Seizure-related Death Research Articles

Doxycycline for the treatment of nodding syndrome: a randomised, placebo-controlled, phase 2 trial

Nodding syndrome is a poorly understood neurological disorder that predominantly occurs in Africa. We hypothesised that nodding syndrome is a neuroinflammatory disorder, induced by antibodies to Onchocerca volvulus or its Wolbachia symbiont, cross-reacting with host neuronal proteins (HNPs), and that doxycycline can be used as treatment. In this randomised, double-blind, placebo-controlled, phase 2 trial, we recruited participants from districts affected by nodding syndrome in northern Uganda. We included children and adolescents aged 8-18 years with nodding syndrome, as defined by WHO consensus criteria. Participants were randomly assigned (1:1) to receive either 100 mg doxycycline daily or placebo for 6 weeks via a computer-generated schedule stratified by skin microscopy results, and all parties were masked to group assignment. Diagnoses of O volvulus and antibodies to HNPs were made using luciferase immunoprecipitation system assays and immunohistochemistry. The primary outcome was change in the proportion with antibodies to HNPs, assessed at 24 months. All participants were included in safety analyses, and surviving participants (those with samples at 24 months) were included in primary analyses. Secondary outcomes were: change in concentrations of antibodies to HNPs at 24 months compared with baseline; proportion of participants testing positive for antibodies to O volvulus-specific proteins and concentrations of Ov16 or OVOC3261 antibodies at 24 months compared with baseline; change in seizure burden, proportion achieving seizure freedom, and the proportions with interictal epileptiform discharges on the diagnostic EEG; overall quality of life; disease severity at 24 months; and incidence of all-cause adverse events, serious adverse events, and seizure-related mortality by 24 months. This trial is registered with ClinicalTrials.gov, NCT02850913. Between Sept 1, 2016, and Aug 31, 2018, 329 children and adolescents were screened, of whom 240 were included in the study. 140 (58%) participants were boys and 100 (42%) were girls. 120 (50%) participants were allocated to receive doxycycline and 120 (50%) to receive placebo. At recruitment, the median duration of symptoms was 9 years (IQR 6-10); 232 (97%) participants had O volvulus-specific antibodies and 157 (65%) had autoantibodies to HNPs. The most common plasma autoantibodies were to human protein deglycase DJ-1 (85 [35%] participants) and leiomodin-1 (77 [32%] participants) and, in cerebrospinal fluid (CSF), to human DJ-1 (27 [11%] participants) and leiomodin-1 (14 [6%] participants). On immunohistochemistry, 46 (19%) participants had CSF autoantibodies to HNPs, including leiomodin-1 (26 [11%]), γ-aminobutyric acid B receptors (two [<1%]), CASPR2 (one [<1%]), or unknown targets (28 [12%]). At 24 months, 161 (72%) of 225 participants had antibodies to HNPs compared with 157 (65%) of 240 at baseline. 6 weeks of doxycycline did not affect the concentration of autoantibodies to HNPs, seizure control, disease severity, or quality of life at the 24-month follow-up but substantially decreased Ov16 antibody concentrations; the median plasma signal-to-noise Ov16 ratio was 16·4 (95% CI 6·4-38·4), compared with 27·9 (8·2-65·8; p=0·033) for placebo. 14 (6%) participants died and, other than one traffic death, all deaths were seizure-related. Acute seizure-related hospitalisations (rate ratio [RR] 0·43 [95% CI 0·20-0·94], p=0·028) and deaths (RR 0·46 [0·24-0·89], p=0·028) were significantly lower in the doxycycline group. At 24 months, 96 (84%) of 114 participants who received doxycycline tested positive for antibodies to Ov16, compared with 97 (87%) of 111 on placebo (p=0·50), and 74 (65%) participants on doxycycline tested positive for antibodies to OVOC3261, compared with 57 (51%) on placebo (p=0·039). Doxycycline was safe; there was no difference in the incidence of grade 3-5 adverse events across the two groups. Nodding syndrome is strongly associated with O volvulus and the pathogenesis is probably mediated through an O volvulus induced autoantibody response to multiple proteins. Although it did not reverse disease symptoms, doxycycline or another prophylactic antibiotic could be considered as adjunct therapy to antiseizure medication, as it might reduce fatal complications from acute seizures and status epilepticus induced by febrile infections. Medical Research Council (UK). For the Luo translation of the abstract see Supplementary Materials section.

