Bridging the Gap: Tailoring an Approach to Treatment in Febrile Infection-Related Epilepsy Syndrome

Molecular biomarkers of glial activation and injury in epilepsy

Increasing evidence from fluid biopsies suggests activation and injury of glial cells in epilepsy. The prevalence of clinical and subclinical seizures in neurodegenerative conditions such as Alzheimer's disease, frontotemporal dementia, and others merits review and comparison of the effects of seizures on glial markers in epilepsy and neurodegenerative diseases with concomitant seizures. Herein, we revisit preclinical and clinical reports of alterations in glial proteins in cerebrospinal fluid and blood associated with various types of epilepsy. We consider shared and distinct characteristics of changes in different age groups and sexes, in humans and animal models of epilepsy, and compare them with those reported in biofluids in neurodegenerative diseases. Our analysis indicates a significant overlap of glial response in these prevalent neurological conditions.

Favorable outcomes and FDG-PET changes following tocilizumab treatment for febrile infection-related epilepsy syndrome in a child

Febrile Infection-Related Epilepsy Syndrome (FIRES) is an infrequent yet severe form of epilepsy that rapidly evolves into status epilepticus following a febrile episode. Prompt diagnosis coupled with effective treatment strategies is critical for improving patient outcomes. Herein, we describe the case of an 11-year-old male with FIRES who was successfully treated with tocilizumab, resulting in no further seizures or residual disability. The patient initially did not respond to antiseizure medications and first-line immunomodulatory therapy. Characteristic EEG patterns and elevated interleukin 6 levels in the cerebrospinal fluid contributed to an early presumptive diagnosis of FIRES. Tocilizumab was administered on day 10 after the seizure onset, leading to seizure cessation within 24 h, with no subsequent episodes. Serial cranial MRI imaging studies demonstrated transient abnormalities that resolved over time. Notably, on day 9, the patient exhibited bilateral frontal lobe hypermetabolism on FDG-PET, with EEG showing global slow waves predominantly in the bilateral frontal regions. As seizure control was achieved and encephalopathy symptoms improved, a follow-up EEG on day 25 revealed persistent slow waves in the bilateral frontal regions, with FDG-PET hypermetabolism present only in the left frontal lobe. By day 88, both EEG and FDG-PET had returned to normal. These findings suggest tocilizumab may play a role in the management of FIRES, though further studies are required to substantiate its therapeutic efficacy. Additionally, early bilateral frontal FDG-PET hypermetabolism and EEG slow-wave activity, may serve as an early biomarker in FIRES patients. However, more research is necessary to establish its validity.

Interleukin-6 in epilepsy and its neuropsychiatric comorbidities: How to bridge the gap

There is growing evidence that interleukin (IL)-6 plays an important role in neurological and psychiatric disorders. This editorial comments on the study published in the recent issue of the World Journal of Psychiatry, which employed Mendelian randomization to identify a causal relationship between IL-6 receptor blockade and decreased epilepsy incidence. The purpose of this editorial is to highlight the dual effects of IL-6 in epilepsy and its related neuropsychiatric comorbidities. IL-6 plays a critical role in the facilitation of epileptogenesis and maintenance of epileptic seizures and is implicated in neuroinflammatory processes associated with epilepsy. Furthermore, IL-6 significantly influences mood regulation and cognitive dysfunction in patients with epilepsy, highlighting its involvement in neuropsychiatric comorbidities. In summary, IL-6 is not only a pivotal factor in the pathogenesis of epilepsy but also significantly contributes to the emergence of epilepsy-related neuropsychiatric complications. Future research should prioritize elucidating the specific mechanisms by which IL-6 operates across different subtypes, stages and neuropsychiatric comorbidities of epilepsy, with the aim of developing more precise and effective interventions. Furthermore, the potential of IL-6 as a biomarker for the early diagnosis and prognosis of epilepsy warrants further investigation.

