Seizure characteristics and outcomes in patients with neurological conditions related to high-risk paraneoplastic antibodies

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 Last, we discuss future efforts needed to diagnose individuals before structural epileptogenesis has superseded inflammation and to develop improved therapeutics that target the specific immunological or functional disturbances in this entity.

Xeroderma pigmentosa associated with spindle cell carcinoma of lung: a case report

Introduction and importance

Xeroderma pigmentosum is a rare autosomal recessive genetic disorder characterized by defective nucleotide excision repair, leading to extreme sensitivity to ultraviolet radiation, skin pigmentation changes, and a heightened risk of malignancies. Neurological symptoms, such as seizures and cognitive decline, are observed in 20% of cases. While xeroderma pigmentosa is commonly associated with skin cancers, systemic malignancies like lung carcinoma are exceedingly rare.

Case presentation

A 22-year-old male with a history of xeroderma pigmentosa presented with a six-month history of non-productive cough, hemoptysis, intermittent fever, and episodic jerky movements in his upper limb. Examination revealed hypo- and hyperpigmented macules, cachexia, cervical lymphadenopathy, and diminished air entry in the left lung. Blood tests indicated leukocytosis, elevated ESR, and abnormal electrolyte levels. Imaging confirmed a left lower lobe lung mass, and biopsy revealed spindle cell carcinoma with p53 positivity on immunohistochemistry.

Clinical discussion

Spindle cell carcinoma is a rare and aggressive subtype of non-small-cell lung cancer, comprising 0.2-0.3% of pulmonary malignancies. Its association with XP is notable, as defective DNA repair mechanisms in xeroderma pigmentosa predispose patients to malignancies driven by p53 mutations. This case emphasizes the need for vigilance for systemic malignancies in XP patients.

Conclusion

This is the first reported case of xeroderma pigmentosa associated with spindle cell carcinoma of the lung and focal seizures. It underscores the importance of early recognition and comprehensive surveillance for rare malignancies in XP patients, given their elevated cancer risk. The patient opted for palliative care and was symptomatically managed.

Seizures Associated with Autoimmune Disorders - Current Treatment Approaches

Autoimmune-associated seizures and epilepsy are increasingly recognized in clinical practice and can arise in the setting of acute encephalitis but in some cases may present with chronic focal epilepsy. These conditions are usually resistant to antiseizure therapy but may respond definitively to timely immunotherapy. Early diagnosis and treatment are critical to minimize neural injury and optimize outcomes. Treatment is guided by consensus opinion because definitive trials are currently lacking. The initial management approach usually involves first-line agents such as corticosteroids, intravenous immunoglobulin (IVIg), or plasma exchange, with second-line agents like rituximab or cyclophosphamide. Maintenance therapy is considered to prevent relapses, which occur in up to 35% of patients. Relapse management requires careful differentiation from postencephalitic epilepsy, which in the absence of active inflammation does not respond to immunotherapy. This review discusses treatment strategies for autoimmune-associated seizure disorders, including acute symptomatic seizures and epilepsy. We discuss expected outcomes on the basis of the underlying pathogenesis including cases mediated by autoantibodies targeting specific neuronal surface/synaptic antigens, and intracellular epitopes, and for cases lacking defined biomarkers. Specific approaches are outlined for disorders such as anti-LGI1, anti-NMDAR, anti-GABA-BR, and anti-GAD65 encephalitides, emphasizing tailored immunotherapy based on pathophysiology and clinical context.

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.

Prognostic factors underlying the development of drug-resistant epilepsy in patients with autoimmune encephalitis: a retrospective cohort study

OBJECTIVE

The aim of our study was to analyze the characteristics of patients with autoimmune encephalitis (AE) to identify prognostic factors associated with the development of drug-resistant epilepsy (DRE).

METHODS

In this retrospective observational cohort study, we enrolled adult patients with AE between January 2016 and December 2022. The patients were categorized into two groups based on the presence or absence of DRE at the last follow-up. The predictors of the development of DRE were investigated using logistic regression analysis.

RESULTS

Among 121 AE patients, 75.2% (n = 91) experienced acute symptomatic seizures, and 29.8% (n = 36) developed DRE at the last follow-up. On multivariate regression analysis, the factors associated with DRE were antibody negativity (OR 3.628, 95% CI 1.092-12.050, p = 0.035), focal seizure (OR 6.431, 95% CI 1.838-22.508, p = 0.004), refractory status epilepticus (OR 8.802, 95% CI 2.445-31.689, p = 0.001), interictal epileptiform discharges on EEG (OR 6.773, 95% CI 2.206-20.790, p = 0.001), and T2/FLAIR hyperintensity in the limbic system (OR 3.286, 95% CI 1.060-10.183, p = 0.039).

