Surgical treatment of delayed epilepsy in hemiconvulsion-hemiplegia-epilepsy syndrome

Epilepsy Surgery for Cognitive Improvement in Epileptic Encephalopathy

Epileptic encephalopathies are defined by the presence of frequent epileptiform activity that causes neurodevelopmental slowing or regression. Here, we review evidence that epilepsy surgery improves neurodevelopment in children with epileptic encephalopathies. We describe an example patient with epileptic encephalopathy without drug refractory seizures, who underwent successful diagnostic and therapeutic surgeries. In patients with epileptic encephalopathy, cognitive improvement alone is a sufficient indication to recommend surgical intervention in experienced centers.

[FIRES Syndrome in a Preschool Child]

Severe epileptic syndromes of childhood are an urgent problem for pediatric neurologists and neuroresuscitators. The article presents a clinical observation of FIRES syndrome in a pediatric patient, which is a form of severe drug-resistant epilepsy in children of preschool and school age, the development of which is caused by hyperthermia, probably associated with herpesvirus (human herpesvirus type 6) infection. The features of the progressive course and the difficulties of diagnostic search are reflected. An empirical approach to etiotropic therapy is described, since the disease manifested itself with respiratory manifestations and fever. The tactic of pathogenetic treatment is described, in which drugs of polyfunctional action, such as Cytoflavin, have a priority, many years of experience in the use of which allows the authors to recommend it as a starting intensive therapy.

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.

Hemiconvulsion-hemiplegia-epilepsy Syndrome: A Case Series

Hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome is an uncommon outcome of prolonged focal status epilepticus in childhood. We present four cases with age between 6 months and 3 years diagnosed with HHE syndrome. Two patients were lost to follow-up; other two cases had severe developmental delay and refractory epilepsy. An early diagnosis, a good seizure control, and a better understanding of the underlying mechanisms of HHE are needed to improve the outcome of this condition.

Hemiconvulsion-hemiplegia-epilepsy syndrome in Niger: A retrospective case series

OBJECTIVE

To report the demographic, clinical and paraclinical characteristics as well as the outcomes during follow-up visits of HHE syndrome in Niger.

PATIENTS AND METHODS

It was a retrospective study conducted at the Neurology Outpatient Clinic of the National Hospital of Niamey (Niger) between May 2003 and May 2018.

RESULTS

During the period of study, 882 patients with epilepsy aged 20 years or less were seen in consultation among whom we collected 22 cases of HHE syndrome with a hospital prevalence of 2.5%. They were 14 men and 8 women (sex ratio = 1.75) with a mean age of 3.76 years (range: 1 and 20 years). At the time of diagnosis, 81.8% of patients were aged under 6 years. The antecedent of febrile convulsions in childhood was found in only 31.8% of cases. The mean age of onset of hemiplegia was 1.9 years (range: 9 months and 5 years). The mean age of onset of epileptic seizures was 2.94 years (range: 1 and 8 years). The mean interval between the onset of hemiplegia and onset of epileptic seizures was 9 months (range: 1 month and 4 years). 31.8% of patients had a delay of acquisitions at the time of diagnosis. 95.5% of patients had drug-resistant epilepsy.

CONCLUSION

HHE syndrome is still seen in the countries of Sub-Saharan Africa. The high morbidity and mortality in children with HHE syndrome highlight the need to improve emergency care for febrile clonic seizures in childhood and the early and adequate management of infectious diseases in the child.

ACTH therapy on intractable epilepsy in Hemiconvulsion-Hemiplegia-Epilepsy syndrome

INTRODUCTION

In the chronic phase of Hemiconvulsion-Hemiplegia-Epilepsy (HHE) syndrome, developing epilepsy may be intractable. Herein, we report a case where adrenocorticotropic hormone (ACTH) ceased an intractable habitual partial seizure in a patient with HHE syndrome.

CASE REPORT

A developmentally normal one-year-old girl presented with left focal motor status epilepticus in the clinical course of rotavirus infection. She was diagnosed with HH syndrome. At 4 months after status epilepticus, she developed partial seizures that occurred daily, and which resulted in a stooped posture, head rotation to the right, and contraction of both upper limbs predominantly in the left arm. At this time, she was diagnosed with idiopathic HHE syndrome. Her seizures were not reduced by sodium valproate, clonazepam, clobazam, zonisamide, phenytoin, phenobarbital, topiramate, lamotrigine, or liposteroid. At the age of 7, ACTH therapy was performed. On the 10th day of ACTH therapy, the habitual seizure was ceased. However, partial seizures characterized by left arm contraction then developed. Treatment with 350 mg/day lamotrigine prevented this emerging seizure. She has been free of both seizure types for more than one year, with no serious adverse effects of ACTH therapy.

