Hemiconvulsion-hemiplegia-epilepsy syndrome: current understandings

International consensus definitions for infection-triggered encephalopathy syndromes

AIM

To develop standardized diagnostic criteria for 'infection-triggered encephalopathy syndrome (ITES)' and five specific clinical syndromes of ITES.

METHOD

The draft definitions were based on existing criteria, standardized, and discussed by a panel of international experts using nominal group technique over 18 months to achieve consensus. All criteria use the same format: (1) presence of infection/fever; (2) clinical features including encephalopathy; (3) neuroradiological features on magnetic resonance imaging; (4) exclusion of other causes.

RESULTS

We first highlighted differences between ITES and infectious and autoimmune encephalitis, which is the most important differential diagnosis. Consensus was achieved to define five specific ITESs: acute encephalopathy with biphasic seizures and late reduced diffusion; acute necrotizing encephalopathy; mild encephalopathy with a reversible splenial lesion; acute fulminant cerebral oedema; and acute shock with encephalopathy and multiorgan failure. Two further conditions that are currently classified as epilepsy syndromes but have similar features to ITES, namely febrile infection-related epilepsy syndrome and hemiconvulsion-hemiplegia-epilepsy syndrome, are also discussed.

INTERPRETATION

The consensus definition is expected to improve awareness of this disease concept, provide diagnostic framework, and facilitate future international research and clinical trials.

Consensus Guideline on the Management of Epilepsy in Egypt: A National Delphi Consensus Study

OBJECTIVE

In epilepsy, early diagnosis, accurate determination of epilepsy type, proper selection of antiseizure medication, and monitoring are all essential. However, despite recent therapeutic advances and conceptual reconsiderations in the classification and management of epilepsy, serious gaps are still encountered in day-to-day practice in Egypt as well as several other resource-limited countries. Premature mortality, poor quality of life, socio-economic burden, cognitive problems, poor treatment outcomes, and comorbidities are major challenges that require urgent actions to be implemented at all levels. In recognition of this, a group of Egyptian epilepsy experts met through a series of consecutive meetings to specify the main concepts concerning the diagnosis and management of epilepsy, with the ultimate goal of establishing a nationwide Egyptian consensus.

METHODS

The consensus was developed through a modified Delphi methodology. A thorough review of the most recent relevant literature and international guidelines was performed to evaluate their applicability to the Egyptian situation. Afterward, several remote and live rounds were scheduled to reach a final agreement for all listed statements.

RESULTS

Of 278 statements reviewed in the first round, 256 achieved ≥80% agreement. Live discussion and refinement of the 22 statements that did not reach consensus during the first round took place, followed by final live voting then consensus was achieved for all remaining statements.

SIGNIFICANCE

With the implementation of these unified recommendations, we believe this will bring about substantial improvements in both the quality of care and treatment outcomes for persons with epilepsy in Egypt.

PLAIN LANGUAGE SUMMARY

This work represents the efforts of a group of medical experts to reach an agreement on the best medical practice related to people with epilepsy based on previously published recommendations while taking into consideration applicable options in resource-limited countries. The publication of this document is expected to minimize many malpractice issues and pave the way for better healthcare services on both individual and governmental levels.

Dyke-Davidoff-Masson syndrome-A rare cause of recurrent seizures in adulthood

It is important to consider DDMS as a differential diagnosis in any patient with early childhood onset of epilepsy. Early diagnosis and optimal management are key to reducing the disabling effect of DDMS.

CSF neopterin and quinolinic acid are biomarkers of neuroinflammation and neurotoxicity in FIRES and other infection-triggered encephalopathy syndromes

OBJECTIVE

Infection-triggered encephalopathy syndromes (ITES) are potentially devastating neuroinflammatory conditions. Although some ITES syndromes have recognisable MRI neuroimaging phenotypes, there are otherwise few biomarkers of disease. Early detection to enable immune modulatory treatments could improve outcomes.

METHODS

We measured CSF neopterin, quinolinic acid, kynurenine and kynurenine/tryptophan ratio using a liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) system. The CSF of 18 children with ITES were compared with acute encephalitis (n = 20), and three control groups, namely epilepsy (n = 20), status epilepticus (n = 18) and neurogenetic controls (n = 20).

RESULTS

The main ITES phenotypes in 18 patients were acute encephalopathy with biphasic seizures and late restricted diffusion (AESD, n = 4), febrile infection-related epilepsy syndrome (FIRES n = 4) and other ITES phenotypes. Influenza A was the most common infectious trigger (n = 5), and 50% of patients had a preceding notable neurodevelopmental or family history. CSF neopterin, quinolinic acid and kynurenine were elevated in ITES group compared to the three control groups (all p < 0.0002). The ROC (area under curve) for CSF neopterin (99.3%, CI 98.1-100) was significantly better than CSF pleocytosis (87.3% CI 76.4-98.2) (p = 0.028). Elevated CSF neopterin could discriminate ITES from other causes of seizures, status epilepticus and febrile status epilepticus (all p < 0.0002). The elevated CSF metabolites normalised during longitudinal testing in two patients with FIRES.

INTERPRETATION

CSF neopterin and quinolinic acid are neuroinflammatory and excitotoxic metabolites. This CSF metabolomic inflammatory panel can discriminate ITES from other causes of new onset seizures or status epilepticus, and rapid results (4 h) may facilitate early immune modulatory therapy.

Clinical and radiological description of 120 pediatric stroke-like episodes

BACKGROUND AND PURPOSE

Stroke-like episodes (SLEs) are defined as acute onset of neurological symptoms mimicking a stroke and radiological lesions non-congruent to vascular territory. We aimed to analyze the acute clinical and radiological features of SLEs to determine their pathophysiology.

METHODS

We performed a monocenter retrospective analysis of 120 SLEs in 60 children over a 20-year period. Inclusion criteria were compatible clinical symptoms and stroke-like lesions on brain magnetic resonance imaging (MRI; performed for all 120 events) with focal hyperintensity on diffusion-weighted imaging in a non-vascular territory.

