Acute Encephalopathy with Biphasic Seizures and Late Reduced Diffusion following SARS-CoV-2 Infection-A Rare Case Report

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is a clinicoradiological syndrome first recognized during the influenza pandemic in Japanese population in the late twentieth century. 1 In this article, we presented a rare case report of AESD in a young child due to severe acute respiratory syndrome coronavirus 2 infection (SARS-CoV-2) who presented with febrile status epilepticus, persistent encephalopathy, and had recurrence of seizures on day 4 of illness with characteristic magnetic resonance imaging findings and a relatively fair outcome.

Refractory Status Epilepticus Associated With a Pathogenic Variant in TNFRSF13B

Febrile infection-related epilepsy syndrome (FIRES) is a rare epileptic syndrome characterized by new-onset refractory status epilepticus preceded by a febrile illness. Limited literature exists regarding the relationship between primary immunodeficiencies and immune-mediated epilepsy, and the relationship between new-onset refractory status epilepticus and common variable immunodeficiency (CVID) is not well-understood. We present a case of a 21-year-old female with a history of recurrent sinus infections, asthma, thrombocytopenia, atrioventricular nodal reentrant tachycardia, and neonatal seizures who presented with fever and new-onset status epilepticus. She was ultimately diagnosed with a heterozygous variant in TNFRSF13B c.311G>A (p.Cys104Tyr), which encodes for a tumor necrosis factor receptor implicated in CVID.

Spatial learning impairments and discoordination of entorhinal-hippocampal circuit coding following prolonged febrile seizures

How the development and function of neural circuits governing learning and memory are affected by insults in early life remains poorly understood. The goal of this study was to identify putative changes in cortico-hippocampal signaling mechanisms that could lead to learning and memory deficits in a clinically relevant developmental pathophysiological rodent model, Febrile status epilepticus (FSE). FSE in both pediatric cases and the experimental animal model, is associated with enduring physiological alterations of the hippocampal circuit and cognitive impairment. Here, we deconstruct hippocampal circuit throughput by inducing slow theta oscillations in rats under urethane anesthesia and isolating the dendritic compartments of CA1 and dentate gyrus subfields, their reception of medial and lateral entorhinal cortex inputs, and the efficacy of signal propagation to each somatic cell layer. We identify FSE-induced theta-gamma decoupling at cortical synaptic input pathways and altered signal phase coherence along the CA1 and dentate gyrus somatodendritic axes. Moreover, increased DG synaptic activity levels are predictive of poor cognitive outcomes. We propose that these alterations in cortico-hippocampal coordination interfere with the ability of hippocampal dendrites to receive, decode and propagate neocortical inputs. If this frequency-specific syntax is necessary for cortico-hippocampal coordination and spatial learning and memory, its loss could be a mechanism for FSE cognitive comorbidities.

Case report: Thyroid storm in a three-year-old girl presenting with febrile status epilepticus and hypoglycemia

Thyroid storm, though extremely rare in toddlers, requires prompt diagnosis and treatment because it can be fatal if left untreated. However, thyroid storm is not often considered in the differential diagnosis of a febrile convulsion due to its rarity in children. Herein, we report the case of a 3-year-old girl with thyroid storm who presented with febrile status epilepticus. Although the seizure was stopped by diazepam administration, her tachycardia and widened pulse pressure persisted, and severe hypoglycemia was observed. Based on the findings of thyromegaly, a history of excessive sweating and hyperactivity, and a family history of Graves' disease, she was eventually diagnosed with a thyroid storm. The patient was successfully treated with thiamazole, landiolol, hydrocortisone, and potassium iodide. Propranolol, a non-selective β-blocker, has been used to manage tachycardia during thyroid storm. However, a cardio-selective β1-blockers, landiolol hydrochloride, was used in our case to avoid worsening hypoglycemia. Febrile status epilepticus is one of the most common medical emergencies in childhood; it is necessary to rule out treatable underlying critical diseases such as septic meningitis and encephalitis. Thyroid storm should be considered in children presenting with prolonged febrile convulsion accompanied by findings that are not usually observed with febrile convulsions.