Audiogenic epileptic DBA/2 mice strain as a model of genetic reflex seizures and SUDEP.

Epilepsy is a chronic neurological disease characterized by abnormal brain activity, which results in repeated spontaneous seizures. Sudden unexpected death in epilepsy (SUDEP) is the leading cause of seizure-related premature death, particularly in drug-resistant epilepsy patients. The etiology of SUDEP is a structural injury to the brain that is not fully understood, but it is frequently associated with poorly controlled and repeated generalized tonic-clonic seizures (GTCSs) that cause cardiorespiratory and autonomic dysfunctions, indicating the involvement of the brainstem. Both respiratory and cardiac abnormalities have been observed in SUDEP, but not much progress has been made in their prevention. Owing to the complexity of SUDEP, experimental animal models have been used to investigate cardiac and/or respiratory dysregulation due to or associated with epileptic seizures that may contribute to death in humans. Numerous rodent models, especially mouse models, have been developed to better understand epilepsy and SUDEP physiopathology. This review synthesizes the current knowledge about dilute brown agouti coat color (DBA/2) mice as a possible SUDEP model because respiratory arrest (RA) and sudden death induced by audiogenic generalized seizures (AGSs) have been observed in these animals. Respiratory/cardiac dysfunction, brainstem arousal system dysfunction, and alteration of the neurotransmitter systems, which are observed in human SUDEP, have also been observed in these mice. In particular, serotonin (5-HT) alteration and adenosine neurotransmission appear to contribute to not only the pathophysiological mechanisms of medication but also seizure-related respiratory dysfunctions in this animal model. These neurotransmitter systems could be the relevant targets for medication development for chronic epilepsy and SUDEP prevention. We reviewed data on AGSs in DBA/2 mice and the relevance of this model of generalized tonic-clonic epilepsy to human SUDEP. Furthermore, the advantages of using this strain prone to AGSs for the identification of possible new therapeutic targets and treatment options have also been assessed.

Kv7/KCNQ potassium channels in cortical hyperexcitability and juvenile seizure-related death in Ank2-mutant mice

Autism spectrum disorders (ASD) represent neurodevelopmental disorders characterized by social deficits, repetitive behaviors, and various comorbidities, including epilepsy. ANK2, which encodes a neuronal scaffolding protein, is frequently mutated in ASD, but its in vivo functions and disease-related mechanisms are largely unknown. Here, we report that mice with Ank2 knockout restricted to cortical and hippocampal excitatory neurons (Ank2-cKO mice) show ASD-related behavioral abnormalities and juvenile seizure-related death. Ank2-cKO cortical neurons show abnormally increased excitability and firing rate. These changes accompanied decreases in the total level and function of the Kv7.2/KCNQ2 and Kv7.3/KCNQ3 potassium channels and the density of these channels in the enlengthened axon initial segment. Importantly, the Kv7 agonist, retigabine, rescued neuronal excitability, juvenile seizure-related death, and hyperactivity in Ank2-cKO mice. These results suggest that Ank2 regulates neuronal excitability by regulating the length of and Kv7 density in the AIS and that Kv7 channelopathy is involved in Ank2-related brain dysfunctions.

TRPM7 kinase mediates hypomagnesemia-induced seizure-related death

Hypomagnesemia (HypoMg) can cause seizures and death, but the mechanism is unknown. Transient receptor potential cation channel subfamily M 7 (TRPM7) is a Mg transporter with both channel and kinase function. In this study, we focused on the kinase role of TRPM7 in HypoMg-induced seizures and death. Wild type C57BL/6J mice and transgenic mice with a global homozygous mutation in the TRPM7 kinase domain (TRPM7K1646R, with no kinase function) were fed with control diet or a HypoMg diet. After 6 weeks of HypoMg diet, mice had significantly decreased serum Mg, elevated brain TRPM7, and a significant rate of death, with females being most susceptible. Deaths were immediately preceded by seizure events. TRPM7K1646R mice showed resistance to seizure-induced death. HypoMg-induced brain inflammation and oxidative stress were suppressed by TRPM7K1646R. Compared to their male counterparts, HypoMg female mice had higher levels of inflammation and oxidative stress in the hippocampus. We concluded that TRPM7 kinase function contributes seizure-induced deaths in HypoMg mice and that inhibiting the kinase reduced inflammation and oxidative stress.

