Role of Anticonvulsants in the Management of Posttraumatic Epilepsy

Pediatric penetrating brain injuries with intact neurological function: Two case reports of a pencil and a toy wheel encounter

Accidental injuries in the pediatric population are common. The response to injury also differs owing to anatomical and physiological differences in children. While such injuries carry a risk of lifelong morbidity, some cases may follow a benign course despite their distressing appearance. We report two cases of accidentally incurred penetrating trauma in the pediatric population with unusual objects, including a pencil and a toy wheel. Despite their intracranial extension, neither of the patients exhibited any discernible neurological deficits. Penetrating brain injuries require early removal and meticulous perioperative care to minimize the risk of long-term adverse neurological events in children.

Acute Treatment with the M-Channel (Kv7, KCNQ) Opener Retigabine Reduces the Long-Term Effects of Repetitive Blast Traumatic Brain Injuries

We investigated whether pharmacological increase of "M-type" (KCNQ, Kv7) K + channel currents by the M-channel opener, retigabine (RTG), acutely after repetitive traumatic brain injuries (rTBIs), prevents or reduces their long-term detrimental effects. rTBIs were studied using a blast shock air wave mouse model. Animals were monitored by video and electroencephalogram (EEG) records for nine months after the last injury to assess the occurrence of post-traumatic seizures (PTS), post-traumatic epilepsy (PTE), sleep-wake cycle architecture alterations, and the power of the EEG signals. We evaluated the development of long-term changes in the brain associated with various neurodegenerative diseases in mice by examining transactive response DNA-binding protein 43 (TDP-43) expression and nerve fiber damage ~ 2 years after the rTBIs. We observed acute RTG treatment to reduce the duration of PTS and impair the development of PTE. Acute RTG treatment also prevented post-injury hypersomnia, nerve fiber damage, and cortical TDP-43 accumulation and translocation from the nucleus to the cytoplasm. Mice that developed PTE displayed impaired rapid eye movement (REM) sleep, and there were significant correlations between seizure duration and time spent in the different stages of the sleep-wake cycle. We observed acute RTG treatment to impair injury-induced reduction of age-related increase in gamma frequency power of the EGG, which has been suggested to be necessary for a healthy aged brain. The data show that RTG, administered acutely post-TBI, is a promising, novel therapeutic option to blunt/prevent several long-term effects of rTBIs. Furthermore, our results show a direct relationship between sleep architecture and PTE.

Cdk5 mediates rotational force-induced brain injury

Millions of traumatic brain injuries (TBIs) occur annually. TBIs commonly result from falls, traffic accidents, and sports-related injuries, all of which involve rotational acceleration/deceleration of the brain. During these injuries, the brain endures a multitude of primary insults including compression of brain tissue, damaged vasculature, and diffuse axonal injury. All of these deleterious effects can contribute to secondary brain ischemia, cellular death, and neuroinflammation that progress for weeks, months, and lifetime after injury. While the linear effects of head trauma have been extensively modeled, less is known about how rotational injuries mediate neuronal damage following injury. Here, we developed a new model of repetitive rotational head trauma in rodents and demonstrated acute and prolonged pathological, behavioral, and electrophysiological effects of rotational TBI (rTBI). We identify aberrant Cyclin-dependent kinase 5 (Cdk5) activity as a principal mediator of rTBI. We utilized Cdk5-enriched phosphoproteomics to uncover potential downstream mediators of rTBI and show pharmacological inhibition of Cdk5 reduces the cognitive and pathological consequences of injury. These studies contribute meaningfully to our understanding of the mechanisms of rTBI and how they may be effectively treated.

Use of antiepileptic drugs as prophylaxis against posttraumatic seizures in the pediatric population: a systematic review and meta-analysis

We aim to assess the effect of anti-epileptic drug (AED) prophylaxis for early or late posttraumatic seizures, targeting the pediatric population with traumatic brain injury (TBI). We systematically searched for studies reporting the incidence of posttraumatic seizures in pediatric patients who suffered from TBI and received AEDs prophylactically following their TBI incident. Studies that included adult patients, adult and pediatric patients but did not report results for the pediatric population separately, and patients who did not suffer from a TBI were excluded. Studies that did not indicate the use of antiepileptic drugs prophylactically following TBI were excluded. A total of 10 studies were included involving 4621 posttraumatic brain injury patients of the pediatric age population (<18). Five studies assessed the effect of prophylaxis on early seizures, four on late seizures and one on any seizure. The mean incidence of posttraumatic seizures with AED prophylaxis was 8% for early seizures and 7.1% for late seizures. Moreover, one study revealed no benefit of AED prophylaxis for early posttraumatic seizures. Meta-analysis revealed a significant difference in the incidence of early posttraumatic seizures with antiepileptic prophylaxis. However, no significant difference for late posttraumatic seizures has been shown. In conclusion, AED prophylaxis seems to be effective against early posttraumatic seizures for the pediatric population, with levetiracetam possibly being more effective. Also, there is no observed benefit for late posttraumatic seizures.

