Sex-related differences in patients with severe head injury: greater susceptibility to brain swelling in female patients 50 years of age and younger

High-fat diet consumption negatively influences closed-head traumatic brain injury in a pediatric rodent model

Traumatic brain injury (TBI) is one of the most common causes of emergency room visits in children, and it is a leading cause of death in juveniles in the United States. Similarly, a high proportion of this population consumes diets that are high in saturated fats, and millions of children are overweight or obese. The goal of the present study was to assess the relationship between diet and TBI on cognitive and cerebrovascular outcomes in juvenile rats. In the current study, groups of juvenile male Long Evans rats were subjected to either mild TBI via the Closed-Head Injury Model of Engineered Rotational Acceleration (CHIMERA) or underwent sham procedures. The animals were provided with either a combination of high-fat diet and a mixture of high-fructose corn syrup (HFD/HFCS) or a standard chow diet (CH) for 9 days prior to injury. Prior to injury, the animals were trained on the Morris water maze for three consecutive days, and they underwent a post-injury trial on the day of the injury. Immediately after TBI, the animals' righting reflexes were tested. Four days post-injury, the animals were euthanized, and brain samples and blood plasma were collected for qRT-PCR, immunohistochemistry, and triglyceride assays. Additional subsets of animals were used to investigate cerebrovascular perfusion using Laser Speckle and perform immunohistochemistry for endothelial cell marker RECA. Following TBI, the righting reflex was significantly increased in TBI rats, irrespective of diet. The TBI worsened the rats' performance in the post-injury trial of the water maze at 3 h, p(injury) < 0.05, but not at 4 days post-injury. Reduced cerebrovascular blood flow using Laser Speckle was demonstrated in the cerebellum, p(injury) < 0.05, but not foci of the cerebral cortices or superior sagittal sinus. Immunoreactive staining for RECA in the cortex and corpus callosum was significantly reduced in HFD/HFCS TBI rats, p < 0.05. qRT-PCR showed significant increases in APOE, CREB1, FCGR2B, IL1B, and IL6, particularly in the hippocampus. The results from this study offer robust evidence that HFD/HFCS negatively influences TBI outcomes with respect to cognition and cerebrovascular perfusion of relevant brain regions in the juvenile rat.

The Association Between Gender and Clinical Outcomes in Patients With Moderate to Severe Traumatic Brain Injury: A Systematic Review and Meta-Analysis

INTRODUCTION

Traumatic brain injuries (TBIs) are a significant cause of morbidity and mortality in the United States. but have a disproportionate impact on patients based on gender. This systematic review and meta-analysis aim to compare gender differences in clinical outcomes between male and female adult trauma patients with moderate and severe TBI.

METHODS

Studies assessing gender differences in outcomes following TBIs on PubMed, Google Scholar, EMBASE, and ProQuest were searched. Meta-analysis was performed for outcomes including in-hospital mortality, hospital length of stay, intensive care unit length of stay, and Glasgow outcome scale (GOS) at 6 mo.

RESULTS

Eight studies were included for analysis with 26,408 female and 63,393 male patients. Meta-analysis demonstrated that males had a significantly lower risk of mortality than females (RR: 0.88; 95% CI 0.78, 0.99; P = 0.0001). Females had a shorter hospital length of stay (mean difference -1.4 d; 95% CI - 1.6 d, -1.2 d). No significant differences were identified in intensive care unit length of stay (mean difference -3.0 d; 95% CI -7.0 d, 1.1 d; P = 0.94) or GOS at 6 mo (mean difference 0.2 d; 95% CI -0.9 d, 1.4 d; P = 1).

CONCLUSIONS

Compared to male patients, female patients with moderate and severe TBI had a significantly higher in-hospital mortality risk. There were no significant differences in long-term outcomes between genders based on GOS at 6 mo. These findings warrant further investigation into the etiology of these gender disparities and their impact on additional clinical outcome measures.

Puberty, brain network connectivity and neuropsychiatric outcomes following pediatric traumatic brain injury in females: A research protocol

BACKGROUND

Examining the role of sex on recovery from pediatric TBI (pTBI) is a complex task, specifically when referring to injuries occurring during critical developmental and maturation periods. The effect of sex hormones on neurological and neuropsychiatric outcomes has been studied among adult TBI females, but not in children. During development, puberty is considered a key milestone accompanied by changes in physical growth, neuronal maturation, sex hormones, and psychological symptoms. Following pTBI, such changes might have a significant effect on brain re-organization and on long-term neuropsychiatric outcomes. While hormonal dysfunction is a common consequence following pTBI, only few studies have systematically evaluated hormonal changes following pTBI.

AIMS

To describe a multimodal protocol aimed to examine the effect of puberty on brain connectivity and long-term neuropsychiatric outcomes following TBI in female girls and adolescents.

METHODS

A case-control longitudinal prospective design will be used. 120 female participants aged 9 to 16 years (N = 60 per group) will be recruited. In the acute phase (T0-1 month), participants will undergo an MRI protocol for brain connectivity, as well as a clinical evaluation for puberty stage and hormonal levels. In the chronic phase (T1-18-24 months), participants will complete a neuropsychiatric assessment in addition to the MRI and puberty evaluations. Hormonal levels will be monitored at T0 and T1. A moderation-mediation model will be used to examine the moderating effects of puberty on the association between pTBI and neuropsychiatric symptoms in female girls and adolescents, through the mediating effect of brain network connectivity.

SIGNIFICANCE

This study will highlight sex-specific factors related to outcomes among females following pTBI and enhance our understanding of the unique challenges they face. Such information has a substantial potential to guide future directions for research, policy and practice.

Growth patterns and ratios of posterior cranial fossa structures in the Japanese pediatric population: a study utilizing CT scans

PURPOSE

The changes in the proportion of posterior cranial fossa structures during pediatric development remain unclear. This retrospective study aimed to investigate the growth patterns and ratios of these structures using CT scans.

METHODS

Head CT scans of pediatric patients with minor head trauma from Osaka Women's and Children's Hospital between March 2006 and May 2023 were analyzed. The study segmented the intracranial volume (ICV), posterior cranial fossa volume (PCFV), cerebellum volume (CBMV), and brainstem volume (BSV). Correlation coefficients were calculated among the parameters. Patients aged 0 to 10 years were divided into 15 age-related clusters, and mean and standard deviation values were measured. Growth curves were created by plotting mean values sequentially. Ratios such as PCFV/ICV and (CBMV + BSV)/PCFV were examined. Statistical analyses, including unpaired t tests and logarithmic curve fitting, were performed.

RESULTS

A total of 234 CT scans (97 from females, 115 from infants under 1 year of age) were analyzed. Positive correlations were observed among the parameters, with the strongest between PCFV and CBMV. The growth curves for ICV, PCFV, CBMV, and BSV exhibited a two-phase process, with rapid growth until approximately 4 years of age, followed by stabilization. The ratios PCFV/ICV and (CBMV + BSV)/PCFV showed increasing trends from birth onwards, stabilizing by 4 and 1 years of age, respectively.

CONCLUSION

This study provides insights into the growth patterns and ratios of posterior cranial fossa structures in the pediatric population. The findings demonstrate a two-phase growth process and increasing trends in the examined ratios.

Is there a weekend effect on mortality rate and outcome for moderate and severe traumatic brain injury? A population-based, observational cohort study

Purpose

The aim of the study was to analyse patient and injury characteristics and the effects of weekend admissions on mortality rate and outcome after moderate and severe traumatic brain injuries.

Methods

This is an observational cohort study based on data from a prospectively maintained regional trauma registry in South Western Norway. Patients with moderate and severe traumatic brain injury admitted between January 1st, 2004 and December 31st, 2019 were included in this study.

Results

During the study period 688 patients were included in the study with similar distribution between moderate (n ​= ​318) and severe (n ​= ​370) traumatic brain injury. Mortality rate was 46% in severe and 13% in moderate traumatic brain injury. Two hundred and thirty-one (34%) patients were admitted during weekends. Patients admitted during weekends were significantly younger (median age (IQR) 32.0 (25.5-67.0) vs 47.0 (20.0-55.0), p ​< ​0.001). Pre-injury ASA 1 was significantly more common in patients admitted during weekends (n ​= ​146, 64%, p ​= ​0.001) while ASA 3 showed significance during weekdays compared to weekends (n ​= ​101, 22%, p ​= ​0.013). On binominal logistic regression analysis mortality rate was significantly higher with older age (OR 1.03, 95% CI for OR 1.02-1.04, p ​< ​0.001) and increasing TBI severity (OR 7.08, 95% CI for OR 4.67-10.73, p ​< ​0.001).