Mortality after a first-ever unprovoked seizure.

Although increased mortality associated with epilepsy is well understood, data in patients after their first-ever seizure are limited. We aimed to assess mortality after a first-ever unprovoked seizure and identify causes of death (CODs) and risk factors. A prospective cohort study was undertaken of patients with first-ever unprovoked seizure between 1999 and 2015 in Western Australia. Two age-, gender-, and calendar year-matched local controls were obtained for each patient. Mortality data, including COD, based on International Statistical Classification of Diseases and Related Health Problems, 10th Revision codes, were obtained. Final analysis was performed in January 2022. One thousand two hundred seventy-eight patients with a first-ever unprovoked seizure were compared to 2556 controls. Mean follow-up was 7.3 years (range = .1-20). Overall hazard ratio (HR) for death after a first unprovoked seizure compared to controls was 3.06 (95% confidence interval [CI] = 2.48-3.79), with HRs of 3.30 (95% CI=2.26-4.82) for those without seizure recurrence and 3.21 (95% CI=2.47-4.16) after a second seizure. Mortality was also increased in patients with normal imaging and no identified cause (HR=2.50, 95% CI=1.82-3.42). Multivariate predictors of mortality were increasing age, remote symptomatic causes, first seizure presentation with seizure cluster or status epilepticus, neurological disability, and antidepressant use at time of first seizure. Seizure recurrence did not influence mortality rate. The commonest CODs were neurological, most relating to the underlying cause of seizures rather than being seizure-related. Substance overdoses and suicide were more frequent CODs in patients compared to controls and were commoner than seizure-related deaths. Mortality is increased two- to threefold after a first-ever unprovoked seizure, independent of seizure recurrence, and is not only attributable to the underlying neurological etiology. The greater likelihood of deaths related to substance overdose and suicide highlights the importance of assessing psychiatric comorbidity and substance use in patients with first-ever unprovoked seizure.

Huntingtin Decreases Susceptibility to a Spontaneous Seizure Disorder in FVN/B Mice.

Huntington disease (HD) is an adult-onset neurodegenerative disorder that is caused by a trinucleotide CAG repeat expansion in the HTT gene that codes for the protein huntingtin (HTT in humans or Htt in mice). HTT is a multi-functional, ubiquitously expressed protein that is essential for embryonic survival, normal neurodevelopment, and adult brain function. The ability of wild-type HTT to protect neurons against various forms of death raises the possibility that loss of normal HTT function may worsen disease progression in HD. Huntingtin-lowering therapeutics are being evaluated in clinical trials for HD, but concerns have been raised that decreasing wild-type HTT levels may have adverse effects. Here we show that Htt levels modulate the occurrence of an idiopathic seizure disorder that spontaneously occurs in approximately 28% of FVB/N mice, which we have called FVB/N Seizure Disorder with SUDEP (FSDS). These abnormal FVB/N mice demonstrate the cardinal features of mouse models of epilepsy including spontaneous seizures, astrocytosis, neuronal hypertrophy, upregulation of brain-derived neurotrophic factor (BDNF), and sudden seizure-related death. Interestingly, mice heterozygous for the targeted inactivation of Htt (Htt+/- mice) exhibit an increased frequency of this disorder (71% FSDS phenotype), while over-expression of either full length wild-type HTT in YAC18 mice or full length mutant HTT in YAC128 mice completely prevents it (0% FSDS phenotype). Examination of the mechanism underlying huntingtin's ability to modulate the frequency of this seizure disorder indicated that over-expression of full length HTT can promote neuronal survival following seizures. Overall, our results demonstrate a protective role for huntingtin in this form of epilepsy and provide a plausible explanation for the observation of seizures in the juvenile form of HD, Lopes-Maciel-Rodan syndrome, and Wolf-Hirschhorn syndrome. Adverse effects caused by decreasing huntingtin levels have ramifications for huntingtin-lowering therapies that are being developed to treat HD.

