Megadose steroids in severe head injury. Results of a prospective double-blind clinical trial

Context is key: glucocorticoid receptor and corticosteroid therapeutics in outcomes after traumatic brain injury

Traumatic brain injury (TBI) is a global health burden, and survivors suffer functional and psychiatric consequences that can persist long after injury. TBI induces a physiological stress response by activating the hypothalamic-pituitary-adrenal (HPA) axis, but the effects of injury on the stress response become more complex in the long term. Clinical and experimental evidence suggests long lasting dysfunction of the stress response after TBI. Additionally, pre- and post-injury stress both have negative impacts on outcome following TBI. This bidirectional relationship between stress and injury impedes recovery and exacerbates TBI-induced psychiatric and cognitive dysfunction. Previous clinical and experimental studies have explored the use of synthetic glucocorticoids as a therapeutic for stress-related TBI outcomes, but these have yielded mixed results. Furthermore, long-term steroid treatment is associated with multiple negative side effects. There is a pressing need for alternative approaches that improve stress functionality after TBI. Glucocorticoid receptor (GR) has been identified as a fundamental link between stress and immune responses, and preclinical evidence suggests GR plays an important role in microglia-mediated outcomes after TBI and other neuroinflammatory conditions. In this review, we will summarize GR-mediated stress dysfunction after TBI, highlighting the role of microglia. We will discuss recent studies which target microglial GR in the context of stress and injury, and we suggest that cell-specific GR interventions may be a promising strategy for long-term TBI pathophysiology.

A historical delve into neurotrauma-focused critical care

Neurocritical care is a multidisciplinary field managing patients with a wide range of aliments. Specifically, neurotrauma is a rapidly growing field with increasing demands. The history of how neurotrauma management came to its current form has not been extensively explored before. Our review delves into the history, timeline, and noteworthy pioneers of neurotrauma-focused neurocritical care. We explore the historical development during early times, the 18th-20th centuries, and modern times, as well as warfare- and sports-related concussions. Research is ever growing in this budding field, with several promising innovations on the horizon.

Brain-Lung Crosstalk: Management of Concomitant Severe Acute Brain Injury and Acute Respiratory Distress Syndrome

Purpose of Review

To summarize pathophysiology, key conflicts, and therapeutic approaches in managing concomitant severe acute brain injury (SABI) and acute respiratory distress syndrome (ARDS).

Recent Findings

ARDS is common in SABI and independently associated with worse outcomes in all SABI subtypes. Most landmark ARDS trials excluded patients with SABI, and evidence to guide decisions is limited in this population. Potential areas of conflict in the management of patients with both SABI and ARDS are (1) risk of intracranial pressure (ICP) elevation with high levels of positive end-expiratory pressure (PEEP), permissive hypercapnia due to lung protective ventilation (LPV), or prone ventilation; (2) balancing a conservative fluid management strategy with ensuring adequate cerebral perfusion, particularly in patients with symptomatic vasospasm or impaired cerebrovascular blood flow; and (3) uncertainty about the benefit and harm of corticosteroids in this population, with a mortality benefit in ARDS, increased mortality shown in TBI, and conflicting data in other SABI subtypes. Also, the widely adapted partial pressure of oxygen (PaO2) target of > 55 mmHg for ARDS may exacerbate secondary brain injury, and recent guidelines recommend higher goals of 80-120 mmHg in SABI. Distinct pathophysiology and trajectories among different SABI subtypes need to be considered.

Summary

The management of SABI with ARDS is highly complex, and conventional ARDS management strategies may result in increased ICP and decreased cerebral perfusion. A crucial aspect of concurrent management is to recognize the risk of secondary brain injury in the individual patient, monitor with vigilance, and adjust management during critical time windows. The care of these patients requires meticulous attention to oxygenation and ventilation, hemodynamics, temperature management, and the neurological exam. LPV and prone ventilation should be utilized, and supplemented with invasive ICP monitoring if there is concern for cerebral edema and increased ICP. PEEP titration should be deliberate, involving measures of hemodynamic, pulmonary, and brain physiology. Serial volume status assessments should be performed in SABI and ARDS, and fluid management should be individualized based on measures of brain perfusion, the neurological exam, and cardiopulmonary status. More research is needed to define risks and benefits in corticosteroids in this population.

The role of the stress system in recovery after traumatic brain injury: A tribute to Bruce S. McEwen

Traumatic brain injury (TBI) represents a major public health concern. Although the majority of individuals that suffer mild-moderate TBI recover relatively quickly, a substantial subset of individuals experiences prolonged and debilitating symptoms. An exacerbated response to physiological and psychological stressors after TBI may mediate poor functional recovery. Individuals with TBI can suffer from poor stress tolerance, impairments in the ability to evaluate stressors, and poor initiation (and cessation) of neuroendocrine stress responses, all of which can exacerbate TBI-mediated dysfunction. Here, we pay tribute to the pioneering neuroendocrinologist Dr. Bruce McEwen by discussing the ways in which his work on stress physiology and allostatic loading impacts the TBI patient population both before and after their injuries. Specifically, we will discuss the modulatory role of hypothalamic-pituitary-adrenal axis responses immediately after TBI and later in recovery. We will also consider the impact of stressors and stress responses in promoting post-concussive syndrome and post-traumatic stress disorders, two common sequelae of TBI. Finally, we will explore the role of early life stressors, prior to brain injuries, as modulators of injury outcomes.

High-dose IgG suppresses local inflammation and facilitates functional recovery after olfactory system injury

OBJECTIVE

Head trauma can be a cause of refractory olfactory dysfunction due to olfactory nervous system injury. Anti-inflammatory treatment using steroids or anti-cytokine agents is known to contribute to functional recovery of the central and peripheral nervous systems in injury models, while there is a concern that they can induce adverse reactions. The present study examines if high-dose immunoglobulin G (IgG) can facilitate olfactory functional recovery following injury.

METHODS

Olfactory nerve transection (NTx) was performed in OMP-tau-lacZ mice to establish injury models. High-dose IgG was intraperitoneally injected immediately after the NTx and histological assessment of recovery within the olfactory bulb was performed at 5, 14, 42, and 100 days after the drug injection. X-gal staining labeled degenerating and regenerating olfactory nerve fibers and immunohistochemical staining detected the presence of reactive astrocytes and macrophages/microglia. Olfactory function was assessed using an olfactory avoidance behavioral test.

RESULTS

High-dose IgG-injected mice showed significantly smaller areas of injury-associated tissue, fewer astrocytes and macrophages/microglia, and an increase in regenerating nerve fibers. An olfactory avoidance behavioral test showed improved functional recovery in the IgG-injected mice.

INTERPRETATION

These findings suggest that high-dose IgG could provide a new therapeutic strategy for the treatment of olfactory dysfunction following head injuries.

Immune responses in the injured olfactory and gustatory systems: a role in olfactory receptor neuron and taste bud regeneration?

