Seizures after aneurysmal subarachnoid hemorrhage: a systematic review of outcomes

The risk for early and late seizures after aneurysmal subarachnoid hemorrhage (aSAH), as well as the effect of antiepileptic drug (AED) prophylaxis and the influence of treatment modality, remain unclear. We conducted a systematic review of case series and randomized trials in the hope of furthering our understanding of the risk of seizures after aSAH and the effect of AED prophylaxis and surgical clipping or endovascular coiling on this important adverse outcome.

We performed a MEDLINE (1985-2011) search to identify randomized controlled trials and retrospective series of aSAH. Statistical analyses of categorical variables such as presentation and early and late seizures were carried out using χ(2) and Fisher exact tests.

We included 25 studies involving 7002 patients. The rate of early postoperative seizure was 2.3%. The rate of late postoperative seizure was 5.5%. The average time to late seizure was 7.45 months. Patients who experienced a late seizure were more likely to have MCA aneurysms, be Hunt/Hess grade III, and be repaired with microsurgical clipping than endovascular coiling.

Despite improved microsurgical techniques and antiepileptic drug prophylaxis, a significant proportion of patients undergoing aneurysm clipping still experience seizures. Seizures may occur years after aneurysm repair, and careful monitoring for late complications remains important. Furthermore, routine perioperative AED use does not seem to prevent seizures after SAH.