Reevaluation of risk factors for aneurysmal subarachnoid hemorrhage associated epilepsy

Symptomatic epilepsy is a common complication of aneurysmal subarachnoid hemorrhage (aSAH) associated with poor outcome. We sought to analyze the risk factors leading to post-SAH epilepsy.

All consecutive aSAH cases treated between 01/2003 and 06/2016 were retrospectively included. Post-aSAH period was followed up to 03/2020 for the occurrence of epilepsy. Demographic characteristics and previous medical history of the patients, parameters of initial severity, performed treatments, certain early and late complications of aSAH, as well as routine laboratory and vital parameter measurements were collected. Functional outcome was assessed at discharge and 6 months after aSAH using the modified Rankin scale (mRS).

During the post-aSAH follow-up (median: 8.93 months/patient), 85 of 948 individuals (9%) in the final analysis developed symptomatic epilepsy (median: 3.43 months). In the majority of cases, epilepsy was diagnosed >3 weeks after aSAH (n = 67, 78.8%) and in survivors with poor outcome at discharge (mRS = 4-5, 15.8% vs. 5.3%, p < 0.0001). Of over 150 analyzed potential risk factors, the following parameters were independently associated with the risk of symptomatic epilepsy after aSAH: thyroid dysfunction (aHR = 1.81, p = 0.029), need for decompressive craniectomy (aHR = 2.32, p = 0.011) and shunt placement (aHR = 1.94, p = 0.022), prolonged tachycardia (≥4 days, aHR = 2.06, p = 0.025), as well as anemia signs (mean red blood cell count <3.6 × 10¹² /L [aHR = 2.4, p = 0.015] and mean hematocrit <31% [aHR = 2.13, p = 0.044]) during first 2 weeks after aSAH.

Symptomatic epilepsy occurs predominantly in individuals with poor outcome at discharge and after the acute phase of aSAH. Knowledge of risk factors associated with aSAH-related epilepsy might help in early identification and treatment of compromised individuals, and therefore, help to improve their outcome.