Sensory cells that specialize in transducing olfactory and gustatory stimuli are renewed throughout life and can regenerate after injury unlike their counterparts in the mammalian retina and auditory epithelium. This uncommon capacity for regeneration offers an opportunity to understand mechanisms that promote the recovery of sensory function after taste and smell loss. Immune responses appear to influence degeneration and later regeneration of olfactory sensory neurons and taste receptor cells. Here we review surgical, chemical, and inflammatory injury models and evidence that immune responses promote or deter chemosensory cell regeneration. Macrophage and neutrophil responses to chemosensory receptor injury have been the most widely studied without consensus on their net effects on regeneration. We discuss possible technical and biological reasons for the discrepancy, such as the difference between peripheral and central structures, and suggest directions for progress in understanding immune regulation of chemosensory regeneration. Our mechanistic understanding of immune-chemosensory cell interactions must be expanded before therapies can be developed for recovering the sensation of taste and smell after head injury from traumatic nerve damage and infection. Chemosensory loss leads to decreased quality of life, depression, nutritional challenges, and exposure to environmental dangers highlighting the need for further studies in this area.

The Dual Dose-Dependent Effects of Corticosterone on Hippocampal Cell Apoptosis After Traumatic Brain Injury Depend on the Activation Ratio of Mineralocorticoid Receptors to Glucocorticoid Receptors

In our recent studies, we reported that mineralocorticoid receptor (MR) had the opposite effects of glucocorticoid receptor (GR) on neural cell survival after traumatic brain injury (TBI). However, whether short-term use of high-dose natural glucocorticoids, which are mixed agonists of both MR and GR, leads to neurotoxic effects by inducing excessive GR activation is unclear, as is the threshold GR activation level and the possible signaling pathways remain unclear. In this study, we examined the dual dose-dependent effects of corticosterone (CORT) on spatial memory, hippocampal cell survival and receptor-mediated downstream signaling pathways after TBI. We found that different doses of CORT exhibited dual effects on hippocampal cell survival and rat spatial memory. Low doses of CORT (0.3 and 3 mg/kg) significantly increased MR activation, upregulated Akt/CREB/Bad phosphorylation and Bcl-2 concentration, reduced the number of apoptotic neural cells, and subsequently improved rat spatial memory. In contrast, a high dose of CORT (30 mg/kg) exerted the opposite effects by overactivating GR, upregulating P53/Bax levels, and inhibiting Erk/CREB activity. The results suggest that the neuroprotective and neurotoxic effects of endogenous GC depend on a threshold level and that a higher dose of GC, even for short-term use, should be avoided after TBI.

Corticosteroid receptor rebalancing alleviates critical illness-related corticosteroid insufficiency after traumatic brain injury by promoting paraventricular nuclear cell survival via Akt/CREB/BDNF signaling

BACKGROUND

We previously found that high-dose methylprednisolone increased the incidence of critical illness-related corticosteroid insufficiency (CIRCI) and mortality in rats with traumatic brain injury (TBI), whereas low-dose hydrocortisone but not methylprednisolone exerted protective effects. However, the receptor-mediated mechanism remains unclear. This study investigated the receptor-mediated mechanism of the opposite effects of different glucocorticoids on the survival of paraventricular nucleus (PVN) cells and the incidence of CIRCI after TBI.

METHODS

Based on controlled cortical impact (CCI) and treatments, male SD rats (n = 300) were randomly divided into the sham, CCI, CCI + GCs (methylprednisolone 1 or 30 mg/kg/day; corticosterone 1 mg/kg/day), CCI + methylprednisolone+RU486 (RU486 50 mg/kg/day), and CCI + corticosterone+spironolactone (spironolactone 50 mg/kg/day) groups. Blood samples were collected 7 days before and after CCI. Brain tissues were collected on postinjury day 7 and processed for histology and western blot analysis.

RESULTS

We examined the incidence of CIRCI, mortality, apoptosis in the PVN, the receptor-mediated mechanism, and downstream signaling pathways on postinjury day 7. We found that methylprednisolone and corticosterone exerted opposite effects on the survival of PVN cells and the incidence of CIRCI by activating different receptors. High-dose methylprednisolone increased the nuclear glucocorticoid receptor (GR) level and subsequently increased cell loss in the PVN and the incidence of CIRCI. In contrast, low-dose corticosterone but not methylprednisolone played a protective role by upregulating mineralocorticoid receptor (MR) activation. The possible downstream receptor signaling mechanism involved the differential effects of GR and MR on the activity of the Akt/CREB/BDNF pathway.

CONCLUSION

The excessive activation of GR by high-dose methylprednisolone exacerbated apoptosis in the PVN and increased CIRCI. In contrast, refilling of MR by corticosterone protects PVN neurons and reduces the incidence of CIRCI by promoting GR/MR rebalancing after TBI.

Biomaterial-mediated reprogramming of monocytes via microparticle phagocytosis for sustained modulation of macrophage phenotype

Monocyte-derived macrophages orchestrate tissue regeneration by homing to sites of injury, phagocytosing pathological debris, and stimulating other cell types to repair the tissue. Accordingly, monocytes have been investigated as a translational and potent source for cell therapy, but their utility has been hampered by their rapid acquisition of a pro-inflammatory phenotype in response to the inflammatory injury microenvironment. To overcome this problem, we designed a cell therapy strategy where monocytes are exogenously reprogrammed by intracellularly loading the cells with biodegradable microparticles containing an anti-inflammatory drug in order to modulate and maintain an anti-inflammatory phenotype over time. To test this concept, poly(lactic-co-glycolic) acid microparticles were loaded with the anti-inflammatory drug dexamethasone (Dex) and administered to primary human monocytes for four hours to facilitate phagocytic uptake. After removal of non-phagocytosed microparticles, microparticle-loaded monocytes differentiated into macrophages and stored the microparticles intracellularly for several weeks in vitro, releasing drug into the extracellular environment over time. Cells loaded with intracellular Dex microparticles showed decreased expression and secretion of inflammatory factors even in the presence of pro-inflammatory stimuli up to 7 days after microparticle uptake compared to untreated cells or cells loaded with blank microparticles, without interfering with phagocytosis of tissue debris. This study represents a new strategy for long-term maintenance of anti-inflammatory macrophage phenotype using a translational monocyte-based cell therapy strategy without the use of genetic modification. Because of the ubiquitous nature of monocyte-derived macrophage involvement in pathology and regeneration, this strategy holds potential as a treatment for a vast number of diseases and disorders. STATEMENT OF SIGNIFICANCE: We report a unique and translational strategy to overcome the challenges associated with monocyte- and macrophage-based cell therapies, in which the cells rapidly take on inflammatory phenotypes when administered to sites of injury. By intracellularly loading monocytes with drug-loaded microparticles prior to administration via phagocytosis, we were able to inhibit inflammation while preserving functional behaviors of human primary macrophages derived from those monocytes up to seven days later. To our knowledge, this study represents the first report of reprogramming macrophages to an anti-inflammatory phenotype without the use of genetic modification.

