EDITORIAL

'EPILEPSY'-A NEW DISEASE? TWO articles in this issue of the journal highlight a disorder which appears to be fast reaching epidemic proportions if we take as an indication the number of articles, books and conferences which are appearing on the subject of intractable childhood epilepsy.

Aicardi (pp. 429-440) points out that occasionally the problem can be due to non-compliant patients or to an incompetent physician. Certainly no situation can make the physician feel more incompetent than the child who appears to be locked into a continuous epileptic state, with tantalising brief bursts of normality which suggest that if we did better we would be able to hold the child in this improved state. When coupled with the niggling doubt that the medication may in some way be having a paradoxical effect, thus making the patient worse because it releases a different type of epilepsy, the physician's rest at night can never be wholly peaceful. One can take comfort from the theory that the fits and dementia are due to idiopathic, progressive, malignant epilepsy or epileptic encephalopathy and not to inadequate therapy. This then suggests that we are incapable of diagnosing one of the most serious neurological diseases in childhood.

The intractable epilepsies can be due to diffuse developmental abnormalities of the cerebral cortex, i.e. a cortical dysplasia as seen in tuberous sclerosis, Aicardi syndrome of Angelman syndrome. The idiopathic cases may be temporally but not necessarily causally related to such events as pertussis immunisation or viral infection. Treatment with immunoglobulin or steroids and abnormal immunological findings in some children has raised the possibility of some type of immune encephalopathy. We accept that auto-antibodies to acetylcholine receptors occur in patients with myasthenia gravis, but why should these be the only receptors to which antibodies form-why not GABA receptors? Would plasmapharesis help some intractable cases? Children known to have suffered extensive brain-damage, as in tetraplegic cerebral palsy, also very commonly suffer from epilepsy, but it is rarely intractable. The possibility of some as yet unidentified degenerative or metabolic disease is a not unattractive theory in view of the relatively recent discovery of Rett syndrome as an explanation for a previously inexplicable constellation of abnormal behaviour and fits.

Is the problem a new one, or were all these children previously locked away in long-term mental deficiency hospitals? That would seem unlikely, since many are normal children at the start of their epilepsy. Do we perform more EEG

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examinations and are we now more aware of electrical status? Were we in the past less aware of the subtle clinical manifestations of seizures, as we are now alerted about transient cognitive impairments? (See the annotation by Livingston, pp. 536-540.) We have recognised only recently that the acute autistic behaviour in West syndrome represents a non-convulsive disorder and that the obvious infantile spasm is possibly less important. Many still rate success as cessation of the spasm and not a return to alertness. Why do our neurology wards nowadays always seem to contain children with intractable epilepsy or refractory non- convulsive status?

We have known for a long time that tridione made major seizures worse and that phenytoin aggravated petit mal. Carbamazepine can make the EEG worse and may cause seizures. Diazepam used for treating tonic-clonic status epilepticus can make some epilepsies worse or precipitate status. Benzodiazepines combined with valproate can precipitate non-convulsive status, and phenytoin, especially at high dose, may produce very resistant convulsions. There seems to be a see-saw between various anticonvulsant drugs. The archipallium or old cerebral cortex appears to behave differently to the neocortex. The spike is the hallmark of epilepsy on the EEG and many of these children have continuous polyspikes and slow waves, yet when they have a clinical fit the spikes disappear and the EEG flattens, i. e. an electrodecremental seizure. Usually spikes require energy and brain metabolism increases, but in the few cases studied by PET scans the brain can be switched off and hypometabolic.

Could it be that the different actions of anticonvulsants, the different metabolic responses and the spike versus electrical flattening suggest that paroxysmal electrical firing in inhibitory circuits is just as important a form of ‘epilepsy’ as excitatory ones? Rather than increase further inhibition, should we be arousing the brain by using excitants such as glutamate agonists? With the advent of magnetic resonance scanning, near infra-red spectrophotometry, PET scanning of receptor sites as well as metabolism, better methods of looking at cerebral blood-flow , brain mapping and long-term ambulatory monitoring, the time has come for major expenditure on a few well-equipped scientific centres for the study of this ‘new’ disease.

KEITH BROWN

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