RESULTS

Three groups were identified: children with mitochondrial diseases (n = 22) involving mitochondrial DNA mutations (55%) or nuclear DNA mutations (45%); those with other metabolic diseases or epilepsy disorders (n = 22); and those in whom no etiology was found despite extensive investigations (n = 16). Age at first SLE was younger in the group with metabolic or epilepsy disorders (18 months vs. 128 months; p < 0.0001) and an infectious trigger was more frequent (69% vs. 20%; p = 0.0001). Seizures occurred in 75% of episodes, revealing 50% episodes of SLEs and mainly leading to status epilepticus (90%). Of the 120 MRI scans confirming the diagnosis, 28 were performed within a short and strict 48-h period and were further analyzed to better understand the underlying mechanisms. The scans showed primary cortical hyperintensity (n = 28/28) with decreased apparent diffusion coefficient in 52% of cases. Systematic hyperperfusion was found on spin labeling sequences when available (n = 18/18).

CONCLUSION

Clinical and radiological results support the existence of a vicious circle based on two main mechanisms: energy deficit and neuronal hyperexcitability at the origin of SLE.

Neurological features related to influenza virus in the pediatric population: a 3-year monocentric retrospective study

Influenza virus is generally characterized by fever, myalgia, and respiratory symptoms. Neurological entities have already been described, such as acute necrotizing encephalitis (ANE). We aimed to highlight the non-exceptional nature and explore the clinical spectrum and evolution of neurological features related to influenza virus in children. This monocentric observational study included patients under 18 years old, positive for influenza virus, between January 2017 and April 2019 in a pediatric university hospital. Patients were classified into two groups: those with or without a previous significant neurological or metabolic disorder. Two hundred eighty-nine children were identified with influenza infection. Thirty seven had a neurological manifestation: 14 patients who had previous significant neurological or metabolic disorder and 23 patients with no medical history. We identified several clinical patterns: 22 patients had seizures, 7 behavior disorders, 5 disturbances of consciousness, and 3 motor deficits. Four were diagnosed with a known influenza-associated neurological syndrome: 1 ANE, 1 cytotoxic lesion of the corpus callosum, 1 hemiconvulsion-hemiplegia-epilepsia syndrome, and 1 recurrent encephalitis in the context of a RANBP2 mutation. The neurological outcome was favorable in most cases. None of the patients with previous significant disorder retained sequalae or had a recurrence. Two patients had a fatal outcome, and both had a predisposing disorder.

CONCLUSION

Various neurological manifestations can be associated with influenza virus. Certain entities led to a poor prognosis, but in most cases, symptoms improved within a few days. The severity of the neurological manifestations correlated with previous neurological or metabolic disorders.

WHAT IS KNOWN

• Influenza viruses are well known pathogens with a seasonal epidemic evolution, particularly affecting children. These viruses cause acute fever with respiratory symptoms, associated with myalgia and headaches. Neurological presentation in influenza-virus infection is a well-established possibility as influenza virus is considered to be responsible for 27 to 36% of childhood encephalitis. Some specific and severe entity as acute necrotizing encephalitis, cytotoxic lesion of the corpus callosum, or Hemiconvulsion-hemiplegia-epilepsy syndrome are well described.

WHAT IS NEW

• In a French monocentric cohort of 37 children with influenza-related neurologic manifestations, the majority of these manifestations, including seizure, drowsiness, motor deficiency, hallucination… are self limiting and do not lead to after-effects. In rare cases (4/37), they may reveal severe encephalitis requiring rapid and appropriate treatment. Otherwise, comparison of a group of 14 children with underlying neurological or metabolic disorder with a group of 23 children free of any significant disorder show that the severity of the neurological manifestations was largely related to previous neurological or metabolic disorders highlighting the importance of vaccination in this population.

Prediction and assessment of acute encephalopathy syndromes immediately after febrile status epilepticus

OBJECTIVE

This study aimed to predict occurrence of acute encephalopathy syndromes (AES) immediately after febrile status epilepticus in children and to explore the usefulness of electroencephalogram (EEG) in the early diagnosis of AES.

METHODS

We reviewed data from 120 children who had febrile status epilepticus lasting >30 min and were admitted to our hospital between 2012 and 2019. AES with reduced diffusion on brain magnetic resonance imaging was diagnosed in 11 of these patients. EEG and serum cytokines were analyzed in AES patients. Clinical symptoms and laboratory data were compared between AES and non-AES patients. Logistic regression analysis was used to identify early predictors of AES.

RESULTS

Multivariate logistic regression identified serum creatinine as a risk factor for developing AES. A scoring model to predict AES in the post-ictal phase that included serum creatinine, sodium, aspartate aminotransferase, and glucose was developed, and a score of 2 or more predicted AES with sensitivity of 90.9% and specificity of 71.6%. Post-ictus EEG revealed non-convulsive status epilepticus in four of the seven AES patients.

CONCLUSION

Children with febrile status epilepticus may be at risk of developing severe AES with reduced diffusion. Post-ictus EEG and laboratory data can predict the occurrence of severe AES.

Prolonged neurologic deficits with brain MRI changes following ECT in an adolescent with a CACNA1a-related disorder; a case report

BACKGROUND

Electroconvulsive therapy is used to treat depression and schizophrenia with infrequent use in pediatric patients. We report a case of an adolescent with autism spectrum disorder and acute catatonia that presented with status epilepticus (SE) and prolonged neurologic deficits with unilateral left cerebral edema on imaging following unilateral electroconvulsive therapy (ECT) on the right side, subsequently found to have a CACNA1a pathogenic variant. This case highlights a potential adverse effect of ECT in patients with CACNA1a related disorders.

