Clinical characteristics and prognostic factors of postencephalitic epilepsy in children

Ictal vomiting as an unusual presentation of herpes simplex encephalitis - Pathophysiological and therapeutic perspectives

Introduction

Herpes Simplex Encephalitis (HSE) is a formidable neurological infection that is often challenging to diagnose owing to its diverse clinical manifestations. This case report details the clinical odyssey of a sixty-year-old female with diabetes, hypothyroidism, and hypertension, who presented with fever, vomiting, and evolving neurological symptoms.

Case Presentation

The patient's initial admission failed to yield a diagnosis, and her condition worsened, marked by behavioral changes, cognitive decline, and focal seizures. Neuroimaging revealed characteristic findings, confirming non-hemorrhagic herpetic encephalitis. Despite antiviral and antiepileptic therapy, persistent vomiting prompted further investigations, uncovering infrequent right temporal sharp waves on EEG, leading to a diagnosis of "ictus emiticus."

Conclusion

This case of Herpes Simplex Encephalitis (HSE) underscores the diverse clinical spectrum and challenges in management. The patient's atypical presentation underscores the importance of considering HSE in patients with fever and unexplained persistent vomiting for early diagnosis and better prognosis.Diagnostic tools (neuroimaging, cerebrospinal fluid analysis, and electroencephalography) confirmed HSE involvement in the right temporal lobe, emphasizing the strong association between HSV encephalitis and seizures, which can be explained by various mechanisms.Timely antiviral therapy and tailored antiepileptic strategies led to gradual clinical improvement, showcasing the potential of valproate beyond antiepileptic use.This case prompts further exploration into HSE's pathophysiology and treatment. It emphasizes individualized patient care and vigilance for potential post-resolution sequelae, contributing to our evolving understanding of HSE.

Associations of Postencephalitic Epilepsy Using Multi-Contrast Whole Brain MRI: A Large Self-Supervised Vision Foundation Model Strategy

BACKGROUND

Postencephalitic epilepsy (PEE) is a severe neurological complication following encephalitis. Early identification of individuals at high risk for PEE is important for timely intervention.

PURPOSE

To develop a large self-supervised vision foundation model using a big dataset of multi-contrast head MRI scans, followed by fine-tuning with MRI data and follow-up outcomes from patients with PEE to develop a PEE association model.

STUDY TYPE

Retrospective.

POPULATION

Fifty-seven thousand six hundred twenty-one contrast-enhanced head MRI scans from 34,871 patients for foundation model construction, and head MRI scans from 144 patients with encephalitis (64 PEE, 80 N-PEE) for the PEE association model.

FIELD STRENGTH/SEQUENCE

1.5-T, 3-T, T1-weighted imaging, T2-weighted imaging, fluid attenuated inversion recovery, T1-weighted contrast-enhanced imaging.

ASSESSMENT

The foundation model was developed using self-supervised learning and cross-contrast context recovery. Patients with encephalitis were monitored for a median of 3.7 years (range 0.7-7.5 years), with epilepsy diagnosed according to International League Against Epilepsy. Occlusion sensitivity mapping highlighted brain regions involved in PEE classifications. Model performance was compared with DenseNet without pre-trained weights.

STATISTICAL TESTS

Performance was assessed via confusion matrices, accuracy, sensitivity, specificity, precision, F1 score, and area under the receiver operating characteristic curve (AUC). The DeLong test evaluated AUC between the two models (P < 0.05 for statistical significance).

RESULTS

The PEE association model achieved accuracy, sensitivity, specificity, precision, F1 score, and AUC of 79.3% (95% CI: 0.71-0.92), 92.3% (95% CI: 0.80-1.00), 68.8% (95% CI: 0.55-0.87), 70.6% (95% CI: 0.61-0.90), 80.0% (95% CI: 0.71-0.93), and 81.0% (95% CI: 0.68-0.92), respectively. A significant AUC improvement was found compared to DenseNet (Delong test, P = 0.03). The association model focused on brain regions affected by encephalitis.

DATA CONCLUSION

Using extensive unlabeled data via self-supervised learning addressed the limitations of supervised tasks with limited data. The fine-tuned foundation model outperformed DenseNet, which was trained exclusively on task data.

PLAIN LANGUAGE SUMMARY

This research develops a model to assess the occurrence epilepsy after encephalitis, a severe brain inflammation condition. By using over 57,000 brain scans, the study trains a computer program to recognize patterns in brain images. The model analyzes whole-brain scans to identify areas commonly affected by the disease, such as the temporal and frontal lobes. It was tested on data from patients with encephalitis and showed better performance than older methods. The model can assess the risk of secondary epilepsy in patients with encephalitis, allowing doctors to intervene early and improve treatment outcomes for those affected by this condition.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 1.

Neurocognitive outcome in children and adolescents following infectious encephalitis

Infectious encephalitis in children is fairly uncommon, but unfavorable outcomes are seen in many survivors. The aim of this study was to prospectively describe the long-term neurocognitive consequences following infectious encephalitis in childhood. Children admitted to a primary and tertiary hospital in Sweden between 2011 and 2016 were asked to participate. Fifty-nine children were assessed at a median time of 18 months (IQR 18-20) after hospitalization. Follow-up included measures of intellectual functioning, attention, working memory, and executive functions. Caregiver ratings of executive functioning and behavioral - emotional symptoms were assessed with standardized questionnaires. Neurocognitive outcome and measures of executive functions and behavioral-emotional symptoms varied greatly among participants. Basic auditory attention, working memory, and mental processing speed were affected and significantly lower compared to a standardized mean. Other domains identified as areas of vulnerability included executive functions, sustained attention, and the exert of self-control. Behavioral-emotional symptoms were less common; however, somatic complaints and behaviors related to conduct problems were seen in about one-third of individuals. This study highlights the importance of a comprehensive neurocognitive examination to identify children with unfavorable outcomes.

Pediatric epilepsy surgery in patients with Lennox-Gastaut syndrome after viral encephalitis

Objective

To analyse the surgical outcomes of pediatric patients with Lennox-Gastaut syndrome (LGS) secondary to viral encephalitis.

Methods

We retrospectively analyzed the data of four patients with LGS secondary to viral encephalitis who underwent surgery at the pediatric epilepsy center of Peking University First Hospital from January 2014 to December 2019. Preoperative evaluations included a detailed history, long-term video electroencephalography (VEEG), brain magnetic resonance imaging (MRI), positron emission tomography (PET) and a neuropsychological test. All patients were followed up at 1, 3, and 6 months and then yearly. The surgical outcome was evaluated according to the Engel classification.

Results

Among the four children, the surgeries were right temporo-parieto-occipital disconnection (case 1), corpus callosotomy (case 2), left temporo-parieto-occipital disconnection (case 3), and left temporal lobectomy (case 4). The pathology was gliosis secondary to viral encephalitis. The median follow-up time was 4 years (3-5 years). At the last follow-up, one case had Engel I, two cases had Engel III, and one case had Engel IV.

