WITHDRAWN: Antiepileptic drugs for preventing seizures following acute traumatic brain injury

Celecoxib treatment alleviates cerebral injury in a rat model of post-traumatic epilepsy

Background

An important factor contributing to the development and occurrence of post-traumatic epilepsy (PTE) is neuroinflammation and oxidative stress. The effects of celecoxib include inhibiting inflammatory reactions and antioxidant stress and reducing seizures, making it a potential epilepsy treatment solution.

Objective

To observe the effect of celecoxib on early epilepsy in post-traumatic epilepsy rats. Methods: Twenty-four adult healthy male Sprague-Dawley rats were randomly assigned to three groups: sham-operated, PTE, and celecoxib. A rat model of PTE was established by injecting ferrous chloride into the right frontal cortex. Afterward, the behavior of rats was observed and recorded. 3.0T superconducting magnetic resonance imaging (MRI) was used to describe the changes in ADC values of the brain. HE and Nissl staining were also used to detect the damage to frontal lobe neurons. Furthermore, the expression of COX-2 protein in the right frontal lobe was detected by Western blot. Moreover, the contents of IL-1 and TNF-α in the right frontal lobe were detected by enzyme-linked immunosorbent assay.

Results

Compared with the PTE group, the degree of seizures in rats treated with celecoxib declined dramatically (P < 0.05). Celecoxib-treated rats had significant decreases in tissue structural damage and cell death in the brain. The results of the MRI showed that celecoxib reduced the peripheral edema zone and ADC value of the cortex around the damaged area of the right frontal lobe in the celecoxib-treatment group, which was significantly decreased compared with the PTE group (P < 0.05). Furthermore, celecoxib decreased the expression of COX-2, IL-1β, and TNF-α in brain tissue (P < 0.05).

Conclusions

In PTE rats, celecoxib significantly reduced brain damage and effectively reduced seizures. As a result of celecoxib's ability to inhibit inflammation, it can reduce the edema caused by injury in rat brain tissue.

Inhibitory Network Bistability Explains Increased Interneuronal Activity Prior to Seizure Onset

Recent experimental literature has revealed that GABAergic interneurons exhibit increased activity prior to seizure onset, alongside additional evidence that such activity is synchronous and may arise abruptly. These findings have led some to hypothesize that this interneuronal activity may serve a causal role in driving the sudden change in brain activity that heralds seizure onset. However, the mechanisms predisposing an inhibitory network toward increased activity, specifically prior to ictogenesis, without a permanent change to inputs to the system remain unknown. We address this question by comparing simulated inhibitory networks containing control interneurons and networks containing hyperexcitable interneurons modeled to mimic treatment with 4-Aminopyridine (4-AP), an agent commonly used to model seizures in vivo and in vitro. Our in silico study demonstrates that model inhibitory networks with 4-AP interneurons are more prone than their control counterparts to exist in a bistable state in which asynchronously firing networks can abruptly transition into synchrony driven by a brief perturbation. This transition into synchrony brings about a corresponding increase in overall firing rate. We further show that perturbations driving this transition could arise in vivo from background excitatory synaptic activity in the cortex. Thus, we propose that bistability explains the increase in interneuron activity observed experimentally prior to seizure via a transition from incoherent to coherent dynamics. Moreover, bistability explains why inhibitory networks containing hyperexcitable interneurons are more vulnerable to this change in dynamics, and how such networks can undergo a transition without a permanent change in the drive. We note that while our comparisons are between networks of control and ictogenic neurons, the conclusions drawn specifically relate to the unusual dynamics that arise prior to seizure, and not seizure onset itself. However, providing a mechanistic explanation for this phenomenon specifically in a pro-ictogenic setting generates experimentally testable hypotheses regarding the role of inhibitory neurons in pre-ictal neural dynamics, and motivates further computational research into mechanisms underlying a newly hypothesized multi-step pathway to seizure initiated by inhibition.

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.

EEG in non-clinical drug safety assessments: Current and emerging considerations

Electroencephalogram (EEG) data in nonclinical species can play a critical role in the successful evaluation of a compound during drug development, particularly in the evaluation of seizure potential and for monitoring changes in sleep. Yet, while non-invasive electrocardiogram (ECG) monitoring is commonly included in preclinical safety studies, pre-dose or post-dose EEG assessments are not. Industry practices as they relate to preclinical seizure liability and sleep assessments are not well characterized and the extent of preclinical EEG testing varies between organizations. In the current paper, we discuss the various aspects of preclinical EEG to characterize drug-induced seizure risk and sleep disturbances, as well as describe the use of these data in a regulatory context. An overview of EEG technology-its correct application and its limitations, as well as best practices for setting up the animal models is presented. Sleep and seizure detection are discussed in detail. A regulatory perspective on the use of EEG data is provided and, tying together the previous topics is a discussion of the translational aspects of EEG.

