50% of childhood epileptics 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). Failing that, Medilog continous monitoring.
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. Most should have an MRI, unless a a clear-cut diagnosis of benign Rolandic, juvenile absence, myoclonic epilepsy of infancy, juvenile myoclonic epilepsy can be made. In these diagnoses 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!
Children with epilepsy should be encouraged to partake in normal activities; need for additional supervision should be considered on an individual basis.
Full syndrome is infantile spasms, hypsarrhythmia on EEG and developmental regression. Described by William James West in ihis own son.
90% present before 1yr. Seizures usually associated with crying so often confused with colic. Clusters of myoclonic flexor spasms, usually of legs but possibly of head on torso. Salaam attack is flexion of head and legs plus adduction of arms into midline. Rarely extensor.
Often associated with brain abnormality eg lissencephaly, post-meningitis or congenital infection. It is quite common in Downs syndrome, where it is more responsive to treatment. 20% cryptogenic ie no significant history, normal neurological exam (and a better prognosis)!
Mechanism? CRH (neurotransmitter + stimulates ACTH) overactivity?
Hormonal treatment (ACTH or prednisolone) quicker to act (although still takes 2/52) than vigabatrin, some evidence to suggest better long term outcome where no underlying cause. Vigabatrin may be better for tuberosclerosis, but associated with visual field defects. High doses of all are recommended. Not yet clear if resolution of EEG findings important. Spasms settle by mid-childhood as neurodevelopmental delay evolves, most develop other epilepsy eg Lennox Gastaut. Treatment is often difficult, and most children do not have a good neurological outcome (with or without underlying brain disorder). Cochrane Rev. PMID: 18843624
Several focal epilepsies, besides the classical rolandic epilepsies, can be hereditary, such as nocturnal frontal epilepsy or familial temporal epilepsy. They usually have a good prognosis or are easily treatable.
Associated with febrile convulsions, hippocampal sclerosis.
Aggression, asymmetric dystonia
Early (PANAYIOTOPOULOS) or Late (GASTAUT)
See below.
Quite different from childhood absence! Less nice.
One or more of:
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 - perceived risk, attitude to medication, lack of positive test results. The risk of accidents due to a seizure is barely or not at all more frequent than in non-epileptic children, probably because seizures mainly occur during states of decreased vigilance (somnolence, sleep, arousal, meals) and much less during intense physical or mental activity.
"There is an old and unjustified prejudice that brain damage may result from seizures: this does not happen in the great majority, and usually only occurs in unpreventable and very special situations." (cf severe migraine, frequent syncope).
For generalized, use Valproate! Associated with PCOS so ?avoid in teenage girls, use lamotrigine.
Others:
For partial, use any of valproate, CBZ or lamotrigine.
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:
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
Neuronal death in status epilepticus is independent of hypoxia etc - ?cell glucopenia, apoptosis. Hence importance of stopping seizures even if cardiovascularly stable. Aim for burst suppression on EEG: step up from coma, but seizure suppressed.
STARS website for parents.
One third of children with febrile convulsion/seizure (FS) will experience further FS; age would appear to be the single, strongest, and most consistent risk factor. Most recurrences will occur during the first year after the initial FS and over 90% recur within two years. Other risks - family history of febrile seizures (but not epilepsy) in a first degree relative, children whose initial FS occurred with a relatively low fever, multiple initial seizures occurring during the same febrile episode. Surprisingly, status in an otherwise normal child does not appear to significantly increase the risk for further febrile seizures or the development of epilepsy.
Following a first FS, 2-4% of children will have an unprovoked ie afebrile seizure (4x risk in general population) and most of these children will subsequently develop epilepsy. Other risk factors - family history of epilepsy, complex features, and the presence of early onset neurodevelopmental abnormalities. Genetic basis common but multiple chromosomes, complex! Current opinion supports an association between prolonged FS and pre-existing lesions within the temporal lobe, otherwise no good link between FS and temporal lobe epilepsy.
No indication for EEG or anti-epileptic treatment in febrile convulsions - see SIGN 81.
15% of status epilepticus with fever have meningitis (observational study) - although low rate of LP so underestimate? Fear of LP due to RICP from fit and/or meningitis, so do CT first if in ICU or abnormal neurology else as soon as no contraindication. Treat empirically for meningitis (+/- herpes encephalitis, although risk unknown) with antibiotics and steroids. Chin RFM, Arch Dis Child 2005;90:66-9.(Ed by Kneen)
Risk of dying slightly raised for 2yr after febrile seizure but only for complex ie more than 15min duration or recurrent within 24hr (RR 1.99, but absolute risk v low).(Denmark, Lancet 08;372)
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