Potential inflammatory mechanisms of the ketogenic diet against febrile infection-related epilepsy syndrome

Febrile infection-related epilepsy syndrome (FIRES) is a rare epilepsy syndrome with unclear pathogenesis, characterized by fever-induced, super-refractory status epilepticus and high mortality. Studies have shown that ketogenic diet (KD) is effective in controlling convulsions in FIRES, but its mechanisms are unclear. This paper intends to summarize the mechanisms by which KD may exert effects against FIRES. Clinical studies have shown that patients with FIRES have elevated levels of various inflammatory factors such as interleukin (IL)-6, IL-8, IL-10, and so on. KD may exert anti-FIRES effects through several potential inflammatory pathways, including nuclear factor -κB (NF-κB) and NLR family pyrin domain containing 3 (NLRP3). Furthermore, the Kyoto Encyclopedia of Genes and Genomes (KEGG) network suggested that KD may play an anti-inflammatory role through several pathways such as cellular senescence and neutrophil extracellular trap formation. These mechanisms need to be further investigated.

Successful Management of Febrile Infection-Related Epilepsy Syndrome Using Cytokine-Directed Therapy

Here we describe a pediatric patient with febrile infection-related epilepsy syndrome with a good functional and neurologic outcome after treatment with early and aggressive cytokine-directed immunomodulatory therapy and a seizure management strategy that intentionally avoided a barbiturate coma. A 5-year-old previously healthy male presented with staring, behavioral arrest, and encephalopathy evolving to super-refractory status epilepticus. He had had onset of fever 5 days prior. He was treated with early and aggressive immunomodulatory therapy targeted to his evolving cytokine profile. He was also treated with the ketogenic diet, antiseizure medications, and continuous anesthetic infusions. Pentobarbital was purposely avoided. Now, 2½ years later, he attends mainstream school, has attention-deficit hyperactivity disorder (ADHD), mild neurocognitive impairment, and well-controlled epilepsy. By using cytokine-directed immunotherapy and avoiding a barbiturate coma, we were able to successfully treat a pediatric patient with febrile infection-related epilepsy syndrome and achieve a good outcome.

NORSE/FIRES: how can we advance our understanding of this devastating condition?

Introduction

New onset refractory status epilepticus (NORSE) is a rare and devastating condition characterised by the sudden onset of refractory status epilepticus (RSE) without an identifiable acute or active structural, toxic, or metabolic cause in an individual without a pre-existing diagnosis of epilepsy. Febrile infection-related epilepsy syndrome (FIRES) is considered a subcategory of NORSE and presents following a febrile illness prior to seizure onset. NORSE/FIRES is associated with high morbidity and mortality in children and adults.

Methods and results

In this review we first briefly summarise the reported clinical, paraclinical, treatment and outcome data in the literature. We then report on existing knowledge of the underlying pathophysiology in relation to in vitro and in vivo pre-clinical seizure and epilepsy models of potential relevance to NORSE/FIRES.

Discussion

We highlight how pre-clinical models can enhance our understanding of FIRES/NORSE and propose future directions for research.

Second-line immunotherapy in new onset refractory status epilepticus

Several pieces of evidence suggest immune dysregulation could trigger the onset and modulate sequelae of new onset refractory status epilepticus (NORSE), including its subtype with prior fever known as febrile infection-related epilepsy syndrome (FIRES). Consensus-driven recommendations have been established to guide the initiation of first- and second-line immunotherapies in these patients. Here, we review the literature to date on second-line immunotherapy for NORSE/FIRES, presenting results from 28 case reports and series describing the use of anakinra, tocilizumab, or intrathecal dexamethasone in 75 patients with NORSE. Among them, 52 patients were managed with anakinra, 21 with tocilizumab, and eight with intrathecal dexamethasone. Most had elevated serum or cerebrospinal fluid cytokine levels at treatment initiation. Treatments were predominantly initiated during the acute phase of the disease (92%) and resulted, within the first 2 weeks, in seizure control for up to 73% of patients with anakinra, 70% with tocilizumab, and 50% with intrathecal dexamethasone. Cytokine levels decreased after treatment for most patients. Anakinra and intrathecal dexamethasone were mainly initiated in children with FIRES, whereas tocilizumab was more frequently prescribed for adults, with or without a prior febrile infection. There was no clear correlation between the response to treatment and the time to initiate the treatment. Most patients experienced long-term disability and drug-resistant post-NORSE epilepsy. Initiation of second-line immunotherapies during status epilepticus (SE) had no clear effect on the emergence of post-NORSE epilepsy or long-term functional outcomes. In a small number of cases, the initiation of anakinra or tocilizumab several years after SE onset resulted in a reduction of seizure frequency for 67% of patients. These data highlight the potential utility of anakinra, tocilizumab, and intrathecal dexamethasone in patients with NORSE. There continues to be interest in the utilization of early cytokine measurements to guide treatment selection and response. Prospective studies are necessary to understand the role of early immunomodulation and its associations with epilepsy and functional outcomes.

