Late-onset seizures and epilepsy: Electroclinical features suggestive of autoimmune etiology

Autoimmune encephalitis-associated epilepsy

Autoimmune encephalitis (AE), defined by clinical criteria and its frequent association with neural autoantibodies, often manifests with seizures, which usually stop with immunotherapy. However, a subset of encephalitic conditions present with recurrent seizures that are resistant to immunotherapy. Three primary neurological constellations that fall within this subset are discussed in this Perspective: temporal lobe epilepsy with antibodies against glutamic acid decarboxylase, epilepsy in the context of high-risk paraneoplastic antibodies, and epilepsy following adequately treated surface antibody-mediated AE. These entities all share a common mechanism of structural injury and potentially epileptogenic focal neural loss, often induced by cytotoxic T cells. Recently, we have proposed conceptualizing these conditions under the term autoimmune encephalitis-associated epilepsy (AEAE). Here, we discuss the new concept of AEAE as an emerging field of study. We consider the clinical characteristics of patients who should be investigated for AEAE and highlight the need for judicious use of traditional epilepsy therapeutics alongside immunotherapeutic considerations that are of uncertain and incomplete efficacy for this group of disorders. Last, we discuss future efforts needed to diagnose individuals before structural epileptogenesis has superseded inflammation and to develop improved therapeutics that target the specific immunological or functional disturbances in this entity.

Late onset epilepsy findings in a developmental country, a report of first results

INTRODUCTION

Older patients with Late onset epilepsy (LOE) provide a special set of difficulties for both the treating doctors and the patients.

OBJECTIVES

To address the characteristics and treatment outcomes of LOE in a cohort of Egyptian population at a tertiary center and to assess factors affecting seizure freedom in this age group.

METHODS

From December 1, 1995, to November 30, 2020, we analysed all patients with newly diagnosed epilepsy above the age of 50 at Cairo University's neurology department. The term "seizure freedom" was used to refer to the absence of seizures or auras for at least 12 months. Patients were classified as either having achieved seizure freedom or not.

RESULTS

One hundred and twenty-one patients were included. The median follow-up time was 24 months. 69.4 % attain seizure freedom. 52.1 % of our patients had symptomatic epilepsy. Among this group, 31.4 % (n = 38) had epilepsy caused by cerebrovascular disease (ischemic or hemorrhagic). Patients with epileptogenic lesions in neuroimaging, and those who are receiving ≥ 2 ASMs had significantly higher probability of not achieving seizure freedom for 12 months compared to those with normal or non-epileptogenic lesions in neuroimaging and receiving ≤ 1 ASMs with significant trends a trend toward lower seizure freedom in both.

CONCLUSION

Patients with Late- onset epilepsy have an excellent chance of achieving seizure freedom, especially those controlled on 1 ASM and those with normal neuroimaging.

Distinguishing seizures in autoimmune limbic encephalitis from mesial temporal lobe epilepsy with hippocampal sclerosis: Clues of a temporal plus network

OBJECTIVE

Diagnosing autoimmune limbic encephalitis (ALE) in adults with new-onset seizures can be challenging, especially when seizures represent the predominant manifestation and MRI findings are not straightforward. By comparison with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS), this study aimed to identify ictal electro-clinical features that might help clinicians recognize ALE-related seizures.

METHODS

This retrospective, multi-centre study analysed the ictal semiology and EEG correlate of 116 video-EEG-captured seizures in 40 ALE patients and 45 ones recorded in 21 MTLE-HS subjects. The proportion of patients presenting each clinical feature on at least one occasion was compared between the study groups. Latent class analysis (LCA) was also performed.

RESULTS

Ictal features were overall more numerous in ALE than in MTLE-HS (33 vs 22), and LCA confirmed the intrinsic variability of ALE-related seizures. Hyperventilation served as a trigger only in ALE (4/40). Awareness impairment (p = 0.032), limb dystonic posturing (p = 0.009) and manual automatisms (p < 0.001) were significantly less common in ALE cases. Conversely, piloerection was observed only in ALE subjects, although it did not reach statistical significance (p = 0.289), as was the case for déjà-vu (p = 0.084), and sensory symptoms (p = 0.079). Regarding EEG, the type of ictal pattern differed significantly (p = 0.007).

SIGNIFICANCE

This study shows that, despite the wide overlap with MTLE-HS, some ictal electro-clinical features could help clinicians suspect the autoimmune origin of adult-onset seizures. Moreover, autoimmune limbic seizures apparently shared similarities with 'temporal plus' epilepsy, which could partly account for the poor surgical outcomes and provide an interesting conceptual framework for future research.

The hidden link between late-onset seizures and cerebral amyloid angiopathy: A case-control study

OBJECTIVE

Epileptic seizures occurring in late adulthood often remain of unknown origin. Sporadic cerebral amyloid angiopathy (CAA) is a cerebral small vessel disease characterized by intracerebral hemorrhage, microhemorrhage and superficial siderosis, occurring mostly in elderly. This observational case-control study aimed to assess the occurrence of CAA in patients experiencing their first seizure in late adulthood.

METHODS

We enrolled consecutive patients aged ≥55 years presenting with late-onset seizures (LOS) to the emergency departments or outpatient clinics of two Italian centers, from April 2021 to October 2022. Two age-matched control subjects with neurological symptoms other than epileptic seizure were recruited for each enrolled case. All participants underwent brain MRI (1.5 Tesla) including blood-sensitive sequences and were assessed for probable CAA diagnosis according to Boston criteria 2.0. Chi-squared test was performed to evaluate group differences. Univariate logistic regression analysis tested the association between clinical variables and CAA.

RESULTS

We included 65 patients with LOS (27 females; mean age 72.2 ± 8.9 years) and 130 controls (49 females; mean age 70.3 ± 8.9 years). Diagnosis of probable CAA was achieved in 10.8% (7/65) of LOS patients and 2.3% (3/130) controls, with a statistically significant difference (p = 0.011). The OR for CAA in the LOS group was 5.2 as compared to the control group (95% CI = 1.3-20.6, p = 0.02).

SIGNIFICANCE

The frequency of CAA is significatively higher in patients with LOS as compared to other neurological diseases, suggesting that a portion of LOS of unknown or vascular origin are associated with CAA.

PLAIN LANGUAGE SUMMARY

Late-onset seizures (LOS) are very frequent in the elderly and often have no clear cause. Cerebral amyloid angiopathy (CAA) is a condition where amyloid proteins build up in the blood vessels of the brain, causing them to become weak and prone to bleeding. In this study, we explored the occurrence of CAA in people with LOS. We found that people with LOS were more likely to have a diagnosis of CAA than controls (i.e., people with other neurological diseases).

Incident anti-LGI1 autoimmune encephalitis during dementia with Lewy bodies: when Occam razor is a double-edged sword

In Dementia with Lewy bodies (DLB), rapid cognitive decline and seizures seldom complicate the typical clinical course. Nevertheless, concurrent, treatable conditions may be responsible. We report a case of DLB with superimposed anti-LGI1 encephalitis, emphasizing the importance of thorough diagnostic reasoning beyond the simplest explanation amid distinct clinical cues.