Conclusions

Mortality rate and poor clinical outcome remain high in severe traumatic brain injury. While a higher number of patients are admitted during the weekend, mortality rate does not differ from weekday admissions.

Females Exhibit Better Cerebral Pressure Autoregulation, Less Mitochondrial Dysfunction, and Reduced Excitotoxicity following Severe Traumatic Brain Injury

The aim of the study was to investigate sex-related differences in intracranial pressure (ICP) dynamics, cerebral pressure autoregulation (PRx55-15), cerebral energy metabolism, and clinical outcome after severe traumatic brain injury (TBI). One-hundred sixty-nine adult TBI patients, treated at the neurointensive care (NIC) unit, at Uppsala University Hospital, 2008-2020, with ICP and cerebral microdialysis (MD) monitoring, were included. Of the 169 TBI patients, 131 (78%) were male and 38 (22%) female. Male patients were more often injured by motor vehicle accidents and less often by bicycle accidents (p < 0.05). There were otherwise no difference in age, neurological status at admission, and types of intracranial hemorrhages between the sexes. The percent of monitoring time with ICP above 20 mmHg and CPP below 60 mmHg were similar for both sexes. Males exhibited more disturbed cerebral pressure autoregulation (PRx55-15 (mean ± SD); 0.28 ± 0.18 vs. 0.17 ± 0.23, p < 0.05) day 1, worse cerebral energy metabolism (MD-lactate-/pyruvate-ratio (median (IQR)); 25 (19-31) vs. 20 (17-25), p < 0.01) and mitochondrial dysfunction (higher burden of MD-LPR > 25 and MD-pyruvate > 120 µM (median (IQR)); 13 (0-58) % vs. 3 (0-17) %, p < 0.05) day 2 to 5, increased excitotoxicity (MD-glutamate median (IQR); 9 (4-32) µM vs. 5 (3-10) µM, p < 0.05) day 2 to 5, and higher biomarker levels of cellular injury (MD-glycerol median (IQR); 103 (66-193) µM vs. 68 (49-106) µM, p < 0.01) most pronounced day 6 to 10. There was no difference in mortality or the degree of favorable outcome between the sexes. Altogether, females exhibited more favorable cerebral physiology post-TBI, particularly better mitochondrial function and reduced excitotoxicity, but this did not translate into better clinical outcome compared to males. Future studies needs to further explore potential sex differences in secondary injury mechanisms in TBI.

Extracellular vesicle neurofilament light is elevated within the first 12-months following traumatic brain injury in a U.S military population

Traumatic brain injury (TBI) can be associated with long-term neurobehavioral symptoms. Here, we examined levels of neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) in extracellular vesicles isolated from blood, and their relationship with TBI severity and neurobehavioral symptom reporting. Participants were 218 service members and veterans who sustained uncomplicated mild TBIs (mTBI, n = 107); complicated mild, moderate, or severe TBIs (smcTBI, n = 66); or Injured controls (IC, orthopedic injury without TBI, n = 45). Within one year after injury, but not after, NfL was higher in the smcTBI group than mTBI (p = 0.001, d = 0.66) and IC (p = 0.001, d = 0.35) groups, which remained after controlling for demographics and injury characteristics. NfL also discriminated the smcTBI group from IC (AUC:77.5%, p < 0.001) and mTBI (AUC:76.1%, p < 0.001) groups. No other group differences were observed for NfL or GFAP at either timepoint. NfL correlated with post-concussion symptoms (rs = - 0.38, p = 0.04) in the mTBI group, and with PTSD symptoms in mTBI (rs = - 0.43, p = 0.021) and smcTBI groups (rs = - 0.40, p = 0.024) within one year after injury, which was not confirmed in regression models. Our results suggest the potential of NfL, a protein previously linked to axonal damage, as a diagnostic biomarker that distinguishes TBI severity within the first year after injury.

Sex differences in cortical thickness and diffusion properties in patients with traumatic brain injury: a pilot study

OBJECTIVE

Cortical thickness and diffusion properties are important measures of gray and white matter integrity in those with traumatic brain injury (TBI). Many studies show that healthy adult females have greater cortical thickness than males across numerous brain sites. In this study, we explored this sex difference in patients with TBI.

METHOD

Participants consisted of 32 patients with TBI and 21 neurologically healthy controls. All were scanned by magnetic resonance imaging (MRI). Differences in cortical thickness and diffusion properties were examined between groups (i.e., TBI/control, male/female).

RESULTS

Patients with TBI had more cortical thinning (both hemispheres) compared to controls. They also showed decreased fractional anisotropy (FA) for several major white matter tracts. Healthy females had significantly greater cortical thickness compared to healthy males. However, this difference was smaller among the patients with TBI. We found no sex differences in diffusion properties. There were moderate correlations between cortical thickness, diffusion properties, and cognitive performance, as measured by the Trail Making Test B.

CONCLUSION

These findings contribute to a growing discussion on sex differences in cortical thickness and diffusion properties. Sexual dimorphism could necessitate different clinical profiles, targets, and rehabilitation strategies in patients with TBI.

Traumatic brain injury in women across lifespan

Traumatic brain injury (TBI) is a leading cause of death and disability and a global public health challenge. Every year more than 50 million people suffer a TBI, and it is estimated that 50% of the global population will experience at least one TBI in their lifetime. TBI affects both men and women of all ages, however there is a male bias in TBI research as women have frequently been left out of the literature despite irrefutable evidence of male and female dimorphism in several posttraumatic measures. Women uniquely experience distinct life stages marked by levels of endogenous circulating sex hormones, as well as by physiological changes that are nonexistent in men. In addition to generalized sex-specific differences, a woman's susceptibility, neurological outcomes, and treatment success may vary considerably depending upon when in her lifespan she incurred a traumatic insult. How women impacted by TBI might differ from other women as a factor of age and physiology is not well understood. Furthermore, there is a gap in the knowledge of what happens when TBI occurs in the presence of certain sex-specific and sex-nonspecific variables, such as during pregnancy, with oral contraceptive use, in athletics, in cases of addiction and nicotine consumption, during perimenopause, postmenopause, in frailty, among others. Parsing out how hormone-dependent and hormone-independent lifespan variables may influence physiological, neurodegenerative, and functional outcomes will greatly contribute to future investigative studies and direct therapeutic strategies. The goal of this review is to aggregate the knowledge of prevalence, prognosis, comorbid risk, and response of women incurring TBI at differing phases of lifespan. We strive to illuminate commonalities and disparities among female populations, and to pose important questions to highlight gaps in the field in order to further the endeavor of targeted treatment interventions in a patient-specific manner.

Intracranial Pressure–Derived Cerebrovascular Reactivity Indices, Chronological Age, and Biological Sex in Traumatic Brain Injury: A Scoping Review

To date, there has been limited literature exploring the association between age and sex with cerebrovascular reactivity (CVR) in moderate/severe traumatic brain injury (TBI). Given the known link between age, sex, and cerebrovascular function, knowledge of the impacts on continuously assessed CVR is critical for the development of future therapeutics. We conducted a scoping review of the literature for studies that had a direct statistical interrogation of the relationship between age, sex, and continuous intracranial pressure (ICP)-based indices of CVR in moderate/severe TBI. The ICP-based indices researched included: pressure reactivity index (PRx), pulse amplitude index (PAx), and RAC. MEDLINE, BIOSIS, EMBASE, SCOPUS, Global Health, and the Cochrane library were searched from inception to June 2021 for relevant articles. A total of 10 original studies fulfilled our inclusion criteria. Nine of the articles documented a correlation between advanced age and worse CVR, with eight using PRx (2192 total patients), three using PAx (978 total patients), and one using RAC (358 total patients), p < 0.05; R ranging from 0.17 to 0.495 for all indices across all studies. Three articles (1256 total patients) displayed a correlation between biological sex and PRx, with females trending towards higher PRx values (p < 0.05) in the limited available literature. However, no literature exists comparing PAx or RAC with biological sex. Findings showed that aging was associated with impaired CVR. We observed a trend between female sex and worse PRx values, but the literature was limited and statistical significance was borderline. The identified studies were few in number, carried significant population heterogeneity, and utilized grand averaging of large epochs of physiology during statistical comparisons with age and biological sex. Because of the heterogeneous nature of TBI populations and limited focus on the effects of age and sex on outcomes in TBI, it is challenging to highlight the differences between the indices and patient age groups and sex. The largest study showing an association between PRx and age was done by Zeiler and colleagues, where 165 patients were studied noting that patients with a mean PRx value above zero had a mean age above 51.4 years versus a mean age of 41.4 years for those with a mean PRx value below zero (p = 0.0007). The largest study showing an association between PRx and sex was done by Czosnyka and colleagues, where 469 patients were studied noting that for patients <50 years of age, PRx was worse in females (0.11 ± 0.047) compared to males (0.044 ± 0.031), p < 0.05. The findings from these 10 studies provide preliminary data, but are insufficient to definitively characterize the impact of age and sex on CVR in moderate/severe TBI. Future work in the field should focus on the impact of age and sex on multi-modal cerebral physiological monitoring.

