The frequency and the diagnosis of pituitary dysfunction after traumatic brain injury

Results of therapy in children diagnosed with severe traumatic brain injury

The aim of this research is to enhance therapeutic outcomes in children diagnosed with severe craniocerebral trauma by evaluating the contributing factors involved in cerebral injury. The investigation focused on evaluating the impact of infusion therapy on the improvement of pediatric patients' conditions with SCCT, particularly by assessing hydrobalance indicators. Adaptive changes associated with the humoral stress response were evaluated through alterations in hormone concentrations (thyrotropin (TSH), cortisol (C), prolactin (P)). Concentrations of plasma protein and glucose were analyzed. A total of 804 children with isolated severe craniocerebral trauma (SCCT) were enrolled and stratified into retrospective (n = 474) and prospective (n = 100) cohorts. Children with negative hydrobalance exhibited a higher mortality rate compared to those with positive hydrobalance (24% vs. 10%, p ≤ 0.05). Positive hydrobalance, in conjunction with appropriate infusion therapy and rehydration, positively influenced the prognosis of severe cranio-cerebral trauma (SCCT). These findings can be applied in clinical practice to optimize the treatment of children with SCCT and improve their prognosis. The level of total protein was higher in conscious children after 48 h (59.9 ± 1.5 g/L, p ≤ 0.05) in comparison to deceased individuals (54.9 ± 1.6 g/L, p ≤ 0.05). Stress-induced hyperglycemia was associated with the severity of severe cranio-cerebral trauma. The study corroborated the significance of infusion therapy in the treatment of children with SCCT. Indicators of total protein, glucose, and P concentrations can serve as valuable tools for assessing the severity and prognostication of SCCT.

Clinical manifestations and treatment of hypopituitarism due to traumatic brain injury

Traumatic brain injury (TBI) is a global health problem with rising incidence. In many patients, pituitary hormone deficiencies after TBI are transient; however, in some cases, they can persist or develop in the chronic phase. Post-traumatic hypopituitarism has a variable clinical course, reflecting its complex pathophysiology and incompletely understood risk factors. The diagnosis can be challenging, because symptoms of hypopituitarism may overlap with other TBI manifestations. Confirmatory endocrine testing is often required for diagnosis. Untreated chronic hypopituitarism can adversely affect physical, neurocognitive, and psychosocial rehabilitation; body composition; glucose metabolism; bone metabolism; and quality of life. Screening for hypopituitarism is recommended after moderate or severe TBI and for selected patients with mild TBI and suggestive clinical symptoms. Management requires an individualized multidisciplinary approach and consideration of endocrine pathology. In this review, we discuss the clinical manifestations and current management standards for hypopituitarism in adults with TBI.

Acute and chronic hypopituitarism following traumatic brain injury: a systematic review and meta-analysis

Traumatic brain injury (TBI) is associated with various endocrine abnormalities, including pituitary axis dysfunction. Understanding the prevalence and temporal patterns of these dysfunctions is crucial for effective clinical management. This study aimed to systematically review the literature and conduct a meta-analysis to determine the prevalence of pituitary axis dysfunction following TBI, assess temporal patterns across different post-injury durations, and identify potential contributing factors. A comprehensive search was conducted across multiple electronic databases between 1st of January 2000 until 31st March 2024. Studies reporting the prevalence of pituitary axis dysfunction post-TBI were included. Pooled estimates with 95% confidence intervals (CIs) were calculated using random-effects models in the R statistical software. Subgroup analyses were performed based on duration post-TBI (< 3 months, 3-6 months, 6-12 months, > 12 months) to explore temporal variations. Heterogeneity was assessed using the I^2 statistic. A total of 52 studies were included in the meta-analysis, encompassing 7367 participants. The pooled estimate for the prevalence of any pituitary axis dysfunction post-TBI was 33% (95% CI [28%; 37%]). Subgroup analysis by duration revealed varying prevalence rates: < 3 months (40%, 95% CI [27%; 53%]), 3-6 months (31%, 95% CI [15%; 47%]), 6-12 months (26%, 95% CI [19%; 33%]), and > 12 months (32%, 95% CI [26%; 38%]). Prevalence of multiple axes affection was 7% (95% CI [6%; 9%]), with varying rates across durations. Specific axes affection varied: Growth Hormone (GH) deficiency was 18% (95% CI [14%; 21%]), adrenocorticotropic hormone (ACTH) deficiency was 10% (95% CI [8%; 13%]), pituitary-gonadal axis hormones deficiency was 16% (95% CI [12%; 19%]), and thyroid-stimulating hormone (TSH) deficiency was 6% (95% CI [5%; 7%]). This meta-analysis highlights a significant prevalence of pituitary axis dysfunction following TBI, with temporal variations observed across different post-injury durations. The findings underscore the importance of tailored clinical management strategies based on the duration and type of dysfunction. Further research addressing potential contributing factors is warranted to enhance understanding and management of these conditions.