Conclusions

Preliminary observations shows that surgical treatment may be challenging for patients with LGS secondary to viral encephalitis. However, suitable surgical candidacy and approaches have a significant impact on the prognosis of the patients.

Startle Seizures and Diffuse Leukoencephalopathy After Resolution of Herpes Simplex Virus 1 Encephalitis in a Child

We describe a unique clinical presentation of a child after the acute phase of herpes simplex virus 1 (HSV1) encephalitis. A 17-month-old boy first presented with HSV1 encephalitis and was promptly treated with antiviral medication. Seven months later, he was re-admitted for startle seizures. Magnetic Resonance Imaging of the brain showed diffuse confluent leukoencephalopathy. This constellation of symptoms has not been previously reported in HSV1 encephalitis. In conclusion, we showed that brain injury due to HSV1 encephalitis can be associated with the development of startle seizures and diffuse white matter injury in the post-acute phase.

Seizures and epilepsy secondary to viral infection in the central nervous system

Viral infection in the central nervous system (CNS) is a common cause of seizures and epilepsy. Acute symptomatic seizures can occur in the context of almost all types of acute CNS viral infection. However, late unprovoked seizures and epilepsy may not be frequent after viral infection of the CNS. The incidence of seizures and epilepsy after CNS viral infection is mainly dependent on the brain region of infection. It remains to be determined whether treatment of CNS viral infection using antiepileptic drugs (AEDs) can prevent seizures and subsequent epilepsy in patients, particularly with regard to the timing, drug choice and dosage, and duration of AEDs. The postoperative outcome of seizures in patients with intractable epilepsy caused by viral encephalitis primarily depends on the epileptogenic zone. In addition, neuroinflammation is known to be widely involved in the generation of seizures during CNS viral infection, and the effects of anti-inflammatory therapies in preventing seizures and epilepsy secondary to CNS viral infection require further studies. In this review, we discuss the incidence, mechanisms, clinical management and prognosis of seizures and epilepsy secondary to CNS viral infection, and summarize common CNS viral infections that cause seizures and epilepsy.

Surgical treatment in children with intractable epilepsy after viral encephalitis

PURPOSE

To investigate the surgical outcome in children with epilepsy after viral encephalitis (VE), we studied the prognostic factors for surgery and summarized the surgical strategies of children with epilepsy secondary to VE.

METHODS

We retrospectively analyzed 23 surgically treated children with VE. The subjects were divided into two groups according to their surgical outcome. All presurgical evaluation data were collected and analyzed.

RESULTS

Among the 23 operated children, the mean age at surgery was 6.1 years. Surgeries were hemispherotomy (n = 12), temporal-parietal-occipital disconnection (n = 4), whole corpus callosotomy (n = 3), lobectomy (n = 3), and vagus nerve stimulation (n = 1). The mean patient follow-up time was 37.2 months, and 13 children had a good outcome (ILAE classification 1-3). Univariate analyses revealed that the latency from infection to the first unprovoked seizure, MRI laterality, concordance of PET and MRI abnormalities, and acute postoperative seizure (APOS) were prognostic factors of seizure outcomes (P < 0.05). No correlation was found between generalized seizures and poor outcome (P = 0.229).

CONCLUSIONS

We concluded that the children who achieve favorable surgical outcomes are those with longer latency, unilateral abnormalities on MRI, consistency of PET and MRI abnormalities, and no APOS. Without invasive studies, epilepsy surgery may be successful for selected children with epilepsy after VE, despite diffuse interictal epileptiform discharges on scalp EEG. In addition, children with generalized seizures were not an absolute contraindication for surgery.

Antiepileptic drugs for acute encephalitic patients presented with seizure

OBJECTIVE

The aim of this study was to clarify the pattern and efficacy of antiepileptic drugs (AEDs) in acute encephalitis and discuss how long AEDs should be used after the acute phase.

METHODS

Patients with acute encephalitis who presented with seizure were enrolled. The clinical features were systematically gathered, and the information about AEDs and seizures was obtained by a clinical follow-up and (or) a telephone interview based on a structured form.

RESULTS

A total of 327 patients were enrolled, and the mean follow-up period was 63.8 (14-123) months. The risk of seizure relapse was estimated as 43.6% five years after the acute phase and the first three months was the peak time for relapse. Univariate analysis showed that status epilepticus, more than one seizure, cerebral spinal fluid protein level, abnormal MRI finding, temporal lobe involvement, and epileptiform discharge were related to seizure relapse. But only more than one seizure (OR = 2.80 (95% CI 1.29-6.09), p = 0.009) and temporal lobe involvement (5.34 (2.68-10.64), p < 0.001) remain predictive on multivariate regression analysis. For patients with only one seizure and no temporal lobe involvement, the risk of seizure relapse was similar between those with or without AED (2/29 vs. 4/28, p = 0.423). For the rest, the risks of relapse were similar among those who took sodium valproate and levetiracetam.

SIGNIFICANCE

For patients with only one seizure and no temporal lobe involvement, AEDs may not be strictly needed. The first three months after acute phase was the peak time for relapse and AEDs may should be used during this period. Both sodium valproate and levetiracetam could be selected.

Immune Challenges and Seizures: How Do Early Life Insults Influence Epileptogenesis?

The development of epilepsy, a process known as epileptogenesis, often occurs later in life following a prenatal or early postnatal insult such as cerebral ischemia, stroke, brain trauma, or infection. These insults share common pathophysiological pathways involving innate immune activation including neuroinflammation, which is proposed to play a critical role in epileptogenesis. This review provides a comprehensive overview of the latest preclinical evidence demonstrating that early life immune challenges influence neuronal hyperexcitability and predispose an individual to later life epilepsy. Here, we consider the range of brain insults that may promote the onset of chronic recurrent spontaneous seizures at adulthood, spanning intrauterine insults (e.g. maternal immune activation), perinatal injuries (e.g. hypoxic–ischemic injury, perinatal stroke), and insults sustained during early postnatal life—such as fever-induced febrile seizures, traumatic brain injuries, infections, and environmental stressors. Importantly, all of these insults represent, to some extent, an immune challenge, triggering innate immune activation and implicating both central and systemic inflammation as drivers of epileptogenesis. Increasing evidence suggests that pro-inflammatory cytokines such as interleukin-1 and subsequent signaling pathways are important mediators of seizure onset and recurrence, as well as neuronal network plasticity changes in this context. Our current understanding of how early life immune challenges prime microglia and astrocytes will be explored, as well as how developmental age is a critical determinant of seizure susceptibility. Finally, we will consider the paradoxical phenomenon of preconditioning, whereby these same insults may conversely provide neuroprotection. Together, an improved appreciation of the neuroinflammatory mechanisms underlying the long-term epilepsy risk following early life insults may provide insight into opportunities to develop novel immunological anti-epileptogenic therapeutic strategies.

