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Epileptology of the first-seizure presentation

1998; Elsevier BV; Volume: 352; Issue: 9143 Linguagem: Inglês

10.1016/s0140-6736(98)00084-1

1474-547X

David Chadwick, David F. Smith,

Neuroscience and Neuropharmacology Research

Mark King and colleagues' report (Sept 26, p 1007)1King MA Newton MR Jackson GD et al.Epileptology of the first-seizure presentation: a clinical electroencephalographic and magnetic resonance imaging study of 300 consecutive patients.Lancet. 1998; 352: 1007-1011Summary Full Text Full Text PDF PubMed Scopus (480) Google Scholar helps to define the best way to investigate people presenting with seizures and epilepsy for the first time. To apply the results to guideline development, further information from these investigators would be helpful. It is perhaps surprising that the study population did not include a group of people for whom the diagnosis of seizures or epilepsy was uncertain since this is such a common clinical situation. This group might have been included in the unclassified group (159 patients), but the way that the data are presented suggests that these patients were clinically definite but unclassified on clinical grounds. No patients with possible or probable seizures were listed under those included. How was uncertainty dealt with? As neurologists treating adult patients, we are somewhat surprised by the value of the electroencephalogram (EEG) in classification of seizure disorders. Although King and colleagues clearly state that the EEG abnormalities were more common in children than in adults, they provide no further breakdown of the frequency of abnormalities and the added value of sleep-deprived records. We strongly suspect that EEG adds very little to the classification or diagnosis of seizure disorders after age 30 years, since from this time onwards all new epilepsies are likely to be partial. Furthermore, we wonder whether the conclusions about the value of an early EEG are valid. Was there any selection bias in the 156 patients who did have an EEG within 24 h? Was the diagnosis clinically more obvious than in those who waited longer for their EEG? The neuroimaging data are of interest. These data seem to show that computed tomography (CT) at diagnosis missed about 50% of tumours. King and colleagues use this finding to make a strong case for all new cases having magnetic resonance (MR) imaging. They say that the tumours were surgically treatable, but this is not the same as saying that they should be treated surgically at diagnosis. Most patients whose tumours present with epilepsy run a very benign course.2Smith DF Hutton JL Sandemann D et al.The prognosis of primary intracerebral tumours presenting with epilepsy: the outcome of medical and surgical management.J Neurol Neurosurg Psychiatry. 1991; 54: 915-920Crossref PubMed Scopus (85) Google Scholar The tumours that are not obvious on CT scan are likely to be the more indolent type of glioma. The risk and benefit of early tumour treatment in this group is far from proven. Since in the UK CT scans can be organised usually within 1–2 weeks, whereas MR scanning may take anything up to 6 months, there may still be arguments for CT scanning as a routine early investigation, with MR reserved for individuals whose epilepsy is not initially controlled by antiepileptic drug treatment. The take-home message seems to be that diagnosis within a specialist unit with high quality neurophysiological and neuroimaging support is optimum. The UK has few centres that combine readily available clinical expertise and the necessary investigational facilities.3Smith DF, Defalla BA, Chawick DW. The misdiagnosis of epilepsy and the management of refractory epilepsy in a specialist clinic Q J Med (in press).Google Scholar King and colleagues' report provides an important argument for an expansion of neurological services so as to meet a large clinical need in a common disorder. Epileptology of the first-seizure presentationAuthors' reply Full-Text PDF