Late-onset seizures: a subclinical cerebrovascular disorder?

Comparing the risk of subsequent ischemic stroke and mortality in patients with epilepsy and patients with ischemic stroke

Patients with stroke or epilepsy face an elevated risk of subsequent strokes. This nationwide retrospective cohort study analyzed data from Taiwan's National Health Insurance Research Database (2012-2020) to compare the risk of future ischemic stroke or transient ischemic attack (IS/TIA) among patients with epilepsy and those with prior IS/TIA. Patients were categorized into four groups: epilepsy with subsequent IS/TIA (E/S), epilepsy without IS/TIA (E), IS/TIA without epilepsy (S), and neither condition (C). Incidence rates and adjusted hazard ratios for IS/TIA and mortality were assessed across groups, which included 5,606, 11,212, 11,212, and 56,060 patients. The corresponding incidence rates of subsequent IS/TIA were 0.67, 0.03, 0.41, and 0.01 per 100 person-years in the E/S, E, S, and C groups, respectively. Compared to the S group, the E/S group had a higher adjusted hazard ratio for IS/TIA (aHR 1.68, 95% CI: 1.30-2.17), whereas the E group had a significantly lower adjusted hazard ratio (aHR 0.08, 95% CI: 0.04-0.14). Mortality risk was significantly elevated in both the E/S group (aHR 1.90, 95% CI: 1.75-2.05) and the E group (aHR 1.21, 95% CI: 1.12-1.30), compared to the S group. These findings suggest that epilepsy increases the risk of subsequent IS/TIA, though to a lesser extent than prior IS/TIA. They underscore the importance of condition-specific prevention strategies and the need for further research into the mechanisms linking epilepsy and stroke risk.

Focused review: Clinico-neuropathological aspects of late onset epilepsies: Pathogenesis

The aim of the present study was to review the current knowledge on the neuropathological spectrum of late onset epilepsies. Several terms including 'neuropathology*' AND 'late onset epilepsy' (LOE) combined with distinct neuropathological diagnostic terms were used to search PubMed until November 15, 2023. We report on the relevance of definitional aspects of LOE with implications for the diagnostic spectrum of epilepsies. The neuropathological spectrum in patients with LOE is described and includes vascular lesions, low-grade neuroepithelial neoplasms and focal cortical dysplasias (FCD). Among the latter, the frequency of the FCD subtypes appears to differ between LOE patients and those with seizure onset at a younger age. Neurodegenerative neuropathological changes in the seizure foci of LOE patients require careful interdisciplinary interpretation with respect to the differential diagnosis of primary neurodegenerative changes or epilepsy-related changes. Innate and adaptive neuroinflammation represents an important cause of LOE with intriguing therapeutic options.

Histopathological characterization of cerebral small vessel disease in epilepsy patients with temporal lobe epilepsy submitted to surgery: A case-control study

BACKGROUND

Cerebrovascular disease (CVD) is a major contributor to epilepsy; however, patients with epilepsy also have a significantly increased risk of stroke. The way in which epilepsy contributes to the increased risk of stroke is still uncertain and is ill-characterized in neuropathological studies. A neuropathological characterization of cerebral small vessel disease (cSVD) in patients with chronic epilepsy was performed.

METHODS

Thirty-three patients with refractory epilepsy and hippocampal sclerosis (HS) submitted to epilepsy surgery from a reference center were selected between 2010 and 2020 and compared with 19 autopsy controls. Five randomly selected arterioles from each patient were analyzed using a previously validated scale for cSVD. The presence of CVD disease imaging markers in pre-surgical brain magnetic resonance imaging (MRI) was studied.

RESULTS

There were no differences in age (43.8 vs. 41.6 years; p = 0.547) or gender distribution (female gender 60.6% vs. male gender 52.6%; p = 0.575) between groups. Most CVD findings in brain MRI were mild. Patients had a mean time between the epilepsy onset and surgery of 26 ± 14.7 years and were medicated with a median number of three antiseizure medication (ASMs) [IQR 2-3]. Patients had higher median scores in arteriolosclerosis (3 vs. 1; p < 0.0001), microhemorrhages (4 vs. 1; p < 0.0001) and total score value (12 vs. 8.9; p = 0.031) in comparison with controls. No correlation was found between age, number of years until surgery, number of ASMs or cumulative defined daily dosage of ASM.

CONCLUSION

The present study provides evidence supporting the increased burden of cSVD in the neuropathological samples of patients with chronic epilepsy.

Detailed risks and characteristics of postepilepsy stroke in non-traumatic adult-onset epilepsy

BACKGROUND

Patients with epilepsy have an increased risk of stroke. However, the detailed risk and characteristics of postepilepsy stroke have not been investigated.

