Cognitive outcome of status epilepticus in children

The burden of epilepsy on long-term outcome of genetic developmental and epileptic encephalopathies: A single tertiary center longitudinal retrospective cohort study

BACKGROUND

This retrospective cohort analysis highlighted neurodevelopmental outcome predictors of genetic developmental and epileptic encephalopathies (DEE).

PATIENTS AND METHODS

Patients' demographic, clinical and molecular genetics data were collected. All patients underwent clinical, developmental, and neuropsychological assessments.

RESULTS

We recruited 100 participants (53 males, 47 females) with a mean follow-up lasting 10.46 ± 8.37 years. Age at epilepsy-onset was predictive of poor adaptive and cognitive functions (VABS-II score, r = 0.350, p = 0.001; BRIEF control subscale, r = -0.253; p = 0.031). Duration of epilepsy correlated negatively with IQ (r = -0.234, p = 0.019) and VABS-II score (r = -0.367, p = 0.001). Correlations were found between delayed/lacking EEG maturation/organization and IQ (r = 0.587, p = 0.001), VABS-II score (r = 0.658, p = 0.001), BRIEF-MI and BRIEF-GEC scores (r = -0.375, p = 0.001; r = -0.236, p = 0.033), ASEBA anxiety (r = -0.220, p = 0.047) and ADHD (r = -0.233, p = 0.035) scores. The number of antiseizure medications (ASMs) correlated with IQ (r = -0.414, p = 0.001), VABS-II (r = -0.496, p = 0.001), and BRIEF-MI (r = 0.294, p = 0.012) scores; while age at the beginning of therapy with ASEBA anxiety score (r = 0.272, p = 0.013). The occurrence of status epilepticus was associated with worse adaptive performances. The linear regression analysis model showed that delayed/lacking EEG maturation/organization had a significant influence on the IQ (R2 = 0.252, p < 0.001) and the BRIEF-GEC variability (R2 = 0.042, p = 0.036). The delayed/lacking EEG maturation/organization and the duration of epilepsy also had a significant influence on the VABS-II score (R2 = 0.455, p = 0.005).

CONCLUSIONS

Age at seizure-onset, EEG maturation/organization, duration of epilepsy, occurrence of status epilepticus, age at the introduction and number of ASMs used are reliable predictors of long-term outcomes in patients with genetic DEE.

Specific profiles of new-onset vs. non-inaugural status epilepticus: From diagnosis to 1-year outcome

While new-onset status epilepticus (NOSE) is a harbinger of chronic epilepsy, prospective medical data are sparse in terms of specifying whether the evolution of status epilepticus (SE) and seizure expression in NOSE resembles what occurs in patients who have already been diagnosed with epilepsy [non-inaugural SE (NISE)] in all aspects apart from its inaugural nature. The aim of this study was to compare the clinical, MRI, and EEG features that could distinguish NOSE from NISE. We conducted a prospective monocentric study in which all patients ≥18 years admitted for SE over a 6-month period were included. A total of 109 patients (63 NISE and 46 NOSE cases) were included. Despite similar modified Rankin scores before SE, several aspects of the clinical history distinguished NOSE from NISE patients. NOSE patients were older and frequently had neurological comorbidity and preexisting cognitive decline, but they had a similar prevalence of alcohol consumption to NISE patients. NOSE and NISE evolve in the same proportions as refractory SE (62.5% NOSE, 61% NISE) and share common features such as the same incidence (33% NOSE, 42% NISE, and p = 0.53) and volumes of peri-ictal abnormalities on MRI. However, in NOSE patients, we observed greater non-convulsive semiology (21.7% NOSE, 6% NISE, and p = 0.02), more periodic lateral discharges on EEG (p = 0.004), later diagnosis, and higher severity according to the STESS and EMSE scales (p < 0.0001). Mortality occurred in 32.6% of NOSE patients and 21% of NISE patients at 1 year (p = 0.19), but with different causes of death occurring at different time points: more early deaths directly linked to SE at 1 month occurred in the NOSE group, while there were more remote deaths linked to causal brain lesions in the NISE group at final follow-up. In survivors, 43.6% of the NOSE cases developed into epilepsy. Despite acute causal brain lesions, the novelty related to its inaugural nature is still too often associated with a delay in diagnosing SE and a poorer outcome, which justifies the need to more clearly specify the various types of SE to constantly raise awareness among clinicians. These results highlight the relevance of including novelty-related criteria, clinical history, and temporality of occurrence in the nosology of SE.