Abstract 9376: TRPM77 Knockdown Prevents Hypomagnesemia-Induced Oxidative Stress and Cardiac Diastolic Dysfunction

Introduction: Our previous study has shown that 6-week low-Mg diet-induced hypomagnesemia results in mitochondrial dysfunction, cardiac diastolic dysfunction, and seizure-related death. Transient receptor potential cation channel subfamily M 7 (TRPM7) is a Mg transporter with both channel and kinase function located in the plasma membrane. We investigated the role of TRPM7 in hypomagnesemia-associated changes. Methods: For cardiac-specific knockdown of TRPM7, pAAV[miR30]-cTnT&gt;EGFP:Scramble-shRNA as control (Con) and pAAV[miR30]-cTnT&gt;EGFP:TRPM7 shRNA as TRPM7 knockdown (T7KD) were injected into mice through the jugular vein at 10 weeks old. One week later, mice were fed with a normal diet (nlMg, 2000 mg/kg Mg) or a low-Mg diet (HypoMg, 15-30 mg/kg Mg) for 4 weeks. Results: TRPM7 was increased significantly in wild type mouse hearts under the low-Mg diet (1.45±0.18-fold of mice with normal diet, P&lt;0.01). We therefore knocked down TRPM7 in the mouse heart to see if HypoMg-induced changes could be prevented. After 4 weeks of low-Mg diet, both Con and T7KD mice had hypomagnesemia with significantly decreased serum Mg levels (0.37±0.03 and 0.45±0.10 mM, respectively, vs 1.05±0.04 mM of Con-nlMg). All T7KD mice showed significantly decreased TRPM7 protein levels in the heart tissue (&lt;30% of Con-nlMg, P&lt;0.01). Cardiac diastolic dysfunction (E/e’) was prevented in T7KD-HypoMg mice (E/e’=16.2±1.9 vs. 20.7±1.5 of Con-HypoMg). Increased total protein oxidation (measured with nitro-tyrosine immunoprecipitation) in Con-HypoMg heart tissue (1.61±0.09-fold increase, P=0.045 vs. Con-nlMg) was normalized in the T7KD-HypoMg group (1.18±0.09-fold of Con-nlMg, P=0.45 vs. Con-nlMg). Conclusions: TRPM7 was upregulated in hypomagnesemia in hearts and its knockdown prevented hypomagnesemia-induced cardiac diastolic dysfunction and increased oxidative stress.

TRPM7 kinase mediates cardiac diastolic dysfunction and death in hypomagnesemia

Hypomagnesemia (HypoMg) induces mitochondrial dysfunction, cardiac diastolic dysfunction, and seizure-related death. Transient receptor potential cation channel subfamily M 7 (TRPM7) is a Mg transporter with both channel and kinase function located in the plasma membrane. We investigated the role of TRPM7 in HypoMg-associated changes. Wild type (WT) C57BL/6J mice and transgenic mice with a homozygous K1646R mutation in the TRPM7 kinase domain (TRPM7K1646R, with no kinase function) were fed with a low-Mg diet (HypoMg mice, 15-30 mg/kg Mg) or a normal Mg diet (control mice, 600 mg/kg Mg) for 6 weeks starting at 10 weeks old.

Acute and chronic cardiorespiratory consequences of focal intrahippocampal administration of seizure-inducing agents. Implications for SUDEP

<h2>Abstract</h2> The risk factors for SUDEP are undoubtedly heterogenous but the main factor is the frequency of generalized tonic-clonic seizures with apnoea and/or cardiac abnormalities likely precipitating the lethal event. By its very nature modelling SUDEP experimentally is challenging, yet insights into the nature of the lethal event and precipitating factors are vital in order to understand and prevent fatalities. Acute animal models, which induce status epilepticus (SE), can be used to help understand pathophysiological processes during and following seizures, which sometimes lead to death. The most commonly used method to induce seizures and status epilepticus is systemic administration of an ictogenic agent. Microinjection of such agents into restricted regions within the brain induces a more localised epileptic focus and circumvents the risk of direct actions on cardiorespiratory control centres. Both approaches have revealed substantial cardiovascular and respiratory consequences, including death as a result of apnoea, which may be of central origin, obstructive due to laryngospasm or, at least in genetically modified mice, a result of spreading depolarisation to medullary respiratory control centres. SUDEP is by definition a result of epilepsy, which in turn is diagnosed on the basis of two or more unprovoked seizures. The incidence of tonic-clonic seizures is the main risk factor, raising the possibility that repeated seizures cause cumulative pathological and/or pathophysiological changes that contribute to the risk of SUDEP. Chronic experimental models, which induce repeated seizures that in some cases lead to death, do show progressive development of pathophysiological changes in the myocardium, e.g. prolongation of QT the interval of the ECG or, over longer periods, ventricular hypertrophy. However, the currently available evidence indicates that seizure-related deaths are primarily due to apnoeas, but cardiac factors, particularly cumulative cardiac pathophysiologies due to repeated seizures, are potential contributing factors.