Postencephalitic epilepsy in dogs with meningoencephalitis of unknown origin: Clinical features, risk factors, and long-term outcome

Background

Although the presence of seizures in dogs with meningoencephalitis of unknown origin (MUO) has been associated with shorter survival times, data regarding the prevalence and risk factors for postencephalitic epilepsy (PEE) is lacking.

Objectives

To describe the clinical features, prevalence, risk factors, and long‐term outcome of PEE in dogs with MUO.

Animals

Sixty‐one dogs with presumptive diagnosis of MUO based on the clinicopathological and diagnostic imaging findings.

Methods

Retrospective study. Cases were identified by search of hospital medical records for dogs with suspected or confirmed MUO. Medical records of dogs meeting inclusion criteria were reviewed. Signalment, seizure history, clinicopathologic, and magnetic resonance imaging (MRI) findings were recorded.

Results

Among 61 dogs at risk of PEE, 14 (23%) dogs developed PEE. Three of 14 dogs with PEE (21%) developed drug‐resistant epilepsy. Dogs with PEE were younger (P = .03; OR_adjusted = 0.75; 95% confidence interval [CI], 0.58‐0.98) and had significantly shorter survival times (log‐rank test P = .04) when compared to dogs that did not develop epilepsy. The risk factors associated with the development of PEE were the presence of acute symptomatic seizures (ASS; P = .04; OR_adjusted = 4.76; 95% CI, 1.11‐20.4) and MRI lesions in the hippocampus (P = .04; OR_adjusted = 4.75; 95% CI, 1.07‐21.0).

Conclusions and Clinical Importance

Dogs with MUO and seizures at the early stage of the disease (ASS) seem to be at a higher risk of developing PEE.

Clinical features and surgical treatment of epilepsy after viral encephalitis

Encephalitis is an acute inflammatory process of the brain parenchyma, which is often caused by viral infection. It is an vital cause of acute symptomatic seizures and subsequent epilepsy. The incidence of unprovoked and recurrent seizures after previous infections of the central nervous system is high and accounts for 1%~5% of the cases of epilepsy. Viral encephalitis (VE) is directly caused by viral infection. The occurrence of seizures after VE is associated with poor prognosis. In survivors of VE, among other neurological sequelae, the risk of developing epilepsy is increased 10-fold. The risk of severe neurological sequelae after VE is particularly high in very young children. Studies on seizure occurrence, possible underlying mechanisms, clinical characteristics, and clinical treatment (especially surgical treatment) of VE have yielded only limited detailed data. We reviewed the most recent literature on the clinical features and surgical treatment of post-VE epilepsy.

Chronic post-encephalitic epilepsy following Japanese encephalitis: Clinical features, neuroimaging data, and outcomes

PURPOSE

Japanese encephalitis (JE), the main cause of viral encephalitis in Asia, usually presents with acute symptomatic seizures; however, there have been very few systematic reports regarding late unprovoked seizures and epilepsy. We aimed to describe the clinical features and outcomes of post-encephalitic epilepsy following JE.

METHODS

Patients with epilepsy with a previous confirmed diagnosis of JE visiting West China Hospital from 2013 to 2019 were enrolled in the observational case-controlled study. Patients with epilepsy with a history of other non-specific viral encephalitis were enrolled as controls. For all enrolled subjects, disease related information was recorded.

RESULTS

Forty-eight patients with JE (20 males; median age, 21.0 years; average epilepsy duration, 8.55 years) were identified. The median duration from JE to the first unprovoked seizure was 7.73 years, which significantly differed from that of the controls (7.73 vs. 2.69 years, respectively; p = 4.59 × 10^-6). Most patients had focal epilepsy, and 29 (78.38%) were drug resistant. Among 45 patients with available neuroimaging data, three in fourth had no obvious abnormality, and the temporal lobe and hippocampus (22.22%) were the most affected brain regions. Six patients had surgery, and three achieved class-one seizure-free status.

CONCLUSION

The latency to the first unprovoked seizure was longer in patients with JE than controls. Regarding chronic epilepsy, three in four had structural abnormalities, and the long-term outcomes of post-encephalitic epilepsy following JE were poor. Surgery remains an option for drug-resistant epilepsy.

Chronic dysfunction of blood-brain barrier in patients with post-encephalitic/encephalopathic epilepsy

PURPOSE

This study aimed to elucidate the characteristics and effects of chronic blood-brain barrier (BBB) dysfunction in patients with post-encephalitic/encephalopathic epilepsy (PEE), using brain images and the cerebral spinal fluid (CSF)/serum albumin ratio (albumin quotient, QAlb) as a marker of BBB function.

METHODS

We examined the albumin levels in CSF and serum samples from 312 patients with refractory epilepsy in our center between 2004 and 2015. Sixty samples from patients with PEE and 97 samples from age- and sex-matched disease controls (DC) were evaluated. We classified PEE patients into a widespread lesion group and a focal lesion group by severity on brain magnetic resonance images in the chronic phase after acute encephalitis/encephalopathy.

RESULTS

Median QAlb was higher in PEE than in DC [median (range) ×10³: PEE 3.6 (1.0-10.3) versus DC 2.7 (1.0-6.7), p = 0.007]. In a linear regression analysis of the relationship between QAlb and patient's age at CSF examination or duration of epilepsy, the slope of the regression line was greater in PEE than in DC. Furthermore, in patients under ten years of age, linear regression analysis of QAlb versus seizure frequency showed a weak but positive correlation. Among PEE patients, seizure frequency was higher in the widespread lesion group than in the focal lesion group [300 (4-3000) versus 30 (1-1500) seizures/month, p <  0.001].

CONCLUSION

Our study suggests that patients with PEE have more severe BBB dysfunction, and that the BBB dysfunction is associated with refractory epilepsy.

Predictive indicators for the development of epilepsy after acute encephalopathy with biphasic seizures and late reduced diffusion

Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is a newly defined clinicoradiologic syndrome characterized by biphasic seizures and altered consciousness followed by restricted diffusion in the white matter on magnetic resonance imaging in acute phase. Intractable epilepsy commonly occurs as the late complication. This study aimed to search predisposing factors to the development of epilepsy after AESD. Consecutively treated 22 patients with AESD in our institution from 2006 to 2016 were grouped into those with post-encephalopathic epilepsy (PEE, n = 10) or without PEE (n = 12). There was no difference between two groups in age at the onset of AESD, duration of the initial seizures, or the follow-up periods after discharge. PEE group patients more frequently showed coma or involuntary movements during the course of AESD than non-PEE group patients (36% vs. 8%, p = 0.008). The quantitative analysis of apparent diffusion coefficient (ADC) map revealed that PEE group showed broader areas with reduced diffusion in the posterior lobes at the onsets of AESD than non-PEE group (0.113 vs. 0.013, p = 0.035). On the other hand, the atrophy on day 30-ADC map did not correlate with the development or control of epilepsy. These results suggest that the clinical severity and ADC profiles in acute phase, rather than the brain atrophy in convalescent phase, may predict the development of post-AESD epilepsy.