Treatment of acute subdural hematoma

OPINION STATEMENT

Clinical presentation, neurologic condition, and imaging findings are the key components in establishing a treatment plan for acute SDH. Location and size of the SDH and presence of midline shift can rapidly be determined by computed tomography of the head. Immediate laboratory work up must include PT, PTT, INR, and platelet count. Presence of a coagulopathy or bleeding diathesis requires immediate reversal and treatment with the appropriate agent(s), in order to lessen the risk of hematoma expansion. Reversal protocols used are similar to those for intracerebral hemorrhage, with institutional variations. Immediate neurosurgical evaluation is sought in order to determine whether the SDH warrants surgical evacuation. Urgent or emergent surgical evacuation of a SDH is largely influenced by neurologic examination, imaging characteristics, and presence of mass effect or elevated intracranial pressure. Generally, evacuation of an acute SDH is recommended if the clot thickness exceeds 10 mm or the midline shift is greater than 5 mm, regardless of the neurologic condition. In patients with patients with an acute SDH with clot thickness <10 mm and midline shift <5 mm, specific considerations of neurologic findings and clinical circumstances will be of importance. In addition, consideration will be given as to whether an individual patient is likely to benefit from surgery. For an acute SDH, evacuation by craniotomy or craniectomy is preferred over burr holes based on available data. Postoperative care includes monitoring of resolution of pneumocephalus, mobilization and drain removal, and monitoring for signs of SDH reaccumulation. Medical considerations include seizure prophylaxis and management as well as management and resumption of antithrombotic and anticoagulant medication.

Updates in the management of the small animal patient with neurologic trauma

Neurologic trauma, encompassing traumatic brain injury (TBI) and acute spinal cord injury (SCI), is a cause of significant morbidity and mortality in veterinary patients. Acute SCIs occurring secondary to trauma are also common. Essential to the management of TBI and SCI is a thorough understanding of the pathophysiology of the primary and secondary injury that occurs following trauma. This article reviews the pathophysiology of this primary and secondary injury, as well as recommendations regarding clinical assessment, diagnostics, pharmacologic and nonpharmacologic therapy, and prognosis.

Survey of prophylactic antiseizure drug use for non-traumatic intracerebral hemorrhage

OBJECTIVE

Prophylactic antiseizure drugs (PAD) are commonly prescribed for non-traumatic intracerebral hemorrhage (ICH) despite limited evidence for this indication. We sought to determine the current prescribing patterns of the use of a PAD for ICH.

METHODS

A 36-item survey was distributed to physicians who manage ICH patients soliciting details of PAD prescription in their practice.

RESULTS

A total of 199 physicians responded to the survey, all of who manage 50 or more ICH patients per year. The respondents were neurologists (32%), neurosurgeons (11%), and intensivists (57%) in academia (69%) and private practice (31%). Prophylactic antiseizure drugs prescriptions used: never (33%), 1-33% (35%), 34-66% (14%), 67-99% (9%) of the time, or always (9%). Most respondents performed electroencephalographic and serum level monitoring in at least some patients. Levetiracetam was used most often (60%), followed by fosphenytoin (37%), for a usual duration of days (36%), weeks (47%), or months (17%). Prophylactic antiseizure drugs prescription varied by patient characteristics and physician specialty. Perception of physician community consensus regarding PAD use for ICH among respondents ranged from strongly (7%) or weakly (23%) against the practice, to a fairly equal division of opinion (41%), to weakly (27%) or strongly (4%) in favor of the practice.

CONCLUSIONS

We found variability of multiple aspects of the current prescribing patterns and opinions regarding the use of a PAD for ICH. This variability is likely secondary to insufficient data. Clinical equipoise exists for this issue, and controlled trials would be both justified and useful.

Traumatic brain injury: A case-based review

BACKGROUND

Traumatic brain injuries are common and costly to hospital systems. Most of the guidelines on management of traumatic brain injuries are taken from the Brain Trauma Foundation Guidelines. This is a review of the current literature discussing the evolving practice of traumatic brain injury.

DATA SOURCES

A literature search using multiple databases was performed for articles published through September 2012 with concentration on meta-analyses, systematic reviews, and randomized controlled trials.

RESULTS

The focus of care should be to minimize secondary brain injury by surgically decompressing certain hematomas, maintain systolic blood pressure above 90 mmHg, oxygen saturations above 93%, euthermia, intracranial pressures below 20 mmHg, and cerebral perfusion pressure between 60-80 mmHg.

CONCLUSION

Much is still unknown about the management of traumatic brain injury. The current practice guidelines have not yet been sufficiently validated, however equipoise is a major issue when conducting randomized control trials among patients with traumatic brain injury.