Objective: To calculate the annual incidence rate of epilepsy, as well as the relative distribution of the different forms of epilepsy and epileptic syndromes in infants and children.
Patients and methods: All incident cases in infants and children aged less than 15 years living in Navarre (Spain) with newly diagnosed epilepsy (2002 to 2005) were prospectively registered. Epidemiological and clinical data and the results of complementary investigations were recorded. The criteria for epileptic seizures and epileptic syndromes of the International League Against Epilepsy (ILAE) and the ILAE guidelines for epidemiological studies were applied.
Results: One hundred ninety-nine patients were diagnosed with childhood epilepsy (22 infants, 66 young children, 54 school children and 49 adolescents). The annual incidence rate was 62.6 cases per 100,000 (95 % CI: 62.3-62.9). The incidence rate was highest during the first year of life (95.3 per 100,000) and gradually decreased until adolescence (48.7/100,000). Focal epilepsy was found in 55 %, generalized epilepsy in 42.9 %, and undetermined epilepsy in 2.1 %. In infants, the most prevalent epileptic syndromes were West syndrome (45.5 %), epilepsies associated with specific syndromes (27.5 %), and focal symptomatic epileptic syndromes (13.6 %). In early childhood, the main syndromes were focal symptomatic epilepsy (22.7 %), cryptogenic epilepsy (21.2 %), and Doose syndrome (13.6 %). In schoolchildren, the most frequent syndromes were focal benign epilepsies (27.8 %), cryptogenic epilepsy (18.5 %), and absence epilepsy (18.5 %). In adolescents, the most frequent syndromes were focal cryptogenic epilepsies (27.6 %) and benign epilepsies (18.4 %).
Conclusions: The annual incidence rate of epilepsy in infants and children in Navarre is similar the rates described for other western countries, with the highest incidence rate being found during the first year of life and gradually diminishing until adolescence. Published data concerning the relative frequency of epilepsy and epileptic syndromes are discordant. These discrepancies highlight the difficulty of establishing a syndromic diagnosis in this age group and the need to apply uniform criteria in order to obtain valid and comparable epidemiological data.