Comparing Seizure-Related Death and Suicide in Younger Adults with Epilepsy.

Younger adults with epilepsy have an increased mortality. Some deaths are seizure-related, for example, sudden unexpected death in epilepsy (SUDEP), whereas others, for example, suicide, have multiple causes, including adverse effects of the treatment on mood. In this retrospective population-based study of all Danish persons with epilepsy aged 18 to 49 years during 2007 to 2009 we evaluated the risk of death from seizures and suicide. SUDEP comprised 82.7% of all seizure-related death. Younger adults with epilepsy had an 8.3-fold increased risk of death from seizure-related causes compared with suicide. This underpins the importance of effective seizure control in preventing premature death. ANN NEUROL 2021;90:983-987.

Neuropathology in the North American sudden unexpected death in epilepsy registry.

Sudden unexpected death in epilepsy is the leading category of epilepsy-related death and the underlying mechanisms are incompletely understood. Risk factors can include a recent history and high frequency of generalized tonic-clonic seizures, which can depress brain activity postictally, impairing respiration, arousal and protective reflexes. Neuropathological findings in sudden unexpected death in epilepsy cases parallel those in other epilepsy patients, with no implication of novel structures or mechanisms in seizure-related deaths. Few large studies have comprehensively reviewed whole brain examination of such patients. We evaluated 92 North American Sudden unexpected death in epilepsy Registry cases with whole brain neuropathological examination by board-certified neuropathologists blinded to the adjudicated cause of death, with an average of 16 brain regions examined per case. The 92 cases included 61 sudden unexpected death in epilepsy (40 definite, 9 definite plus, 6 probable, 6 possible) and 31 people with epilepsy controls who died from other causes. The mean age at death was 34.4 years and 65.2% (60/92) were male. The average age of death was younger for sudden unexpected death in epilepsy cases than for epilepsy controls (30.0 versus 39.6 years; P = 0.006), and there was no difference in sex distribution respectively (67.3% male versus 64.5%, P = 0.8). Among sudden unexpected death in epilepsy cases, earlier age of epilepsy onset positively correlated with a younger age at death (P = 0.0005) and negatively correlated with epilepsy duration (P = 0.001). Neuropathological findings were identified in 83.7% of the cases in our cohort. The most common findings were dentate gyrus dysgenesis (sudden unexpected death in epilepsy 50.9%, epilepsy controls 54.8%) and focal cortical dysplasia (FCD) (sudden unexpected death in epilepsy 41.8%, epilepsy controls 29.0%). The neuropathological findings in sudden unexpected death in epilepsy paralleled those in epilepsy controls, including the frequency of total neuropathological findings as well as the specific findings in the dentate gyrus, findings pertaining to neurodevelopment (e.g. FCD, heterotopias) and findings in the brainstem (e.g. medullary arcuate or olivary dysgenesis). Thus, like prior studies, we found no neuropathological findings that were more common in sudden unexpected death in epilepsy cases. Future neuropathological studies evaluating larger sudden unexpected death in epilepsy and control cohorts would benefit from inclusion of different epilepsy syndromes with detailed phenotypic information, consensus among pathologists particularly for more subjective findings where observations can be inconsistent, and molecular approaches to identify markers of sudden unexpected death in epilepsy risk or pathogenesis.

Improving access to epilepsy care for homeless patients in the Dublin Inner City: a collaborative quality improvement project joining hospital and community care

Homelessness is associated with significant psychosocial and health disparities. The rate of epilepsy among this cohort is eight times greater than that in the settled population, and the associated morbidity...

Seizure-related deaths in children: The expanding spectrum.

