Effects of Hemosiderosis on Epilepsy Following Subarachnoid Hemorrhage

Epilepsy after aneurysmal subarachnoid hemorrhage (post-SAH epilepsy) is a critical complication that influences clinical and social prognoses. However, the underlying mechanisms remain unclear. We investigated the relationship between hemosiderosis and the incidence of post-SAH epilepsy. About 50 patients with aneurysmal SAH who were admitted to Sapporo Medical University and Oji General Hospital between April 2010 and June 2016 were enrolled in this retrospective study. Hemosiderosis detected by T2*-weighted magnetic resonance imaging(MRI) and the incidence of post-SAH epilepsy were retrospectively analyzed. Post-SAH epilepsy was defined as an unprovoked seizures occurring more than 1 week after the onset of SAH. Six patients (12%) developed post-SAH epilepsy. In all patients, hemosiderosis in the cortex or cerebral parenchyma was detected by T2*-weighted MRI. Statistical analyses revealed that hemosiderosis and the co-existence of intracerebral hemorrhage (ICH) related with post-SAH epilepsy (Fisher's exact test, univariate exact logistic regression analysis: P < 0.05). Post-SAH epilepsy was predicted by hemosiderosis and the co-existence of ICH. The present results suggest that hemosiderin is the principal cause of post-SAH epilepsy and may be a predictor of this critical complication.