Epileptic phenotypes, electroclinical features and clinical characteristics in 17 children with anti-NMDAR encephalitis

BACKGROUND

Anti-N-methyl d-aspartate receptor (NMDAR) encephalitis is a rare disorder characterized by seizures, neuropsychiatric symptoms, dyskinesia and autonomic instability.

OBJECTIVE

Aim of the present study was to evaluate the seizure phenotypes and electroencephalogram (EEG) features in children with anti-NMDAR encephalitis.

METHODS

Seizure types, electroclinical features and clinical characteristics of 17 children with anti-NMDAR encephalitis were analysed in a retrospective case series from nine centres in Europe.

RESULTS

Nearly half (8/17) of the children presented with psychiatric symptoms, whereas in 4/17 patients seizures were the first symptom and in 5/17 both symptoms occurred at the same time. During the following course seizures were reported in 16/17 children. The first EEG detected generalized slowing in 11/17 patients, focal slowing in 3/17 and normal background activity in only 3/17 children. The extreme delta brush (EDB) pattern was detected in 9/17 (53%) patients.

CONCLUSION

In addition to psychiatric symptoms, children with anti-NMDAR encephalitis often show generalized slowing in EEG with or without seizures at initial presentation. EDB is present in half of all children and is potentially a helpful tool for early detection of this immune-mediated disease.

Long-term outcomes of infective encephalitis in children: a systematic review and meta-analysis

AIM

The long-term outcomes of childhood infective encephalitis are variable and not well quantified. We aimed to systematically review the literature and undertake meta-analyses on predetermined outcomes to address this knowledge gap and identify areas for future research.

METHOD

We searched electronic databases, performed complementary reviews of references of fully extracted articles, and made contact with experts on infective encephalitis. Articles published up until April 2016 were selected for screening.

RESULTS

We evaluated sequelae of 1018 survivors of childhood infective encephalitis (934 with complete follow-up) from 16 studies. Mean age during acute encephalitis episodes was 5 years 3.6 months (range 1.2mo-17y), 57.6% were male (500/868), and mean follow-up period was 4 years 1.2 months (range 1-12y). Incomplete recovery was reported in 312 children (42.0%; 95% confidence interval [CI] 31.6-53.1% in pooled estimate). Among the other sequelae, developmental delay, abnormal behaviour, motor impairment, and seizures were reported among 35.0% (95% CI 10.0-65.0%), 18.0% (95% CI 8.0-31.0%), 17.0% (95% CI 10.0-26.0%), and 10.0% (95% CI 6.0-14.0%) respectively.

INTERPRETATION

Almost half of childhood infective encephalitis survivors report incomplete recovery in the long-term; most commonly developmental delay, behavioural abnormality, and neurological impairments (i.e. seizure). Well designed, large-scale prospective studies are needed to better quantify neurodevelopmental sequelae among childhood encephalitis survivors.

Antiepileptic drugs for the primary and secondary prevention of seizures in viral encephalitis

BACKGROUND

Viral encephalitis is characterised by diverse clinical and epidemiological features. Seizures are an important clinical manifestation and are associated with increased mortality and morbidity. Patients may have seizures during the acute illness or they may develop after recovery. There are no recommendations regarding the use of antiepileptic drugs for the primary or secondary prevention of seizures in patients with viral encephalitis.This is an updated version of the original Cochrane review published in The Cochrane Library 2014, Issue 10.

OBJECTIVES

To assess the efficacy and tolerability of antiepileptic drugs for the primary and secondary prophylaxis of seizures in viral encephalitis. We had intended to answer the following questions.1. Do antiepileptic drugs used routinely as primary prophylaxis for all patients with suspected or proven viral encephalitis reduce the risk of seizures during the acute illness and reduce neurological morbidity and mortality?2. Do antiepileptic drugs used routinely as secondary prophylaxis for all patients who have had at least one seizure due to suspected or proven viral encephalitis reduce the risk of further seizures during the acute illness and reduce neurological morbidity and mortality?

SEARCH METHODS

For the latest version of this review, we searched the Cochrane Epilepsy Group Specialized Register (11 April 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO, 11 April 2016), MEDLINE (Ovid 1946 to 11 April 2016), the WHO International Clinical Trials Registry Platform (ICTRP, 11 April 2016), and ClinicalTrials.gov (11 April 2016). We did not impose any language restrictions.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials in which patients were assigned to a treatment or control group (placebo or no drug).

DATA COLLECTION AND ANALYSIS

One review author (SP) searched the publications by title, abstract and keywords, and decided on their suitability for the review. For any studies where their suitability was unclear, the co-authors (CR, BM) were consulted. The co-authors (CR, BM) independently evaluated the selected studies. Since there were no included studies, we carried out no data analysis.

MAIN RESULTS

We did not find any randomised or quasi-randomised controlled trials that compared the effects of antiepileptic drugs with placebo (or no drug) for the primary or secondary prevention of seizures in viral encephalitis. We identified two studies from the literature search where different antiepileptic drugs were used in patients with viral encephalitis, however both failed to meet the inclusion criteria.

AUTHORS' CONCLUSIONS

There is insufficient evidence to support or refute the routine use of antiepileptic drugs for the primary or secondary prevention of seizures in viral encephalitis. There is a need for adequately powered randomised controlled trials in patients with viral encephalitis to assess the efficacy and tolerability of antiepileptic drugs for the primary and secondary prophylaxis of seizures, which is an important clinical problem.

Can we differentiate between herpes simplex encephalitis and Japanese encephalitis?

BACKGROUND

Herpes simplex encephalitis (HSE) occurs without regional and seasonal predilections. HSE is important to differentiate from arboviral encephalitis in endemic areas because of therapeutic potential of HSE. This study evaluates clinical features, MRI and laboratory findings which may help in differentiating HSE from Japanese encephalitis (JE).

METHODS

Confirmed patients with JE and HSE in last 10years were included. The presenting clinical symptoms including demographic information, seizure, behavioral abnormality, focal weakness and movement disorders were noted. Cranial MRI was done and location and nature of signal alteration were noted. Electroencephalography (EEG), cerebrospinal fluid (CSF), blood counts and serum chemistry were done. Outcome was measured by modified Rankin Scale (mRS). Death, functional outcome and neurological sequelae were noted at 3, 6 and 12months follow up, and compared between HSE and JE. Outcome was categorized as poor (mRS;>2) and good (mRS≤2).