Impact of Age and Biological Sex on Cerebrovascular Reactivity in Adult Moderate/Severe Traumatic Brain Injury: An Exploratory Analysis

Age and biological sex are two potential important modifiers of cerebrovascular reactivity post-traumatic brain injury (TBI) requiring close evaluation for potential subgroup responses. The goal of this study was to provide a preliminary exploratory analysis of the impact of age and biological sex on measures of cerebrovascular function in moderate/severe TBI. Forty-nine patients from the prospectively maintained TBI database at the University of Manitoba with archived high-frequency digital cerebral physiology were evaluated. Cerebrovascular reactivity indices were derived as follows: PRx (correlation between intracranial pressure [ICP] and mean arterial pressure [MAP]), PAx (correlation between pulse amplitude of ICP [AMP] and MAP), and RAC (correlation between AMP and cerebral perfusion pressure [CPP]). Time above clinically significant thresholds for each index was calculated over different periods of the acute intensive care unit stay. The association between PRx, PAx, and RAC measures with age was assessed using linear regression, and an age trichotomization scheme (<40, 40-60, >60) using Kruskal-Wallis testing. Similarly, association with biological sex was tested using Mann-Whitney U testing. Biological sex did not demonstrate an impact on any measures of cerebrovascular reactivity. Linear regression between age and PAx and RAC demonstrated a statistically significant positive linear relationship. Median PAx and RAC measures between trichotomized age categories demonstrated statistically significant increases with advancing age. The PRx failed to demonstrate any statistically significant relationship with age in this cohort, suggesting that in elderly patients with controlled ICP, PAx and RAC may be better metrics for detecting impaired cerebrovascular reactivity. Biological sex appears to not be associated with differences in cerebrovascular reactivity in this cohort. The PRx performed the worst in detecting impaired cerebrovascular reactivity in those with advanced age, where PAx and RAC appear to have excelled. Future work is required to validate these findings and explore the utility of different cerebrovascular reactivity indices.

Direct Consequences of Cranioplasty to the Brain: Intracranial Pressure Study

ABSTRACT

Intracranial pressure (ICP) is a crucial factor that we need to take into account in all major pathophysiological changes of the brain after decompressive craniectomy (DC) and cranioplasty (CP). The purpose of our study was to check ICP values before and after cranioplasty and its relation to various parameters (imaging, demographics, time of cranioplasty, and type of graft) as well as its possible relation to postsurgical complications. The authors performed a prospective study in which they selected as participants adults who had undergone unilateral frontotemporoparietal DC and were planned to have cranioplasty. Intracranial pressure was measured with optical fiber sensor in the epidural space and did not affect cranioplasty in any way.Twenty-five patients met the criteria. The mean vcICP (value change of ICP) was 1.2 mm Hg, the mean ΔICP (absolute value change of the ICP) was 2.24 mm Hg and in the majority of cases there was an increase in ICP. The authors found 3 statistically significant correlations: between gender and ΔICP, Δtime (time between DC and CP) and vcICP, and pre-ICP and ±ICP (quantitative change of the ICP).Μale patients tend to develop larger changes of ICP values during CP. As the time between the 2 procedures (DC and CP) gets longer, the vcICP is decreased. However, after certain time it shows a tendency to remain around zero. Lower pre-ICP values (close to or below zero) are more possible to increase after bone flap placement. It seems that the brain tends to restore its pre-DC conditions after CP by taking near-to-normal ICP values.

Moderators of gene-outcome associations following traumatic brain injury

The field of genomics is the principal avenue in the ongoing development of precision/personalised medicine for a variety of health conditions. However, relating genes to outcomes is notoriously complex, especially when considering that other variables can change, or moderate, gene-outcome associations. Here, we comprehensively discuss moderation of gene-outcome associations in the context of traumatic brain injury (TBI), a common, chronically debilitating, and costly neurological condition that is under complex polygenic influence. We focus our narrative review on single nucleotide polymorphisms (SNPs) of three of the most studied genes (apolipoprotein E, brain-derived neurotrophic factor, and catechol-O-methyltransferase) and on three demographic variables believed to moderate associations between these SNPs and TBI outcomes (age, biological sex, and ethnicity). We speculate on the mechanisms which may underlie these moderating effects, drawing widely from biomolecular and behavioural research (n = 175 scientific reports) within the TBI population (n = 72) and other neurological, healthy, ageing, and psychiatric populations (n = 103). We conclude with methodological recommendations for improved exploration of moderators in future genetics research in TBI and other populations.

Subarachnoid Hemorrhage Early Brain Edema Score (SEBES) as a radiographic marker of clinically relevant intracranial hypertension and unfavorable outcome after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

The severity of early brain edema (EBE) after aneurysm rupture was reported to be strongly associated with the risk of poor outcome after aneurysmal subarachnoid hemorrhage (SAH). Using the recently developed Subarachnoid Hemorrhage Early Brain Edema Score (SEBES), we analyzed the predictors of EBE and its impact on complications related to intracranial pressure (ICP) increase after SAH and on poor outcome.

METHODS

All consecutive SAH cases treated between January 2003 and June 2016 with assessable SEBES were included (n = 745). Data on demographic characteristics, medical history, initial severity of SAH, need for conservative ICP treatment and decompressive craniectomy, occurrence of cerebral infarctions and unfavorable outcome at 6 months (modified Rankin scale score > 2) were collected. Univariable and multivariable analyses were performed.

RESULTS

Younger age (<55 years; adjusted odds ratio [aOR] 3.16, 95% confidence interval [CI] 2.28-4.38), female sex (aOR 1.64, 95% CI 1.16-2.31), poor initial clinical condition (World Federation of Neurosurgical Societies score 4-5; aOR 1.74, 95% CI 1.23-2.46), presence of intracerebral hemorrhage (aOR 1.63, 95% CI 1.12-2.36), hypothyroidism (aOR 0.60, 95% CI 0.37-0.98) and renal comorbidity (aOR 0.29, 95% CI 0.11-0.78) were independently associated with SEBES (scores 3-4). There was an independent association between SEBES 3-4 and the need for conservative ICP treatment (aOR 2.43, 95% CI 1.73-3.42), decompressive craniectomy (aOR 2.68, 95% CI 1.84-3.89), development of cerebral infarcts (aOR 2.24, 95% CI 1.53-3.29) and unfavorable outcome (aOR 1.48, 95% CI 1.0-2.17).

CONCLUSIONS

SEBES is a reliable predictor of ICP-related complications and poor outcome of SAH. Our findings highlight the need for further research of the impact of patients' demographic characteristics and comorbidities on the severity of EBE after SAH.

Sex and age differences in isolated traumatic brain injury: a retrospective observational study

Background

Among the many factors that may influence traumatic brain injury (TBI) progression, sex is one of the most controversial. The objective of this study was to investigate sex differences in TBI-associated morbidity and mortality using data from the largest trauma registry in Japan.

Methods

This retrospective, population-based observational study included patients with isolated TBI, who were registered in a nationwide database between 2004 and 2018. We excluded patients with extracranial injury (Abbreviated Injury Scale score ≥ 3) and removed potential confounding factors, such as non-neurological causes of mortality. Patients were stratified by age and mortality and post-injury complications were compared between males and females.