Managing Acute Seizures: New Rescue Delivery Option and Resources to Assist School Nurses

Approximately 470,000 children and adolescents in the United States have epilepsy, 30% of whom experience seizures despite antiseizure drug regimens. School nurses, teachers, caregivers, and parents play integral roles in implementing a care plan that avoids triggers, recognizes signs, and provides supportive care—ideally, guided by a patient-specific seizure action plan, which may include the use of rescue medication. Benzodiazepines are the mainstay of seizure rescue medication; for decades, rectally administered diazepam was the only approved rescue medication for seizure clusters outside the hospital setting. However, rectal administration has limitations that could delay treatment (e.g., social acceptability, removal of clothing, positioning). More recently, intranasal midazolam (for patients ≥12 years) and intranasal diazepam (for patients ≥6 years) were approved for this indication. Training and education regarding newer forms of rescue medication should improve confidence in the ability to treat seizures in school with the goal of increasing the safety of students with epilepsy.

Relationship between changes in mitochondrial function and hippocampal neuronal apoptosis after recurrent convulsion during developmental stage

The aim of the present study was to establish a recurrent convulsion model during the developmental stage using inhalation of flurothyl, and to observe the relationship between the changes in mitochondrial function in hippocampal neurons and hippocampal neuronal apoptosis after recurrent convulsion. A total of 36 Sprague-Dawley male rats were selected and randomly divided into the control (NS) group and recurrent-seizure (RS) group for 0, 1.5, 3, 12 and 24 h. After the last seizure the rats were subdivided with 6 animals in each group. Rats in the seizure group inhaled flurothyl repeatedly to induce status convulsivus, 30 min once daily, for 7 consecutive days, while the same operation was conducted in the control group without inhalation of flurothyl. At each time-point after the last seizure, blood was taken from the heart, followed by decapitation and immediate removal of the brain. Half of the brain tissue was immediately fixed in 10% paraformaldehyde to prepare paraffin-embedded tissues for hematoxylin and eosin (H&E) histological staining. Hippocampus was taken from the other half of the brain and stored at -80°C. Changes in mitochondrial membrane potential (ΔΨm) in hippocampal neurons were detected by flow cytometer. Dynamic changes of mitochondrial fusion and division-related genes, mitochondrial fusion protein 2 (Mfn2) and dynamin-related protein 1 (Drp1), in the hippocampus after recurrent convulsion were observed using reverse transcription-polymerase chain reaction (RT-PCR)and western blot analysis. The expression of caspase-3 and cytochrome c (Cyt c) was determined by RT-PCR and western blot analysis. After successful establishment of the recurrent convulsion model in rats during developmental stage using flurothyl, H&E staining results exhibited that in the CA1 region of hippocampus in the NS group, karyopyknosis occurred in nucleus that was stained to be brown and yellow, and the expression peak of apoptotic cells mainly existed at 24 h after the last convulsion. RT-PCR and western analysis revealed that apoptosis-related gene caspase-3 expression in the RS group was elevated at 1.5 h after the last convulsion, and lasted 24 h after convulsion. Detection results of mitochondrial ΔΨm revealed a significant reduction 1.5, 3 and 12 h after convulsion in hippocampal neurons of experimental rats, which reached the trough at 12 h, and rapidly increased after 24 h. The expression of Mfn2 mRNA in the RS group was significantly lower than that in the control group, while the expression of Drp1 mRNA in RS group was distinctly higher than that in the control group. RT-PCR and western blot analysis revealed that, mitochondrial apoptosis-related gene Cyt c expression was increased at 3 h after the last convulsion, and lasted 24 h after convulsion. Correlation analysis showed that the changes in mitochondrial function were closely related to neuronal apoptosis. The results of the study show that apoptosis exists in the hippocampus of rats after recurrent convulsion, which is closely related to the changes in mitochondrial function.