RESULTS

97 patients with JE and 40 HSE were included. JE patients were younger than HSE and occurred in post monsoon period whereas HSE occurred throughout the year. Seizure (86% vs 40%) and behavioral abnormality (48% vs 10%) were commoner in HSE; whereas movement disorders (76% vs 0%) and focal reflex loss (42% vs 10%) were commoner in JE. CSF findings and laboratory parameters were similar in both the groups. Thalamic involvement in JE and temporal involvement in HSE were specific markers of respective encephalitis. Delta slowing on EEG was more frequent in JE than HSE. 20% JE and 30% HSE died in the hospital, and at 1year follow up JE patients showed better outcome compared to HSE (48% vs 24%). Memory loss (72% vs 22%) was the predominant sequelae in HSE.

CONCLUSION

Seizure and behavioral abnormality are common features in HSE whereas focal reflex loss is commoner in JE. In a patient with acute encephalitis, thalamic lesion suggests JE and temporal lobe involvement HSE. Long term outcome in JE is better compared to HSE.

Prognostic Value of Initial Standard EEG and MRI in Patients with Herpes Simplex Encephalitis

Background and Purpose

Herpes simplex encephalitis (HSE) is the most common type of sporadic encephalitis worldwide, and it remains fatal even when optimal antiviral therapy is applied. There is only a weak consensus on the clinical outcomes and prognostic factors in patients with HSE. This study examined whether the radiological and electrophysiological findings have a prognostic value in patients with HSE.

Methods

We retrospectively analyzed patients who were diagnosed with HSE by applying the polymerase chain reaction to cerebrospinal fluid and who received intravenous acyclovir at our hospital from 2000 to 2014. We evaluated the clinical outcomes at 6 months after onset and their correlations with initial and clinical findings, including the volume of lesions on MRI, the severity of EEG findings, and the presence of epileptic seizures at the initial presentation.

Results

Twenty-nine patients were enrolled (18 men and 11 women). Univariate analysis revealed that the presence of severe EEG abnormality and epileptic seizures at the initial presentation were significant correlated with a poor clinical outcome at 6 months (p=0.005 and p=0.009, respectively). In multivariate analysis, the presence of severe EEG abnormality was the only independent predictor of a poor outcome at 6 months (p=0.006).

Conclusions

In cases of HSE, the initial EEG severity and seizure presentation may be useful predictive factors for the outcome at 6 months after acyclovir treatment.

Postencephalitic epilepsy and drug-resistant epilepsy after infectious and antibody-associated encephalitis in childhood: Clinical and etiologic risk factors

To define the risk factors for postencephalitic epilepsy (PE) and drug-resistant epilepsy (DRE) in childhood following infectious and autoimmune encephalitis, we included 147 acute encephalitis patients with a median follow-up of 7.3 years (range 2-15.8 years). PE was defined as the use of antiepileptic drugs (AEDs) for ≥24 months, and DRE was defined as the persistence of seizures despite ≥2 appropriate AEDs at final follow-up. PE and DRE were diagnosed in 31 (21%) and 15 (10%) of patients, respectively. The features during acute encephalitis predictive of DRE (presented as odds ratio [OR] with confidence intervals [CIs]) were status epilepticus (OR 10.8, CI 3.4-34.3), visual disturbance (6.4, 1.4-29.9), focal seizures (6.2, 1.9-20.6), magnetic resonance imaging (MRI) hippocampal/amygdala involvement (5.0, 1.7-15.4), intensive care admission (4.7, 1.4-15.4), use of >3 AEDs (4.5, 1.2-16.1), MRI gadolinium enhancement (4.1, 1.2-14.2), any seizure (3.9, 1.1-14.4), and electroencephalography (EEG) epileptiform discharges (3.9, 1.3-12.0). On multivariable regression analysis, only status epilepticus remained predictive of DRE in all models. DRE was common in herpes simplex virus (3/9, 33%) and unknown (8/40, 20%) encephalitis, but absent in acute disseminated encephalomyelitis (ADEM) (0/32, 0%), enterovirus (0/18), and anti-N-methyl-d-aspartate receptor-NMDAR encephalitis (0/9). We have identified risk factors for DRE and demonstrated "high-risk," and "low-risk" etiologies.

Postencephalitic epilepsy: clinical characteristics and predictors

OBJECTIVE

To describe the etiologies, clinical presentations, outcomes, and predictors of postencephalitic epilepsy (PE) in a large series of adult patients with acute encephalitis.

METHODS

We conducted a retrospective review of patients diagnosed with acute encephalitis at Mayo Clinic, Rochester, between January 2000 and December 2012. The patients were categorized into two groups based on the presence or absence of PE at last follow-up. Multivariate logistic regression analysis was used to analyze factors associated with PE.

RESULTS

We identified 198 consecutive patients (100 [50.5%] male and 98 [49.5%] female) with a median age of 58 years (range 41.8-69). Etiologies included viral infection (n=95, 48%), autoimmune (n=44, 22%), and unknown/others (n=59, 30%). During hospitalization, seizures were seen in patients with autoimmune encephalitis (n=24, 54.5%), unknown/others (n=20, 33.9%), and viral encephalitis (n=23, 24.2%). Interictal epileptiform discharges on electroencephalography (EEG) were present in 34 (54%), whereas periodic lateralized epileptiform discharges (PLEDs) and generalized periodic discharges (GPDs) were seen in 14 (41.2%) and 2 (5.9%) patients. Forty-six patients with seizures (70.8%) had fluid-attenuated inversion recovery (FLAIR)/T2 abnormalities, 20 (31.3%) diffusion abnormalities, and 43 (66.2%) cortical involvement. Good outcome at discharge among patients with seizures was seen in 8/23 patients with viral etiology (34.8%), 10/24 patients with autoimmune encephalitis (45.5%), and 12/20 patients with unknown cause (60%). PE was present in 43 patients (29.9%). On multivariate regression analysis, the factors associated with PE were generalized seizures during hospitalization (p=0.03), focal seizures (p≤0.001), and the presence of FLAIR/T2 abnormalities on brain magnetic resonance imaging (MRI) (p=0.003).

SIGNIFICANCE

The presence of seizures during hospitalization and an abnormal brain MRI are the strongest predictors of the development of PE. The etiology of encephalitis, presence of focal neurologic deficits, and interictal EEG abnormalities did not influence the development of PE.

Outcome of children with acute encephalitis and refractory status epilepticus

Acute encephalitis in children is a life-threatening neurological emergency. However, little is reported about the outcome of this devastating illness in the United States. The authors retrospectively reviewed the charts of patients admitted to a regional pediatric intensive care unit with the diagnosis of acute encephalitis between 2006 and 2011. In 41 cases that met the inclusion criteria, the most common presenting symptoms were fever (65.9%), altered mental status (61%), and seizures (58.5%). Eight patients (19.5%) who presented with refractory status epilepticus had a longer median length of stay in the pediatric intensive care unit (46 vs. 4 days; P < .0001) and a significant worsening of Pediatric Cerebral Performance Category score on discharge by 2 or more points (odds ratio 20.38; 95% confidence interval, 2.89-143.52). All children survived to hospital discharge. In conclusion, children with acute encephalitis who present with refractory status epilepticus have a worse neurological outcome and a longer stay in the pediatric intensive care unit.

