Epilepsy and its mimickers in children referred to a dedicated first seizure clinic

Purpose: We evaluated the range of diagnoses in children referred to the first seizure clinic of a tertiary hospital. Methods: We retrospectively reviewed medical records of all children referred to our first seizure clinic - that combines consultation and a routine EEG recording - between 2008 and 2018 after experiencing one or more paroxysmal events, possibly seizures. The initial diagnosis, made after the first consultation, was compared with the diagnosis obtained after additional examinations and clinical follow-up of at least one year. Results: We included 938 children (56.8% boys) with a mean age at presentation of 6.7 ± 4.7 years. In total, 312 children (33.3%) eventually received a definite diagnosis of epilepsy. In 60.6% of those the diagnosis was made after the first consultation. Epileptic abnormalities were seen on first EEG recordings in 63.1% children with a final diagnosis of epilepsy. In only two children, an initial diagnosis of epilepsy was rejected after follow-up. Half of the children with epilepsy were diagnosed with an electroclinical epilepsy syndrome. Childhood epilepsy with centro-temporal spikes, childhood absence epilepsy, and juvenile myoclonic epilepsy were the most common syndromes. Epilepsy etiologies included, among others, structural lesions (21.5%) and presumed or established genetic abnormalities (37.5%). Children without epilepsy often had staring spells, reflex syncope, sleep related conditions, tics, migraine, and breath-holding spells. Epileptic EEG abnormalities were seen in 4.0% of those in whom the diagnosis of epilepsy was rejected. Conclusions: One third of all children referred to our first seizure clinic were diagnosed with epilepsy. Fast and reliably diagnosing epilepsy in children who present after one or more seizure-like events remains challenging due to the variety of seizure mimickers and the moderate diagnostic yield of routine EEG recordings. This study highlights the value of dedicated first seizure clinics in the diagnostic process.