Results

A total of 51,726 patients with isolated TBI were included (16,901 females and 34,825 males). Mortality across all ages was documented in 12.01% (2030/16901) and 12.76% (4445/34825) of males and females, respectively. The adjusted odds ratio (OR) of TBI mortality for males compared to females was 1.32 (95% confidence interval [CI], 1.22–1.42]. Males aged 10–19 years and ≥ 60 years had a significantly higher mortality than females in the same age groups (10–19 years: adjusted OR, 1.97 [95% CI, 1.08–3.61]; 60–69 years: adjusted OR, 1.24 [95% CI, 1.02–1.50]; 70–79 years: adjusted OR, 1.20 [95% CI, 1.03–1.40]; 80–89 years: adjusted OR, 1.50 [95% CI, 1.31–1.73], and 90–99 years: adjusted OR, 1.72 [95% CI, 1.28–2.32]). In terms of the incidence of post-TBI neurologic and non-neurologic complications, the crude ORs were 1.29 (95% CI, 1.19–1.39) and 1.14 (95% CI, 1.07–1.22), respectively, for males versus females. This difference was especially evident among elderly patients (neurologic complications: OR, 1.27 [95% CI, 1.14–1.41]; non-neurologic complications: OR, 1.29 [95% CI, 1.19–1.39]).

Conclusions

In a nationwide sample of patients with TBI in Japan, males had a higher mortality than females. This disparity was particularly evident among younger and older generations. Furthermore, elderly males experienced more TBI complications than females of the same age.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02305-6.

Considering Biological Sex in Traumatic Brain Injury

Published epidemiological studies of traumatic brain injury (TBI) of all severities consistently report higher incidence in men. Recent increases in the participation of women in sports and active military service as well as increasing awareness of the very large number of women who sustain but do not report TBI as a result of intimate partner violence (IPV) suggest that the number of women with TBI is significantly larger than previously believed. Women are also grossly under-represented in clinical and natural history studies of TBI, most of which include relatively small numbers of women, ignore the role of sex- and age-related gonadal hormone levels, and report conflicting results. The emerging picture from recent studies powered to detect effects of biological sex as well as age (as a surrogate of hormonal status) suggest young (i.e., premenopausal) women are more likely to die from TBI relative to men of the same age group, but this is reversed in the 6th and 7th decades of life, coinciding with postmenopausal status in women. New data from concussion studies in young male and female athletes extend this finding to mild TBI, since female athletes who sustained mild TBI are significantly more likely to report more symptoms than males. Studies including information on gonadal hormone status at the time of injury are still too scarce and small to draw reliable conclusions, so there is an urgent need to include biological sex and gonadal hormone status in the design and analysis of future studies of TBI.

Sex-Dependent Macromolecule and Nanoparticle Delivery in Experimental Brain Injury

The development of effective therapeutics for brain disorders is challenging, in particular, the blood-brain barrier (BBB) severely limits access of the therapeutics into the brain parenchyma. Traumatic brain injury (TBI) may lead to transient BBB permeability that affords a unique opportunity for therapeutic delivery via intravenous administration ranging from macromolecules to nanoparticles (NPs) for developing precision therapeutics. In this regard, we address critical gaps in understanding the range/size of therapeutics, delivery window(s), and moreover, the potential impact of biological factors for optimal delivery parameters. Here we show, for the first time, to the best of our knowledge, that 24-h postfocal TBI female mice exhibit a heightened macromolecular tracer and NP accumulation compared with male mice, indicating sex-dependent differences in BBB permeability. Furthermore, we report for the first time the potential to deliver NP-based therapeutics within 3 days after focal injury in both female and male mice. The delineation of injury-induced BBB permeability with respect to sex and temporal profile is essential to more accurately tailor time-dependent precision and personalized nanotherapeutics. Impact statement In this study, we identified a sex-dependent temporal profile of blood/brain barrier disruption in a preclinical mouse model of traumatic brain injury (TBI) that contributes to starkly different macromolecule and nanoparticle delivery profiles post-TBI. The implications and potential impact of this work are profound and far reaching as it indicates that a demand of true personalized medicine for TBI is necessary to deliver the right therapeutic at the right time for the right patient.

Predictors of Intraspinal Pressure and Optimal Cord Perfusion Pressure After Traumatic Spinal Cord Injury

Background/Objectives

We recently developed techniques to monitor intraspinal pressure (ISP) and spinal cord perfusion pressure (SCPP) from the injury site to compute the optimum SCPP (SCPP_opt) in patients with acute traumatic spinal cord injury (TSCI). We hypothesized that ISP and SCPP_opt can be predicted using clinical factors instead of ISP monitoring.

Methods

Sixty-four TSCI patients, grades A–C (American spinal injuries association Impairment Scale, AIS), were analyzed. For 24 h after surgery, we monitored ISP and SCPP and computed SCPP_opt (SCPP that optimizes pressure reactivity). We studied how well 28 factors correlate with mean ISP or SCPP_opt including 7 patient-related, 3 injury-related, 6 management-related, and 12 preoperative MRI-related factors.

Results

All patients underwent surgery to restore normal spinal alignment within 72 h of injury. Fifty-one percentage had U-shaped sPRx versus SCPP curves, thus allowing SCPP_opt to be computed. Thirteen percentage, all AIS grade A or B, had no U-shaped sPRx versus SCPP curves. Thirty-six percentage (22/64) had U-shaped sPRx versus SCPP curves, but the SCPP did not reach the minimum of the curve, and thus, an exact SCPP_opt could not be calculated. In total 5/28 factors were associated with lower ISP: older age, excess alcohol consumption, nonconus medullaris injury, expansion duroplasty, and less intraoperative bleeding. In a multivariate logistic regression model, these 5 factors predicted ISP as normal or high with 73% accuracy. Only 2/28 factors correlated with lower SCPP_opt: higher mean ISP and conus medullaris injury. In an ordinal multivariate logistic regression model, these 2 factors predicted SCPP_opt as low, medium–low, medium–high, or high with only 42% accuracy. No MRI factors correlated with ISP or SCPP_opt.

Conclusions

Elevated ISP can be predicted by clinical factors. Modifiable factors that may lower ISP are: reducing surgical bleeding and performing expansion duroplasty. No factors accurately predict SCPP_opt; thus, invasive monitoring remains the only way to estimate SCPP_opt.

Electronic supplementary material

The online version of this article (10.1007/s12028-018-0616-7) contains supplementary material, which is available to authorized users.

Sex Differences in Traumatic Brain Injury: What We Know and What We Should Know

There is growing recognition of the problem of male bias in neuroscience research, including in the field of traumatic brain injury (TBI) where fewer women than men are recruited to clinical trials and male rodents have predominantly been used as an experimental injury model. Despite TBI being a leading cause of mortality and disability worldwide, sex differences in pathophysiology and recovery are poorly understood, limiting clinical care and successful drug development. Given growing interest in sex as a biological variable affecting injury outcomes and treatment efficacy, there is a clear need to summarize sex differences in TBI. This scoping review presents an overview of current knowledge of sex differences in TBI and a comparison of human and animal studies. We found that overall, human studies report worse outcomes in women than men, whereas animal studies report better outcomes in females than males. However, closer examination shows that multiple factors including injury severity, sample size, and experimental injury model may differentially interact with sex to affect TBI outcomes. Additionally, we explore how sex differences in mitochondrial structure and function might contribute to possible sex differences in TBI outcomes. We propose recommendations for future investigations of sex differences in TBI, which we hope will lead to improved patient management, prognosis, and translation of therapies from bench to bedside.

Sex Differences in Acute Neuroinflammation after Experimental Traumatic Brain Injury Are Mediated by Infiltrating Myeloid Cells

The inflammatory response to moderate-severe controlled cortical impact (CCI) in adult male mice has been shown to exhibit greater glial activation compared with age-matched female mice. However, the relative contributions of resident microglia and infiltrating peripheral myeloid cells to this sexually dimorphic neuroinflammatory responses remains unclear. Here, 12-week-old male and female C57Bl/6 mice were subjected to sham or CCI, and brain samples were collected at 1, 3, or 7 days post-injury for flow cytometry analysis of cytokines, reactive oxygen species (ROS), and phagocytosis in resident microglia (CD45^intCD11b+) versus infiltrating myeloid cells (CD45^hiCD11b+). Motor (rotarod, cylinder test), affect (open field), and cognitive (Y-maze) function tests also were performed. We demonstrate that male microglia had increased phagocytic activity and higher ROS levels in the non-injured brain, whereas female microglia had increased production of tumor necrosis factor (TNF) α and interleukin (IL)-1β. Following CCI, males showed a significant influx of peripheral myeloid cells by 1 day post-injury followed by proliferation of resident microglia at 3 days. In contrast, myeloid infiltration and microglial activation responses in female CCI mice were significantly reduced. No sex differences were observed for TNFα, IL-1β, transforming growth factor β, NOX2, ROS production, or phagocytic activity in resident microglia or infiltrating cells at any time. However, across these functions, infiltrating myeloid cells were significantly more reactive than resident microglia. Female CCI mice also had improved motor function at 1 day post-injury compared with male mice. Thus, we conclude that sexually dimorphic responses to moderate-severe CCI result from the rapid activation and infiltration of pro-inflammatory myeloid cells to brain in male, but not female, mice.

