Panayiotopoulos syndrome and diffuse paroxysms as the first EEG manifestation at clinical onset: a study of nine patients.

To present a retrospective study of nine children with Panayiotopoulos syndrome associated with diffuse spikes and waves as the sole EEG manifestation at onset. Charts of children with typical clinical criteria of Panayiotopoulos syndrome, electroclinically followed between February 2000 and February 2012, were reviewed. Among 150 patients who met the electroclinical criteria of Panayiotopoulos syndrome, we identified nine children who presented with the typical clinical manifestations but who, on EEG, only had diffuse paroxysms at onset that continued along the course of the syndrome. In three, in addition to the diffuse paroxysms, focal spikes appeared later. From a clinical point of view, other features were otherwise unremarkable. Diffuse spike-and-wave discharges were observed in all patients when awake and during sleep (100%). Later, three children also had focal spikes during sleep, which were occipital in one, frontal in one, and temporo-occipital in the remaining patient. Spikes were activated by sleep in all three cases. During disease evolution, no particular electroclinical pattern was observed. Two patients who received clobazam and carbamazepine, respectively, did not respond well to the drugs and valproic acid was added with excellent seizure control. Outcome was good. We present evidence that patients with Panayiotopoulos syndrome may have diffuse discharges at onset as the sole EEG manifestation, which last throughout the course of the syndrome. In some, focal paroxysms developed later. The course was benign. In our group of patients, clinical features and evolution were similar to those of typical cases of Panayiotopoulos syndrome.