Although seizures are common in children, they are often overlooked as a potential cause of death. Febrile and nonfebrile seizures can be fatal in children with or without an epilepsy diagnosis and may go unrecognized by parents or physicians. Sudden unexpected infant deaths, sudden unexplained death in childhood, and sudden unexpected death in epilepsy share clinical, neuropathological, and genetic features, including male predominance, unwitnessed deaths, death during sleep, discovery in the prone position, hippocampal abnormalities, and variants in genes regulating cardiac and neuronal excitability. Additionally, epidemiological studies reveal that miscarriages are more common among individuals with a personal or family history of epilepsy, suggesting that some fetal losses may result from epileptic factors. The spectrum of seizure‐related deaths in pediatrics is wide and underappreciated; accurately estimating this mortality and understanding its mechanism in children is critical to developing effective education and interventions to prevent these tragedies.

Assessment of cardiac structure and function in a murine model of temporal lobe epilepsy

Sudden unexpected death in epilepsy (SUDEP) is a significant cause of premature seizure-related death. An association between SUDEP and cardiac remodeling has been suggested. However, whether SUDEP is a direct consequence of acute or recurrent seizures is unsettled. The purpose of this study was to evaluate the impact of status epilepticus (SE) and chronic seizures on myocardial structure and function.We used the intracortical kainate injection model of temporal lobe epilepsy to elicit SE and chronic epilepsy in mice. In total, 24 C57/BL6 mice (13 kainate, 11 sham) were studied 2 and 30 days post-injection. Cardiac structure and function were investigated in-vivo with a 9.4 T MRI, electrocardiography (ECG), echocardiography, and histology [Haematoxylin/Eosin (HE) and Martius Scarlet Blue (MSB)] for staining of collagen proliferation and fibrin accumulation.In conclusion, we did not detect any significant changes in cardiac structure and function neither in mice 2 days nor 30 days post-injection.

SIRT3 Haploinsufficiency Aggravates Loss of GABAergic Interneurons and Neuronal Network Hyperexcitability in an Alzheimer's Disease Model.

Impaired mitochondrial function and aberrant neuronal network activity are believed to be early events in the pathogenesis of Alzheimer's disease (AD), but how mitochondrial alterations contribute to aberrant activity in neuronal circuits is unknown. In this study, we examined the function of mitochondrial protein deacetylase sirtuin 3 (SIRT3) in the pathogenesis of AD. Compared with AppPs1 mice, Sirt3-haploinsufficient AppPs1 mice (Sirt3+/-AppPs1) exhibit early epileptiform EEG activity and seizure. Both male and female Sirt3+/-AppPs1 mice were observed to die prematurely before 5 months of age. When comparing male mice among different genotypes, Sirt3 haploinsufficiency renders GABAergic interneurons in the cerebral cortex vulnerable to degeneration and associated neuronal network hyperexcitability. Feeding Sirt3+/-AppPs1 AD mice with a ketone ester-rich diet increases SIRT3 expression and prevents seizure-related death and the degeneration of GABAergic neurons, indicating that the aggravated GABAergic neuron loss and neuronal network hyperexcitability in Sirt3+/-AppPs1 mice are caused by SIRT3 reduction and can be rescued by increase of SIRT3 expression. Consistent with a protective role in AD, SIRT3 levels are reduced in association with cerebral cortical Aβ pathology in AD patients. In summary, SIRT3 preserves GABAergic interneurons and protects cerebral circuits against hyperexcitability, and this neuroprotective mechanism can be bolstered by dietary ketone esters.SIGNIFICANCE STATEMENT GABAergic neurons provide the main inhibitory control of neuronal activity in the brain. By preserving mitochondrial function, SIRT3 protects parvalbumin and calretinin interneurons against Aβ-associated dysfunction and degeneration in AppPs1 Alzheimer's disease mice, thus restraining neuronal network hyperactivity. The neuronal network dysfunction that occurs in Alzheimer's disease can be partially reversed by physiological, dietary, and pharmacological interventions to increase SIRT3 expression and enhance the functionality of GABAergic interneurons.

A national surveillance study of childhood epilepsy mortality in the UK and Ireland.