Estrogens as neuroprotectants: Estrogenic actions in the context of cognitive aging and brain injury

There is ample empirical evidence to support the notion that the biological impacts of estrogen extend beyond the gonads to other bodily systems, including the brain and behavior. Converging preclinical findings have indicated a neuroprotective role for estrogen in a variety of experimental models of cognitive function and brain insult. However, the surprising null or even detrimental findings of several large clinical trials evaluating the ability of estrogen-containing hormone treatments to protect against age-related brain changes and insults, including cognitive aging and brain injury, led to hesitation by both clinicians and patients in the use of exogenous estrogenic treatments for nervous system outcomes. That estrogen-containing therapies are used by tens of millions of women for a variety of health-related applications across the lifespan has made identifying conditions under which benefits with estrogen treatment will be realized an important public health issue. Here we provide a summary of the biological actions of estrogen and estrogen-containing formulations in the context of aging, cognition, stroke, and traumatic brain injury. We have devoted special attention to highlighting the notion that estrogen appears to be a conditional neuroprotectant whose efficacy is modulated by several interacting factors. By developing criteria standards for desired beneficial peripheral and neuroprotective outcomes among unique patient populations, we can optimize estrogen treatments for attenuating the consequences of, and perhaps even preventing, cognitive aging and brain injury.

Traumatic brain injuries during development disrupt dopaminergic signaling

Traumatic brain injuries (TBI) sustained during peri-adolescent development produce lasting neuro-behavioral changes that render individuals at an increased risk for developing substance abuse disorders. Experimental and clinical evidence of a prolonged period of hypodopaminergia after TBI have been well documented, but the effect of juvenile TBI on dopaminergic dysfunction and its relationship with substance abuse have not been investigated. In order to determine the effect of juvenile brain injury on dopaminergic signaling, female mice were injured at 21days of age and then beginning seven weeks later were assessed for behavioral sensitization to amphetamine, a drug that increases synaptic dopamine availability. Together with a histological analysis of tyrosine hydroxylase, dopamine transporter, and dopamine D2 receptor expression, our data are indicative of a persistent state of hypodopaminergia well into adulthood after a juvenile TBI. Further, mice that sustained a juvenile TBI exhibited a significantly reduced activation of cFos in the urocortin-positive cells of the Edinger-Westphal nucleus in response to ethanol administration. Taken together, these data provide strong evidence for the vulnerability of juveniles to the development of lasting neuro-behavioral problems following TBI, and indicate a role of injury-induced hypodopaminergia as a risk factor for substance abuse later in life.

Early stage alterations of catecholamine and adrenocorticotropic hormone levels in posttraumatic acute diffuse brain swelling

Posttraumatic acute diffuse brain swelling (PADBS) is characterized by serious brain bulk enlargement rapidly following trauma and is a major cause of elevated intracranial pressure and thus mortality. The pathogenesis of PADBS is not clearly understood, and the early stage alterations of catecholamine (CA) and adrenocorticotropic hormone (ACTH) levels in PADBS also remain largely unknown. The objective of this study was to investigate CA and ACTH levels in the patients with PADBS in the early stage and discuss the possible roles CA and ACTH in the pathogenesis of PADBS. It is a cross-sectional study. A group of patients with PADBS (n=10) was compared with a group of patients with severe brain injury (SBI) (n=33). A control group of healthy adults (n=25) was also included. Blood samples were obtained to measure levels of epinephrine (EPI), norepinephrine (NE), dopamine (DA), and ACTH as soon as the patients arrived at the neurosurgery department, which was done within 4h after trauma. Both SBI and PADBS groups of patients had higher levels of EPI, NE, DA, and ACTH than the control group. The PADBS group had significantly higher levels of EPI, NE, and ACTH than the SBI group. CA and ACTH levels are significantly increased in early stage PADBS. These results imply that CA and ACTH may play important roles in the pathogenesis of PADBS. To eliminate the effects of CA and ACTH at the early stage, and thereby protect the hypothalamus and brain stem, might be critical measures for treating patients with PADBS.

Interrelation between Neuroendocrine Disturbances and Medical Complications Encountered during Rehabilitation after TBI

Traumatic brain injury is not a discrete event but an unfolding sequence of damage to the central nervous system. Not only the acute phase but also the subacute and chronic period after injury, i.e., during inpatient rehabilitation, is characterized by multiple neurotransmitter alterations, cellular dysfunction, and medical complications causing additional secondary injury. Neuroendocrine disturbances also influence neurological outcome and are easily overlooked as they often present with diffuse symptoms such as fatigue, depression, poor concentration, or a decline in overall cognitive function; these are also typical sequelae of traumatic brain injury. Furthermore, neurological complications such as hydrocephalus, epilepsy, fatigue, disorders of consciousness, paroxysmal sympathetic hyperactivity, or psychiatric-behavioural symptoms may mask and/or complicate the diagnosis of neuroendocrine disturbances, delay appropriate treatment and impede neurorehabilitation. The present review seeks to examine the interrelation between neuroendocrine disturbances with neurological complications frequently encountered after moderate to severe TBI during rehabilitation. Common neuroendocrine disturbances and medical complications and their clinical implications are discussed.

Severe Falciparum Malaria-Difference in Mortality among Male and Nonpregnant Females

BACKGROUND

There are many studies regarding the gender difference in severe falciparum malaria. But most of these studies indeed refer to pregnant females only. There are scanty and conflicting reports regarding the mortality trend in nonpregnant females.

MATERIALS AND METHODS

This is a case control study which is open, single centre, single blind, prospective and interventional study. SPSS 19 was used at the end of the study for all statistical analysis. Student's t-test was used for nominal variables and chi-squared test was used for categorical variables.

RESULTS

The mean pre hospitalization illness period is significantly lower in females. Incidence of convulsion is significantly higher in females. The mean haemoglobin concentration in females is significantly lower. The mortality in females is significantly higher. Females over 40 years have higher mortality than females less than 40 years and also males over 40 years. Shock in female was associated with significantly high mortality.

CONCLUSION

The mortality in females is significantly higher in males. The females had lower haemoglobin level and increased incidence of convulsion than their male counterparts. Shock in females has significantly higher mortality. So prompt treatment can save many lives. The increased mortality in females cannot be explained by relative inaccessibility of females to health care system as previously explained, because they have reached hospital earlier than males. Causes of shock and their association with increased mortality in females need further studies.

Impact of aromatase genetic variation on hormone levels and global outcome after severe TBI

Although experimental traumatic brain injury (TBI) studies support estradiol as a neuroprotectant and potent stimulator of neuroplasticity, clinical studies suggest a negative association between endogenous estradiol profiles and mortality/poor outcomes. However, no studies have evaluated associations with cerebral spinal fluid (CSF) hormone profiles and aromatase gene (cytochrome P450 [CYP]19A1) variability on clinical TBI outcomes. We evaluated 110 adults with severe TBI. Average and daily estradiol, testosterone, and estradiol/testosterone ratios (E2:T) were measured using CSF and serum samples and compared to healthy controls. Eighteen tagging and four functional single-nucleotide polymorphisms (SNPs) for CYP19A1 were genotyped and compared to hormones, acute mortality, and Glasgow Outcome Scale (GOS) scores 6 months post-TBI. TBI subjects had lower CSF estradiol over time versus controls. CSF testosterone was initially high, but declined over time. E2/T ratios were initially low, compared to controls, but rose over time. Higher mean E2/T ratio in bivariate analysis was associated with lower mortality (p=0.019) and better GOS-6 scores (p=0.030). rs2470152 influenced CSF E2/T ratio and also serum and CSF testosterone (p≤0.05 all comparisons). Multiple-risk SNPs rs2470152, rs4646, and rs2470144 were associated with worse GOS-6 scores (p≤0.05, all comparisons), and those with>1 risk SNP variant had a higher risk for poor outcome, compared with those with ≤1 risk variant. TBI results in low CSF estradiol and dynamic CSF testosterone and E2/T ratio. In contrast to clinical serum hormone studies, higher CSF E2/T ratio was associated with better outcome. Further, genetic variation in CYP19A1 influences both hormone dynamics and outcome post-TBI.

Are there cognitive and neurobehavioural correlates of hormonal neuroprotection for women after TBI?