CASE

The patient received unilateral ECT to the right side and subsequently had an episode of SE with right-sided hemiplegia for 72 h prior to regaining some function with persistent mild right-hand weakness that persisted for at least 1-2 weeks. A brain MRI 2 days after ECT was unremarkable, but a repeat MRI on day four of admission showed left hemisphere cortical diffusion restriction, increased perfusion and T2 prolongation suggestive of cortical edema. They had whole exome genetic testing sent after discharge that showed a known pathogenic CACNA1a variant (p.I1709T). CACNA1a encodes the P/Q type calcium channels and deleterious variants in this gene result in a channelopathy associated with a spectrum of neurodevelopmental disorders that include autism spectrum disorder, hemiplegic migraine with unilateral cerebral edema, epileptic encephalopathies, or episodic ataxia syndromes.

CONCLUSION

A literature review of ECT and neurologic deficits showed that most neurologic deficits resolve within 30 min of ECT. Case reports of prolonged deficits are rare and there are no prior reports of acute MRI changes related to ECT. Thus, the acute deterioration and MRI findings in this patient are likely related to the underlying CACNA1a channelopathy disorder with ECT as a precipitating event. This case report suggests care should be taken when using ECT in patients with pathogenic variants in CACNA1a. Furthermore, it reinforces the utility and importance of expanded genetic testing in patients with neurodevelopmental disorders as findings can provide valuable information that can guide treatment decisions.

Child Neurology: Hemiconvulsion-Hemiplegia-Epilepsy Syndrome in the Setting of COVID-19 Infection and Multisystem Inflammatory Syndrome

Hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome is a rare pediatric epilepsy syndrome characterized by prolonged focal febrile convulsive status epilepticus with unilateral hemispheric cerebral edema, followed by the subsequent development of hemiplegia, global atrophy of the affected hemisphere, and epilepsy. The pathophysiology of HHE syndrome remains poorly understood though is clearly multifactorial. Factors thus far implicated are hyperthermia, proinflammatory state, and cytotoxic edema from prolonged ictal activity. Prognosis is variable, from the resolution of hemiplegia and seizures to permanent hemiparesis and refractory epilepsy. We describe a 2-year-old boy who presented with superrefractory focal status epilepticus in the setting of acute coronavirus infectious disease-2019 (COVID-19) and multisystem inflammatory syndrome in children (MIS-C). He had right-sided hemiplegia on neurologic examination, and an MRI examination of the brain showed left cerebral hemispheric edema consistent with HHE syndrome. Our case represents the first report in the literature on HHE syndrome in the setting of acute COVID-19 and MIS-C.

Epilepsy and inborn errors of metabolism in adults: The diagnostic odyssey of a young woman with medium-chain acyl-coenzyme A dehydrogenase deficiency

We describe a case of epileptic encephalopathy in a young woman with undiagnosed medium-chain acyl-coenzyme A dehydrogenase deficiency (MCADD), who presented with an early-onset focal motor status epilepticus (SE) then followed by permanent left hemiplegia and drug-resistant epilepsy with neurodevelopmental delay. Throughout her clinical history, recurrent episodes of lethargy, feeding difficulties, and clustering seizures occurred, progressing into a super refractory SE and death at the age of 25 years. Although epilepsy is not a distinctive feature of MCADD, we advise considering this metabolic disease as a possible etiology of epileptic encephalopathy and hemiconvulsion-hemiplegia-epilepsy syndrome of unknown origin, on the chance to provide a timely and targeted treatment preventing development delay and evolution to SE. Adult patients with epilepsy of unknown etiology not screened at birth for inborn errors of metabolism, such as MCADD, should be promptly investigated for these treatable conditions.

International League Against Epilepsy classification and definition of epilepsy syndromes with onset in childhood: Position paper by the ILAE Task Force on Nosology and Definitions

The 2017 International League Against Epilepsy classification has defined a three-tier system with epilepsy syndrome identification at the third level. Although a syndrome cannot be determined in all children with epilepsy, identification of a specific syndrome provides guidance on management and prognosis. In this paper, we describe the childhood onset epilepsy syndromes, most of which have both mandatory seizure type(s) and interictal electroencephalographic (EEG) features. Based on the 2017 Classification of Seizures and Epilepsies, some syndrome names have been updated using terms directly describing the seizure semiology. Epilepsy syndromes beginning in childhood have been divided into three categories: (1) self-limited focal epilepsies, comprising four syndromes: self-limited epilepsy with centrotemporal spikes, self-limited epilepsy with autonomic seizures, childhood occipital visual epilepsy, and photosensitive occipital lobe epilepsy; (2) generalized epilepsies, comprising three syndromes: childhood absence epilepsy, epilepsy with myoclonic absence, and epilepsy with eyelid myoclonia; and (3) developmental and/or epileptic encephalopathies, comprising five syndromes: epilepsy with myoclonic-atonic seizures, Lennox-Gastaut syndrome, developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep, hemiconvulsion-hemiplegia-epilepsy syndrome, and febrile infection-related epilepsy syndrome. We define each, highlighting the mandatory seizure(s), EEG features, phenotypic variations, and findings from key investigations.

Infantile Hemiconvulsion-Hemiplegia and Epilepsy (IHHE) in a boy with tuberous sclerosis complex

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Case of IHHE with hemiclonic status epilepticus in a patient with TSC2.

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MRI revealed unihemispheric edema and restricted diffusion evolving to atrophy.

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Brain malformations and genetic predisposition may contribute to acquiring IHHE.