Young Age, Liver Dysfunction, and Neurostimulant Use as Independent Risk Factors for Post-Traumatic Seizures: A Multiracial Single-Center Experience

We aimed to determine the potentially modifiable risk factors that are predictive of post-traumatic brain injury seizures in relation to the severity of initial injury, neurosurgical interventions, neurostimulant use, and comorbidities. This retrospective study was conducted on traumatic brain injury (TBI) patients admitted to a single center from March 2008 to October 2017. We recruited 151 patients from a multiracial background with TBI, of which the data from 141 patients were analyzed, as 10 were excluded due to incomplete follow-up records or a past history of seizures. Of the remaining 141 patients, 33 (24.4%) patients developed seizures during long-term follow up post-TBI. Young age, presence of cerebral contusion, Indian race, low Glasgow Coma Scale (GCS) scores on admission, and use of neurostimulant medications were associated with increased risk of seizures. In conclusion, due to increased risk of seizures, younger TBI patients, as well as patients with low GCS on admission, cerebral contusions on brain imaging, and those who received neurostimulants or neurosurgical interventions should be monitored for post-TBI seizures. While it is possible that these findings may be explained by the differing mechanisms of injury in younger vs. older patients, the finding that patients on neurostimulants had an increased risk of seizures will need to be investigated in future studies.

A prospective study to determine the risk factors associated with post traumatic seizures: A single institution experience

Background

Post traumatic seizures (PTS) are a known sequel of traumatic brain injury (TBI). Incidence of PTS is dependent on many factors including study design and characteristics of the study population. As incidence of TBI increases and death due to TBI decreases, more individuals will be at risk of developing and living with chronic complications. The objective of the present study was to determine the frequency and risk factors for PTS following TBI.

Methods

A prospective study was conducted on patients admitted with TBI from April 1, 2019, to May 31, 2020, to determine the frequency, time to event, and risk factors for PTS following TBI. We classified the severity of head injury using a standard criterion, into mild, moderate and severe injury. Follow-up of 3 months was undertaken for all patients. Variables include age, sex, trauma severity, Glasgow coma scale, onset of PTS, and neuroradiological finding.

Results

We enrolled 450 post traumatic subjects, out of which 36 (8%) developed seizures. Of the total of 36 patients detected to have hemorrhagic contusion on computerized tomography scan, 12 patients developed seizures. We found that the independent risk factors associated with occurrence of PTS were frontal- temporal lobar contusion and severity of head injury. All these findings were statistically significant.

Conclusion

We found that the independent risk factors associated with occurrence of PTS were frontal-temporal lobar contusion and severity of head injury. Type of management (Operative vs. Non operative) does not affect the outcome of PTS.

Use of Anti-epileptic Drugs for Post Traumatic Seizure: A Global Survey

BACKGROUND

Post traumatic seizures (PTS) and post traumatic epilepsy (PTE) are potential consequences of traumatic brain injury (TBI). There is no consensus regarding its management among treating doctors.

PURPOSE

We have undertaken a global survey to assess the variability of management practices of PTS and PTE and highlight the pressing need to formulate uniform practice guidelines.

METHODS

A questionnaire consisting of sixteen questions were developed with the help of Google survey and sent through e-mail, or social media platforms like WhatsApp, Facebook messenger or Telegram, to practicing Neurologists and Neurosurgeons round the world.

RESULTS

There were a total of 220 responses. Majority of our responders (n = 202; 91.8%) would start an anti-epileptic (AED) prophylaxis to prevent PTS; 18 people (8.18%) told that they would not start AED prophylaxis for TBI. Phenytoin (n = 98; 48.5%) followed by Levetiracetam (n = 78; 38.6%) was the preferred drug, although the latter was significantly preferred by high and upper middle-income countries (p<.001). Majority (n = 99; 49%) would not use it beyond two weeks. Most clinicians would manage PTE with a single drug (n = 160; 72.7%) either Phenytoin (n = 69; 31.3%) or levetiracetam (n = 67; 30.4%). Most of them (n = 174; 86%) would treat for less than one year.