This study examined possible cognitive correlates of hormonal neuroprotection following traumatic brain injury (TBI) using archival neuropsychological findings for 1563 individuals undergoing acute TBI rehabilitation between 1989 and 2002. Presumed age of menopause was based on the STRAW (Stages of Reproductive Aging) staging system (Soules, 2005; Soules et al., 2001) and general linear model (GLM) analysis of performance on neuropsychological testing by participants across gender and age groups (25-34, 35-44, 45-54, and 55-64) was performed. Hypotheses were (1) women with TBI in the oldest age group would have lower scores on neuropsychological tests and functional outcome measures than women in the younger groups, and (2) men in the oldest age group would have higher scores than women of the same age group. Analyses revealed that oldest females had significantly worse Trails B and SDMT written and oral scores than the youngest females. In addition, oldest females had significantly better Trails B, Rey AVLT and SDMT written scores than the oldest males. Possible cohort exposure to hormone replacement therapy, unknown hormonal status at time of testing, and sample-specific injury characteristics may have contributed to these findings.

Antioxidant therapies in traumatic brain and spinal cord injury

Free radical formation and oxidative damage have been extensively investigated and validated as important contributors to the pathophysiology of acute central nervous system injury. The generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) is an early event following injury occurring within minutes of mechanical impact. A key component in this event is peroxynitrite-induced lipid peroxidation. As discussed in this review, peroxynitrite formation and lipid peroxidation irreversibly damages neuronal membrane lipids and protein function, which results in subsequent disruptions in ion homeostasis, glutamate-mediated excitotoxicity, mitochondrial respiratory failure and microvascular damage. Antioxidant approaches include the inhibition and/or scavenging of superoxide, peroxynitrite, or carbonyl compounds, the inhibition of lipid peroxidation and the targeting of the endogenous antioxidant defense system. This review covers the preclinical and clinical literature supporting the role of ROS and RNS and their derived oxygen free radicals in the secondary injury response following acute traumatic brain injury (TBI) and spinal cord injury (SCI) and reviews the past and current trends in the development of antioxidant therapeutic strategies. Combinatorial treatment with the suggested mechanistically complementary antioxidants will also be discussed as a promising neuroprotective approach in TBI and SCI therapeutic research. This article is part of a Special Issue entitled: Antioxidants and antioxidant treatment in disease.

Early hospital care of severe traumatic brain injury

Head injury is one of the major causes of trauma-related morbidity and mortality in all age groups in the United Kingdom, and anaesthetists encounter this problem in many areas of their work. Despite a better understanding of the pathophysiological processes following traumatic brain injury and a wealth of research, there is currently no specific treatment. Outcome remains dependant on basic clinical care: management of the patient's airway with particular attention to preventing hypoxia; avoidance of the extremes of lung ventilation; and the maintenance of adequate cerebral perfusion, in an attempt to avoid exacerbating any secondary injury. Hypertonic fluids show promise in the management of patients with raised intracranial pressure. Computed tomography scanning has had a major impact on the early identification of lesions amenable to surgery, and recent guidelines have rationalised its use in those with less severe injuries. Within critical care, the importance of controlling blood glucose is becoming clearer, along with the potential beneficial effects of hyperoxia. The major improvement in outcome reflects the use of protocols to guide resuscitation, investigation and treatment and the role of specialist neurosciences centres in caring for these patients. Finally, certain groups are now recognised as being at greater risk, in particular the elderly, anticoagulated patient.

Sex differences in concussion symptoms of high school athletes

CONTEXT

More than 1.6 million sport-related concussions occur every year in the United States, affecting greater than 5% of all high school athletes who participate in contact sports. As more females participate in sports, understanding possible differences in concussion symptoms between sexes becomes more important.

OBJECTIVE

To compare symptoms, symptom resolution time, and time to return to sport between males and females with sport-related concussions.

DESIGN

Descriptive epidemiology study.

SETTING

Data were collected from 100 high schools via High School RIO (Reporting Information Online).

PATIENTS OR OTHER PARTICIPANTS

Athletes from participating schools who sustained concussions while involved in interscholastic sports practice or competition in 9 sports (boys' football, soccer, basketball, wrestling, and baseball and girls' soccer, volleyball, basketball, and softball) during the 2005-2006 and 2006-2007 school years. A total of 812 sport concussions were reported (610 males, 202 females).

MAIN OUTCOME MEASURE(S)

Reported symptoms, symptom resolution time, and return-to-play time.

RESULTS

No difference was found between the number of symptoms reported (P  =  .30). However, a difference was seen in the types of symptoms reported. In year 1, males reported amnesia (exact P  =  .03) and confusion/disorientation (exact P  =  .04) more frequently than did females. In year 2, males reported more amnesia (exact P  =  .002) and confusion/disorientation (exact P  =  .002) than did females, whereas females reported more drowsiness (exact P  =  .02) and sensitivity to noise (exact P  =  .002) than did males. No differences were observed for symptom resolution time (P  =  .40) or return-to-play time (P  =  .43) between sexes.

CONCLUSIONS

The types of symptoms reported differed between sexes after sport-related concussion, but symptom resolution time and return-to-play timelines were similar.

Sex differences in outcome after mild traumatic brain injury

The objective of this study was to estimate the independent association of sex with outcome after mild traumatic brain injury (mTBI). We performed an analysis of a subset of an established cohort involving 1425 mTBI patients presenting to an academic emergency department (ED). The associations between sex and three outcomes determined 3 months after the initial ED visit were examined: post-concussive symptom (PCS) score (0, 1-5, 6-16, and >16), the number of days to return of normal activities (0, 1-7, and >7), and the number of days of work missed (0, 1-7,and >7). Logistic regression analyses were used to determine the relationship between sex and each outcome after controlling for 12 relevant subject-level variables. Of the 1425 subjects, 643 (45.1%) were female and 782 (54.9%) were male. Three months after mTBI, males had significantly lower odds of being in a higher PCS score category (odds ratio [OR] 0.62, 95% confidence interval [CI]: 0.50, 0.78); this association appeared to be more prominent during child-bearing years for females. Males and females did not significantly differ with respect to the odds of poorer outcome as defined by the number of days to return of normal activities or the number of days of work missed. Female sex is associated with significantly higher odds of poor outcome after mTBI, as measured by PCS score, after control for appropriate confounders. The observed pattern of peak disability for females during the child-bearing years suggests disruption of endogenous estrogen or progesterone production. Attempts to better understand how mTBI affects production of these hormones acutely after injury and during the recovery period may shed light on the mechanism behind poorer outcome among females and putative therapeutic interventions.

Effects of acute substance use and pre-injury substance abuse on traumatic brain injury severity in adults admitted to a trauma centre

BACKGROUND

The aims of this study were to describe the occurrence of substance use at the time of injury and pre-injury substance abuse in patients with moderate-to-severe traumatic brain injury (TBI). Effects of acute substance use and pre-injury substance abuse on TBI severity were also investigated.

METHODS

A prospective study of 111 patients, aged 16-55 years, injured from May 2005 to May 2007 and hospitalised at the Trauma Referral Centre in Eastern Norway with acute TBI (Glasgow Coma Scale 3-12). Based on structural brain damages shown on a computed tomography (CT) scan, TBI severity was defined by modified Marshall classification as less severe (score <3) and more severe (score >/=3). Clinical definition of substance use (alcohol and/or other psychoactive substances) was applied when hospital admission records reflected blood alcohol levels or a positive drug screen, or when a physician verified influence by examining the patient. Pre-injury substance abuse (alcohol and drug problems) was screened by using the CAGE questionnaire.

RESULTS

Forty-seven percent of patients were positive for substance use on admission to hospital. Significant pre-injury substance abuse was reported by 26% of patients. Substance use at the time of injury was more frequent in the less severe group (p = 0.01). The frequency of pre-injury substance abuse was higher in the more severe group (30% vs. 23%). In a logistic regression model, acute substance use at time of injury tended to decrease the probability of more severe intracranial injury, but the effect was not statistically significant after adjusting for age, gender, education, cause of injury and substance abuse, OR = 0.39; 95% CI 0.11-1.35, p = 0.14. Patients with positive screens for pre-injury substance abuse (CAGE >/=2) were more likely to have more severe TBI in the adjusted regression analyses, OR = 4.05; 95% CI 1.10-15.64, p = 0.04.

CONCLUSIONS

Acute substance use was more frequent in patients with less severe TBI caused by low-energy events such as falls, violence and sport accidents. Pre-injury substance abuse increased the probability of more severe TBI caused by high-energy trauma such as motor vehicle accidents and falls from higher levels. Preventive efforts to reduce substance consumption and abuse in at-risk populations are needed.