Case report: Febrile infection-related epilepsy syndrome in a 14-year-old girl with multiple organ failure and lethal outcome

We report a case of an otherwise healthy 14-year-old girl with febrile infection-related epilepsy syndrome (FIRES), multiple organ failure (MOF), and ultimately a lethal outcome. This is a rare case of FIRES with MOF and consecutive death. Only a few cases have been described in the literature. The adolescent girl was initially admitted to our pediatric emergency department with a first episode of generalized tonic-clonic seizures after a short history of fever a week before admission. Seizures progressed rapidly into refractory status epilepticus without any evidence of the underlying cause, and treatment subsequently had to be escalated to thiopental anesthesia. Since the initial diagnostics showed no promising leads, the rare syndrome of FIRES was suspected, representing a catastrophic epileptic encephalopathy linked to a prior benign febrile infection. Methylprednisolone, intravenous immunoglobulins, and a ketogenic diet were initiated. Respiratory, circulatory, kidney, and liver failure developed during treatment, requiring increasing intensive care. Multiple attempts to deescalate antiepileptic treatment resulted in recurrent status epilepticus. A cranial MRI on the 10th day of treatment revealed diffuse brain edema and no cerebral perfusion. The patient was declared dead on the 11th day of treatment. FIRES should be taken into account in previously healthy children with a new onset of difficult-to-treat seizures after a short febrile infection when no other cause is apparent. First-line treatment, besides seizure control, is the early initiation of immunomodulatory therapy and the start of a ketogenic diet. As treatment is difficult and MOF may develop, patients should be transferred to a specialized children's hospital providing full intensive care.

Severe, Refractory Seizures: New-Onset Refractory Status Epilepticus and Febrile Infection-Related Epilepsy Syndrome

NORSE (new-onset refractory status epilepticus) and FIRES (febrile infection-related epilepsy syndrome) represent presentations of new-onset status epilepticus without apparent underlying structural, metabolic, or toxic etiology. The cause of NORSE/FIRES remains cryptogenic in up to half of cases, and an abnormal response of the innate immune system has been implicated. Consensus guidelines recommend broad diagnostic investigation and empiric treatment with immunotherapy. NORSE/FIRES is associated with poor outcomes including cognitive impairment and epilepsy, but early recognition and treatment may be important for improving outcomes.

Febrile infection-related epilepsy syndrome in childhood: A clinical review and practical approach

Febrile infection-related epilepsy syndrome (FIRES) of unknown aetiology is an extremely rare but severe epilepsy syndrome. It is characterized by a nonspecific febrile infection a few days before the onset of super-refractory status epilepticus, followed by refractory epilepsy and high morbidity in previously healthy children and young adults. To date, FIRES is incurable and irreversible. The clinical course may depend more on time than on therapy, while the outcome may depend more on the clinical spectrum than on therapy. Based on a literature search, retrospective data analysis, and personal observations, this review aimed to explore the clinical spectrum and therapeutic options for FIRES to improve outcomes by optimized and more standardized diagnosis and therapy, including adapted immunotherapy and a less aggressive approach to manage seizures, as seizure-freeness is difficult to achieve and, therefore, not the primary goal for cryptogenic FIRES.