Antiepileptic drugs for the primary and secondary prevention of seizures in viral encephalitis

BACKGROUND

Viral encephalitis is characterised by diverse clinical and epidemiological features. Seizures are an important clinical manifestation and associated with increased mortality and morbidity. Patients may have seizures during the acute illness or they may develop after recovery. There are no recommendations regarding the use of antiepileptic drugs for the primary or secondary prevention of seizures in patients with viral encephalitis.

OBJECTIVES

To assess the efficacy and safety of antiepileptic drugs for the primary and secondary prophylaxis of seizures in viral encephalitis. We intended to answer the following questions.1. Do antiepileptic drugs used as primary prophylaxis routinely for all patients with suspected or proven viral encephalitis reduce the risk of seizures during the acute illness and reduce neurological morbidity and mortality?2. Do antiepileptic drugs used as secondary prophylaxis routinely for all patients who have had at least one seizure due to suspected or proven viral encephalitis reduce the risk of further seizures during the acute illness and reduce neurological morbidity and mortality?

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialised Register (13 May 2014), the Cochrane Central Register of Controlled Trials (CENTRAL 2014, Issue 4) (April 2014), MEDLINE (Ovid, 1946 to 13 May 2014), the WHO ICTRP search portal (13 May 2014) and ClinicalTrials.gov (13 May 2014). We did not impose any language restrictions.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials in which patients were assigned to a treatment or control group (placebo or no drug).

DATA COLLECTION AND ANALYSIS

One author (SP) searched the publications by title, abstract and keywords and decided on their suitability for inclusion in the review. For any studies where it was unclear whether they would be suitable for inclusion, the co-authors (CR, BM) were consulted. The co-authors (CR, BM) evaluated the selected studies independently. Since there were no included studies, we carried out no data analysis.

MAIN RESULTS

We did not find any randomised or quasi-randomised controlled trials that compared the effects of antiepileptic drugs with placebo (or no drug) for the primary or secondary prevention of seizures in viral encephalitis. We identified two studies from the literature search where different antiepileptic drugs were used in patients with viral encephalitis, however both failed to meet the inclusion criteria. The first study included children with viral encephalitis where antiepileptic drugs were given. However, it is not clear how the diagnosis was established or the aetiologies. In addition, the randomisation and blinding method is not disclosed; the patients received a diverse and ill-defined range of antiepileptic drugs and adjunctive therapies, and none of the primary or secondary outcome measures was assessed. In the second study, adults with status epilepticus (of whom a proportion had viral encephalitis), who had failed to respond to two initial boluses of diazepam, were randomised to either valproate or diazepam. The study was open-label and the randomisation methodology was not disclosed; none of the primary or secondary outcomes were reported. Data on treatment response between the two arms for those patients with viral encephalitis are not presented for subgroup analysis; the Cochrane Epilepsy Group have contacted the authors for these data but have yet to receive a response.

AUTHORS' CONCLUSIONS

There is insufficient evidence to support the routine use of antiepileptic drugs for the primary or secondary prevention of seizures in viral encephalitis. There is a need for adequately powered randomised controlled trials in viral encephalitis patients to assess the efficacy and safety of antiepileptic drugs for the primary and secondary prophylaxis of seizures, which is an important clinical problem.

Etiology and complications of central nervous system infections in children treated in a pediatric intensive care unit in Poland

Central nervous system infections are significant causes of mortality and long-term neurologic complications in children. Survivors often require an extended period of rehabilitation. The authors carried out a retrospective analysis of 1158 children (aged 1 month to 16 years; 31 boys) treated in one pediatric intensive care unit in Warsaw between 2002 and 2010. Forty-three of 1158 (3.7%) children presented with neuroinfections. Nearly two-thirds of the children were younger than age 5 years. The majority of cases (62.8%) were vaccine-preventable bacterial infections. The most frequent complications were brain edema (30.2%), brain hemorrhage (27.9%), and secondary nosocomial pneumonia (25.6%). One-fifth of children developed late, long-term neurologic complications. The mortality rate was 20.9%. The study showed that central nervous system infections are significant causes of hospitalization in the pediatric intensive care unit and often result in death or long-term complications. These infections mainly affect children younger than age 5 years. The majority could be prevented with immunizations.

Long-term motor and cognitive outcome of acute encephalitis

OBJECTIVES

To examine the long-term motor and neurocognitive outcome of children with acute encephalitis and to look at possible prognostic factors.

METHODS

Children who were treated for acute encephalitis in 2000-2010 were reevaluated. All children and their parents were interviewed by using structured questionnaires, and the children underwent full neurologic examinations, along with comprehensive neurocognitive, attention, and behavioral assessments.

RESULTS

Of the 47 children enrolled, 1 died and 29 had neurologic sequelae, including motor impairment, mental retardation, epilepsy, and attention and learning disorders. Children with encephalitis had a significantly higher prevalence of attention-deficit/hyperactivity disorder (50%) and learning disabilities (20%) compared with the reported rate (5%-10%) in the general population of Israel (P < .05) and lower IQ scores. Lower intelligence scores and significantly impaired attention and learning were found even in children who were considered fully recovered at the time of discharge. Risk factors for long-term severe neurologic sequelae were focal signs in the neurologic examination and abnormal neuroimaging on admission, confirmed infectious cause, and long hospital stay.

CONCLUSIONS

Encephalitis in children may be associated with significant long-term neurologic sequelae. Significant cognitive impairment, attention-deficit/hyperactivity disorder, and learning disabilities are common, and even children who were considered fully recovered at discharge may be significantly affected. Neuropsychological testing should be recommended for survivors of childhood encephalitis.

Epidemiology, outcomes and predictors of recovery in childhood encephalitis: a hospital-based study

BACKGROUND

Pediatric encephalitis is a devastating diagnosis with little guidance regarding prognostic indicators early in the hospitalization.

METHODS

This is a retrospective cohort study of patients with encephalitis referred to the California Encephalitis Project from Children's Hospital & Research Center Oakland from 1998 to 2010. Demographic, clinical, laboratory and neuroimaging data were collected by California Encephalitis Project and chart review. Outcomes were classified into "recovery" or "incomplete recovery" and evaluated at discharge and other times (7-10 days postadmission, 3 and 12 months postdischarge). Using logistic regression, predictors associated with recovery were identified.

RESULTS

Of 190 patients with outcomes available at discharge, 128 patients (67.4%) recovered, whereas 62 (32.6%) had an incomplete recovery, including 13 deaths (6.8%). Variables predictive of outcomes at discharge in the bivariate and multivariable analyses included Asian/Pacific Islander race, neuroimaging results and Glasgow Coma Score. Asian/Pacific Islander patients were less likely to recover than patients of other races (adjusted odds ratio = 0.43, P = 0.046). Patients with normal neuroimaging studies were more likely to recover than patients with abnormal neuroimaging (adjusted odds ratio = 2.54, P = 0.008). Patients with Glasgow Coma Score ≥7 were more likely to recover than patients with Glasgow Coma Score <7 (adjusted odds ratio = 5.82, P < 0.001). In a multivariable analysis, similar statistically significant findings were noted at all other analyzed times. Results were similar using a different population for validation, however, due to the small number of Asian/Pacific Islander patients; this finding could not be validated.