Race\ethnicity and outcome after traumatic brain injury at a single, diverse center

BACKGROUND

Many factors may predict mortality and disability after traumatic brain injury (TBI), including age and injury severity. However, the role of race\ethnicity has typically been studied tangentially or in homogeneous settings. We investigated whether race\ethnicity was associated with medical outcomes at a single, diverse center.

METHODS

We retrospectively identified patients with TBI older than 17 years with blunt injuries admitted to a Level I trauma center from 2001 to 2004. Glasgow Outcome Scale (GOS) was used to determine outcome at discharge. We performed multivariable logistic regression on two measures of outcome by dichotomizing Glasgow Outcome Scale scores.

RESULTS

We identified 357 patients with TBI from five categories: whites (46.2%), Asians (19.9%), Hispanics (17.9%), blacks (10.9%), and other\unknown (5.0%). Without adjusting for other factors, Asians experienced higher mortality (odds ratio [OR] = 2.25, p = 0.01) compared with whites but not degree of disability. After adjusting for age and Injury Severity Score, a weaker trend remained for higher mortality in Asians (OR = 1.38, p = 0.35), and after excluding cases of assault, the finding was again significant (OR = 2.00, p = 0.04). We also confirmed the recently reported OR of higher mortality among blacks (OR = 1.30). Hispanics seemed to do slightly better at discharge.

CONCLUSIONS

The question of whether and how race plays a role in TBI is controversial. At a single, diverse center, we found that mortality is associated with race, age, and Injury Severity Score. Future clinical studies will benefit from detailed genotypic and phenotypic data and should balance larger sample sizes with ethnic diversity.

Investigating gender differences in outcome following severe traumatic brain injury in a predominantly Asian population

The objective of this study was to investigate if there are possible gender differences in relation to outcome following closed severe traumatic brain injury (TBI) in a predominantly Asian population. A study was conducted using our prospectively maintained TBI database of 672 patients with severe TBI admitted into our neurosurgical intensive care unit. All patients were managed on a standardized protocol in accordance with the Guidelines to the management of severe traumatic brain injury. Glasgow Outcome Score was used to measure the outcome of patients 6 months postinjury. There were 525 males and 147 females, with the latter significantly older than their counterpart. Females had a significantly higher mortality and poorer outcome compared with males. However, this difference was no longer significant when variables (presence of multiple injuries, postresuscitation pupil abnormalities and Glasgow Coma Score) are controlled for. However, both crude and adjusted odd ratios revealed that females aged 60 and below were significantly more likely to have a poorer outcome.

Clinical and neuroimaging features of severely brain-injured patients treated in a neurosurgical unit compared with patients treated in peripheral non-neurosurgical hospitals

Most European TBI patients are managed in peripheral hospitals without benefit of guidelines for transfer of such patients to neurosurgical units as needed. This report compares clinical features and outcomes in two series of severe TBI patients: those admitted to a neurosurgical centre or to a general hospital, all in the Piedmont Region of Italy. Of 630 patients with a GCS of 3-8, 351 were admitted to a centralized neurosurgical unit, and 279 were admitted and treated at a peripheral hospital. All patients had a CT scan read by a neurosurgeon on duty and were classified using the Marshall criteria as having a diffuse injury or non-surgical mass lesions. Outcomes were assessed between 6 months and 6 years using either the GOS Extended or the GOS. Independent variables were age, sex, GCS score and Marshall classification. All the examined factors were significantly different between the two groups (p<0.001). For patients admitted to the neurosurgical centre, age, Marshall classification of the CT and GCS were predictors of a favourable outcome, while for patients treated in general hospitals, Marshall classification of the CT, gender and age were predictors of a favourable outcome. Patients admitted to neurosurgical centres are different from those treated in general hospitals not having these specialized facilities and personnel. The absence of guidelines for the transfer of these patients for more advanced care are lacking and should be the focus of new studies on patient referral.

Gender and traumatic brain injury: Do the sexes fare differently?

OBJECTIVE

To examine the relationship between gender and cognitive recovery 1 year following traumatic brain injury (TBI).

METHODS

Patients with blunt TBI were identified from the TBI Model Systems of Care National Database, multi-centre cohort study. The included patients (n = 325) were 16-45 years at injury, admitted to an acute care facility within 24 hours, received inpatient rehabilitation, had documented admission Glasgow Coma Scale (GCS) scores, completed neuropsychological follow-up 1 year post-injury and did not report pre-morbid learning problems. Multivariate analyses of variance examined the unadjusted association between gender and six cognitive domains examining attention/working memory, verbal memory, language, visual analytic skills, problem-solving and motor functioning. Analyses of covariance models were constructed to determine if confounding factors biased the observed associations.

RESULTS

Females performed significantly better than males on tests of attention/working memory and language. Males outperformed females in visual analytic skills. Gender remained significantly associated with performance in these areas when controlling for confounding variables.

CONCLUSIONS

These results suggest a better cognitive recovery of females than males following TBI. However, future studies need to include non-TBI patients to control for possible pre-injury gender-related differences, as well as to conduct extended follow-ups to determine the stability of the observed differences.

Concussion in sports: postconcussive activity levels, symptoms, and neurocognitive performance

CONTEXT

Evidence suggests that athletes engaging in high-intensity activities after concussion have more difficulties with cognitive recovery.

OBJECTIVE

To examine the role postinjury activity level plays in postconcussive symptoms and performance on neurocognitive tests in a population of student-athletes.

DESIGN

Retrospective cohort study with repeated measures of neurocognitive performance and symptom reporting.

SETTING

University-based sports concussion clinic.

PATIENTS OR OTHER PARTICIPANTS

Ninety-five student-athletes (80 males, 15 females: age = 15.88 +/- 1.35 years) were retrospectively assigned to 1 of 5 groups based on a postinjury activity intensity scale.

MAIN OUTCOME MEASURE(S)

We employed a regression analysis for repeated measures to evaluate the relationship of activity intensity to symptoms and neurocognitive outcome up to 33 days after concussion. Postconcussion symptom scores and neurocognitive (verbal memory, visual memory, visual motor speed, and reaction time) scores served as the primary outcome measures.

RESULTS

Level of exertion was significantly related to all outcome variables (P < .02 for all comparisons). With multivariate analysis, activity intensity remained significant with respect to visual memory (P = .003) and reaction time (P < .001).

CONCLUSIONS

Activity level after concussion affected symptoms and neurocognitive recovery. Athletes engaging in high levels of activity after concussion demonstrated worse neurocognitive performance. For these tasks, those engaging in moderate levels of activity demonstrated the best performance.

Gender and the injured brain

Anesthesiologists are frequently confronted with patients who are at risk for neurological complications due to perioperative stroke or prior traumatic brain injury. In this review, we address the growing and fascinating body of data that suggests gender and sex steroids influence the pathophysiology of injury and outcome for these patients. Cerebral ischemia, traumatic brain injury, and epilepsy are reviewed in the context of potential sex differences in mechanisms and outcomes of brain injury and the role of estrogen, progesterone, and androgens in shaping these processes. Lastly, implications for current and future perioperative and intensive care are identified.

Early prediction of outcome in very severe closed head injury

BACKGROUND

People with severe head injury and admission Glasgow Coma Scale (GCS) score < or =5 have a poor outcome and greatly strain limited resources.

AIM

To identify patients with the best chances of survival, using routine clinical measures.

METHODS

People attending the trauma intensive care unit, who had isolated blunt head injury and GCS< or =5 and who had survived > or =4h, were included in the study, resuscitated and clinically assessed. The GCS score was followed serially after admission. Bivariate analysis of various parameters with outcome was performed using the chi-square test. Serial GCS scores were compared with admission GCS by paired t-testing.

RESULTS

Of the 102 patients who were studied prospectively, 78 (76.5%) died and 24 (23.5%) survived. Age, gender, pre-hospital delay and admission GCS scores were comparable between the two groups. Adequate spontaneous respiration, brisk pupillary light reactivity on admission and increase in GCS by at least 2 at 24h after admission significantly affected the outcome (p<0.05). In the presence of all these factors, the survival rate increased from 6.1% to 57.1% (p<0.001).

CONCLUSIONS

People with GCS score < or =5 still have a reasonable chance of survival, so all patients should be aggressively managed initially. Better survival was observed among those with adequate spontaneous respiration, good pupillary reaction and improvement in GCS of at least 2 at 24h. These clinical parameters can help to predict survival and thus make best use of limited resources.