CONCLUSION

We suggest that ACTH therapy may be useful for patients with HHE, although further studies are required.

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.

Functional neuroimaging findings in patients with lateral and mesio-lateral temporal lobe epilepsy; FDG-PET and ictal SPECT studies

The differentiation of combined mesial and lateral temporal onset of seizures (mesio-lateral TLE, MLTLE) from lateral TLE (LTLE) is critical to achieve good surgical outcomes. However, the functional neuroimaging features in LTLE patients based on the ictal onset zone utilizing intracranial EEG (iEEG) in a large series have not been investigated. We enrolled patients diagnosed with MLTLE (n = 35) and LTLE (n = 53) based on the site of ictal onset zone from iEEG monitoring. MLTLE is defined when ictal discharges originate from the mesial and lateral temporal cortices independently, whereas seizures of LTLE arise exclusively from the lateral temporal cortex. Compared to patients with LTLE, patients with MLTLE were more likely to have 18F- fluorodeoxyglucose positron emission tomography (FDG-PET) hypometabolism and hyperperfusion on ictal single-photon emission computed tomography (SPECT) restricted to the temporal areas. MLTLE patients had more frequent aura or secondarily generalized seizures than LTLE patients. No significant differences were found in scalp EEG, MRI, and Wada asymmetry between groups. The overall seizure-free rate was good (73.8%, mean follow-up = 9.7 years), which was not different (Engel class I, 74.3% in MLTLE vs. 73.6% in LTLE). Postsurgical memory function was spared in LTLE patients, while visual memory was impaired in MLTLE patients when their mesial temporal structures were sufficiently resected. It suggests that functional neuroimaging (interictal PET and ictal and interictal SPECT) may play a crucial role to differentiate between MLTLE and LTLE.

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.

Hemiconvulsion-hemiplegia syndrome revisited: longitudinal MRI findings in 10 children

AIM

Hemiconvulsion-hemiplegia syndrome (HHS) is a rare severe epilepsy of infancy consisting of unilateral convulsive status epilepticus immediately followed by transient or lasting ipsilateral hemiplegia. HHS may occur either in patients with previous brain pathology or without any identified cause, so-called 'idiopathic HHS'.

METHOD

We retrospectively analysed clinical and MRI longitudinal findings of a series of 10 patients (six females, four males) presenting with HHS. Age at the study inclusion ranged from 2 years 6 months to 15 years (mean of 5 y 10 mo, median 4 y 2 mo). After defining magnetic resonance imaging (MRI) features as 'typical', i.e. strictly unilateral involvement, and 'atypical', i.e. bilateral, we compared clinical data from both groups. Cognitive level was assessed using Brunet-Lézine or Wechsler scales.

RESULTS

HHS occurred at a mean age of 20.5 months (range 8-48 mo). In all cases, status epilepticus lasted for more than 1 hour and was characterised by unilateral clonic seizures followed by ipsilateral hemiplegia (persistent in five patients). Two patients in this series died: the first from multi-organ failure 2 weeks after the status epilepticus and the other from a second episode of ipsilateral intractable febrile status epilepticus 3 years after the first episode. Early MRI (days 1-7 from status epilepticus) showed hemispheric cytotoxic oedema in all, extending to the contralateral side for one. T2 hyperintensity in the basal ganglia was disclosed in 70% of patients and in the hippocampus in 60%. After 1 month (in intermediate and chronic phases), all surviving patients but one showed hemispheric cortical atrophy corresponding to the regions involved during the early stage. Comparing clinical features of patients presenting with 'typical' features, to those with 'atypical' findings, the second group presented psychomotor delay before status epilepticus.

INTERPRETATION

This series underlines the major value of early MRI for the prompt diagnosis of HHS, and shows that involvement of subcortical structures has been underestimated. Hippocampal involvement is not constant.