Corticosterone Replacement Alleviates Hippocampal Neuronal Apoptosis and Spatial Memory Impairment Induced by Dexamethasone via Promoting Brain Corticosteroid Receptor Rebalance after Traumatic Brain Injury

The balance of mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) is indispensable for maintaining the normal function and structure of the hippocampus. However, changes in GR/MR and their effect on the survival of hippocampal neurons after traumatic brain injury (TBI) are still unclear. Previous studies have indicated that high-dose glucocorticoids (GC) aggravate hippocampal neuronal damage after TBI. We hypothesize that the imbalance of GR/MR expression and activation caused by injury and irrational use of dexamethasone (DEX) aggravates post-traumatic hippocampal apoptosis and spatial memory dysfunction, but that restoration by refilling MR and inhibiting GR promotes the survival of neurons. Using rat controlled cortical impact model, we examined the plasma corticosterone (CORT), corticosteroid receptor expression, apoptosis, and cell loss in the hippocampus, and, accordingly, the spatial memory after TBI and GC treatment within 7 days. Plasma CORT, MR, and GR expression level were significantly reduced at 2 days after TBI. Accordingly, the number of apoptotic cells also peaked at 2 days. Compared with the TBI control group, DEX treatment (5 mg/kg) significantly reduced plasma CORT, upregulated GR expression, and increased the number of apoptotic cells and cell loss, whereas CORT replacement (0.3 mg/kg) upregulated MR expression, inhibited apoptosis, and improved spatial memory. The deleterious and protective effects of DEX and CORT were counteracted by spironolactone and mifepristone respectively. The results suggest that inhibition of GR by RU486 or the refilling of MR by CORT protects hippocampal neurons and alleviates spatial memory impairment via promoting GR/MR rebalancing after TBI.

Modulation of macrophage phenotype via phagocytosis of drug-loaded microparticles

Monocyte-derived macrophages play a critical role in directing wound pathology following injury. Depending on their phenotype, macrophages also promote tissue regeneration. However, the therapeutic administration of macrophages with a controlled phenotype is challenging because macrophages are highly plastic and quickly revert to a detrimental, inflammatory phenotype in response to the environment of a damaged tissue. To address this issue, we developed a novel strategy to modulate macrophage phenotype intracellularly through phagocytosis of drug-loaded microparticles. Poly(lactic-co-glycolic acid) microparticles loaded with the anti-inflammatory drug dexamethasone (Dex) were phagocytosed by monocytes and stored intracellularly for at least 5 days. After differentiation into macrophages, cell phenotype was characterized over time with high-throughput gene expression analysis via NanoString. We found that the microparticles modulated macrophage phenotype for up to 7 days after microparticle uptake, with decreases in inflammation-related genes at early timepoints and upregulation of homing- and phagocytosis-related genes at multiple timepoints in a manner similar to cells treated with continuous free Dex. These data suggest that intracellularly loading macrophages with Dex microparticles via phagocytosis could be a unique methodology to selectively modulate macrophage phenotype over time. This strategy would allow therapeutic administration of macrophages for the treatment of a number of inflammatory disease and disorders. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1213-1224, 2019.

Dexamethasone does not prevent hydrocephalus after severe intraventricular hemorrhage in newborn rats

The aim of this study was done to determine whether dexamethasone treatment prevents posthemorrhagic hydrocephalus (PHH) development and attenuates brain damage after severe IVH in newborn rats. Severe IVH was induced by injecting; 100 μL of blood into each lateral ventricle of postnatal day 4 (P4) Sprague-Dawley rats. Dexamethasone was injected intraperitoneally into rat pups at a dose of 0.5 mg/kg, 0.3 mg/kg, and 0.1 mg/kg on P5, P6, and P7, respectively. Serial brain magnetic resonance imaging and behavioral function tests, such as the negative geotaxis test and the rotarod test, were performed. On P32, brain tissues were obtained for histological and biochemical analyses. Dexamethasone treatment significantly improved the severe IVH-induced increase in the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling-positive cells, glial fibrillary acidic protein-positive astrocytes and ED-1 positive microglia, and the decrease in myelin basic protein. IVH reduced a survival of 71%, that showed a tendency to improve to 86% with dexamethasone treatment, although the result was not statistically significant. However, dexamethasone failed to prevent the progression to PHH and did not significantly improve impaired behavioral tests. Similarly, dexamethasone did not decrease the level of inflammatory cytokines such as interleukin (IL) -1α and ß, IL-6, and tumor necrosis factor-α after severe IVH. Despite its some neuroprotective effects, dexamethasone failed to improve the progress of PHH and impaired behavioral tests after severe IVH.

Worldwide Steroid Prescription for Acute Spinal Cord Injury

STUDY DESIGN

Cross-sectional study.

OBJECTIVES

To continue the line of a previous publication using steroid for acute spinal cord injury (SCI) by spine surgeons from Latin America (LA) and assess the current status of methylprednisolone (MP) prescription in Europe (EU), Asia Pacific (AP), North America (NA), and Middle East (ME) to determine targets for educational activities suitable for each region.

METHODS

The English version of a previously published questionnaire was used to evaluate opinions about MP administration in acute SCI in LA, EU, AP, NA, and ME. This Internet-based survey was conducted by members of AOSpine. The questionnaire asked about demographic features, background with management of spine trauma patients, routine administration of MP in acute SCI, and reasons for MP administration.

RESULTS

A total of 2659 responses were obtained for the electronic questionnaire from LA, EU, AP, NA, and ME. The number of spine surgeons that treat SCI was 2206 (83%). The steroid was used by 1198 (52.9%) surgeons. The uses of MP were based predominantly on the National Acute Spinal Cord Injury Study III study (n = 595, 50%). The answers were most frequently given by spine surgeons from AP, ME, and LA. These regions presented a statistically significant difference from North America (P < .001). The number of SCI patients treated per year inversely influenced the use of MP. The higher the number of patients treated, the lower the administration rates of MP observed.

CONCLUSIONS

The study identified potential targets for educational campaigns, aiming to reduce inappropriate practices of MP administration.

Anti-high mobility group box 1 antibody suppresses local inflammatory reaction and facilitates olfactory nerve recovery following injury

Background

Refractory olfactory dysfunction is a common finding in head trauma due to olfactory nerve injury. Anti-inflammatory treatment using steroids is known to contribute to functional recovery of the central and peripheral nervous systems in injury models, while there is a concern that steroids can induce side effects. The present study examines if the inhibition of proinflammatory cytokine, high mobility group box 1 (HMGB1), can facilitate olfactory functional recovery following injury.

Methods

Olfactory nerve transection (NTx) was performed in OMP-tau-lacZ mice to establish injury models. We measured HMGB1 gene expression in the olfactory bulb using semi-quantitative polymerase chain reaction (PCR) assays and examined HMGB1 protein localization in the olfactory bulb using immunohistochemical staining. Anti-HMGB1 antibody was intraperitoneally injected immediately after the NTx and histological assessment of recovery within the olfactory bulb was performed at 5, 14, 42, and 100 days after the drug injection. X-gal staining labeled OMP in the degenerating and regenerating olfactory nerve fibers, and immunohistochemical staining detected the presence of reactive astrocytes and macrophages/microglia. Olfactory function was assessed using both an olfactory avoidance behavioral test and evoked potential recording.

Results

HMGB1 gene and protein were significantly expressed in the olfactory bulb 12 h after NTx. Anti-HMGB1 antibody-injected mice showed significantly smaller areas of injury-associated tissue, fewer astrocytes and macrophages/microglia and an increase in regenerating nerve fibers. Both an olfactory avoidance behavioral test and evoked potential recordings showed improved functional recovery in the anti-HMGB1 antibody-injected mice.

Conclusions

These findings suggest that inhibition of HMGB1 could provide a new therapeutic strategy for the treatment of olfactory dysfunction following head injuries.

Steroids and Survival in Critically Ill Adult Patients: A Meta-analysis of 135 Randomized Trials

OBJECTIVE

Corticosteroids have important effects on intermediate outcomes in critically ill patients, but their effect on survival is unknown. The objective of this meta-analysis was to analyze the effect on mortality of corticosteroids in critical and perioperative settings.

DESIGN

A meta-analysis of randomized trials.