CONCLUSIONS

This study is unique in identification of race/ethnicity as an independent predictor of pediatric encephalitis outcomes. Additional variables may be useful ancillary tools in determining prognosis.

Children often present with infantile spasms after herpetic encephalitis

PURPOSE

To determine what epilepsy types occur after herpetic encephalitis and what are the determinant factors for subsequent infantile spasms.

METHODS

We analyzed retrospectively the clinical history of 22 patients, referred to Necker and Saint Vincent de Paul Hospitals (Paris) through the French pediatric epilepsy network from March 1986 to April 2010 and who developed epilepsy some months after herpetic encephalitis. We focused on seizure semiology with video-electroencephalography (EEG) recording, and on neuroradiology and epilepsy follow-up.

KEY FINDINGS

Fourteen patients developed pharmacoresistant spasms, and eight developed focal epilepsy, but none had both. The patients who developed spasms were more frequently younger than 30 months at age of onset of epilepsy and had herpetic encephalitis earlier (mean 10.6 months of age) than those who developed focal epilepsy (mean 59.7 and 39.6 months, respectively). Epilepsy follow-up was similar in both groups (8.5 and 11 years, respectively). We found 26 affected cerebral areas; none alone was related to the development of epileptic spasms.

SIGNIFICANCE

Risk factors to develop epileptic spasms were to have had herpetic encephalitis early (mean 10 months); to be significantly younger at onset of epilepsy (mean 22.1 months); and to have cerebral lesions involving the insula, the hippocampus, and the temporal pole.

Problems and controversies in status epilepticus: a review and recommendations

Status epilepticus (SE) is a neurologic emergency that require immediate vigorous treatment in order to prevent serious morbidity or even death. Several investigators have suggested that the underlying etiology is the primary determinant of outcome. We believe that this may be true in aggressively treated SE, but not when the treatment is less than optimal. In this article, we will discuss the factors that have been implicated in affecting SE outcomes, and argue, on the basis of both human and experimental animal data, that aggressive treatment is necessary and appropriate for all presentations of SE in order to maximize the probability of a successful outcome even when the etiology suggests a poor prognosis.

Cutaneous adverse drug reaction in patients with epilepsy after acute encephalitis

Patients with epilepsy after encephalitis/encephalopathy (EAE) often have refractory seizures, resulting in polytherapy with the risk of adverse reactions due to anti-epileptic drugs (AEDs). We focused on the characteristics of cutaneous adverse reaction (CAR). In this retrospective study, the medical records of 67 patients who were diagnosed as having EAE in our hospital were reviewed and the clinical characteristics were analyzed. Immunological biomarkers including cytokines, chemokines, granzyme B, soluble tumor necrosis factor receptor 1 (s-TNFR 1), matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were measured in 22 patients. CARs attributed to AEDs were observed in 16 of 67 EAE patients (23.9%) (CAR group). High CAR rates were observed with phenytoin, lamotrigine, phenobarbital, and carbamazepine. Severe CARs were found in three of 67 patients (4.5%). The frequencies of CARs were significantly higher in patients with encephalitis onset older than five years of age. CAR occurred only in patients who had onset of EAE within 6 months after encephalitis. The durations from acute encephalitis to CARs were within one year for almost all AEDs, except lamotrigine. The proportion of patients with serumregulated on activation normal T cell expressed and secreted (RANTES) levels higher than the upper limit of normal range was significantly higher in CAR group than in non-CAR group. Patients in the early stage of EAE and patients with encephalitis onset older than five years of age may be at higher risk of CARs to AEDs, especially to phenytoin, lamotrigine, phenobarbital, and carbamazepine. RANTES may be a biomarker for susceptibility to CARs in EAE patients.

Seizures in 204 comatose children: incidence and outcome

Purpose

Seizures are common in comatose children, but may be clinically subtle or only manifest on continuous electroencephalographic monitoring (cEEG); any association with outcome remains uncertain.

Methods

cEEG (one to three channels) was performed for a median 42 h (range 2–630 h) in 204 unventilated and ventilated children aged ≤15 years (18 neonates, 61 infants) in coma with different aetiologies. Outcome at 1 month was independently determined and dichotomized for survivors into favourable (normal or moderate neurological handicap) and unfavourable (severe handicap or vegetative state).

Results

Of the 204 patients, 110 had clinical seizures (CS) before cEEG commenced. During cEEG, 74 patients (36 %, 95 % confidence interval, 95 % CI, 32–41 %) had electroencephalographic seizures (ES), the majority without clinical accompaniment (non-convulsive seizures, NCS). CS occurred before NCS in 69 of the 204 patients; 5 ventilated with NCS had no CS observed. Death (93/204; 46 %) was independently predicted by admission Paediatric Index of Mortality (PIM; adjusted odds ratio, aOR, 1.027, 95 % CI 1.012–1.042; p < 0.0005), Adelaide coma score (aOR 0.813, 95 % CI 0.700–0.943; p = 0.006), and EEG grade on admission (excess slow with >3 % fast, aOR 5.43, 95 % CI 1.90–15.6; excess slow with <3 % fast, aOR 8.71, 95 % CI 2.58–29.4; low amplitude, 10th centile <9 µV, aOR 3.78, 95 % CI 1.23–11.7; and burst suppression, aOR 10.68, 95 % CI 2.31–49.4) compared with normal cEEG, as well as absence of CS at any time (aOR 2.38, 95 % CI 1.18–4.81). Unfavourable outcome (29/111 survivors; 26 %) was independently predicted by the presence of ES (aOR 15.4, 95 % CI 4.7–49.7) and PIM (aOR 1.036, 95 % CI 1.013–1.059).

Conclusion

Seizures are common in comatose children, and are associated with an unfavourable outcome in survivors. cEEG allows the detection of subtle CS and NCS and is a prognostic tool.

Mycoplasma pneumoniae-related postencephalitic epilepsy in children

PURPOSE

Mycoplasma pneumoniae, a common respiratory pathogen, has been implicated as an etiology of encephalitis, but there are few reports about it and postencephalitic epilepsy. This study aimed to investigate clinical factors, electroencephalography, and neuroradiologic features of M. pneumoniae-related encephalitis in a series of children with postencephalitic epilepsy and to examine possible prognostic factors.

METHODS

Cases of M. pneumoniae-related encephalitis between January 2001 and June 2010 were retrospectively reviewed. Systematic clinical data were evaluated.