Patients with epilepsy are significantly more likely to die prematurely than the general population, with causes ranging from associated comorbidities to sudden unexpected death in epilepsy (SUDEP). The aim was to estimate the UK and Ireland incidence of childhood epilepsy deaths and to describe case demographics and clinical characteristics. This was a prospective, population-based surveillance study using established active surveillance methodology designed by the British Paediatric Surveillance Unit. Eighty-eight confirmed cases were reported with an overall annual incidence of 0.65 per 100000 children aged <16years (95% confidence interval 0.52-0.81). More cases were male (65%) and cases fell across all age groups, with more deaths reported in older children. Twenty-five per cent of deaths were epilepsy-related (including SUDEP); 75% of deaths were non-epilepsy-related. SUDEP was the most common cause of seizure-related deaths, accounting for 13 out of 17 children (76%). An underlying epilepsy syndrome was present in 36% of deaths, and 88% had global developmental delay. In addition, 90% of the children had comorbid conditions in addition to epilepsy. In this study, it has been demonstrated that death in children diagnosed with epilepsy occurs mainly in 'complicated epilepsy' secondary to factors associated with neurodisability, consolidating previous data. SUDEP is also a significant cause of paediatric epilepsy mortality that needs further attention. There is a clear need to better understand and reduce the number of epilepsy deaths in children in the UK, and national surveillance of SUDEP is warranted to better understand this entity in paediatric populations.

Epilepsy and seizure-related deaths: Mortality statistics do not tell the complete story

IntroductionThe objective of the study was to identify where epilepsy or seizures may be the underlying cause of death but not identified by the death certification process in the Australian coronial system and to better characterize such deaths. MethodsAustralian National Coronial Information System (NCIS) closed cases for the Australian Capital Territory (ACT) (population average 348,000) over 13 years were searched using cause of death, and a text search of police and autopsy reports, to identify all deaths where epilepsy or seizures were mentioned. Deaths where the underlying cause of death was not seizures or epilepsy were excluded (including suicide). The remaining cases (75) were categorized by the circumstances of death. Suspected sudden unexpected death in epilepsy (SUDEP) cases were further classified using the unified definition of SUDEP of Nashef and colleagues (2012). ResultsOf the final 75 cases, only 44 were found by the cause of death search. Key word document searches found another 31. Cases were classified as Definite SUDEP (37), Definite SUDEP Plus (10), Probable SUDEP (1), Possible SUDEP (3), Near SUDEP (4), Near SUDEP Plus (1), Asphyxia (3), Treatment-related (1), Head injury (2), Drowning (2), motor vehicle accident (MVA) (1), deaths related to a single convulsive seizure (6), and status epilepticus (SE) (4). Cases were 80% male. ConclusionsEpilepsy and seizure-related deaths are underreported in the Australian Coronial system. Enhanced documentation of the causal chain of events leading to deaths would increase recognition. Using the unified SUDEP definition would expand SUDEP identification.

Brainstem spreading depolarization and cortical dynamics during fatal seizures inCacna1aS218L mice

Sudden unexpected death in epilepsy (SUDEP) is a fatal complication of epilepsy in which brainstem spreading depolarization may play a pivotal role, as suggested by animal studies. However, patiotemporal details of spreading depolarization occurring in relation to fatal seizures have not been investigated. In addition, little is known about behavioural and neurophysiological features that may discriminate spontaneous fatal from non-fatal seizures. Transgenic mice carrying the missense mutation S218L in the α1A subunit of Cav2.1 (P/Q-type) Ca2+ channels exhibit enhanced excitatory neurotransmission and increased susceptibility to spreading depolarization. Homozygous Cacna1aS218L mice show spontaneous non-fatal and fatal seizures, occurring throughout life, resulting in reduced life expectancy. To identify characteristics of fatal and non-fatal spontaneous seizures, we compared behavioural and electrophysiological seizure dynamics in freely-behaving homozygous Cacna1aS218L mice. To gain insight on the role of brainstem spreading depolarization in SUDEP, we studied the spatiotemporal distribution of spreading depolarization in the context of seizure-related death. Spontaneous and electrically-induced seizures were investigated by video monitoring and electrophysiological recordings in freely-behaving Cacna1aS218L and wild-type mice. Homozygous Cacna1aS218L mice showed multiple spontaneous tonic-clonic seizures and died from SUDEP in adulthood. Death was preceded by a tonic-clonic seizure terminating with hindlimb clonus, with suppression of cortical neuronal activity during and after the seizure. Induced seizures in freely-behaving homozygous Cacna1aS218L mice were followed by multiple spreading depolarizations and death. In wild-type or heterozygous Cacna1aS218L mice, induced seizures and spreading depolarization were never followed by death. To identify temporal and regional features of seizure-induced spreading depolarization related to fatal outcome, diffusion-weighted MRI was performed in anaesthetized homozygous Cacna1aS218L and wild-type mice. In homozygous Cacna1aS218L mice, appearance of seizure-related spreading depolarization in the brainstem correlated with respiratory arrest that was followed by cardiac arrest and death. Recordings in freely-behaving homozygous Cacna1aS218L mice confirmed brainstem spreading depolarization during spontaneous fatal seizures. These data underscore the value of the homozygous Cacna1aS218L mouse model for identifying discriminative features of fatal compared to non-fatal seizures, and support a key role for cortical neuronal suppression and brainstem spreading depolarization in SUDEP pathophysiology.