CONCLUSIONS

Practices in the management of PTS and PTE vary widely among clinicians. Our study point towards the need for the development of a more robust and comprehensive practice guidelines for the management of the same.

Effectiveness of antiseizure medications therapy in preventing seizures in brain injury patients: A network meta-analysis

Purpose: To explore the effectiveness of different anti-seizure medications in preventing early and late post-traumatic epilepsy (PTE). The efficacy, treatment-related side-effects, and mortality of the different treatments were compared using a ranking model to identify the optimal treatment.

Methods: A comprehensive literature search was performed using Pubmed, Medline, Embase, and Cochrane library databases. All relevant published articles up to 10 March 2022 were evaluated. The quality of the extracted data was assessed using either the Cochrane risk of bias tool or the Newcastle-Ottawa scale. The primary outcome measures were early or late post-traumatic seizures. The secondary outcome measures were mortality, treatment-related adverse effects, length of hospital stay, and length of stay within the intensive care unit (ICU).

Results: A total of seven randomized controlled trials and 18 non-randomized controlled trials were included in this network meta-analysis. The trials included six interventions: Phenytoin (PHT)+phenobarbital (PB), levetiracetam (LEV), PHT, PHT-LEV, lacosamide (LCM), and valproate (VPA). All interventions except VPA significantly reduced the rate of early PTE in TBI patients compared with the placebo. Seven studies reported the impact of four treatments (PHT + PB, LEV, PHT, VPA) on late seizures and showed a significant reduction in the incidence of late seizures in patients with TBI compared with placebo. The impact of PHT, LEV, and VPA on mortality was reported in nine studies. PHT had no impact on mortality, but patients treated with both LEV and VPA had higher mortality than those treated with placebo. The treatment-related adverse effects of LEV, PHT, and LCM were reported in five studies. LEV and PHT had higher treatment-related adverse effects incidence than placebo, while LCM had no effect on treatment related-adverse effects.

Conclusion: LEV and PHT prevented early and late PTE. PHT also reduced the mortality rate in patients with TBI. Both LEV and PHT had higher treatment-related adverse effects compared with placebo. However, LEV had a slightly lower incidence of treatment-related adverse effects when compared with PHT. Compared with PHT, LEV did not reduce the length of hospital stay but shortened the length of ICU stays. Therefore, based on the findings of this meta-analysis, we speculate that LEV is the best treatment option for TBI patients. However, further high-quality randomized controlled trials are required to confirm these findings.

Neurocritical Management of Traumatic Acute Subdural Hematomas

Acute subdural hematoma (ASDH) has been a major part of traumatic brain injury. Intracranial hypertension may be followed by ASDH and brain edema. Regardless of the complicated pathophysiology of ASDH, the extent of primary brain injury underlying the ASDH is the most important factor affecting outcome. Ongoing intracranial pressure (ICP) increasing lead to cerebral perfusion pressure (CPP) decrease and cerebral blood flow (CBF) decreasing occurred by CPP decrease. In additionally, disruption of cerebral autoregulation, vasospasm, decreasing of metabolic demand may lead to CBF decreasing. Various protocols for ICP lowering were introduced in neuro-trauma field. Usage of anti-epileptic drugs (AEDs) for ASDH patients have controversy. AEDs may reduce the risk of early seizure (<7 days), but, does not for late-onset epilepsy. Usage of anticoagulants/antiplatelets is increasing due to life-long medical disease conditions in aging populations. It makes a difficulty to decide the proper management. Tranexamic acid may use to reducing bleeding and reduce ASDH related death rate. Decompressive craniectomy for ASDH can reduce patient's death rate. However, it may be accompanied with surgical risks due to big operation and additional cranioplasty afterwards. If the craniotomy is a sufficient management for the ASDH, endoscopic surgery will be good alternative to a conventional larger craniotomy to evacuate the hematoma. The management plan for the ASDH should be individualized based on age, neurologic status, radiologic findings, and the patient's conditions.