KEY FINDINGS

The 99 enrolled patients with M. pneumoniae-related encephalitis were all positive by serology and 47 (47.5%) of them developed postencephalitic epilepsy. During the acute phase, 53 patients (53.5%) had seizures, the most common type of which was primary focal with secondary generalized tonic-clonic seizure (39.6%). The most common initial electroencephalography was focal/diffuse cortical dysfunction (37.4%) and focal epileptiform discharge (26.4%). The time of follow-up ranged from 6-131 months. At the end of the study, 19 (40.4%) of the 47 children with postencephalitic epilepsy had intractable seizures.

SIGNIFICANCE

Postencephalitic epilepsy is not a rare complication of M. pneumoniae-related encephalitis. Seizures in the acute phase and focal epileptiform discharges in initial electroencephalography are significant prognostic factors.

Infectious causes of seizures and epilepsy in the developing world

Central nervous system (CNS) infections are the main cause of seizures and acquired epilepsy in the developing world. Geographical variations determine the common causes in a particular region. Acute seizures are common in severe meningitis, viral encephalitis, malaria, and neurocysticercosis, and in most cases are associated with increased mortality and morbidity, including subsequent epilepsy. Neuronal excitability secondary to proinflammatory signals induced by CNS infections are an important common mechanism for the generation of seizures, in addition to various other specific mechanisms. Newer insights into the neurobiology of these infections and the associated epilepsy could help in developing neuroprotective interventions. Management issues include prompt treatment of acute seizures and the underlying CNS infection, correction of associated predisposing factors, and decisions regarding the appropriate choice and duration of antiepileptic therapy. Strategies for the prevention of epilepsy in CNS infections such as early anti-infective and anti-inflammatory therapy need scientific exploration. Prevention of CNS infections is the only definitive way forward to reduce the burden of epilepsy in developing countries.

Acute encephalitis with refractory, repetitive partial seizures (AERRPS): a peculiar form of childhood encephalitis

OBJECTIVE

We conducted a nationwide multicenter study in Japan to elucidate the clinical and laboratory characteristics of acute encephalitis with refractory, repetitive partial seizures (AERRPS).

MATERIALS AND METHODS

Clinical and laboratory features, treatment, and outcome were assessed using a structured questionnaire.

RESULTS

Twenty-nine children were enrolled in the study. Refractory and repetitive partial seizures accompanied by fever were the cardinal clinical features. Partial seizures consisted principally of eye deviation or facial twitching, being periodically repeated during the acute phase. These seizures were refractory to conventional anticonvulsants and were only suppressed by high-dose intravenous barbiturate administration. Rhythmic activities on electroencephalography and non-specific cerebral atrophy on neuroimaging were common. Serum or cerebrospinal antibodies against GluRepsilon2 were positive in six patients. General prognosis was unfavorable due to intractable epilepsy and cognitive deficits.

CONCLUSION

Based on the peculiar and homogenous features, AERRPS can be regarded as a distinct clinical entity.

Viral-like brain inflammation during development causes increased seizure susceptibility in adult rats

Viral infections of the CNS and their accompanying inflammation can cause long-term neurological effects, including increased risk for seizures. To examine the effects of CNS inflammation, we infused polyinosinic:polycytidylic acid, intracerebroventricularly to mimic a viral CNS infection in 14 day-old rats. This caused fever and an increase in the pro-inflammatory cytokine, interleukin (IL)-1beta in the brain. As young adults, these animals were more susceptible to lithium-pilocarpine and pentylenetetrazol-induced seizures and showed memory deficits in fear conditioning. Whereas there was no alteration in adult hippocampal cytokine levels, we found a marked increase in NMDA (NR2A and C) and AMPA (GluR1) glutamate receptor subunit mRNA expression. The increase in seizure susceptibility, glutamate receptor subunits, and hippocampal IL-1beta levels were suppressed by neonatal systemic minocycline. Thus, a novel model of viral CNS inflammation reveals pathophysiological relationships between brain cytokines, glutamate receptors, behaviour and seizures, which can be attenuated by anti-inflammatory agents like minocycline.

Viral encephalitis and epilepsy

Viral encephalitis presents with seizures not only in the acute stage but also increases the risk of late unprovoked seizures and epilepsy. Acute symptomatic and late unprovoked seizures in different viral encephalitides are reviewed here. Among the sporadic viral encephalitides, Herpes simplex encephalitis (HSE) is perhaps most frequently associated with epilepsy, which may often be severe. Seizures may be the presenting feature in 50% patients with HSE because of involvement of the highly epileptogenic frontotemporal cortex. The occurrence of seizures in HSE is associated with poor prognosis. In addition, chronic and relapsing forms of HSE have been described and these may be associated with antiepileptic drug-resistant seizures. Among the epidemic (usually due to flaviviruses) viral encephalitides, Japanese encephalitis (JE) is most common and is associated with acute symptomatic seizures, especially in children. The reported frequency of acute symptomatic seizures in JE is 7-46%. Encephalitis due to other flaviviruses such as equine, St. Louis, and West Nile viruses may also manifest with acute symptomatic seizures. In Nipah virus encephalitis, seizures are more common in relapsed and late-onset encephalitis in comparison to acute encephalitis (4% vs. 1.8%). Other viruses like measles, varicella, mumps, influenza, and entero-viruses may cause seizures depending on the area of brain involved. There is no comprehensive data regarding late unprovoked seizures in different viral encephalitides. Prospective studies are required to document the risk of late unprovoked seizures and epilepsy following viral encephalitis due to different viruses as well as to determine the clinical characteristics, course, and outcome of post-encephalitic epilepsy.

Epilepsy surgery: eligibility criteria and presurgical evaluation

Epilepsy surgery has benefited from major advances during the last 20 years, thanks to the development of neuroimaging and long-term video-electroencephalographic (EEG) monitoring. However, it remains the case that only a small minority of potential epilepsy surgery candidates will have access to a comprehensive presurgical evaluation. Furthermore, this subset of patients are operated on after an average of 20 to 25 years of epilepsy duration. Among the various reasons that prevent many patients from benefiting from a timely presurgical evaluation, we need to emphasize the role of inaccurate information regarding eligibility criteria and lack of standardized practice. This review aims at providing an indepth discussion of the current views regarding the definition of surgical candidates, and the role of the numerous investigations used in the presurgical evaluation of patients with drug-resistant epilepsy.

The eligibility criteria required to enter a presurgical evaluation in 2008 should be relatively liberal, provided that the patient suffers from disabling seizures unrelated to an idiopathic generalized epileptic syndrome, despite appropriate antiepileptic drug treatment However, the decision as to whether or not to perform a presurgical evaluation must be individualized, and take into account the likelihood of meeting the patient's expectations in terms of outcome. These expectations need to be balanced with the apparent severity of the epileptic condition, the chance of achieving a successful surgical treatment, and the risk of a postoperative neurological, cognitive, or psychiatric deterioration. The roles and specific features of the main types of presurgical investigations are reviewed.