Tuberous sclerosis complex (TSC) is a rare autosomal dominant disease due to pathogenic variants in TSC1 or TSC2 genes. In the brain, TSC is associated with multiple cortical and subcortical malformations including tubers and abnormalities of radial neuronal migration. Approximately 80% of patients develop epilepsy in the first two years of life, most often focal seizures and infantile spasms. As with all seizure disorders, systemic illness and fever can trigger a seizure, and result in status epilepticus or even refractory status epilepticus. Infantile Hemiconvulsion-Hemiplegia and Epilepsy (IHHE) is considered a subcategory of new-onset refractory status epilepticus (NORSE) and presents with hemiclonic seizures in the setting of fever, unihemispheric brain imaging abnormality and hemiparesis. Here, we present an 18-month-old boy with TSC who developed IHHE. His extensive brain malformations and neuronal hyperexcitability in peri-tuberal tissue could have predisposed him to IHHE. In addition to these factors, we postulate that another prerequisite for IHHE is likely a genetic predisposition for an excessive inflammatory response that is yet to be elucidated.

Infant with right hemiplegia due to acute encephalopathy with biphasic seizures and late reduced diffusion (AESD): A case report

RATIONALE

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is a condition characterized by biphasic convulsions and disturbance of consciousness. In Japan, the most common pediatric cases of acute encephalopathy are associated with infection. AESD usually occurs in early childhood, with the characteristic magnetic resonance imaging (MRI) appearance called "bright tree appearance." The disease often has neurological sequelae and interferes with the schooling of children and their activities of daily living; however, there are few clinical case reports of hemiplegia caused by AESD.

PATIENT CONCERNS

A case with right-sided hemiplegia due to AESD in an 11-month-old girl who was followed up to 30 mo of age.

DIAGNOSES

The patient was diagnosed with overlap AESD and hemiconvulsion-hemiplegia-epilepsy syndrome (HHE syndrome), based on the clinical course and imaging findings. DNA tests of her blood and cerebrospinal fluid revealed the presence of human herpesvirus 6.

INTERVENTIONS

Pharmacotherapy and rehabilitation therapy.

OUTCOME

Gross motor function has recovered considerably, but she had a mild developmental delay at 30 mo old.

LESSONS

Hemiplegia due to AESD was extremely rare, and appropriate rehabilitation treatment resulted in recovery of physical function. However, as mild developmental delay was observed, the patient was referred to a specialized facility before entering school.

Prognostic Factors for Pediatric Acute Encephalopathy Associated with Severe Brain Edema

BACKGROUND AND OBJECTIVE

Acute encephalopathy is a life-threatening brain dysfunction in children, often associated with a preceding infection and diffuse noninflammatory brain edema. At present, the role of decompressive craniectomy (DC) over the swollen area of the brain is unclear. The risk factors for predicting clinical deterioration also need clarification.

METHODS

A retrospective study of pediatric patients admitted between 2015 and 2019 with acute cerebral encephalopathy was carried out. Patients were classified according to: (1) the preceding pathogens, (2) the syndromic classification, and (3) the extent of brain edema. The syndromic classification is a relatively new classification of acute encephalopathy proposed in 2016 and divides patients into 3 groups: those with systemic inflammatory reactions or "cytokine storms" (group 1), those with status epilepticus but no cytokine storm (group 2), and others (group 3). Glasgow Outcome Scale (GOS) scores of 1-3 were defined as unfavorable, while a GOS score of 4 or 5 was defined as a favorable outcome in this study. DC was performed for select patients with life-threatening signs of brainstem compression.

RESULTS

Nineteen patients (mean age: 23.3 months) were included in the study, 8 (42.1%) of whom had an unfavorable outcome. There was no significant correlation between the types of pathogens and outcome. Unfavorable outcomes were observed in significantly more patients in group 1 (87.5%) than group 2 (14.3%) and group 3 (0%). There was a significant association between diffuse brain edema and unfavorable outcomes (72.7%). Neurosurgical DC was performed in 2 patients to alleviate life-threatening brainstem compression: one with a cytokine storm and diffuse bilateral brain edema, and the other with prolonged status epilepticus causing diffuse right-sided brain edema. The GOS score was 3 and 4, respectively.

CONCLUSION

The risk factors for clinical deterioration in pediatric acute encephalopathy were evaluated based on a variety of classifications, including the new syndromic classification. Laboratory features of cytokine storms and radiological evidence of diffuse brain edema were associated with unfavorable outcomes. The role of surgical decompression is still controversial and should be assessed on a case-by-case basis.

Hemiconvulsion-Hemiplegia-Epilepsy Syndrome in Adult with Uncontrolled Seizures and Phenytoin Toxicity

Hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome is a rare condition, characterized by sudden onset of unilateral seizures leading to cerebral hemisphere atrophy and hemiplegia which might persist for lifetime. It is believed to be outcome of prolonged or unmanaged status epilepticus in pediatric age group. HHE is diagnosed during childhood but we report an undiagnosed case of 30-year-old male who was dealing with uncontrolled seizure, phenytoin toxicity and hemiparesis. He was diagnosed with HHE based on characteristic imaging findings leading to complete alteration of management and opened wide array of surgical options to manage this debilitating condition.

Mutational and phenotypic expansion of ATP1A3-related disorders: Report of nine cases

BACKGROUND

Mutations in the ATP1A3 gene are known to be the cause of three distinct neurological syndromes including alternating hemiplegia of childhood (AHC), rapid-onset dystonia parkinsonism (RDP) and cerebellar ataxia, arefexia, pes cavus, optic atrophy and sensorineural hearing impairment (CAPOS). Recent studies have suggested the broader diversity of ATP1A3-related disorders. This study aimed to investigate the clinical spectrum in patients carrying causative mutations within the ATP1A3 gene.

METHOD

The medical histories of nine unrelated patients with diverse phenotypes harboring variants in ATP1A3 were retrospectively analyzed after they were referred to a tertiary epilepsy center in one of the two different health care systems (Germany or Thailand). Clinical features, neurophysiological data, imaging results, genetic characteristics and treatments were reviewed.

RESULTS

Three patients harbor novel mutations in the ATP1A3 gene. Atypical clinical features and imaging findings were observed in two cases, one with hemiplegia-hemiconvulsion-epilepsy syndrome, and the other with neurodegeneration with brain iron accumulation. All nine patients presented with intellectual impairment. Alternating hemiplegia of childhood (AHC) was the most common phenotype (67%). Flunarizine and topiramate led to symptom reduction in 83% and 25% of AHC cases administered, respectively.

