Syncope-like epileptic seizures in Panayiotopoulos syndrome.

Objective: To describe the clinical features of syncope-like epileptic seizures (SLES) and their frequency in Panayiotopoulos syndrome (PS).

Methods: This was a 6-year prospective study of all children aged 1-15 years referred for an EEG. PS was defined by the occurrence of at least one autonomic seizure (AS) in a neurodevelopmentally normal child and at least one EEG with focal spikes. SLES were defined as self-terminating events of sudden loss of postural tone and unresponsiveness, occurring either concurrently with other ictal autonomic symptoms and signs that characterize PS (AS + SLES) or on their own (pure SLES).

Results: PS was diagnosed in 33 of 394 consecutive children with at least one afebrile seizure (8.4%). SLES occurred at least once in 17 of 33 children (51.5%); 12 presented SLES in all their AS, and 5 had also AS without SLES. Overall, 53 of 74 AS manifested with SLES (71.6%); 25 were AS + SLES and 28 were pure SLES. The latter occurred in 7 children suddenly and without premonition or obvious triggers while standing, sitting, lying down, or asleep, did not resolve in the horizontal position, and were not associated with stiffening or any involuntary movements, even when longer than a few minutes. Concurrent autonomic symptoms during AS + SLES included emesis, incontinence, mydriasis, miosis, and cardiorespiratory abnormalities.

Conclusions: SLES is a common ictal manifestation of PS and should be considered in the differential diagnosis of suspected syncope, particularly when clinical signs are atypical for neurocardiogenic syncope and the EEG shows focal spikes.