SETTING

PubMed, Embase, BioMed Central, Google Scholar, and the Cochrane Central Register of Controlled Trials were searched to February 1, 2018, for randomized trials comparing corticosteroids with placebo or standard care.

PARTICIPANTS

Critically ill or surgical adult patients.

INTERVENTIONS

Corticosteroids compared with placebo or standard care.

MEASUREMENTS AND MAIN RESULTS

A total of 44,553 patients from 135 studies were included. Overall, mortality in the corticosteroid group and in the control group were similar (16% v 16%; p = 0.9). Subanalyses identified a beneficial effect of corticosteroids on survival in patients with respiratory system diseases (9% v 13%; p < 0.001) and bacterial meningitis (28% v 32%; p= 0.04), and a detrimental effect on survival in patients with traumatic brain injury (22% v 19%; p < 0.001). No differences in mortality were found in patients with cardiac diseases (7% v 6%; p = 0.7), in patients undergoing cardiac surgery (2.8% v 3.2% p = 0.14), and when treatment duration or patient age were considered.

CONCLUSIONS

This meta-analysis documents the safety of corticosteroids in the overall critically ill population with the notable exception of brain injury patients, a setting where the authors confirmed their detrimental effect on survival. A possible beneficial effect of corticosteroids on survival was found among patients with respiratory diseases and in patients with bacterial meningitis.

A Time Limit for Initiating Anti-Inflammatory Treatment for Improved Olfactory Function after Head Injury

We previously reported that treatment with an anti-inflammatory drug, specifically a steroid, is effective in improving recovery during the acute phase of head injury. Clinically, however, patients with head injury usually become aware of their olfactory loss several weeks or months after the injury, which may be a critical factor in poor recovery from olfactory dysfunction. This raises an important question: When should steroid administration begin in order to achieve optimum improvement of olfactory dysfunction? The present study was designed to reveal the time limit for starting anti-inflammatory treatment for better improvement of post-traumatic olfactory dysfunction. Olfactory nerve transection (NTx) was performed in olfactory marker protein (OMP)-tau-lacZ mice and subcutaneous injections of dexamethasone sodium phosphate for 5 consecutive days was started at 7, 14, 28, and 42 days after the NTx (7-, 14-, 28-, and 42-day time-points). Histological assessment of olfactory nerve recovery in the olfactory bulb was made at 5, 14, and 42 days after the start of drug treatment. Olfactory function assessments using both an olfactory avoidance behavioral test and evoked potential testing also were performed. Animals treated at 7 days post-injury had less injury-associated tissue with fewer astrocytes and macrophages and better histological and functional nerve recovery, compared with control mice. However, those treated at 14, 28, or 42 days post-injury did not show significant histological or functional differences between saline control and treatment groups. These findings suggest that an anti-inflammatory treatment using steroids for traumatic olfactory dysfunction may be effective if started at least by 7 days, but may be ineffective at 14 days or later after head injury.

The far-reaching scope of neuroinflammation after traumatic brain injury

The 'silent epidemic' of traumatic brain injury (TBI) has been placed in the spotlight as a result of clinical investigations and popular press coverage of athletes and veterans with single or repetitive head injuries. Neuroinflammation can cause acute secondary injury after TBI, and has been linked to chronic neurodegenerative diseases; however, anti-inflammatory agents have failed to improve TBI outcomes in clinical trials. In this Review, we therefore propose a new framework of targeted immunomodulation after TBI for future exploration. Our framework incorporates factors such as the time from injury, mechanism of injury, and secondary insults in considering potential treatment options. Structuring our discussion around the dynamics of the immune response to TBI - from initial triggers to chronic neuroinflammation - we consider the ability of soluble and cellular inflammatory mediators to promote repair and regeneration versus secondary injury and neurodegeneration. We summarize both animal model and human studies, with clinical data explicitly defined throughout this Review. Recent advances in neuroimmunology and TBI-responsive neuroinflammation are incorporated, including concepts of inflammasomes, mechanisms of microglial polarization, and glymphatic clearance. Moreover, we highlight findings that could offer novel therapeutic targets for translational and clinical research, assimilate evidence from other brain injury models, and identify outstanding questions in the field.

Do corticosteroids play a role in the management of traumatic brain injury?

Neuroprotective strategies for the medical management of traumatic brain injury (TBI) have been elusive. While laboratory studies provide a conceptual framework for the potential efficacy of corticosteroids in this context, clinical trials testing this hypothesis have yielded no convincing evidence of clinical benefit. Here, we review the five key randomized control trials (RCTs) that have examined this issue. Based on the proposed primary endpoints of these RCTs, the five RCTs consistently showed that corticosteroids do not confer significant benefit in the TBI population.

Management of Elevated Intracranial Pressure

Elevated intracranial pressure (ICP) is a primary cause of morbidity and mortality for many neurologic disorders. The relationship between ICP and brain volume is influenced by autoregulatory processes that can become dysfunctional. As a result, neurologic damage can occur by systemic and intracranial insults such as ischemia and excitatory amino acids. Therefore, survival is dependent on optimizing ICP and cerebral perfusion pressure. Treatment of intracranial hypertension requires intensive monitoring and aggressive therapy. Intracranial pressure monitoring techniques such as intraventricular catheters are useful for determining ICP elevations before changes in vital signs and neurologic status. Therapeutic modalities, generally aimed at reducing cerebral blood volume, brain tissue, and cerebrospinal fluid (CSF) volume, include nonpharmacologic (CSF removal, controlled hyperventilation, and elevating the patient’s head) and pharmacologic management. Mannitol and sedation are first-line agents used to lower ICP. Barbiturate coma may be beneficial in patients with elevated ICP refractory to conventional treatment. The use of prophylactic antiseizure therapy and optimal nutrition prevents significant complication. Currently, investigations are directed at discovering useful neuroprotective agents that prevent secondary neurologic injury.

Past, Present, and Future of Traumatic Brain Injury Research

Traumatic brain injury (TBI) is the greatest cause of death and severe disability in young adults; its incidence is increasing in the elderly and in the developing world. Outcome from severe TBI has improved dramatically as a result of advancements in trauma systems and supportive critical care, however we remain without a therapeutic which acts directly to attenuate brain injury. Recognition of secondary injury and its molecular mediators has raised hopes for such targeted treatments. Unfortunately, over 30 late-phase clinical trials investigating promising agents have failed to translate a therapeutic for clinical use. Numerous explanations for this failure have been postulated and are reviewed here. With this historical context we review ongoing research and anticipated future trends which are armed with lessons from past trials, new scientific advances, as well as improved research infrastructure and funding. There is great hope that these new efforts will finally lead to an effective therapeutic for TBI as well as better clinical management strategies.

Analytic Reviews : State-of-the-art Management of Severe Closed-head Injury

Brain injury represents the most serious result of head trauma. In the last decade we have witnessed important advances in understanding the pathophysiological re sponses of the brain and body to severe head injury. A significant increase in good recoveries and reduction in mortality have been realized by using programs that provide rapid transport and patient triage, early diag nosis of intracranial masses and removal of large lesions, controlled positive-pressure ventilation, treatment of elevated intracranial pressure, prevention of secondary insults, and intensive management. This review empha sizes acute management of severe closed-head injury in an intensive care unit setting. Many of these same princi ples for trauma can be applied to the intensive manage ment of any brain injury, including stroke. Future ad vances are discussed.

