Newly Diagnosed Unprovoked Epileptic Seizures: Presentation at Diagnosis in CAROLE Study.
Jallon P, Loiseau P, Loiseau J, and on behalf of Groupe CAROLE(Coordination Active du Reseau Observatoire Longitudinal de l'Epilepsie)
Epilepsia 2001;42:464-475
PURPOSE: We describe first unprovoked seizures and newly diagnosed epilepsies at initial presentation, with a special emphasis on epilepsy syndromes, in a large cohort recruited in the mid-1990s in France.
METHODS: The French Foundation for Research on Epilepsy set up a network to conduct a prospective study of patients with newly diagnosed unprovoked seizures. Information was provided by 243 child or adult neurologists. Four neurologists classified each case according to the International League Against Epilepsy (ILAE) criteria. First-seizure patients and patients with previously undiagnosed seizures were compared.
RESULTS: Between May 1, 1995, and June 30, 1996, 1,942 patients aged from 1 month to 95 years were identified: 926 (47.7%) with a single seizure and 1,016 (52.3%) with newly diagnosed epilepsy. All but 17 patients had EEGs. In the first-seizure and newly-diagnosed-epilepsy groups, neuroimaging studies were performed in 78.2 and 68.3% of patients, and medication prescribed in 54.1 and 89.6%, respectively. There were significant differences between the two groups with respect to age at onset and diagnosis, sex, etiology, several specific syndromes, as well as the type and presentation of initial seizure. In patients for whom the first seizure was convulsive, only sex, multiple seizures in a day or status epilepticus, and cryptogenic localization-related syndrome differed between the two groups.
CONCLUSIONS: Approximately half of patients who first came to attention for an unprovoked seizure already met epidemiologic criteria for epilepsy. There were significant differences between the types of patients with a first seizure and those with newly diagnosed epilepsy. One or several seizures at diagnosis did not influence the diagnostic assessment of the patients but had a strong influence on the initiation of treatment.
COMMENTARY
Ideally, identification of an epilepsy syndrome should help direct evaluation and treatment as well as provide some information about likely prognosis. The usefulness of the ILAE classification of the epilepsies 1 depends, in part, on whether it can be applied early in the course of the disorder in typical community practice.
There are many cross-sectional studies from tertiary referral centers that have examined the distribution of syndromes in what are often poorly characterized samples of patients. There are now a handful of studies that have prospectively identified patients at initial presentation, either with a first seizure or with newly diagnosed epilepsy (2+ seizures) 2, 3, 4, 5 on a population or community basis. The recent study by Jallon et al. represents the largest and most comprehensive of these efforts. The investigators were able to assign specific syndromes in 52% of first seizure patients and in 82% of epilepsy patients. Indispensable to the successful classification of such a high proportion of cases is the near universal access to health care in France and the relatively routine use of neurologists for diagnosing, evaluating and treating epilepsy: 99% of patients in the cohort had an EEG and ∼80% had neuroimaging. Such a result might not be attainable in countries where healthcare is not as widely available or where specialists do not routinely make the initial diagnosis.
Although someone with a single seizure technically does not (yet) meet the criteria for “epilepsy” [2 or more seizures 6], the authors correctly point out that this does not preclude assigning an individual to a specific syndrome if the electrographic and other criteria are met. This is key to fully understanding the natural progression of specific syndromes from the very outset. Because they have included both first seizures and epilepsy, they are in a unique position to study this issue and to provide a bridge between the first seizure and epilepsy literature. This topic is further explored in a separate article from this group 7.
The continued follow-up of this superbly assembled and elegantly described cohort will teach us much regarding the prognostic significance of syndromes as identified at onset in the population as well as about the stability of the classification system over time.
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