Human herpesvirus 6 DNA was not detected in a brain specimen from a patient with mesial temporal sclerosis after status epilepticus due to human herpesvirus 6 infection

We performed virological analysis of resected brain tissues from a patient with temporal lobe epilepsy associated with mesial temporal sclerosis after febrile status epilepticus caused by human herpesvirus 6 infection. The patient had febrile status epilepticus at 9 months of age associated with human herpesvirus 6 infection. Magnetic resonance imaging revealed reduced water diffusion in the right temporal lobe and hippocampus. Polymerase chain reaction analysis detected 1.6 × 10⁵ copies/μg of human herpesvirus 6 DNA in whole blood, but none in the cerebrospinal fluid. The patient developed temporal lobe epilepsy associated with mesial temporal sclerosis at 67 months of age, necessitating surgical treatment. Anterior temporal lobectomy was performed at 171 months of age. Real-time polymerase chain reaction analysis of resected brain tissues revealed no viral DNA. In our patient, human herpesvirus 6 infection triggered febrile status epilepticus, while direct evidence to prove contribution of HHV-6 to the development of MTS was not obtained.

Provoked seizures and status epilepticus in the pediatric population with COVID-19 disease

We are reporting 16 pediatric patients (ages 0–18‐years‐old) who presented to our urban hospital emergency room with seizures and coronavirus disease 2019 (COVID‐19) during the surge of the Omicron variant. There was an increased number of pediatric patients with seizures and COVID‐19 during this period as compared to prior COVID‐19 surges. The 16 patients ranged in age from 3 months to 12 years of age. Five of the 16 patients (31%) had a prior history of epilepsy. Eight patients (50%) presented in status epilepticus, and in six patients (38%) the seizures appeared to have focal features. Fourteen patients (88%) presented with a complex provoked seizure defined as exhibiting either focality, seizure >5 min in length, or more than one seizure in 24 h. We suggest that in the pediatric population, when compared to prior variants of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), the Omicron variant is more likely to be associated with neurologic symptoms, including complex provoked seizures.

Non-convulsive febrile status epilepticus mimicking a postictal state after a febrile seizure: an ictal electroclinical and evolutive study

Febrile status epilepticus evolves from a febrile seizure (FS) in 5% of cases. Its prompt recognition is challenging, especially when motor manifestations are absent or subtle. We describe the ictal electroclinical features of non-convulsive febrile status epilepticus (NCFSE) following an apparently concluded FS, initially misinterpreted as postictal obtundation and in some way mimicking the described "non-epileptic twilight state". We present an electroclinical study of 18 children, collected in our unit, who presented with NCFSE after an apparently resolved FS, longitudinally followed for one year to seven years and nine months (mean: four years and three months). The age at first NCFSE ranged between one year and two months and five years and eight months (mean: two years and six months). Patients were examined after spontaneous or rectal diazepam-induced resolution of a FS, while showing persisting impairment of awareness. A lack of responsiveness to painful stimulation, abnormal posturing and aphasia were present in all cases, variably associated with perioral cyanosis, hypersalivation, automatisms, gaze deviation and other lateralizing signs; eyes were open. The EEG recording started 20 to 140 minutes after the apparent resolution of the FS and was invariably characterized by delta or theta-delta pseudorhythmic activity, mainly involving the fronto-temporal regions, with hemispheric predominance in two thirds of the cases. The electroclinical condition, lasting 25 to 210 minutes, quickly recovered after intravenous diazepam. Follow-up revealed normal neurodevelopment and EEG in almost all patients (learning disability emerged in three). In five subjects, NCSE relapsed (twice in two). None presented afebrile seizures. Our series highlights the electroclinical features of focal NCFSE. Distinctive elements are a lack of reactivity, cyanosis, lateralizing clinical and EEG signs, and resolution clearly tied to intravenous benzodiazepine administration.

Human Herpesviruses 6A and 6B in Brain Diseases: Association versus Causation

Human herpesvirus 6A (HHV-6A) and human herpesvirus 6B (HHV-6B), collectively termed HHV-6A/B, are neurotropic viruses that permanently infect most humans from an early age. Although most people infected with these viruses appear to suffer no ill effects, the viruses are a well-established cause of encephalitis in immunocompromised patients. In this review, we summarize the evidence that the viruses may also be one trigger for febrile seizures (including febrile status epilepticus) in immunocompetent infants and children, mesial temporal lobe epilepsy, multiple sclerosis (MS), and, possibly, Alzheimer's disease. We propose criteria for linking ubiquitous infectious agents capable of producing lifelong infection to any neurologic disease, and then we examine to what extent these criteria have been met for these viruses and these diseases.