Acorus calamus Linn.: A novel neuroprotective approach for traumatic brain injury in Drosophila melanogaster

BACKGROUND

Traumatic brain injury (TBI) causes substantial mortality and morbidity globally. Current treatments only alleviate symptoms and do not halt secondary injury progression.

OBJECTIVES

Evaluate the neuroprotective potential of Acorus calamus Linn. (AC) in a Drosophila melanogaster model of high-impact TBI.

METHODS

Fruit flies (Drosophila melanogaster) of the Oregon R + strain were administered hydroalcoholic extracts of Acorus calamus Linn. (HAEAC) at concentrations of 25 and 50 µg/mL, 24 h and continuously for 72 h, respectively, following TBI induction. Mortality rate, locomotor function, neurotransmitter levels, and oxidative stress markers were assessed at 24 and 72 h post-injury as outcomemeasures.

RESULTS

AC significantly reduced post-TBI mortality and improved locomotor function in a dose-dependent manner. Additionally, AC increased acetylcholinesterase, gamma-aminobutyric acid, serotonin, and dopamine levels while reducing glutamate. It also boosted antioxidant activity (superoxide dismutase, glutathione, and catalase) and lowered markers of oxidative damage (malondialdehyde, nitrite).

CONCLUSIONS

AC mitigated behavioral deficits, oxidative damage, and neurotransmitter imbalance in fruit flies after TBI. These findings indicate AC may be more effective than individual drugs for TBI therapy. Further research into its neuroprotective phytochemicals is warranted.

Increased Adrenocorticotropic Hormone Levels Predict Recovery of Consciousness in Patients With Disorders of Consciousness

The potential influence of pituitary-related hormones (including both pituitary gland and target gland hormones) on functional recovery after traumatic brain injury has been observed. However, the relationship between these hormones and the recovery of consciousness in patients with disorders of consciousness (DOC) remains unclear. In this retrospective and observational study, 208 patients with DOC were recruited. According to the Glasgow Outcome Scale (GOS) scores after 6 months, patients with DOC were categorized into two subgroups: a favorable prognosis subgroup (n = 38) comprising those who regained consciousness (GOS score ≥3), and a poor prognosis subgroup (n = 156) comprising those who remained in DOC (GOS score <3). Comparative analyses of pituitary-related hormone levels between the two subgroups were conducted. Further, a binary logistic regression analysis was conducted to assess the predictive value of pituitary-related hormones for the patients' prognosis. The favorable prognosis subgroup showed a significant increase in adrenocorticotropic hormone (ACTH) levels (p = 0.036). Moreover, higher ACTH levels and shorter days since injury were significantly associated with a better prognosis, with odds ratios (ORs) of 0.928 (95% confidence interval [CI] = 0.873-0.985, p = 0.014) and 1.015 (95% CI = 1.005-1.026, p = 0.005), respectively. A subsequent receiver operating characteristic (ROC) analysis demonstrated the potential to predict patients' prognosis with an area under the curve value of 0.78, an overall accuracy of 75.5%, a sensitivity of 77.5%, and a specificity of 66.7%. Our findings indicate that ACTH levels could serve as a clinically valuable and convenient predictor for patients' prognosis.