REVIEW ■ : Calcium and the Pathogenesis of Traumatic CNS Injury: Cellular and Molecular Mechanisms

Under normal conditions in the central nervous system (CNS), the calcium ion (Ca2+) is known to mediate a variety of neuronal functions, including synaptic neurotransmitter release, neuronal plasticity, protein phos phorylation, and gene expression. Whereas intracellular calcium concentrations ([Ca2+]i) are precisely reg ulated through intracellular buffering, binding, and sequestration, alterations in calcium ion homeostasis and influx of Ca 2+ have been implicated in the pathogenesis of neuronal death and degeneration, as well as cerebral vasospasm associated with multiple types of CNS injury. This review revisits the "calcium hypoth esis" of neuronal death associated with traumatic injury to the CNS and examines both the direct and indirect molecular and cellular evidence for calcium-mediated neuropathology, as well as the potential for novel therapeutic strategies targeted at the downstream intracellular effects of calcium signaling and calcium- activated neutral protease (calpain) activation. NEUROSCIENTIST 3:169-175, 1997

Methods to place a value on additional evidence are illustrated using a case study of corticosteroids after traumatic brain injury

OBJECTIVES

To establish whether evidence about the effectiveness of a health care intervention is sufficient to justify the use of the intervention in practice and show how value of information (VOI) analysis can be used to place a value on the need for additional evidence and inform research prioritization decisions.

STUDY DESIGN AND SETTING

Meta-analysis provides an estimate of the effect of an intervention with uncertainty. VOI analysis determines the adverse health consequences of not resolving this uncertainty. A case study examining the evidence before the high profile trial of Corticosteroid Randomisation After Significant Head injury (CRASH) shows the consequences on patient outcomes if this trial had not been successfully funded.

RESULTS

The consequences of uncertainty before CRASH were high at 40 deaths and 1,067 years of full health per annum. VOI analysis indicates that CRASH was worthwhile and the UK National Health Service would have had to spend an additional £205 million elsewhere to generate health benefits similar to CRASH.

CONCLUSIONS

VOI analysis can be integrated with the results of meta-analysis to help inform whether a particular research proposal is potentially worthwhile and whether it should be prioritized over other research topics that could be commissioned with the same resources.

Design of acute neuroprotection studies

Traumatic brain injury (TBI) is a substantial public health problem. The discovery of progressive, ongoing damage to the brain by means of complex molecular mechanisms which follow the initial injury has raised the possibility of targeted therapeutic intervention. Despite a substantial investment in trials testing dozens of therapeutics in humans, however, to date none has demonstrated robust efficacy. Deficiencies in the design of human clinical trials is likely to explain many translational failures, at least in part. Here we review secondary injury mediators and key trials which have targeted them. We provide a thorough discussion of putative reasons why trials thus far have failed and suggestions for the design of future clinical studies. Important insights from the IMPACT study are also presented in detail; in addition to providing critical insights for future trial design and analysis it suggests that reanalysis of completed studies may reveal inappropriately discarded treatments. Unfortunately limited resources are available for translational research and it is difficult to procure funds needed for well-resourced, large and definitive studies. History suggests, however, that investing in studies that are unlikely to provide a definitive answer only serves to increase required investment as they tend to mandate further study.

Randomized controlled trials in adult traumatic brain injury: a review of compliance to CONSORT statement

OBJECTIVE

To describe the extent to which adherence to Consolidated Standards of Reporting Trials (CONSORT) statement in randomized controlled trials (RCTs) in adult traumatic brain injury (TBI) has improved over time.

DATA SOURCES

MEDLINE, PsycINFO, and CINAHL databases were searched from inception to September 2013.

STUDY SELECTION

Primary report of RCTs in adult TBI. The quality of reporting on CONSORT checklist items was examined and compared over time. Study selection was conducted by 2 researchers independently. Any disagreements were solved by discussion.

DATA EXTRACTION

Two reviewers independently conducted data extraction based on a set of structured data extraction forms. Data regarding the publication years, size, locations, participation centers, intervention types, intervention groups, and CONSORT checklist items were extracted from the including trials.

DATA SYNTHESIS

Of 105 trials reviewed, 38.1%, 5.7%, and 32.4% investigated drugs, surgical procedures, and rehabilitations as the intervention of interest, respectively. Among reports published between the 2 periods 2002 and 2010 (n=51) and 2011 and September 2013 (n=16), the median sample sizes were 99 and 118; 39.2% and 37.5% of all reports detailed implementation of the randomization process; 60.8% and 43.8% provided information on the method of allocation concealment; 56.9% and 31.3% stated how blinding was achieved; 15.7% and 43.8% reported information regarding trial registration; and only 2.0% and 6.3% stated where the full trial protocol could be accessed, all respectively.

CONCLUSIONS

Reporting of several important methodological aspects of RCTs conducted in adult TBI populations improved over the years; however, the quality of reporting remains below an acceptable level. The small sample sizes suggest that many RCTs are likely underpowered. Further improvement is recommended in designing and reporting RCTs.

Randomized controlled trials in adult traumatic brain injury

BACKGROUND

To optimize strategies for achieving the effectiveness of interdisciplinary interventions, this study conducted a comprehensive literature review of all Randomized Controlled Trials (RCT) in adults with traumatic brain injury (TBI) over the past 30 years.

METHOD

Three major databases including Medline, PsycINFO and CINAHL were searched, yielding 1176 peer reviewed publications. One hundred RCTs were included, encompassing 55 pharmacologic and non-pharmacologic acute phase trials and 45 rehabilitation and pharmacologic post-acute trials.

RESULTS

The majority of acute phase pharmacologic or non-pharmacologic trials (40/55) showed either no effect or adverse effect on TBI outcomes. Several trials involving early nutritional therapy or pre-hospital rapid intubation demonstrated significant treatment effects. The effect of decompressive craniectomy, therapeutic hypothermia and osmotic therapy remained controversial. The majority of post-acute phase trials (36/45), consisting of cognitive rehabilitation, physical rehabilitation and pharmacotherapy, produced various beneficial treatment effects.

CONCLUSION

The data indicate that several active interventions during the acute phase of TBI are likely to be more effective than pharmacotherapy, whereas a comprehensive rehabilitation approach is preferred in post-acute phase TBI management. Great progress has been made in understanding the heterogeneous injury mechanisms as well as the complexity of medical management and rehabilitation following the recovery course of TBI.

Quercetin as a prophylactic measure against high altitude cerebral edema

The present study was undertaken to elucidate the intervention of quercetin against high altitude cerebral edema (HACE) using male Sprague Dawley rats as an animal model. This study was also programmed to compare and correlate the effect of both quercetin (flavonoid) and dexamethasone (steroid) against HACE. Six groups of animals were designed for this experiment, (I) normoxia, (II) hypoxia (25,000 ft, 24 h), (III) normoxia+quercetin (50 mg/kg body wt), (IV) normoxia+dexamethasone (4 mg/kg body wt), (V) hypoxia+quercetin (50 mg/kg body wt), (VI) hypoxia+dexamethasone (4 mg/kg body wt). Quercetin at 50 mg/kg body wt, orally 1h prior to hypoxia exposure, was considered as the optimum dose, due to a significant reduction in the level of brain water content and cerebral transvascular leakage (P < 0.001), as compared to control (24 h hypoxia). Dexamethasone was administered at 4 mg/kg body wt, orally, 1h prior to hypoxia exposure. Both drugs (quercetin and dexamethasone) could efficiently reduce the hypoxia-induced hematological changes. Quercetin was observed to be a more potent antioxidative and anti-inflammatory agent. It blocks nuclear factor kappa-beta (NFκB) more significantly (P < 0.05) than the dexamethasone-administered hypoxia-exposed rats. Histopathological findings demonstrate the absence of an edema and inflammation in the brain sections of quercetin-administered hypoxia-exposed rats. The present study reveals quercetin to be a potent drug against HACE, as it efficiently attenuates inflammation as well as cerebral edema formation without any side effects of steroid therapy (dexamethasone).