Dead in the water: Epilepsy‐related drowning or sudden unexpected death in epilepsy?

Both drowning and sudden unexpected death in epilepsy (SUDEP) are diagnoses of exclusion with predominantly nonspecific autopsy findings. We hypothesized that people with epilepsy found dead in water with no clear sign of submersion could be misdiagnosed as SUDEP. All reported seizure-related deaths undergoing medicolegal investigation in three medical examiner's offices (New York City, Maryland, San Diego County) over different time periods were reviewed to identify epilepsy-related drownings and SUDEPs. Drowning cases that fulfilled inclusion criteria were divided into two groups according to the circumstances of death: definite drowning and possible drowning. The SUDEP group included two sex- and age (±2years)-matched definite SUDEP/definite SUDEP plus cases for each drowning case. Of 1346 deaths reviewed, we identified 36 definite (76.6%) and 11 possible drowning deaths (23.4%), most of which occurred in a bathtub (72.3%). There were drowning-related findings, including fluid within the sphenoid sinuses, foam in the airways, clear fluid in the stomach content, and lung hyperinflation in 58.3% (21/36) of the definite drowning group, 45.5% (5/11) of the possible drowning group, and 4.3% of the SUDEP group (4/92). There was no difference in the presence of pulmonary edema/congestion between the definite drowning group, possible drowning group, and SUDEP group. The definite drowning group had a higher mean combined lung weight than the SUDEP group, but there was no difference in mean lung weights between the possible drowning and SUDEP groups or between the possible drowning and definite drowning groups. No distinguishable autopsy finding could be found between SUDEPs and epilepsy-related drownings when there were no drowning-related signs and no clear evidence of submersion. SUDEP could be the cause of death in such possible drowning cases. As most drowning cases occurred in the bathtub, supervision and specific bathing precautions could be effective prevention strategies.

Predictors of Seizure-Related Injuries in an Epilepsy Cohort from North India.

Background and PurposeTo identify predictors of seizure-related injury (SRI) and death in people with epilepsy (PWE) in a North Indian cohort.MethodsThis ambispective cohort study included PWE registered in an epilepsy clinic in Delhi between May 2010 and December 2011. Five hundred twenty-six patients were enrolled and followed for 25 months. Patients were categorized into two groups based on SRI/no SRI during the study period. We analyzed various factors to identify predictors of SRI and death.ResultsOf 526 patients, 355 (67.5%) reported having no SRIs and 171 (32.5%) had sustained an SRI. Among patients with SRI, 72.5% were male; 62% of those with no SRI were male. The injury type included soft tissue (60%), head trauma (20%), dental trauma (10%), orthopedic (10%), and burns (5%). On univariate analysis, factors predicting SRI occurrence were male gender, abnormal birth history (p < 0.01), abnormal mental status (p < 0.01), seizure duration (p < 0.04), daytime seizures (p < 0.05), dependence on a caregiver (p < 0.008), and uncontrolled seizures (p < 0.001), history of cluster seizures or status epilepticus (p < 0.001), occurrence of generalized tonic-clonic seizures (GTCS), and use of >3 antiepileptic drugs (p < 0.008). On multiple logistic regression analysis, male gender, uncontrolled seizures, history of cluster seizures or status epilepticus, and GTCS were significant risk factors. Sixteen deaths occurred in our cohort, and 13 fit the definition of probable sudden unexpected death in epilepsy (SUDEP). Most patients with SUDEP had an unwitnessed event (69.2%). The only significant factor in predicting death was uncontrolled seizures.ConclusionsMale gender, occurrence of GTCS, uncontrolled seizures, and history of cluster seizures or status epilepticus predicted SRI occurrence in PWE. Precautions should be taken by caregivers of patients with these risk factors, to prevent injury.