METHODS

This study utilized the National Health Insurance Research Database in Taiwan. We classified adult patients with newly diagnosed epilepsy from 2003 to 2016 as the epilepsy cohort. Patients in the nonepilepsy cohort were selected with propensity score matching at a case-control ratio of 1:5. The incidence, hazard ratio (HR), period-specific HR, recurrent HR in the Wei-Lin-Weissfeld model, stroke severity index, complications, and mortality of all stroke, ischemic stroke (IS) and hemorrhagic stroke events in the two cohorts were analyzed.

RESULTS

We enrolled 23,810 patients in the epilepsy cohort and 119,050 persons in the nonepilepsy cohort. The period-specific HRs of all stroke, IS and hemorrhagic stroke peaked immediately after epilepsy diagnosis and trended downward [Adjusted HRs of all stroke: 4.88 (3.88-6.14), 4.47 (3.50-5.70), 3.17 (2.62-3.84), 2.81 (2.27-3.48), 2.81 (2.36-3.34) and 2.33 (2.07-2.62) in 0-0.5, 0.5-1, 1-2, 2-3, 3-5 and ≥5 years after epilepsy diagnosis, respectively]. The recurrent stroke HRs in the epilepsy cohort were >1 from the first [3.06 (2.71-3.34)] to the fourth events [6.33 (1.08-37.03)]. IS events in the epilepsy cohort were associated with a younger onset age, a higher IS severity index, a higher rate of urinary tract infection, a lower in-hospital mortality, while 90-day stroke mortality was similar between the 2 cohorts.

CONCLUSION

Since the increased risk of stroke in epilepsy cohort peaked immediately after epilepsy diagnosis, early implementation of prevention strategies is considered.

Increased risk of stroke and myocardial infarction in patients with epilepsy: A systematic review of population-based cohort studies

OBJECTIVE

The objective of the study was to review the current epidemiological evidence about the relationship between epilepsy and increased risk of cardio- and cerebrovascular events.

METHODS

We systematically searched MEDLINE (from inception to 19th October 2018) to identify population-based cohort studies evaluating the risk of subsequent stroke or myocardial infarction (MI) in patients with epilepsy without history of prior cerebrovascular disease in comparison with subjects without epilepsy.

RESULTS

A total of 16,641 records were screened, and 6 studies were included. Data on the risk of subsequent stroke and MI were provided by five and two studies, respectively. The adjusted hazard ratios (_adjHRs) of subsequent ischemic stroke for patients with epilepsy ranged from 1.09 (95% confidence interval (CI): 1.00-1.19) to 2.85 (95% CI: 2.49-3.26). Two studies assessing the incidence of hemorrhagic stroke showed an increased risk in patients with epilepsy (_adjHR: 3.30; 95% CI: 2.46-4.43 and _adjHR: 2.27; 95% CI: 1.80-2.85). The _adjHRs of subsequent MI ranged between 1.09 (95% CI: 1.00 to 1.19) and 1.48 (95% CI: 1.31-1.67). Age, hypertension, MI, diabetes, hyperlipidemia, and arteriosclerosis were significantly associated with the increase in stroke risk. A gradient between the antiepileptic drug (AED) dose and risk of subsequent stroke was found. In comparison with carbamazepine (CBZ), oxcarbazepine (OXC) was associated with an increased risk of stroke and valproate (VPA) with a reduction in risk of stroke and MI, whereas no significant associations with vascular disease were found for phenobarbital (PB), lamotrigine (LMT), phenytoin (PHT), clonazepam (CLZ), and clobazam (CLB).

CONCLUSIONS

Patients with epilepsy are at higher risk of subsequent stroke and MI in comparison with subjects without epilepsy. Although individual AEDs may carry different risks of cardio- and cerebrovascular disease, the clinical relevance of the metabolic effects of the enzyme-inducing AEDs is still uncertain. This article is part of the Special Issue "Seizures & Stroke".

Seizures in the context of occult cerebrovascular disease

There is an important bidirectional relationship between seizures and cerebrovascular disease (CVD). Aside from poststroke epilepsy, Occult CVD is an important cause of late-onset seizures (LOS) and late-onset epilepsy (LOE). Late-onset seizures/LOE are associated with a threefold increased risk of subsequent clinical stroke. This relationship exists not only in later life, but with 'late-onset' seizures or epilepsy occurring from the fourth decade of life onwards. There is increasing evidence for the importance of hypertension and cerebral small vessel disease (SVD) in epileptogenesis, but there is a considerable need for further work to elucidate underlying mechanisms. There may be a disproportionately increased risk of intracerebral hemorrhage (ICH) after LOS/LOE; this too requires further study. There is also a bidirectional relationship between LOS/LOE and cognitive impairment/dementia: it is likely that there are important interactions between vascular and neurodegenerative pathological processes mediating LOE, stroke, and dementia. There is a pressing need for better epidemiological and natural history data as well as elucidation of epileptogenic mechanisms, in order to progress our understanding and to better inform clinical practice.