should have an ECG with calculated QTc. Children under 2 with epilepsy or with recurrent focal seizures (other than CECTS) should have an elective MRI brain scan. In most other cases the course is predictable. A normal MRI does not rule out a small dysplastic lesion, equally the finding of a lesion does not mean that it is the cause of the epilepsy. However, at least you can exclude a tumour or malformation.
Focal/partial often have acquired or congenital lesions, often specific precipitating factors eg sleep, startle!
- Drug treatment (see below)
- Education – written, peer support
- Specialist epilepsy nurse review
- Emergency medication, if appropriate
- First aid advice
- Safety advice
- When/how to access health services
Should not be started after first tonic-clonic generalized seizure. Try not to start before EEG done as may mask features.
When to start? Complex – consider:
- risk of further seizures (about 30% after first seizure if EEG normal, over 50% after second) – time interval less than 6/12, seizure during sleep, and previous febrile convulsions increase risk. Status at presentation does NOT increase risk!
- natural history of the epilepsy (if known)
- safety issues and perceived risk
- mental health and psychosocial issues
- Risk of death
- attitude to medication, lack of positive test results, etc.
The risk of accidents due to a seizure is marginal, probably because seizures mainly occur during times of reduced activity (eg somnolence, sleep, meals) rather than during intense physical or mental activity. Risk assessment should be done and documented including bathing, showering, swimming. NICE only specifically mentions with reference to epilepsy and learning disability. SIGN states that normal activities should be encouraged, but supervision requirements should be individualized taking into account type of activity and seizure activity.
For generalized, use Valproate! Associated with PCOS so best to avoid in teenage girls, use lamotrigine.
- Benzodiazepines (BZP) good for myoclonus
- (Carbemazepine (CBZ) can exacerbate! esp childhood/juvenile absence, JME)
- Vigabatrin for infantile spasms – but ACTH and Pred better! Side effects common with all! (Lancet. 2004 Nov 13;364(9447):1773-8.)
- Ethosuximide for childhood absence.
For partial, use any of valproate, carbamazepine (CBZ) or lamotrigine.
- Topiramate for partial lesional epilepsies
- Sulthiame for idiopathic partial epilepsies
Carbamazepine and phenytoin may worsen childhood/juvenile absence epilepsy and juvenile myoclonic epilepsy! If 6 months therapy with 2 different but appropriate drugs does not control (at adequate doses), then refer to tertiary centre for re-think on diagnosis.
Routine drug level monitoring is not required. Warn teenage girls about risks of pregnancy.
Consider withdrawing treatment when seizure free for 2+ years. But treatment may also be aimed at reducing cognitive effects, not just seizures: evidence for this comes from surgically treated epilepsies where rapid cognitive-behavioural improvement can be seen; and the fact that behavioural problems are more common in the months leading up to the first fit before diagnosis. For example:
- Prolonged ictal/postictal cognitive deficits in partial epilepsies. These may last for days or weeks.
- Transient cognitive impairment (TCI) without recognisable clinical seizures – may be associated with EEG discharge.
- Epileptic syndromes with cognitive/behavioural manifestation as the main or only symptom eg acquired epileptic aphasia (Landau-Kleffner syndrome)
More efficient use of known drugs (doses, slow release preparations), side effects of drugs, and new therapeutic options (treatment of acute seizures with nasal or buccal midazolam (EPISTAT) by parents at home, or in schools) can make a big difference to families.
Temporal lobe epilepsies, most often due to mesial temporal sclerosis (and often refractory to medical therapy) can be treated surgically with excellent prognosis. An increasing number of intractable focal epilepsies can now be treated surgically.
Archives of Disease in Childhood 2005;90:5-10, T Deonna
SIGN guideline 81
Refer to tertiary if –
- child fails to respond to two AEDs appropriate to the epilepsy in adequate dosages over a period of 6 months (SIGN), or 3 over 12 months (NICE)
- children less than 2 years with epilepsy as defined
See also Living with Epilepsy