Hemiconvulsion-hemiplegia-epilepsy syndrome: current understandings

Hemiconvulsion-Hemiplegia (HH) syndrome is an uncommon consequence of prolonged focal febrile convulsive seizures in infancy and early childhood. It is characterized by the occurrence of prolonged clonic seizures with unilateral predominance occurring in a child and followed by the development of hemiplegia. Neuroradiological studies showed unilateral edematous swelling of the epileptic hemisphere at the time of initial status epilepticus (SE). This acute phase is followed by characteristic cerebral hemiatrophy with subsequent appearance of epilepsy, so called Hemiconvulsion-Hemiplegia-Epilepsy (HHE) syndrome. The etiologies and the underlying mechanisms remain to be understood. Using a review of the literature, we summarized the data of the last 20 years. It appears that idiopathic HH/HHE syndrome is the most common reported form. The basic science data suggest that immature brain is relatively resistant to SE-induced cell injury. Several factors might contribute to the pathogenesis of HH/HHE syndrome: 1. prolonged febrile seizure in which inflammation may worsen the level of cell injury; 2. inflammation and prolonged ictal activity that act on blood-brain-barrier permeability; 3. predisposing factors facilitating prolonged seizure such as genetic factors or focal epileptogenic lesion. However, these factors cannot explain the elective involvement of an entire hemisphere. We draw new hypothesis that may explain the involvement of one hemisphere such as maturation of brain structure such as corpus callosum or genetic factors (CACNA1A gene) that are specifically discussed. An early diagnosis and a better understanding of the underlying mechanisms of HHE are needed to improve the outcome of this condition.

Hemiconvulsion-hemiplegia-epilepsy syndrome in South African children: insights from a retrospective case series

INTRODUCTION

Hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome is a recognized sequel of febrile partial status in children younger than 4 years.

OBJECTIVE

To describe the clinical features, neuroradiology and outcome in 8 South African children with HHE syndrome.

METHOD

A retrospective descriptive study of 8 consecutive cases of HHE syndrome presenting to tertiary hospitals in the Western Cape over a 2 year period.

RESULTS

The median age of onset of convulsive status was 16 months (range: 9-36 months). Gender distribution was equal. The duration of the initial episode of status exceeded 2 h in all children. All children were reported to have been developmentally normal prior to the onset of the first seizure and none previously suffered seizures or had a family history of febrile seizures and epilepsy. In 7 of the 8 cases the initial seizure was not associated with fever or preceding illness. Imaging demonstrated cerebral hemiatrophy in all and additional crossed cerebellar atrophy in 2 children. Moderate to severe intellectual disability ensued in the majority of children. The severity of the intellectual disability correlated with the degree of the motor deficit and occurred irrespective of the cerebral hemisphere involved.

CONCLUSION

In contrast to developed countries, HHE syndrome is still prevalent in South Africa. The neurological morbidity in South African children is significant and highlights the need for improved emergency care of status epilepticus.

Long-term cognitive outcome of hemiconvulsion-hemiplegia-epilepsy syndrome affecting the left cerebral hemisphere

Long-term cognitive outcome following hemiconvulsion-hemiplegia-epilepsy (HHE) syndrome has been poorly studied, with little attention to the implications of side of involvement in HHE. This retrospective study describes language lateralization and cognitive performance in five patients with HHE syndrome affecting the left cerebral hemisphere. All of the patients had to have intracarotid sodium amytal testing (IAT) to be included in this study. The mean age of the patients was 30.2 years (range: 13-50). All patients had their hemiconvulsive seizures before age 1(1/2) years (range: 6-13 months). All patients had right-sided hemiatrophy of the body, left mesial temporal sclerosis, and seizures originating from the left temporal lobe. The habitual seizures began at a mean age of 4.5 years (range: 1.5-12 years). Performance on tests of intelligence, verbal memory, and visual memory was examined. Language was represented in the right cerebral hemisphere in three patients, the left hemisphere in one patient, and both hemispheres with predominance on the right side in the fifth patient. Intellectual functioning was in the borderline to extremely low range among the patients with right hemispheric or bilateral representation for language. These patients were variably impaired on measures of verbal and visual memory. The patient with left hemispheric representation for language performed in the average range on tests of intellectual functioning and verbal memory, whereas scores on visual memory were variable. This study demonstrated that reorganization of language to the right cerebral hemisphere or its bilateral representation is common in patients with HHE syndrome affecting the left cerebral hemisphere, and is associated with poor cognitive outcome.