Clinical trials in traumatic brain injury: past experience and current developments

In this article, we review past and current experience in clinical trials of traumatic brain injuries (TBIs), we discuss limitations and challenges, and we summarize current directions. The focus is on severe and moderate TBIs. A systematic literature search of the years from 1980 to 2009 revealed 27 large phase III trials in TBI; we were aware of a further 6 unpublished trials. Analysis of these 33 trials yielded interesting observations: There was a peak incidence of trial initiations that occurred in the mid-1990s with a sharp decline during the period from 2000 to 2004. Most trials that reported a significant treatment effect were studies on a therapeutic strategy (e.g., decompressive craniectomy, hypothermia), and these were single-center studies. Increasingly, studies have been shifting toward the Far East. The currently existing trial registries permit insight into ongoing or recently conducted trials. Compared with the past decade, the number of studies on neuroprotective agents taken forward into efficacy-oriented studies is low. In contrast, the number of studies on therapeutic strategies appears to be increasing again. The disappointing results in trials on neuroprotective agents in TBI have led to a critical reappraisal of clinical trial methodology. This has resulted in recommendations for preclinical workup and has triggered extensive analysis on approaches to improve the design and analysis of clinical trials in TBI. An interagency initiative toward standardization on selection and coding of data elements across the broad spectrum of TBI is ongoing, and will facilitate comparison of research findings across studies and encourage high-quality meta-analysis of individual patient data in the future.

Impact of early pharmacological treatment on cognitive and behavioral outcome after traumatic brain injury in adults: a meta-analysis

Early pharmacological treatment has the potential to reduce some of the disabling cognitive and behavioral problems that result from traumatic brain injury (TBI). Although a large number of treatments have been developed, clinical research has yielded inconsistent findings with respect to the effectiveness of these pharmacological treatments on cognitive and behavioral outcomes. Furthermore, their relative efficacy has not been evaluated, thereby hindering advances in the treatment of TBI. A meta-analysis of research that examined the impact of pharmacological treatments on cognitive and behavioral outcomes in the early stages after TBI between January 1980 and May 2008 was therefore undertaken. The PubMed and PsycINFO databases were searched using 35 terms. All articles were screened using detailed inclusion criteria. Weighted Cohen's d effect sizes, percent overlap statistics, and fail-safe N statistics were calculated for each pharmacological agent. Studies that used different experimental designs were examined separately. Eleven pharmacological treatments were investigated by 22 clinical studies, comprising 6472 TBI patients in the treatment groups and 6460 TBI controls. One dopamine agonist (amantadine) and 1 bradykinin antagonist (CP-0127 [Bradycor]) produced marked treatment benefits (d > or = 0.8) for a single measure of arousal (Glasgow Coma Scale). Notably, drug dosage and the measure chosen to assess outcome influenced the probability of finding a treatment benefit.

Olfactory nerve recovery following mild and severe injury and the efficacy of dexamethasone treatment

To investigate factors that influence the degree of neural regeneration and recovery, we studied 2 olfactory nerve injury models. Transection of the olfactory nerves along the surface of the olfactory bulb was performed in OMP-tau-lacZ mice using either a flexible Teflon blade (mild injury) or a stainless steel blade (severe injury). Histological assessment of recovery within the olfactory bulb was made at 5, 14, and 42 days after injury. We used X-gal staining to label the degenerating and regenerating olfactory nerve fibers and immunohistochemical staining to detect the presence of reactive astrocytes and macrophages. Areas of injury-associated tissue were significantly smaller in the mild injury model, and at 42 days, the regenerated nerves had reestablished connections to the glomerular layer of the bulb. With severe injury, there were larger areas of injury-associated tissue, more astrocytes and macrophages, and a decrease in regenerated nerve fibers. When dexamethasone (DXM) was injected after severe injury, there was a significant reduction in injury-associated tissue, better nerve recovery, and fewer astrocytes and macrophages. These results demonstrate that recovery in the olfactory system varies with the severity of injury and that DXM treatment may have therapeutic value by reducing injury-associated tissue and improving recovery outcome.

Comparative evaluation of megadose methylprednisolone with dexamethasone for treatment of primary typical optic neuritis

AIM

To compare the efficacy of intravenous methylprednisolone and intravenous dexamethasone on visual recovery and evaluate their side-effects for the treatment of optic neuritis.

MATERIALS AND METHODS

Prospective, randomized case-controlled study including 21 patients of acute optic neuritis presenting within eight days of onset and with visual acuity less then 20/60 in the affected eye who were randomly divided into two groups. Group I received intravenous dexamethasone 200 mg once daily for three days and Group II received intravenous methylprednisolone 250 mg/six-hourly for three days followed by oral prednisolone for 11 days. Parameters tested were pupillary reactions, visual acuity, fundus findings, color vision, contrast sensitivity, Goldmann visual fields and biochemical investigations for all patients at presentation and follow-up.

RESULTS

Both groups were age and sex-matched. LOGMAR visual acuity at presentation was 1.10 +/- 0.52 in Group I and 1.52 +/- 0.43 in Group II. On day 90 of steroid therapy, visual acuity improved to 0.28 +/- 0.33 in Group I and 0.36 +/- 0.41 in Group II ( P =0.59). At three months there was no statistically significant difference in the color vision, contrast sensitivity, stereoacuity, Goldman fields and the amplitude and latency of visually evoked response between the two groups. The concentration of vitamin C, glucose, sodium, potassium, urea and creatinine were within the reported normal limits.

CONCLUSION

Intravenous dexamethasone is an effective treatment for optic neuritis. However, larger studies are required to establish it as a safe, inexpensive and effective modality for the treatment of optic neuritis.

Traumatic brain injury in horses: 34 cases (1994-2004)

OBJECTIVE

To investigate the clinical, clinicopathologic, and diagnostic characteristics; treatment; and outcome associated with acute traumatic brain injury (TBI) in horses and assess risk factors for nonsurvival in TBI-affected horses.

DESIGN

Retrospective case series.

ANIMALS

34 horses with TBI. Procedures-Medical records of horses that had sustained trauma to the head and developed neurologic signs were reviewed. Data that included signalment, clinicopathologic findings, diagnosis, treatment, and outcome were analyzed. Clinicopathologic variables among horses in survivor and nonsurvivor groups were compared, and risk factors for nonsurvival were determined.