MicroRNA-34b mediates hippocampal astrocyte apoptosis in a rat model of recurrent seizures

Background

Recurrent convulsions can cause irreversible astrocyte death, impede neuron regeneration, and further aggravate brain damage. MicroRNAs have been revealed as players in the progression of numerous diseases including cancer and Alzheimer’s disease. Particularly, microRNA has been found linked to seizure-induced neuronal death. In this study, a rat model of recurrent convulsions induced by flurothyl treatments was utilised to assess the alterations of microRNA expressions in hippocampus tissues. We also applied an in vitro model in which primary astrocytes were exposed to kainic acid to verify the targets of miR-34b-5p identified in the animal model.

Results

We discovered that miR-34b-5p, a member of the miR-34 family, increased significantly in flurothyl-treated rat hippocampus tissue. More surprisingly, this upregulation occurred concurrently with accumulating astrocyte apoptosis, indicating the involvement of miR-34b-5p in seizures caused astrocyte apoptosis. Results from the in vitro experiments further demonstrated that miR-34b-5p directly targeted Bcl-2 mRNA, translationally repressed Bcl-2 protein, and thus modulated cell apoptosis by influencing Bcl-2, Bax, and Caspase-3.

Conclusion

Our findings prove microRNAs play a role in mediating recurrent convulsions-induced astrocyte death and further indicate that miR-34b-5p could acts as a regulator for astrocyte apoptosis induced by recurrent seizures.

Electronic supplementary material

The online version of this article (doi:10.1186/s12868-016-0291-6) contains supplementary material, which is available to authorized users.

Neuroinflammation-Induced Memory Deficits Are Amenable to Treatment with D-Cycloserine

Cognitive deficits, especially memory loss, are common following many types of brain insults which are associated with neuroinflammation, although the underlying mechanisms are not entirely clear. The present study aimed to characterize the long-term cognitive and behavioral impairments in a mouse model of neuroinflammation in the absence of other insults and to evaluate the therapeutic potential of D-cycloserine (DCS). DCS is a co-agonist of the NMDA receptor that ameliorates cognitive deficits in models of TBI and stroke. Using a mouse model of global neuroinflammation induced by intracisternal (i.c.) administration of endotoxin (LPS), we found long-lasting microgliosis, memory deficits, impaired LTP, and reduced levels of the obligatory NR1 subunit of the NMDA receptor. A single administration of DCS, 1 day after i.c. LPS reduced microgliosis, reversed the cognitive deficits and restored LTP and NR1 levels. These results demonstrate that neuroinflammation alone, in the absence of trauma or ischemia, can cause persistent (>6 months) memory deficits linked to deranged NNMDA receptor function and suggest a possible role for NMDA co-agonists in reducing the cognitive sequelae of neuroinflammation.

Behavioral assessment of NIH Swiss mice acutely intoxicated with tetramethylenedisulfotetramine