Unusual and lesser-known rare causes of adult growth hormone deficiency

Growth hormone is among the most common hormones to be deficient in pituitary insult. It can occur either in isolation or combined with other hormone deficiencies. Growth hormone deficiency in adults (AGHD) can be due to causes acquired in adulthood or have a childhood-onset etiology, but the former is about three times more common. Usual causes of AGHD include mass effects due to a pituitary tumour, and/or its treatment (surgery, medical therapy, or radiotherapy), or radiotherapy to the head and neck region for non-pituitary lesions. The unusual or lesser-known causes of AGHD, are usually due to non-tumoral etiology and range from vascular and infective to inflammatory and miscellaneous causes. These not only expand the spectrum of AGHD but may also contribute to increased morbidity, adverse metabolic consequences, and mortality due to the primary condition, if unrecognised. The review features these lesser-known and rare causes of AGHD and highlights their clinical and diagnostic implications.

Endocrine Dysfunction After Traumatic Brain Injury: An Ignored Clinical Syndrome?

Traumatic brain injury (TBI) incurs substantial health and economic burden, as it is the leading reason for death and disability globally. Endocrine abnormalities are no longer considered a rare complication of TBI. The reported prevalence is variable across studies, depending on the time frame of injury, time and type of testing, and variability in hormonal values considered normal across different studies. The present review reports evidence on the endocrine dysfunction that can occur after TBI. Several aspects, including the pathophysiological mechanisms, clinical consequences/challenges (in the acute and chronic phases), screening and diagnostic workup, principles of therapeutic management, and insights on future directions/research agenda, are presented. The management of hypopituitarism following TBI involves hormonal replacement therapy. It is essential for health care providers to be aware of this complication because at times, symptoms may be subtle and may be mistaken to be caused by brain injury itself. There is a need for stronger evidence for establishing recommendations for optimum management so that they can be incorporated as standard of care in TBI management.

Menstrual Cycle Patterns After Concussion in Adolescent Patients

OBJECTIVE

To describe menstrual cycle patterns in adolescents with concussion and investigate whether menstrual cycle phase at injury influenced postconcussion cycle pattern changes or concussion symptoms.

STUDY DESIGN

Data were collected prospectively from patients aged 13-18 years presenting to a specialty care concussion clinic for an initial visit (≤28 days postconcussion) and, if clinically indicated, at a follow-up visit 3-4 months postinjury. Primary outcomes included menstrual cycle pattern change since injury (change/no change), menstrual cycle phase at time of injury (calculated using date of last period before injury), and symptom endorsement and severity, measured by Post-Concussion Symptom Inventory (PCSI). Fisher exact tests were used to determine the association between menstrual phase at injury and change in cycle pattern. Multiple linear regression was used to determine whether menstrual phase at injury was associated with PCSI endorsement and symptom severity, adjusting for age.

RESULTS

Five hundred twelve postmenarchal adolescents were enrolled (age 15.2 ± 1.4 years), with 111 (21.7%) returning for follow-up at 3-4 months. Menstrual pattern change was reported by 4% of patients at initial visit and 10.8% of patients at follow-up. At 3-4 months, menstrual phase at injury was not associated with menstrual cycle changes (P = .40) but was associated with endorsement of concussion symptoms on the PCSI (P = .01).

CONCLUSIONS

At 3-4 months' postconcussion, 1 in 10 adolescents experienced a change in menses. Menstrual cycle phase at injury was associated with postconcussion symptom endorsement. Leveraging a large sample of postconcussion menstrual patterns, this study represents foundational data regarding potential menstrual cycle effects of concussion in female adolescents.