CONCLUSION

The present case series expands the clinical and genetic spectrum of ATP1A3-related disorders.

Acute encephalopathy with biphasic seizures and late reduced diffusion in a Spanish girl

We report a case of a 22-month-old Spanish girl who presented acute encephalopathy with biphasic seizures and late reduced diffusion (AESD). Serum procalcitonin (PCT) reached a maximum of 50.5 ng/mL on the first day whereas C-reactive protein (CRP) peaked at 1.21 mg/dL on the second. At the time of discharge, right spastic hemiparesis persisted. MR spectroscopy on day 23 revealed a decrease in N-acetylaspartate and an increase in choline. To our knowledge, we report the first case of AESD in Europe. These findings support the role of PCT and PCT/CRP ratio in the early diagnosis of AESD and correlation of MR spectroscopy findings with neurological outcome.

Hemiconvulsion-Hemiplegia-Epilepsy in a girl with cobalamin C deficiency

Hemiconvulsion‐Hemiplegia‐Epilepsy initially involves an infantile presentation of febrile focal motor status epilepticus, with subsequent hemiplegia of the initially affected side. Months to years later, affected children go on to develop a chronic epilepsy with recurrent focal seizures which are often refractory to treatment. This uncommon paediatric epilepsy syndrome is poorly understood, with only a very small minority of cases associated with an underlying genetic or metabolic abnormality.

We present a four‐year‐old girl with genetic cobalamin C deficiency who had a dramatic presentation with Hemiconvulsion‐Hemiplegia‐Epilepsy. She had febrile focal status epilepticus, with right hemiconvulsive seizures for nearly 10 hours, ultimately requiring a midazolam infusion. Over subsequent days, she developed progressively worsening cerebral oedema, leading to herniation and requiring a craniectomy to relieve pressure.

This girl's presentation is the first association of cobalamin deficiency with hemiconvulsion‐hemiplegia‐epilepsy; and illustrates the importance of considering this entity when patients with this metabolic disorder present with acute deterioration. More importantly, the case also raises the possibility that derangements of cobalamin metabolism could be a contributing factor in cases of hemiconvulsion‐hemiplegia‐epilepsy, as well as febrile seizures in general.

Development of a Model of Hemispheric Hypodensity ("Big Black Brain")

Subdural hematoma (SDH) is the most common finding after abusive head trauma (AHT). Hemispheric hypodensity (HH) is a radiological indicator of severe brain damage that encompasses multiple vascular territories, and may develop in the hemisphere(s) underlying the SDH. In some instances where the SDH is predominantly unilateral, the widespread damage is unilateral underlying the SDH. To date, no animal model has successfully replicated this pattern of injury. We combined escalating severities of the injuries and insults commonly associated with HH including SDH, impact, mass effect, seizures, apnea, and hypoventilation to create an experimental model of HH in piglets aged 1 week (comparable to human infants) to 1 month (comparable to human toddlers). Unilateral HH evolved over 24 h when kainic acid was applied ipsilateral to the SDH to induce seizures. Pathological examination revealed a hypoxic-ischemic injury-type pattern with vasogenic edema through much of the cortical ribbon with relative sparing of deep gray matter. The percentage of the hemisphere that was damaged was greater on the ipsilateral versus contralateral side and was positively correlated with SDH area and estimated seizure duration. Further studies are needed to parse out the pathophysiology of this injury and to determine if multiple injuries and insults act synergistically to induce a metabolic mismatch or if the mechanism of trauma induces severe seizures that drive this distinctive pattern of injury.

Epilepsy Syndromes in Childhood

PURPOSE OF REVIEW

Epilepsy syndromes are an important clinical construct in pediatric epilepsy, as they encompass recognizable patterns seen in patients with epilepsies, whether of the more benign variety or associated with encephalopathy.

RECENT FINDINGS

Syndromes may be organized by age of onset: neonatal, infantile, childhood, or adolescent. The assignment of a syndrome has specific implications for diagnosis, management, and prognostication. The 2010 revised classification of the epilepsies by the International League Against Epilepsy preserved the syndrome approach, while progress in genetics continues to advance our understanding of the pathophysiology and overlap of the epilepsy syndromes.

SUMMARY

Given that mutations of the same gene may cause both encephalopathic and relatively benign epilepsies, an understanding of the pediatric epilepsy syndromes remains vital to patient care.

Classical oral manifestations of Dyke-Davidoff-Masson syndrome: a case report with review of the literature

Dyke-Davidoff-Masson syndrome is a non-inherited rare condition that presents during childhood and is characterized by seizures, hemiplegia, mental retardation, cerebral hemiatrophy, calvarial thickening, and hyperpneumatization of the frontal sinuses. The present article highlights a case of a 12-year-old male child with additional clinical findings of café-au-late pigmentation and ocular lipodermoid. This is the first case report of Dyke-Davidoff-Masson syndrome to describe oral manifestations, such as unilateral delayed eruption of teeth, hypoplasia, and taurodontism, which could be unique and characteristic of this condition. Oral health care providers and physicians should be aware of these oral observations as dental referrals could warrant early dental prophylactic care and can be useful in diagnosing the possible time of injury and type of Dyke-Davidoff-Masson syndrome.

Clinical aspects, neuroimaging, and electroencephalography of 35 cases of hemiconvulsion-hemiplegia syndrome

INTRODUCTION

The hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome is a rare consequence of febrile seizures during childhood. It is characterized by the presence of prolonged unilateral clonic seizures occurring during febrile illness in a child less than 4years of age. Then, a flaccid unilateral hemiplegia with variable duration occurs.

OBJECTIVES

The objective of the study was to describe the clinical, electroencephalogram (EEG), and neuroimaging treatment and outcome of series of cases of HHE syndrome followed for 10years in our clinical neurophysiology department of the specialty hospital of Rabat.