Tetramethylenedisulfotetramine (TETS) is a potent convulsant poison that is thought to trigger seizures by inhibiting the function of the type A gamma-aminobutyric acid receptor (GABAAR). Acute intoxication with TETS can cause vomiting, convulsions, status epilepticus (SE) and even death. Clinical case reports indicate that individuals who survive poisoning may exhibit long-term neuropsychological issues and cognitive deficits. Therefore, the objective of this research was to determine whether a recently described mouse model of acute TETS intoxication exhibits persistent behavioral deficits. Young adult male NIH Swiss mice received a seizure-inducing dose of TETS (0.15mg/kg, ip) and then were rescued from lethality by administration of diazepam (5mg/kg, ip) approximately 20min post-TETS-exposure. TETS-intoxicated mice typically exhibited 2 clonic seizures prior to administration of diazepam with no subsequent seizures post-diazepam injection as assessed using behavioral criteria. Seizures lasted an average of 72s. Locomotor activity, anxiety-like and depression-relevant behaviors and cognition were assessed at 1week, 1month and 2months post-TETS exposure using open field, elevated-plus maze, light↔dark transitions, tail suspension, forced swim and novel object recognition tasks. Interestingly, preliminary validation tests indicated that NIH Swiss mice do not respond to the shock in fear conditioning tasks. Subsequent evaluation of hot plate and tail flick nociception tasks revealed that this strain exhibits significantly decreased pain sensitivity relative to age- and sex-matched C57BL/6J mice, which displayed normal contextual fear conditioning. NIH Swiss mice acutely intoxicated with TETS exhibited no significant anxiety-related, depression-relevant, learning or memory deficits relative to vehicle controls at any of the time points assessed with the exception of significantly increased locomotor activity at 2months post-TETS intoxication. The general absence of long-term behavioral deficits in TETS-intoxicated mice on these six assays suggests that the neurobehavioral consequences of TETS exposure described in human survivors of acute TETS intoxication are likely due to sustained seizure activity, rather than a direct effect of the chemical itself. Future research efforts are directed toward developing an animal model that better recapitulates the SE and seizure duration reported in humans acutely intoxicated with TETS.

Sex-specific consequences of early life seizures

Seizures are very common in the early periods of life and are often associated with poor neurologic outcome in humans. Animal studies have provided evidence that early life seizures may disrupt neuronal differentiation and connectivity, signaling pathways, and the function of various neuronal networks. There is growing experimental evidence that many signaling pathways, like GABAA receptor signaling, the cellular physiology and differentiation, or the functional maturation of certain brain regions, including those involved in seizure control, mature differently in males and females. However, most experimental studies of early life seizures have not directly investigated the importance of sex on the consequences of early life seizures. The sexual dimorphism of the developing brain raises the question that early seizures could have distinct effects in immature females and males that are subjected to seizures. We will first discuss the evidence for sex-specific features of the developing brain that could be involved in modifying the susceptibility and consequences of early life seizures. We will then review how sex-related biological factors could modify the age-specific consequences of induced seizures in the immature animals. These include signaling pathways (e.g., GABAA receptors), steroid hormones, growth factors. Overall, there are very few studies that have specifically addressed seizure outcomes in developing animals as a function of sex. The available literature indicates that a variety of outcomes (histopathological, behavioral, molecular, epileptogenesis) may be affected in a sex-, age-, region-specific manner after seizures during development. Obtaining a better understanding for the gender-related mechanisms underlying epileptogenesis and seizure comorbidities will be necessary to develop better gender and age appropriate therapies.

Are we failing to provide adequate rescue medication to children at risk of prolonged convulsive seizures in schools?

OBJECTIVE

This paper explores the issues that arise from the discussion of administering rescue medication to children who experience prolonged convulsive seizures in mainstream schools in the UK.

SITUATION ANALYSIS

Current guidelines recommend immediate treatment of children with such seizures (defined as seizures lasting more than 5 min) to prevent progression to status epilepticus and neurological morbidity. As children are unconscious during prolonged convulsive seizures, whether or not they receive their treatment in time depends on the presence of a teacher or other member of staff trained and able to administer rescue medication. However, it is thought that the situation varies between schools and depends mainly on the goodwill and resources available locally.

RECOMMENDATIONS

A more systematic response is needed to ensure that children receive rescue medication regardless of where their seizure occurs. Possible ways forward include: greater use of training resources for schools available from epilepsy voluntary sector organisations; consistent, practical information to schools; transparent guidance outlining a clear care pathway from the hospital to the school; and implementation and adherence to each child's individual healthcare plan.

IMPLICATIONS

Children requiring emergency treatment for prolonged convulsive seizures during school hours test the goals of integrated, person-centred care as well as joined-up working to which the National Health Service (NHS) aspires. As changes to the NHS come into play and local services become reconfigured, every effort should be made to take account of the particular needs of this vulnerable group of children within broader efforts to improve the quality of paediatric epilepsy services overall.