CONCLUSIONS

In this study, the risk of developing DRE was mainly observed among AE patients who were negative for antibodies or had focal seizures, refractory status epilepticus, interictal epileptiform discharges on EEG, and T2/FLAIR hyperintensity in the limbic system.

Autoimmune-associated seizure disorders

With the discovery of an expanding number of neural autoantibodies, autoimmune etiologies of seizures have been increasingly recognized. Clinical phenotypes have been identified in association with specific underlying antibodies, allowing an earlier diagnosis. These phenotypes include faciobrachial dystonic seizures with LGI1 encephalitis, neuropsychiatric presentations associated with movement disorders and seizures in NMDA-receptor encephalitis, and chronic temporal lobe epilepsy in GAD65 neurologic autoimmunity. Prompt recognition of these disorders is important, as some of them are highly responsive to immunotherapy. The response to immunotherapy is highest in patients with encephalitis secondary to antibodies targeting cell surface synaptic antigens. However, the response is less effective in conditions involving antibodies binding intracellular antigens or in Rasmussen syndrome, which are predominantly mediated by cytotoxic T-cell processes that are associated with irreversible cellular destruction. Autoimmune encephalitides also may have a paraneoplastic etiology, further emphasizing the importance of recognizing these disorders. Finally, autoimmune processes and responses to novel immunotherapies have been reported in new-onset refractory status epilepticus (NORSE) and febrile infection-related epilepsy syndrome (FIRES), warranting their inclusion in any current review of autoimmune-associated seizure disorders.

Autoimmune-associated epilepsy - a challenging concept

The current International League Against Epilepsy (ILAE) definition and classification guidelines for the first time introduced the category of immune-mediated focal epilepsy in addition to structural, genetic, infectious, and metabolic aetiologies. Moreover, the ILAE Autoimmunity and Inflammation Taskforce recently provided a conceptual framework for the distinction between acute "provoked" seizures in the acute phase of autoimmune encephalitis from chronic "unprovoked" seizures due to autoimmune-associated epilepsy. The first category predominately applies to those autoimmune encephalitis patients with autoantibodies against cell surface neural antigens, in whom autoantibodies are assumed to exert a direct ictogenic effect without overt structural damage. These patients do not exhibit enduring predisposition to seizures after the "acute phase" encephalitis, and thus do not fulfil the definition of epilepsy. The second category applies to those autoimmune encephalitis patients with autoantibodies against intracellular neural antigens and Rasmussen's encephalitis, in whom T cells are assumed to cause epileptogenic effects through immune-inflammation and overt structural damage. These patients do exhibit enduring predisposition to seizures after the "acute phase" of encephalitis and thus fulfil the definition of epilepsy. AAE may result from both, ongoing brain autoimmunity and associated structural brain damage according to the current ILAE definition and classification guideline. We here discuss the difficulties of this concept and suggest an unbiased translationally validated and data-driven approach to predict in an individual encephalitis patient the propensity to develop (or not) AAE and the cognitive and behavioural outcome.

A not so incidental 'incidentaloma' - pediatric ganglioneuroma-associated cerebellar degeneration and super-refractory status epilepticus: case report and literature review

Paraneoplastic neurological disorders are rare in children, with paraneoplastic cerebellar degeneration (PCD) considered highly atypical. We describe a 13-year-old girl with progressive neurobehavioral regression, cerebellar ataxia, and intractable epilepsy presenting in super-refractory status epilepticus. After an extensive evaluation, her clinical picture was suggestive of probable autoimmune encephalitis (AE). Further diagnostic testing revealed a molecularly undefined neural-restricted autoantibody in both serum and CSF, raising suspicion over an adrenal mass previously considered incidental. Surgical resection led to a robust clinical improvement, and pathology revealed a benign ganglioneuroma. This report widens the spectrum of paraneoplastic manifestations of ganglioneuroma, reviews the diagnostic approach to antibody-negative pediatric AE, and raises important clinical considerations regarding benign and incidentally found tumors in the setting of a suspected paraneoplastic neurologic syndrome.