Coronavirus Disease 2019 (COVID-19) Associated With Febrile Status Epilepticus in a Child

Infection associated with the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been named coronavirus disease 2019 (COVID-19). The emerging literature suggests that SARS-CoV-2 infection affects children of all age groups. COVID-19 as a cause of febrile seizures and status epilepticus is not yet reported in children. We report the case of a two-year-old child who presented to our pediatric intensive care unit with febrile status epilepticus and was diagnosed to have COVID-19 infection. The child recovered fully and was discharged home after three days.

Epilepsy-predictive magnetic resonance imaging changes following experimental febrile status epilepticus: Are they translatable to the clinic?

OBJECTIVE

A subset of children with febrile status epilepticus (FSE) are at risk for development of temporal lobe epilepsy later in life. We sought a noninvasive predictive marker of those at risk that can be identified soon after FSE, within a clinically realistic timeframe.

METHODS

Longitudinal T₂ -weighted magnetic resonance imaging (T₂ WI MRI) of rat pups at several time points after experimental FSE (eFSE) was performed on a high-field scanner followed by long-term continuous electroencephalography. In parallel, T₂ WI MRI scans were performed on a 3.0-T clinical scanner. Finally, chronic T₂ WI MRI signal changes were examined in rats that experienced eFSE and were imaged months later in adulthood.

RESULTS

Epilepsy-predicting T₂ changes, previously observed at 2 hours after eFSE, persisted for at least 6 hours, enabling translation to the clinic. Repeated scans, creating MRI trajectories of T₂ relaxation times following eFSE, provided improved prediction of epileptogenesis compared with a single MRI scan. Predictive signal changes centered on limbic structures, such as the basolateral and medial amygdala. T₂ WI MRI changes, originally described on high-field scanners, can also be measured on clinical MRI scanners. Chronically elevated T₂ relaxation times in hippocampus were observed months after eFSE in rats, as noted for post-FSE changes in children.

SIGNIFICANCE

Early T₂ WI MRI changes after eFSE provide a strong predictive measure of epileptogenesis following eFSE, on both high-field and clinical MRI scanners. Importantly, the extension of the acute signal changes to at least 6 hours after the FSE enables its inclusion in clinical studies. Chronic elevations of T₂ relaxation times within the hippocampal formation and related structures are common to human and rodent FSE, suggesting that similar processes are involved across species.

Children infected by human herpesvirus 6B with febrile seizures are more likely to develop febrile status epilepticus: A case-control study in a referral hospital in Zambia

BACKGROUND

Human herpesvirus 6B (HHV-6B) is the causative agent of Roseola infantum, and has also been suggested to play a role in the pathogenesis of febrile seizures in young children, a percentage of whom go on to develop febrile status epilepticus (FSE), but the existing data is conflicting and inconclusive. HHV-6A is a distinct species, rarely detected in most parts of the world, but prior studies suggest a higher prevalence in febrile African children. We describe a case-control study comparing the frequency of HHV-6A and/or HHV-6B infections in children with febrile seizures (including FSE) and a control group of febrile children without seizures.

METHODS

We recruited children aged 6 to 60 months admitted with a febrile illness with (cases) or without (controls) seizures presenting within 48 hours of commencement of fever. Three milliliters of whole blood was centrifuged and plasma stored at -80°C for pooled screening for HHV-6B and HHV-6A by Taqman real-time polymerase chain reaction.

RESULTS

102 cases and 95 controls were recruited. The prevalence of HHV-6B DNA detection did not differ significantly between cases (5.8% (6/102)) and controls (10.5% (10/95)) but HHV-6B infection was associated with FSE (OR, 15; 95% CI, [1.99-120]; P= 0.009). HHV-6A was not detected.

CONCLUSION

Prevalence of HHV-6B was similar among cases and controls. Within the FS group, HHV-6B infection was associated with FSE, suggesting HHV-6B infections could play a role in the pathogenesis of FSE.

Febrile seizures: an overview

Background

Febrile seizures are the most common neurologic disorder in childhood. Physicians should be familiar with the proper evaluation and management of this common condition.

Objective

To provide an update on the current understanding, evaluation, and management of febrile seizures.

Methods

A PubMed search was completed in Clinical Queries using the key terms ‘febrile convulsions’ and ‘febrile seizures’. The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews.

