New Risk Factors in Poststroke Epilepsy

Abstract

The overall aim of the present research was to identify new risk factors for poststroke epilepsy (PSE). Specifically, we wanted to assess the impact of having a first-degree relative with epilepsy on PSE risk (Paper I), and to investigate if endovascular treatment (EVT) affects PSE risk and possible factors that modify PSE risk in EVT (Paper II and IV). Additionally, we explored if blood-brain injury markers can assess stroke severity and assist in predicting PSE or in identifying individuals of high risk of epilepsy (Paper II and III).

Family history influences the risk of epilepsy in young persons, but such association in adults is less clear. Investigations of how family history impacts PSE risk in adults are rare. We conducted a nationwide register study to estimate the effect of having a first-degree relative with epilepsy on PSE risk. We found that family history increased the PSE risk both in the univariate analysis and after adjustment for stroke severity.

EVT is a new treatment, and the literature on the risk of subsequent PSE is conflicting. EVT is indicated in large vessel occlusion, in itself, a substantial risk factor for PSE. We first assessed PSE risk after EVT in a local cohort at the Sahlgrenska University Hospital. The included individuals had severe stroke, but despite this, the incidence of PSE after EVT was only 4.4%. Blood concentrations of biochemical brain injury markers were generally higher in individuals with PSE, but the low number of individuals prevented further analysis.

Thereafter, PSE risk after EVT was assessed in a nationwide register study comparing EVT to cases receiving other acute stroke treatments matched for pre-treatment stroke severity. The incidence of PSE was lower after EVT compared to treatment with intravenous thrombolysis (IVT) or no acute treatment. EVT was associated with a lower risk of PSE in univariate analysis and after adjustment for stroke severity. Stroke severity was a risk factor for PSE after EVT. IVT in combination with EVT and no radiological infarction on day one was associated with a decreased PSE risk.

To elaborate on the biochemical results from Paper II, we conducted an exploratory local cohort study of individuals with first-ever seizures. The PSE group had increased Neurofilament light (NfL) compared to individuals with single seizures and no previous stroke.

In summary, having a positive family history increased the risk of PSE, and EVT was associated with a decreased PSE risk in cases of severe stroke. Whether biochemical brain injury markers can aid in predicting and diagnosing PSE requires further study.