RESULTS

Median age of affected horses was 12 months. Findings of conventional survey radiography of the head alone failed to identify all horses with fractures of the calvarium. Horses with basilar bone fractures were 7.5 times as likely not to survive as horses without this type of fracture. Depending on clinical signs, horses received supportive care, osmotic or diuretic treatments, antimicrobials, anti-inflammatory drugs, analgesics, or anticonvulsants. Twenty-one (62%) horses survived to discharge from the hospital. In the nonsurvivor group, mean PCV was significantly higher, compared with the value in the survivor group (40% vs 33%). Risk factors associated with nonsurvival included recumbency of more than 4 hours' duration after initial evaluation (odds ratio, 18) and fracture of the basilar bone (odds ratio, 7.5).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that prognosis for survival in horses with acute TBI may be more favorable than previously reported. Among horses with TBI, persistent recumbency and fractures involving the basilar bones were associated with a poor prognosis.

Head trauma

Head trauma is a common and devastating injury. Along with a high mortality rate, the long-term morbidity is consequential for both the individual patient and society. A thorough knowledge of the clinical approach will assist the emergency physician in providing optimal care and helping to minimize secondary brain injury. Using a case-based scenario, the initial management strategies along with rational evidence-based treatments are reviewed.

Treatment of cerebral edema

BACKGROUND

Cerebral edema is a potentially devastating complication of various acute neurologic disorders. Its successful treatment may save lives and preserve neurologic function.

REVIEW SUMMARY

Different pathophysiological mechanisms are responsible for the formation of cytotoxic and vasogenic edema. Yet, these 2 types of edema often coexist and their treatment tends to overlap, with the exception of corticosteroids, which should be only used to ameliorate vasogenic edema. Currently available to control brain swelling include osmotic agents (with emphasis on mannitol and hypertonic saline solutions), corticosteroids, hyperventilation, sedation (propofol, barbiturates), neuromuscular paralysis, hypothermia, and surgical interventions. This article discusses the indications, advantages, and limitations of each treatment modality following an evidence-based approach.

CONCLUSIONS

The therapy for brain edema remains largely empirical. More research aimed at enhancing our understanding of the pathophysiology of cerebral edema is needed to identify new and more effective forms of treatment.

Subgroup analysis and covariate adjustment in randomized clinical trials of traumatic brain injury: a systematic review

OBJECTIVE

Few randomized clinical trials (RCTs) in the field of traumatic brain injury (TBI) have shown a significant treatment benefit. We critically reviewed the use of two types of secondary analyses, covariate adjustment and subgroup analysis, which are common in TBI trials.

METHODS

We performed a systematic review of therapeutic phase III RCTs, including adult patients with acute, moderate-to-severe TBI. Glasgow Outcome Scale (GOS) at > or =3 months as outcome, and > or =50 patients per arm were required. We compared the actual reporting of covariate adjustment and subgroup analyses with the Consolidated Standards of Reporting Trials (CONSORT) recommendations. Likewise, we reviewed six protocols of large multicenter RCTs and compared planned and reported subgroups.

RESULTS

We identified 18 RCTs (n = 6439). Sixteen trials used GOS at 6 months as outcome. Five RCTs reported covariate adjustment. The number of covariates was limited (< or =5), most frequently including age. Many covariates were outcome predictors. Four RCTs reported only adjusted treatment effects as the main efficacy parameter. Eleven RCTs reported subgroup analyses. Several subgroup factors (< or =7, mainly outcome predictors) and outcomes (< or =4) were included. The highest total number of subgroups was 15, and only three RCTs completely pre-specified subgroups. Notably, 10 of 11 RCTs performed inappropriate separate subgroup analyses. Of 11 RCTs, 5 gave subgroups the same emphasis as the overall effect. Reported subgroup analyses were insufficiently described and clearly differed from those planned in the protocol.

CONCLUSION

The reported covariate adjustment and subgroup analyses from TBI trials had several methodological shortcomings. Appropriate performance and reporting of covariate adjustment and subgroup analysis should be considerably improved in future TBI trials because interpretation of treatment benefits may be misleading otherwise.

Glucocorticoid therapy in neurologic critical care

BACKGROUND

The pivotal role of inflammation and edema across the spectrum of central nervous system injury has driven extensive investigation into the therapeutic potential of glucocorticoids.

OBJECTIVE

To review the experimental and clinical data relating to the efficacy and adverse effects of glucocorticoids in conditions encountered in critical neurologic and neurosurgical illness.

DATA SOURCE

Search of MEDLINE and Cochrane databases, manual review of article bibliographies.

DATA SYNTHESIS AND CONCLUSIONS

The efficacy of glucocorticoids is well established in ameliorating edema associated with brain tumors and in improving outcome in subsets of patients with bacterial meningitis. Despite frequently encouraging experimental results, clinical trials of glucocorticoids in ischemic stroke, intracerebral hemorrhage, aneurysmal subarachnoid hemorrhage, and traumatic brain injury have not shown a definite therapeutic effect. The evidence supporting glucocorticoid therapy for spinal cord injury is controversial; however methylprednisolone continues to be widely employed in this setting.

[Shock trauma room management of the multiple-traumatized patient with skull-brain injuries. A systematic review of the literature]

This overview reviews the literature on multiply injured patients with traumatic brain injuries. Clinical trials were systematically collected (MEDLINE, Cochrane, and hand searches) and classified into evidence levels (1 to 5 according to the Oxford system).A detailed analysis of the literature of traumatic brain injuries has been elaborated by the Brain Trauma Foundation and has been published in the World Wide Web (http://www2.braintrauma.org/). The following procedures should be performed in the emergency room for multiply injured patients with traumatic brain injuries: (1) recording of precise history to identify risk factors for severe traumatic brain injury, (2) measurement of the Glasgow Coma Scale (GCS), pupillary reflex, and mean arterial pressure, (3) diagnostic evaluation with a CT scan, and (4) rapid surgical decompression if indicated.

Corticosteroids for acute traumatic brain injury

BACKGROUND

Traumatic brain injury is a leading cause of death and disability. Corticosteroids have been widely used in treating people with traumatic brain injury.

OBJECTIVES

To quantify the effectiveness and safety of corticosteroids in the treatment of acute traumatic brain injury.

SEARCH STRATEGY

Electronic sources: MEDLINE, EMBASE, Cochrane Library and specialised database searches. Additional hand searching and contact with trialists. Date of the most recent search October 2004.

SELECTION CRITERIA

All randomised controlled trials of corticosteroid use in acute traumatic brain injury with adequate or unclear allocation concealment.

DATA COLLECTION AND ANALYSIS

Quality of allocation concealment was scored. Data on numbers of participants randomised, numbers lost to follow up, length of follow up, case fatality rates, disablement, infections and gastrointestinal bleeds were extracted independently and checked.

MAIN RESULTS

We identified 20 trials with 12303 randomised participants. The effect of corticosteroids on the risk of death was reported in 17 included trials. Due to significant heterogeneity we did not calculate a pooled estimate of the risk of death. The largest trial, with about 80% of all randomised participants, found a significant increase in the risk ratio of death with steroids 1.18 (1.09 to 1.27). For the nine trials that reported death or severe disability, the pooled relative risk was 1.01 (0.91 to 1.11), although this does not yet contain data from the largest trial. For infections the pooled risk ratio from five trials was 1.03 (0.99 to 1.07) and for the ten trials reporting gastrointestinal bleeding 1.23 (0.91 to 1.67).

AUTHORS' CONCLUSIONS

In the absence of a meta-analysis, we feel most weight should be placed on the result of the largest trial. The increase in mortality with steroids in this trial suggest that steroids should no longer be routinely used in people with traumatic head injury.

