Abstracts

Rationale: Cavum septum pellucidum (CSP) usually closes between 6 months gestation to 2 months post-term. Non-closure of the septum pellucidum is considered a normal variant, with prevalence of 0.79 to 5.5%. CSP secondary to head trauma is well recognised and has a direct relationship to cerebral volume loss and poorer cognitive outcomes (1). There is very little published on CSP in epilepsy, other than case reports and small centre studies. We reviewed the incidence of CSP in patients admitted to our Epilepsy Monitoring Unit (EMU), relative to epilepsy classification and in particular the presence of convulsive seizures (ILAE 2017). Following findings from an initial review of patients over a two-year period, we extended our study to include four years.

Methods: We reviewed MRI neuroimaging on 453 patients admitted to the EMU at Beaumont Hospital, Ireland from 2016 to 2020. Epilepsy classification at discharge, alternate diagnoses (Non-epileptic attack disorder [NEAD] or other pathology [syncope, parasomnia or stereotyped behavioural events]), and inconclusive studies were recorded. Only patients with available MRI studies were included. Patients were then stratified into those with CSP on MRI.

Results: Of the 453 patients, patients studied had an age range of 16 to 87 years (mean, 41 years), with 59% being female. A diagnosis of epilepsy was established in 270 patients. NEAD was diagnosed in 122 patients, 20 had other pathology and 54 had inconclusive studies. _x000D_  _x000D_ In our epilepsy cohort, 43.7% had CSP vs. 27% in other groups. In those with both epilepsy and CSP, 76.2% had a documented history of bilateral tonic-clonic seizures.

Conclusions: In our study, individuals with epilepsy had higher rates of CSP compared to the general population  (43.7% vs. 0.7-5.5%). The majority of patients with epilepsy and CSP experienced generalised convulsions (76.2%). When we extended our study to include four years we yielded similarly significant results. This suggests that CSP is an anatomic marker of uncontrolled convulsive epilepsy. These findings should prompt greater awareness of CSP during initial patient evaluation and epilepsy classification, and may indicate need for earlier referral for video EEG monitoring in patients where there is diagnostic uncertainty.
_x000D_ Reference:
1.   Lee JK, Wu J, Bullen J, et al. Association of Cavum Septum Pellucidum and Cavum Vergae With Cognition, Mood, and Brain Volumes in Professional Fighters. JAMA Neurol. 2020;77(1):35–42. doi:10.1001/jamaneurol.2019.2861_x000D_
Funding: There was no funding received in support of this abstract.