PATIENTS AND METHODS

We report a retrospective study of 35 patients followed up for HHE syndrome from January 2005 to December 2015. All patients included in the study met the definition criteria for HHE syndrome.

RESULTS

The age of onset ranged from 1 to 10years. Hemiplegia or spastic hemiparesis of the ipsilateral side to the convulsion was present in all patients. Abnormal brain magnetic resonance imaging (MRI) was found in all patients. All patients developed drug-resistant focal epilepsy during the course of the disease.

CONCLUSIONS

The management of HHE syndrome constitutes a real public health problem in developing countries like Morocco. The neurological morbidity and the severe sequels are of high impact in these young kids. On the one hand, authors highlight the need for improving emergency care of status epilepticus. On the other hand, in our context, the prophylaxis of febrile seizures seems to be the corner stone of the prevention of HHE Syndrome.

New-Onset Status Epilepticus in Pediatric Patients: Causes, Characteristics, and Outcomes

BACKGROUND

Many pediatric patients presenting with status epilepticus have no history of seizures.

METHODS

We retrospectively analyzed the clinical characteristics of patients aged one month to 21 years who presented during six consecutive years with convulsive status epilepticus and without a history of seizures. New-onset refractory status epilepticus was defined as status epilepticus refractory to two lines of treatment, without an identified cause in the first 48 hours.

RESULTS

Of 460 patients with status epilepticus, 79 (17.2%) presented with new-onset status epilepticus, including four (0.9%) with new-onset refractory status epilepticus. Of those patients, 54.4% were female, and the median age was 3.5 years (IQR: 1.08 to 6.75). The median seizure duration was 20 minutes (IQR: 10 to 40 minutes). Etiology was unknown in 36.7%, symptomatic in 30.3%, provoked in 16.5%, and provoked with an existing symptomatic etiology in 16.5%. Patients were followed for a median duration of 63 months (IQR: 21 to 97). The mortality rate was 3.8%. Of 55 patients who were developmentally normal at baseline, 29.1% had a significant cognitive impairment at the last follow-up, and 20% had academic difficulties or behavioral problems. Patients with symptomatic etiology had greater odds of having cognitive and behavioral problems compared with patients with unknown etiology (odds ratio = 3.83, P = 0.012).

CONCLUSIONS

Patients with new-onset status epilepticus are at risk for recurrent seizures, recurrent status epilepticus, death, and subsequent cognitive-behavioral impairment. Specific monitoring and care interventions might be required in this high-risk population.

Intracranial germinoma causing cerebral haemiatrophy and hypopituitarism

A young woman presented with primary amenorrhoea, progressive haemiparesis, visual disturbance, dementia and focal motor seizures. Investigations showed hypopituitarism, unilateral cerebral atrophy and inflamed cerebrospinal fluid. A trans-sphenoidal biopsy gave a unifying diagnosis of a pituitary germinoma.

PARS2 and NARS2 mutations in infantile-onset neurodegenerative disorder

Here we present four unrelated families with six individuals that have infantile-onset developmental delay/regression and epilepsy. Whole-exome sequencing revealed compound heterozygous mutations, c.[283G>A];[607G>A] in a gene encoding prolyl-tRNA synthetase (PARS2) in one family. Two pairs of compound heterozygous mutations, c.[151C>T];[1184T>G] and c.[707T>G];[594+1G>A], and a homozygous mutation, c.[500A>G];[500A>G], in a gene encoding asparaginyl-tRNA synthetase (NARS2) were also identified in the other three families. Mutations in genes encoding aminoacyl-tRNA synthetases cause gene-specific mitochondrial disorders. Biallelic PARS2 or NARS2 mutations are reported to cause Alpers' syndrome, which is an autosomal recessive neurodegenerative disorder characterized by psychomotor regression and epilepsy with variable degree of liver involvement. Moreover, it is known that NARS2 mutations cause various clinical phenotypes, including non-syndromic hearing loss, Leigh syndrome, intellectual disability with epilepsy and severe myopathy. The individuals with PARS2 and NARS2 mutations, we have reported here demonstrate similar neurological features as those previously reported, with diversity in clinical presentation such as hearing loss and seizure type. Our data broaden the clinical and mutational spectrum of PARS2- and NARS2-related disorders.

Survival following decompressive hemicraniectomy for hemiconvulsion-hemiplegia-epilepsy syndrome: case report

Hemiconvulsion-hemiplegia-epilepsy (HHE) is an uncommon epileptic syndrome that affects young children. Typical management includes early initiation of benzodiazepines to abate the initial seizure activity quickly. Patients in whom epilepsy develops require prolonged use of antiepileptic agents. Herniation due to diffuse cerebral edema from HHE is rare; however, decompressive craniectomy has been described as a lifesaving measure. The authors present the case of a patient in whom a decompressive craniectomy was performed. They advocate a proactive approach in the detection and management of cerebral edema in HHE causing intracranial hypertension. In HHE cases that exhibit radiographic evidence of malignant cerebral edema (although not previously described in this disease, but similar to the setting of stroke and trauma), the authors advocate early neurosurgical consultation and evaluation for insertion of an intracranial pressure monitor for those patients who do not have a reliable neurological examination (i.e., Glasgow Coma Scale score ≤ 8).

Refractory Seizure in Childhood: Dyke-Davidoff-Masson Syndrome Revisited

Dyke-Davidoff-Masson syndrome (DDMS) is a rare disorder characterized by recurrent seizures, facial asymmetry, contralateral hemiplegia, radiologic features of cerebral hemiatrophy, and ipsilateral compensatory hypertrophy of the skull bone and sinuses. We describe three cases of children with DDMS, who initially presented with refractory seizure to the pediatric department of North Bengal Medical College and Hospital, India. In each case, the clinical features noted along with computed tomography or magnetic resonance imaging helped confirm the diagnosis of DDMS. DDMS should be considered as a differential diagnosis of refractory seizures in children. We seek to emphasize the importance of thorough clinical and neuroimaging workup of seizure disorder in children for the proper management of the condition.