Prevention of brain damage after traumatic brain injury by pharmacological enhancement of KCNQ (Kv7, "M-type") K+ currents in neurons

Nearly three million people in the USA suffer traumatic brain injury (TBI) yearly; however, there are no pre- or post-TBI treatment options available. KCNQ2-5 voltage-gated K⁺ channels underlie the neuronal "M current", which plays a dominant role in the regulation of neuronal excitability. Our strategy towards prevention of TBI-induced brain damage is predicated on the suggested hyper-excitability of neurons induced by TBIs, and the decrease in neuronal excitation upon pharmacological augmentation of M/KCNQ K⁺ currents. Seizures are very common after a TBI, making further seizures and development of epilepsy disease more likely. Our hypothesis is that TBI-induced hyperexcitability and ischemia/hypoxia lead to metabolic stress, cell death and a maladaptive inflammatory response that causes further downstream morbidity. Using the mouse controlled closed-cortical impact blunt TBI model, we found that systemic administration of the prototype M-channel "opener", retigabine (RTG), 30 min after TBI, reduces the post-TBI cascade of events, including spontaneous seizures, enhanced susceptibility to chemo-convulsants, metabolic stress, inflammatory responses, blood-brain barrier breakdown, and cell death. This work suggests that acutely reducing neuronal excitability and energy demand via M-current enhancement may be a novel model of therapeutic intervention against post-TBI brain damage and dysfunction.

Role of Astrocytes in Post-traumatic Epilepsy

Traumatic brain injury, a common cause of acquired epilepsy, is typical to find necrotic cell death within the injury core. The dynamic changes in astrocytes surrounding the injury core contribute to epileptic seizures associated with intense neuronal firing. However, little is known about the molecular mechanisms that activate astrocytes during traumatic brain injury or the effect of functional changes of astrocytes on seizures. In this comprehensive review, we present our cumulated understanding of the complex neurological affection in astrocytes after traumatic brain injury. We approached the problem through describing the changes of cell morphology, neurotransmitters, biochemistry, and cytokines in astrocytes during post-traumatic epilepsy. In addition, we also discussed the relationship between dynamic changes in astrocytes and seizures and the current pharmacologic agents used for treatment. Hopefully, this review will provide a more detailed knowledge from which better therapeutic strategies can be developed to treat post-traumatic epilepsy.

Dysregulated Glucose Metabolism as a Therapeutic Target to Reduce Post-traumatic Epilepsy

Traumatic brain injury (TBI) is a significant cause of disability worldwide and can lead to post-traumatic epilepsy. Multiple molecular, cellular, and network pathologies occur following injury which may contribute to epileptogenesis. Efforts to identify mechanisms of disease progression and biomarkers which predict clinical outcomes have focused heavily on metabolic changes. Advances in imaging approaches, combined with well-established biochemical methodologies, have revealed a complex landscape of metabolic changes that occur acutely after TBI and then evolve in the days to weeks after. Based on this rich clinical and preclinical data, combined with the success of metabolic therapies like the ketogenic diet in treating epilepsy, interest has grown in determining whether manipulating metabolic activity following TBI may have therapeutic value to prevent post-traumatic epileptogenesis. Here, we focus on changes in glucose utilization and glycolytic activity in the brain following TBI and during seizures. We review relevant literature and outline potential paths forward to utilize glycolytic inhibitors as a disease-modifying therapy for post-traumatic epilepsy.

Epidemiology of traumatic brain injury-associated epilepsy and early use of anti-epilepsy drugs: An analysis of insurance claims data, 2004-2014

BACKGROUND

About 2.8 million TBI-related emergency department visits, hospitalizations and deaths occurred in 2013 in the United States. Post-traumatic epilepsy (PTE) can be a disabling, life-long outcome of TBI.

OBJECTIVES

The purpose of this study is to address the probability of developing PTE within 9 years after TBI, the risk factors associated with PTE, the prevalence of anti-epileptic drug (AEDs) use, and the effectiveness of using AEDs prophylactically after TBI to prevent the development of PTE.

METHODS

Using MarketScan® databases covering commercial, Medicare Supplemental, and multi-state Medicaid enrollees from 2004 to 2014, we examined the incidence of early seizures (within seven days after TBI) and cumulative incidence of PTE, the hazard ratios (HR) of PTE by age, gender, TBI severity, early seizure and AED use (carbamazepine, clonazepam, divalproex sodium, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, phenytoin, pregabalin, topiramate, acetazolamide). We used backward selection to build the final Cox proportional hazard model and conducted multivariable survival analysis to obtain estimates of crude and adjusted HR (cHRs, aHRs) of PTE and 95% confidence intervals (CI).

