Epileptic seizures and outcome in different subtypes of subarachnoid haemorrhage - Results of a single-center retrospective analysis

Background: Symptomatic epileptic seizures are an important complication in subarachnoid haemorrhage (SAH) with a frequency of 0.9-25% with importance for patient outcome. The majority of previous studies investigated the incidence of symptomatic epileptic seizures after aneurysmatic SAH. Here we compared the seizure incidence and its impact on the outcome between non-aneurysmatic and aneurysmatic SAH.

Methods: We analysed retrospectively 109 consecutive patients with spontaneous, non-traumatic SAH. Patients were divided in three groups (perimesencephalic, non-aneurysmatic and aneurysmatic SAH). All patients received standard-of-care treatment. The occurrence of acute (0-7 days after SAH) and remote symptomatic epileptic seizures (7 days or more after SAH), severity of SAH as well as clinical outcome parameters (modified Rankin scale [mRS]) at discharge and the frequency of in-house complications were assessed. mRS scores were dichotomized in 0-3 vs. 4-6 to stratify for good versus bad outcome.

Results: Perimesencephalic SAH patients did not experience acute seizures whereas non-aneurysmatic and aneurysmatic SAH patients showed acute seizures with similar frequency (9% and 11%, p = 0.23). The frequency of remote symptomatic seizures was similar in all subgroups (12% vs. 9% vs. 7%, p = 0.72). Seizure occurrence was not predictive for a poor outcome (mRS >4; acute seizures: OR 0.35 [95%CI: 0.02-6.96], p = 0.49; remote seizures: OR 1.72 [95%CI: 0.14-20.1], p = 0.67).

Conclusions: Seizures are important neurologic complications of SAH of all etiologies. Nevertheless, acute as well as remote symptomatic seizures are unrelated to the short-term outcome. These results should be treated as hypothesis generating and require confirmation.