Stroke-Like Presentation Following Febrile Seizure in a Patient with 1q43q44 Deletion Syndrome

Hemiconvulsion-hemiplegia-epilepsy syndrome (HHE) is a rare outcome of prolonged hemiconvulsion that is followed by diffuse unilateral hemispheric edema, hemiplegia, and ultimately hemiatrophy of the affected hemisphere and epilepsy. Here, we describe the case of a 3-year-old male with a 1;3 translocation leading to a terminal 1q43q44 deletion and a terminal 3p26.1p26.3 duplication that developed HHE after a prolonged febrile seizure and discuss the pathogenesis of HHE in the context of the patient's complex genetic background.

Epidemiology of epilepsy

Epilepsy is a burden affecting no fewer than 50 million patients worldwide. It is a heterogeneous group of disorders comprising both common and very rare forms, thus rendering its epidemiological investigations rather difficult. Moreover, making an epilepsy diagnosis per se can be challenging due to an evolving system of classification, and its dependency on local habits and culture. Any attempt at meta-analyses must consider such biases when pooling data from different centers and countries. Differentiating a contextual seizure from chronic epilepsy is every epileptologist's daily mission, yet it is also crucial for achieving a proper estimation of the epidemiology of epilepsy. Our present objective was to provide an overview of the epidemiology of both syndromic and non-syndromic epilepsy. Most epileptic syndromes tend to be rare and, thus, the feasibility of epidemiological quantification in populations is also addressed. Regarding its prevalence and cost, epilepsy deserves greater attention than it generally receives, as it appears to continue to be a condition under persistent taboos.

An autopsy case of hemiconvulsion-hemiplegia-epilepsy syndrome manifesting as cerebral hemiatrophy in an elderly man

We report an autopsy case of hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome in a 79-year-old man. HHE syndrome usually occurs in children younger than 4 years of age. Although most HHE syndrome patients live into adult life, only a few cases of the syndrome have been reported in the elderly. In our case, cerebral hemiatrophy, left mesial temporal sclerosis and crossed cerebellar atrophy were observed. Because this is the oldest case ever reported, we further investigated age-related neuropathological changes and found an interhemispheric difference in amyloid-β-related neuropathologic changes. There were almost no senile plaques or amyloid-laden vessels in the left hemisphere. As far as we know, this is the first report of age-related neuropathology in a brain manifesting HHE syndrome.

Demographics and outcomes of patients with pediatric febrile convulsive status epilepticus

BACKGROUND

Convulsive status epilepticus with fever is common and may be related to neurological sequela in children. However, there are limited data on the demographics and risk factors of this phenomenon. Thus, we aimed to describe the demographics and risk factors of neurological sequela among children with convulsive status epilepticus with fever.

METHODS

We reviewed convulsive status epilepticus with fever cases in the pediatric intensive care unit at Kobe Children's Hospital between 2002 and 2013. We included patients with intrinsic neurological disease, and excluded those with obvious central nervous system infection. Cases of neurological worsening were categorized as poor outcome using the pediatric cerebral performance category scale. Possible risk factors for poor outcome included age, sex, neurological medical history, seizure duration, body temperature, and level of consciousness.

RESULTS

A total of 253 patients (128 males), aged 1 month to 15 years (mean 45 ± 40 months), were enrolled. Three patients (1.2%) died during hospitalization, and 32 (12.6%) patients had a poor outcome. A univariate analysis identified male sex, absence of epilepsy history, body temperature above 40°C on admission, seizure duration longer than 120 minutes, impaired consciousness at 12 hours after onset, and presence of nonconvulsive seizure as potential predictors of poor outcome. A multivariate analysis, revealed that an absence of epilepsy history (odds ratio = 11.18), body temperature above 40°C on admission (odds ratio = 3.39), or impaired consciousness at 12 hours after onset (odds ratio = 41.85) was associated with poor outcome.

CONCLUSIONS

Our study indicated that absence of epilepsy history, high temperature, and/or prolonged impaired consciousness were associated with brain injury.

Seizures in patients with cerebral hemiatrophy: A prognostic evaluation

PURPOSE

Cerebral hemiatrophy is a common childhood disease. It clinically manifests with seizures, hemiparesis and mental retardation.

MATERIALS AND METHODS

In this prospective study, previously untreated patients with seizures and cerebral hemiatrophy were recruited. Cerebral hemiatrophy was diagnosed on the basis of hemispheric ratio. Patients with acquired hemiconvulsion, hemiplegia, and epilepsy (HHE) syndrome were included in group A. Group B included patients with congenital HHE syndrome. Patients were followed up for 6 months for seizure recurrence.

RESULTS

Out of 42 patients 26 were in group A and 16 were in group B. After 6 months, there was significant reduction in seizure frequency (P < 0.0001) in both the groups. At least 50% reduction in seizure frequency was noted in all the patients. Complete seizure freedom was observed in 15 (35.7%) patients. Seizure recurrences were significantly higher (P = 0.008) in group A. On univariate analysis, predictors of seizure recurrences were history of febrile seizures (P = 0.013), hippocampal sclerosis (P = 0.001), thalamic atrophy (P = 0.001), basal ganglia atrophy (P = 0.001), cerebellar atrophy (P = 0.01), ventricular dilatation (P = 0.001), epileptiform discharges at presentation (P = 0.023), complex partial seizures (P = 0.006) and status epilepticus (P = 0.02). On multivariate analysis, hemispheric ratio was the only significant factor for seizure recurrence.

CONCLUSION

Patients with congenital hemiatrophy had better seizure control than that in patients with HHE syndrome.