Gender-related differences in intracranial hypertension and outcome after traumatic brain injury

BACKGROUND

We have previously studied possible gender-related differences in intracranial hypertension and outcome following head injury. The results were always close to the limit of significance so that to achieve greater statistical power we have continued recruitment of patients for further 5 years.

METHODS

Head injury patients (612) who were sedated and ventilated were studied from 1992-2007. All had intracranial pressure (ICP), arterial blood pressure (ABP) and cerebral perfusion pressure (CPP) monitored continuously. Patients' outcome was assessed at 6 months post-injury (469 were available for follow-up).

RESULTS

This retrospective analysis enrolled 98 females and 371 males. Males and females were well matched for age (mean +/- standard deviation: 33 +/- 17 and 33 +/- 16 years respectively) and the initial median Glasgow Coma Score (GCS) [females and males 6]. The difference in mortality rate between sexes was age-related. In the subgroup of patients younger than 50 years mortality was 17% in males and 29% in females (p = 0.026), whereas there was no difference above 50 years (around 40% both males and females). Mean ICP, CPP and ABP were not different between males and females. However, cerebrovascular pressure reactivity was found to be significantly worse in females than in males in the age group below 50 years (PRx; males: 0.044 +/- 0.031; females 0.11 +/- 0.047; p < 0.05).

CONCLUSION

Following head injury females younger than 50 have a significantly worse pressure reactivity and greater mortality rate than males of the same age.

Gender differences in outcome in patients with hypotension and severe traumatic brain injury

BACKGROUND

Animal studies have identified hormonal influences on responses to injury and recovery, creating a potential gender effect on outcome. Progesterone and oestrogen are thought to afford protection in the immediate post-injury period, suggesting females have an advantage, although there has been limited evidence of this in human outcome studies.

METHODS

This study examined the influence of gender on outcome in 229 adults (151 males), aged >17 years, with severe blunt head trauma, initial GCS <9 and hypotension, recruited into a randomised controlled trial of pre-hospital hypertonic saline resuscitation versus conventional fluid management. Outcome was measured by survival and Glasgow Outcome Scale-Extended version (GOS-E) scores at 6 months post-injury.

RESULTS

Females recruited into the study had a higher mean age. Females were more likely to be injured as passengers and pedestrians and males as drivers or motorcyclists. There were no gender differences in GCS or injury severity scores, ICP, cerebral perfusion pressure, gas exchange (PaO2/FiO2 ratio), or duration of mechanical ventilation. After controlling for GCS, age and cause of injury, females had a lower rate of survival. They also showed a lower rate of good outcome (GOS-E score >4) at 6 months, but this appeared to reflect the lower rate of initial survival. Those females surviving had similar outcomes to males.

CONCLUSIONS

The study provides no evidence that females fare better than males following severe TBI, suggesting rather that females may fare worse.

Employment after traumatic brain injury: differences between men and women

OBJECTIVE

To determine whether there are sex differences in employment 1 year after traumatic brain injury.

DESIGN

Prospective cohort.

SETTING

Acute care hospitals in South Carolina and Traumatic Brain Injury Model Systems (TBIMS) rehabilitation centers.

PARTICIPANTS

Subjects in the TBIMS national dataset and the South Carolina Traumatic Brain Injury Follow-up Registry who were expected to be working before injury and followed at 1 year postinjury.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Change in employment from preinjury to 1 year postinjury.

RESULTS

When other measured influences on change in hours worked were held constant, there were significant interactions for sex by age and sex by marital status. Compared with men, women were more likely to decrease hours or stop working, except in the oldest age group (55-64y) in which men were more likely to stop working. For women, there was a pattern showing better employment outcomes as age increased. Decreased employment for women was most evident for married women, who were much more likely to reduce hours or stop working. There was also a tendency for divorced women to be more likely to stop working when compared with divorced men.

CONCLUSIONS

These findings run counter to the current literature. Although definitive explanations must await future studies, causal factors arising from differential societal behavior toward women as well as discriminatory attitudes about women and employment deserve further study.

Incidence and outcome of traumatic brain injury in an urban area in Western Europe over 10 years

INTRODUCTION

Valid epidemiological data on incidence and outcome of traumatic brain injury (TBI) show great variability. A study on incidence, severity and outcome of TBI was conducted in an urban area of one million inhabitants.

MATERIALS AND METHODS

130,000 prehospital emergencies were screened for TBI.

INCLUSION CRITERIA

Glasgow Coma Scale (GCS) score <or=8 and/or Abbreviated Injury Scale for head injuries (AIS(head)) score >or=2 with confirmed TBI via appropriate diagnostics.

RESULTS

Annual incidence was 7.3/100,000. Overall mortality rate was 45.8%: 182 (28%) were prehospital deaths, 116 (17.8%) patients died in hospital. Two hundred and fourteen of 352 (60.8%) surviving patients were sufficiently rehabilitated at discharge [Glasgow Outcome Scale (GOS) score = 1], but 138 patients (39.2%) survived with persisting deficits. GOS was associated with initial GCS and AIS(head).

CONCLUSION

The incidence of TBI was lower compared to the literature. The overall mortality was high, especially prehospital and early in-hospital mortality rates.

The role of early follow-up computed tomography imaging in the management of traumatic brain injury patients with intracranial hemorrhage

BACKGROUND

The purpose of this study was to investigate whether routine follow-up computed tomography (CT) for patients with head injury, in the absence of clinical indications, alters patient management.

METHODS

Nonpenetrating head injury patients admitted to San Francisco General Hospital during an 18-month period were reviewed. Patients not surgically treated at presentation and with a routine follow-up head CT within 24 hours were included. Surgical and nonsurgical interventions after repeat CT were assessed. Clinical and imaging parameters were correlated with progressive hemorrhagic injury (PHI) and with delayed development of surgical lesions.

RESULTS

PHI was identified in 49 (42%) of 116 patients. None of these patients required a nonoperative intervention in response to the PHI. Six of these patients developed a neurologic change concurrent with routine follow-up imaging and required operative intervention. Thus, no patient underwent an intervention in response to a worsening head CT in the absence of clinical findings. Of the six patients who developed a surgical lesion, two had increased intracranial pressure, one had a change in pupillary examination, three had worsening mental status, and one had change in the motor examination. Univariate risk factors for development of a delayed surgical lesion included 5 to 10 mm of midline shift (p = 0.001), basal cistern effacement (p = 0.01), and higher Marshall score (p = 0.01) on initial CT imaging.

CONCLUSIONS

Although PHI is common with head injury, delayed interventions in the absence of clinical indicators are uncommon. Our data suggest that early follow-up CT imaging in the setting of head trauma is not routinely indicated. We suggest that assessment, based on the severity of findings on initial brain imaging and serial clinical examinations, should guide the need for follow-up imaging in the setting of head trauma.

Prognostic value of demographic characteristics in traumatic brain injury: results from the IMPACT study

Outcome following traumatic brain injury (TBI) is not only dependent on the nature and severity of injury and subsequent treatment, but also on constituent characteristics of injured individuals. We aimed to describe and quantify the relationship between demographic characteristics and six month outcome assessed by the Glasgow Outcome Scale (GOS) after TBI. Individual patient data on age (n = 8719), gender (n = 8720), race (n = 5320), and education (n = 2201) were extracted from eight therapeutic Phase III randomized clinical trials and three surveys in moderate or severe TBI, contained in the IMPACT database. The strength of prognostic effects was analyzed with binary and proportional odds regression analysis and expressed as an odds ratio. Age was analyzed as a continuous variable with spline functions, and the odds ratio calculated over the difference between the 75 th and 25 th percentiles. Associations with other predictors were explored. Increasing age was strongly related to poorer outcome (OR 2.14; 95% CI 2.00-2.28) in a continuous fashion that could be approximated by a linear function. No gender differences in outcome were found (OR: 1.01; CI 0.92-1.11), and exploratory analysis failed to show any gender/age interaction. The studies included predominantly Caucasians (83%); outcome in black patients was poorer relative to this group (OR 1.30; CI 1.09-1.56). This relationship was sustained on adjusted analyses, and requires further study into mediating factors. Higher levels of education were weakly related to a better outcome (OR: 0.70; CI 0.52-0.94). On multivariable analysis adjusting for age, motor score, and pupils, the prognostic effect of race and education were sustained. We conclude that outcome following TBI is dependent on age, race, to a lesser extent on education, but not on gender.