RESULTS

The incidence of early seizure among TBI patients in our study was 0.5%. The cumulative incidence of PTE increased from 1.0% in one year to 4.0% in nine years. Most patients with TBI (93%) were not prescribed any AED. Gender was not associated with PTE. The risk of PTE was higher for individuals with older age, early seizures, and more severe TBI. Only individuals using prophylactic acetazolamide had significantly lower risk of PTE (aHR = 0.6, CI 0.4-0.9) compared to those not using any AED.

CONCLUSION

The probability of developing PTE increased within the study period. The risk of developing PTE significantly increased with age, early seizure and TBI severity. Most of the individuals did not receive AED after TBI. There was no evidence suggesting AEDs helped to prevent PTE with the possible exception of acetazolamide. However, further studies may be needed to test the efficacy of acetazolamide in preventing PTE.

Effects of Human ES-Derived Neural Stem Cell Transplantation and Kindling in a Rat Model of Traumatic Brain Injury

Traumatic brain injury (TBI) is one of the leading causes of death and disability in the population worldwide, with a broad spectrum of symptoms and disabilities. Posttraumatic hyperexcitability is one of the most common neurological disorders that affect people after a head injury. A reliable animal model of posttraumatic hyperexcitability induced by TBI which allows one to test effective treatment strategies is yet to be developed. To address these issues, in the present study, we tested human embryonic stem cell-derived neural stem cell (NSC) transplantation in an animal model of posttraumatic hyperexcitability in which the brain injury was produced in one hemisphere of immunodeficient athymic nude rats by controlled cortical impact, and spontaneous seizures were produced by repeated electrical stimulation (kindling) in the contralateral hemisphere. At 14 wk posttransplantation, we report human NSC (hNSC) survival and differentiation into all 3 neural lineages in both sham and injured animals. We observed twice as many surviving hNSCs in the injured versus sham brain, and worse survival on the kindled side in both groups, indicating that kindling/seizures are detrimental to survival or proliferation of hNSCs. We also replicated our previous finding that hNSCs can ameliorate deficits on the novel place recognition task,33 but such improvements are abolished following kindling. We found no significant differences pre- or post-kindling on the elevated plus maze. No significant correlations were observed between hNSC survival and cognitive performance on either task. Together these findings suggest that Shef6-derived hNSCs may be beneficial as a therapy for TBI, but not in animals or patients with posttraumatic hyperexcitability.

Inflammation in epileptogenesis after traumatic brain injury

Background

Epilepsy is a common and debilitating consequence of traumatic brain injury (TBI). Seizures contribute to progressive neurodegeneration and poor functional and psychosocial outcomes for TBI survivors, and epilepsy after TBI is often resistant to existing anti-epileptic drugs. The development of post-traumatic epilepsy (PTE) occurs in a complex neurobiological environment characterized by ongoing TBI-induced secondary injury processes. Neuroinflammation is an important secondary injury process, though how it contributes to epileptogenesis, and the development of chronic, spontaneous seizure activity, remains poorly understood. A mechanistic understanding of how inflammation contributes to the development of epilepsy (epileptogenesis) after TBI is important to facilitate the identification of novel therapeutic strategies to reduce or prevent seizures.

Body

We reviewed previous clinical and pre-clinical data to evaluate the hypothesis that inflammation contributes to seizures and epilepsy after TBI. Increasing evidence indicates that neuroinflammation is a common consequence of epileptic seizure activity, and also contributes to epileptogenesis as well as seizure initiation (ictogenesis) and perpetuation. Three key signaling factors implicated in both seizure activity and TBI-induced secondary pathogenesis are highlighted in this review: high-mobility group box protein-1 interacting with toll-like receptors, interleukin-1β interacting with its receptors, and transforming growth factor-β signaling from extravascular albumin. Lastly, we consider age-dependent differences in seizure susceptibility and neuroinflammation as mechanisms which may contribute to a heightened vulnerability to epileptogenesis in young brain-injured patients.

Conclusion

Several inflammatory mediators exhibit epileptogenic and ictogenic properties, acting on glia and neurons both directly and indirectly influence neuronal excitability. Further research is required to establish causality between inflammatory signaling cascades and the development of epilepsy post-TBI, and to evaluate the therapeutic potential of pharmaceuticals targeting inflammatory pathways to prevent or mitigate the development of PTE.