Evaluation of dexamethasone for the treatment of intracerebral hemorrhage using a collagenase-induced intracerebral hematoma model in rats

Dexamethasone was evaluated for the treatment of intracerebral hemorrhage using a rat model of cerebral hematoma induced by intracerebral injection of collagenase. The treatment group consisted of hematoma rats receiving dexamethasone 1 mg/kg intraperitoneal (i.p.) at 1 and 24 h following surgery. Controls included hematoma rats receiving saline i.p. and sham-operated animals receiving saline i.p. Each animal was evaluated neurologically prior to, as well as 24 and 48 h following surgery. After the last neurological evaluation, animals were deeply anesthetized and the brain was removed following perfusion for microscopic examination and glial fibrillary acidic protein immunohistochemistry. Behavioral scores were significantly improved in the treated group (P < 0.0001). The hematoma volume was significantly smaller (P < 0.02). Neutrophils and astrocytes were less numerous in the hematoma of dexamethasone-treated animals (P < 0.001), however the number of necrotic neurons in the penumbra was not changed by the treatment. The number of necrotic neurons in the cerebral cortex was less in treated than in nontreated animals (P < 0.01). Controls had many vascular changes including necrotic endothelium and fibrin deposits compared with treated animals. In conclusion, dexamethasone administered shortly after an intracerebral hematoma appears beneficial for the treatment of this condition.

Cerebral pathophysiology and critical care neurology: basic hemodynamic principles, cerebral perfusion, and intracranial pressure

Pediatric neurologic intensive care differs from standard pediatric intensive care in two important respects. First, the diagnosis, monitoring, and management of problems related to disorders of cerebral perfusion and intracranial pressure (ICP) are central to nearly all of pediatric neurologic and neurosurgical intensive care. Second, various clinical problems normally encountered in the intensive care unit (ICU) have additional implications when associated with neurologic disease. Regardless of the cause, treatment should be undertaken as expeditiously as possible and should be based on the principles of resuscitation, reducing the volume of the intracranial contents, and reassessment. This chapter aims to outline some basic principles underlying the diagnosis and management of elevated ICP in children.

Clinical trials in traumatic brain injury: current problems and future solutions

Over the past decade many neuroprotective agents have been developed with the hope of being able to improve outcome in patients with traumatic brain injury. Unfortunately, none of the phase III trials performed have convincingly demonstrated efficacy in the overall population. A common misconception is that consequently these agents are ineffective. Such has not been proven and some trials show evidence of efficacy in subgroups of the population studied. The negative results, as reported in the overall population, may in part be caused by specific aspects of the TBI population, as well as by aspects of clinical trial design and analysis. Clinical trials in TBI pose several complicated design issues. Methodological challenges relate particularly to heterogeneity of the population and to outcome assessment. Heterogeneity pertains both to the range of pathologies included in TBI, and to prognostic factors, each causing specific problems. Mechanistic and/or prognostic targeting, as well as possibilities for covariate adjustment, are suggested as possible solutions to deal with the problems of heterogeneity. The aim in most trials was to demonstrate a 10% absolute improvement in favorable outcome in patients with head injury. This may be considered overoptimistic and unrealistic in relation to the heterogeneous patient population. Specific problems are further incurred by the use of the dichotomized Glasgow Outcome Scale as primary outcome measure. Optimal statistical power may expected to be present when the point of dichotomization results in a 50:50 distribution of outcome categories. It is proposed to differentiate the point of dichotomization according to prognostic risk profile, in order to maintain statistical power. Solutions described may be expected to enhance chances of demonstrating benefit of potentially effective neuroprotective agents in future studies. The complexity of problems occurring in clinical trial design and analysis in TBI is such that a strong and sustained multidisciplinary input and effort is required from all experts involved in the field of neurotrauma.

[Treatment of cerebral oedema]

Progress in brain imaging, monitoring and physiopathology allows the identification of brain oedema from brain swelling, determination of its interstitial or intracellular nature, as well as blood-brain barrier permeability and the evaluation of the impact on cerebral haemodynamic. Common treatment of all types of cerebral oedema is based on prevention of self-sustained disorders due to increased intracranial pressure resulting in ischemic cerebral oedema. The specific treatment of each type of cerebral oedema is reviewed. Optimization of conventional anti-oedematous strategies is based on the precise determination of the nature of the cerebral oedema and of the blood-brain barrier status.

Management of head trauma

Traumatic brain injury (TBI) is a major cause of disability and death in most Western nations and consumes an estimated $100 billion annually in the United States alone. In the last 2 decades, the management of TBI has evolved dramatically, as a result of a more thorough understanding of the physiologic events leading to secondary neuronal injury as well as advances in the care of critically ill patients. However, it is likely that many patients with TBI are not treated according to current treatment principles. This article presents an overview of the current management of patients with TBI.

Clinical trials in head injury

Traumatic brain injury (TBI) remains a major public health problem globally. In the United States the incidence of closed head injuries admitted to hospitals is conservatively estimated to be 200 per 100,000 population, and the incidence of penetrating head injury is estimated to be 12 per 100,000, the highest of any developed country in the world. This yields an approximate number of 500,000 new cases each year, a sizeable proportion of which demonstrate significant long-term disabilities. Unfortunately, there is a paucity of proven therapies for this disease. For a variety of reasons, clinical trials for this condition have been difficult to design and perform. Despite promising pre-clinical data, most of the trials that have been performed in recent years have failed to demonstrate any significant improvement in outcomes. The reasons for these failures have not always been apparent and any insights gained were not always shared. It was therefore feared that we were running the risk of repeating our mistakes. Recognizing the importance of TBI, the National Institute of Neurological Disorders and Stroke (NINDS) sponsored a workshop that brought together experts from clinical, research, and pharmaceutical backgrounds. This workshop proved to be very informative and yielded many insights into previous and future TBI trials. This paper is an attempt to summarize the key points made at the workshop. It is hoped that these lessons will enhance the planning and design of future efforts in this important field of research.

Guidelines for head injury: their use and limitations

Within medicine in general, and particularly in the field of head injury, a revolution is currently occurring wherein the traditional expert opinion-based approach to therapy is quickly changing towards a standardized approach, based on scientific analysis of available evidence. The guideline movement may be considered a child of this revolution. Correct understanding, interpretation and application of guidelines requires an understanding of the reasons for formulating the guidelines and of the methodology on which they are based. From this perspective the North American guidelines and the EBIC guidelines, as main international exponents towards guidelines in head injury, are discussed. Specific attention is focussed on the interpretation of the practice recommendations from the North American guidelines at the level of a standard. The evidence underlying these standards is critically discussed and the conclusions put in to further perspective. The EBIC guidelines were formulated from a desire to obtain a 'common core approach' to basic therapy in centers participating in clinical trials. The recommendations are more pragmatic, based on an understanding of the pathophysiology, and address various issues not analyzed in the North American guidelines. The recommendations of both initiatives however are very similar, illustrating the consensus that already exists to general approach of management in head injury. Guidelines should be considered a very important topic in clinical practice, but on the other hand recommendations should not always be accepted uncritically. The lack of evidence underlying many aspects of management in head injury, as illustrated by the North American approach, should form an incentive for further scientific studies, especially towards targeted therapy. Clinical experience and an understanding of the pathophysiology are the basic ingredients for developing alternative and more targeted approaches which can then be subjected to scientific analysis. Guidelines should be considered a tool which we need to learn how to use; they form part of a process which, following implementation and dissemination should lead to standardized registration, an important element in facilitating improved quality control and assurance.