16p13.11 microdeletion in a patient with hemiconvulsion-hemiplegia-epilepsy syndrome: a case report

We describe a patient with hemiconvulsion-hemiplegia-epilepsy syndrome. The pathophysiology of hemiconvulsion-hemiplegia-epilepsy syndrome remains uncertain and there are probably multiple potential contributing factors. Our patient had a chromosomal 16p13.11 microdeletion that confers susceptibility to various types of epilepsy. This is the first report detailing an association of hemiconvulsion-hemiplegia-epilepsy syndrome with a 16p13.11 deletion and identifies another potential causal factor for hemiconvulsion-hemiplegia-epilepsy syndrome.

Inflammation and epilepsy in the developing brain: clinical and experimental evidence

There is an increasing evidence to support a role of inflammatory processes in epilepsy. However, most clinical and experimental studies have been conducted in adult patients or using adult rodents. The pediatric epilepsies constitute a varied group of diseases that are most frequently age specific. In this review, we will focus on the possible role of inflammation in pediatric epilepsy syndromes. We will first describe the clinical data available and provide an overview of our current understanding of the role of inflammation in these clinical situations. We will then review experimental data regarding the role of inflammation in epilepsy in the developing brain. To summarize, inflammation contributes to seizure precipitation, and reciprocally, prolonged seizures induce inflammation. There is also a relationship between inflammation and cell injury following status epilepticus, which differs according to the developmental stage. Finally, inflammation seems to contribute to epileptogenesis even in the developing brain. Based on the available data, we highlight the need for further studies dissecting the exact role of inflammation in epilepsy during development.

Midazolam fails to prevent neurological damage in children with convulsive refractory febrile status epilepticus

BACKGROUND

We conducted a retrospective study to compare the outcome of intravenous midazolam infusion without electroencephalography or targeted temperature management and barbiturate coma therapy with electroencephalography and targeted temperature management for treating convulsive refractory febrile status epilepticus.

PATIENTS

Of 49 consecutive convulsive refractory febrile status epilepticus patients admitted to the pediatric intensive care unit of our hospital, 29 were excluded because they received other treatments or because of various underlying illnesses. Thus, eight patients were treated with midazolam and 10 with barbiturate coma therapy using thiamylal. Midazolam-treated patients were intubated only when necessary, whereas barbiturate coma therapy patients were routinely intubated. Continuous electroencephalography monitoring was utilized only for the barbiturate coma group. The titration goal for anesthesia was clinical termination of status epilepticus in the midazolam group and suppression or burst-suppression patterns on electroencephalography in the barbiturate coma group. Normothermia was maintained using blankets and neuromuscular blockade in the barbiturate coma group and using antipyretics in the midazolam group. Prognoses were measured at 1 month after onset; children were classified into poor and good outcome groups.

RESULTS

Good outcome was achieved in all the barbiturate coma group patients and 50% of the midazolam group patients (P = 0.02, Fisher's exact test).

CONCLUSIONS

Although the sample size was small and our study could not determine which protocol element is essential for the neurological outcome, the findings suggest that clinical seizure control using midazolam without continuous electroencephalography monitoring or targeted temperature management is insufficient in preventing neurological damage in children with convulsive refractory febrile status epilepticus.

Hemiconvulsion-Hemiplegia-Epilepsy syndrome associated with inflammatory-degenerative hystopathological findings in child with congenital adrenal hyperplasia

Hemiconvulsion-Hemiplegia (HH) syndrome represents an uncommon consequence of prolonged unilateral clonic or hemiconvulsive status epilepticus in childhood, usually occurring during a febrile illness, followed by ipsilateral hemiplegia. The subsequent appearance of focal seizures configures the so called Hemiconvulsion-Hemiplegia-Epilepsy (HHE) syndrome. The pathogenesis of HH/HHE syndrome is still unclear. We describe the case of a 4 year-old girl with congenital adrenal hyperplasia (CAH) whom developed HH/HHE syndrome with drug resistant seizures at the age of 21 months and underwent left cerebral hemispherotomy at the age of 3 years and 6 months. Histopathological findings showed the presence of an underlying inflammatory-degenerative process. Disregulation of the inflammatory cascade has been proposed as one of the possible pathogenetic mechanisms underlying HH/HHE syndrome. To our knowledge however, this is the first report of an association with a histologically documented inflammatory process. The clinical and histopathological findings of our reported case lend support to the possible role of inflammation in the pathogenesis of HH/HHE syndrome.

Fatal outcome in hemiconvulsion-hemiplegia syndrome

Hemiplegia-hemiconvulsion-epilepsy syndrome is characterized by prolonged unilateral clonic seizures in a child followed by the development of hemiplegia. Focal status epilepticus results in unilateral cerebral edema of the epileptic hemisphere in the acute phase followed by cerebral hemiatrophy. Literature in the last 5 years does not describe malignant cerebral edema or resultant death. We report a case of a 3-year-old girl with hemiplegia-hemiconvulsion-epilepsy syndrome who died due to malignant cerebral edema and temporal lobe herniation. The first indication of worsening of clinical status after being seizure free was voltage suppression on continuous electroencephalography (EEG). We describe neuroimaging, EEG findings, and neuropathologic findings at autopsy and review pertinent literature. We also evaluate the evolving role of continuous EEG monitoring in the pediatric intensive care unit.

Unilateral brain oedema related to focal status epilepticus

We present a female patient in her late 30s, with baseline vegetative state following prior traumatic brain injury, who presented with prolonged right hemispheric status epilepticus. The neuroimaging revealed a striking right-sided pancortical oedema with left (crossed) cerebellar diaschisis and dilation of right hemispheric arteries. EEG was concordant and showed nearly continuous right hemispheric seizure discharges with suppressed background. Infective and vascular aetiologies were ruled out. The patient showed clinical and electrographic improvement following treatment with antiepileptic drugs. Unilateral cerebral oedema is a rare presentation of focal status epilepticus, and should be considered as a differential diagnosis in the appropriate clinical scenario.