Results

Febrile seizures, with a peak incidence between 12 and 18 months of age, likely result from a vulnerability of the developing central nervous system to the effects of fever, in combination with an underlying genetic predisposition and environmental factors. The majority of febrile seizures occur within 24 hours of the onset of the fever. Febrile seizures can be simple or complex. Clinical judgment based on variable presentations must direct the diagnostic studies which are usually not necessary in the majority of cases. A lumbar puncture should be considered in children younger than 12 months of age or with suspected meningitis. Children with complex febrile seizures are at risk of subsequent epilepsy. Approximately 30–40% of children with a febrile seizure will have a recurrence during early childhood. The prognosis is favorable as the condition is usually benign and self-limiting. Intervention to stop the seizure often is unnecessary.

Conclusion

Continuous preventative antiepileptic therapy for the prevention of recurrent febrile seizures is not recommended. The use of intermittent anticonvulsant therapy is not routinely indicated. Antipyretics have no role in the prevention of febrile seizures.

How Different Are the Patients With Bilateral Hippocampal Sclerosis From the Unilateral Ones Clinically?

PURPOSE

There is a lack of knowledge on consecutive patients with epilepsy associated with bilateral hippocampal sclerosis (BHS). We aimed to investigate the differentiating features of BHS in comparison with unilateral HS (UHS).

METHOD

We investigated our database for patients with epilepsy fulfilling the major magnetic resonance imaging criteria for BHS; namely, presence of bilateral atrophy and high signal changes on T2 and FLAIR series in the hippocampi. UHS patients seen in past 2 years were included as the control group. Clinical, EEG, and other laboratory findings, data on treatment response and epilepsy surgery were investigated from their files.

RESULTS

A total of 124 patients (31 with BHS and 93 with UHS; 49 right-sided and 44 left-sided) were included. We found that 16.1% of the BHS and 18.3% of the UHS groups were not drug-refractory. A binary logistic regression analysis performed with significant clinical features disclosed that history of febrile status epilepticus, mental retardation, and status epilepticus were statistically more common in BHS group. Moreover, diagnosis of psychosis established by an experienced psychiatrist and slowing of the EEG background activity were both found significantly more frequent in BHS. 66.67% of the operated BHS patients showed benefit from epilepsy surgery.

CONCLUSIONS

BHS is a heterogeneous group, showing significant differences such as increased frequencies of mental retardation, status epilepticus, febrile status epilepticus and psychosis, in comparison to UHS. In all, 16.1% of the BHS cases showed a benign course similar to the UHS group and some patients with drug-resistant epilepsy may show benefit from epilepsy surgery.

Transient restricted diffusion of corpus callosum and subcortical white matter following febrile status epilepticus

We describe the case of a 4½-year-old girl with prolonged febrile status followed by abnormal behavior and loss of speech. Interesting findings on diffusion-restricted imaging were noted. The clinicoradiologic possibilities are discussed.

Symptomatic neonatal seizures followed by febrile status epilepticus: the two-hit hypothesis for the subsequent development of epilepsy

Neonatal seizures have been associated with the later development of postneonatal epilepsy, mainly beginning within the first year of life. Mechanisms of epileptogenesis in the immature brain still need to be fully elucidated but a two-hit hypothesis, showing that an early insult heightens later susceptibility to seizure-induced brain damage, has been demonstrated in animal models. We describe 2 cases of preterm babies sustaining recurrent neonatal seizures in the context of a severe perinatal brain damage who presented with symptomatic epilepsy only after the occurrence of an episode of febrile status epilepticus. In the context of preexisting perinatal brain damage, febrile status epilepticus acted as a second hit for developing epilepsy, confirming animal evidence.

Origins of temporal lobe epilepsy: febrile seizures and febrile status epilepticus

Temporal lobe epilepsy (TLE) and hippocampal sclerosis (HS) commonly arise following early-life long seizures, and especially febrile status epilepticus (FSE). However, there are major gaps in our knowledge regarding the causal relationships of FSE, TLE, HS and cognitive disturbances that hamper diagnosis, biomarker development and prevention. The critical questions include: What is the true probability of developing TLE after FSE? Are there predictive markers for those at risk? A fundamental question is whether FSE is simply a marker of individuals who are destined to develop TLE, or if FSE contributes to the risk of developing TLE. If FSE does contribute to epileptogenesis, then does this happen only in the setting of a predisposed brain? These questions are addressed within this review, using information gleaned over the past two decades from clinical studies as well as animal models.