Growth Hormone Deficiency following Traumatic Brain Injury in Pediatric and Adolescent Patients: Presentation, Treatment, and Challenges of Transitioning from Pediatric to Adult Services

Traumatic brain injury (TBI) is increasingly recognized, with an incidence of approximately 110 per 100,000 in pediatric populations and 618 per 100,000 in adolescent and adult populations. TBI often leads to cognitive, behavioral, and physical consequences, including endocrinopathies. Deficiencies in anterior pituitary hormones (e.g., adrenocorticotropic hormone, thyroid-stimulating hormone, gonadotropins, and growth hormone [GH]) can negatively impact health outcomes and quality of life post-TBI. This review focuses on GH deficiency (GHD), the most common post-TBI pituitary hormone deficiency. GHD is associated with abnormal body composition, lipid metabolism, bone mineral density, executive brain functions, behavior, and height outcomes in pediatric, adolescent, and transition-age patients. Despite its relatively frequent occurrence, post-TBI GHD has not been well studied in these patients; hence, diagnostic and treatment recommendations are limited. Here, we examine the occurrence and diagnosis of TBI, retrospectively analyze post-TBI hypopituitarism and GHD prevalence rates in pediatric and adolescent patients, and discuss appropriate GHD testing strategies and GH dosage recommendations for these patients. We place particular emphasis on the ways in which testing and dosage recommendations may change during the transition phase. We conclude with a review of the challenges faced by transition-age patients and how these may be addressed to improve access to adequate healthcare. Little information is currently available to help guide patients with TBI and GHD through the transition phase and there is a risk of interrupted care; therefore, a strength of this review is its emphasis on this critical period in a patient's healthcare journey.

Approach to a case with an unusual cause of hypopituitarism

Hypopituitarism refers to insufficiency of one or more hormones of the pituitary and can be due to myriad causes. The clinical and radiological spectrum of the condition is heterogeneous, based on the age, gender, clinical setting and/or other past medical history. Hypopituitarism includes central hypocortisolism, hypothyroidism, hypogonadism and growth hormone deficiency. Both hypo- and hyperprolactinemia can be associated with hypopituitarism, with low prolactin signifying more extensive pituitary damage. Posterior pituitary insufficiency (arginine vasopressin deficiency), occurs either in isolation or with anterior pituitary hormone deficiency. Clinical symptomatology of hypopituitarism is usually non-specific and insidious in onset and progression. Overall, the most common cause of hypopituitarism is a pituitary adenoma and/or its management (surgery, radiotherapy, pharmacotherapy or a combination of these). However, it is this subset of patients which is more likely to be identified and managed timely, possibly alleviating the premature mortality associated with hypopituitarism. What is more challenging is the recognition of hypopituitarism in less common settings, which may be either due to direct involvement of the pituitary (infection, traumatic brain injury, or infiltrative causes) or indirectly as a consequence of the primary process (thalassemia, vasculotoxic snakebite, subarachnoid hemorrhage). These entities are often under-recognised, and increased awareness can help in greater recognition of the problem burden. Further, pituitary insufficiency in most of these settings is dynamic, which may progress, or rarely, show recovery of function. This renders complexity to the problem, but makes it even more imperative to suspect, screen and appropriately manage patients with less common causes of hypopituitarism.

Persisting neuroendocrine abnormalities and their association with physical impairment 5 years after critical illness

Background

Critical illness is hallmarked by neuroendocrine alterations throughout ICU stay. We investigated whether the neuroendocrine axes recover after ICU discharge and whether any residual abnormalities associate with physical functional impairments assessed 5 years after critical illness.

Methods

In this preplanned secondary analysis of the EPaNIC randomized controlled trial, we compared serum concentrations of hormones and binding proteins of the thyroid axis, the somatotropic axis and the adrenal axis in 436 adult patients who participated in the prospective 5-year clinical follow-up and who provided a blood sample with those in 50 demographically matched controls. We investigated independent associations between any long-term hormonal abnormalities and physical functional impairments (handgrip strength, 6-min walk distance, and physical health-related quality-of-life) with use of multivariable linear regression analyses.

Results

At 5-year follow-up, patients and controls had comparable serum concentrations of thyroid-stimulating hormone, thyroxine (T₄), triiodothyronine (T₃) and thyroxine-binding globulin, whereas patients had higher reverse T₃ (rT₃, p = 0.0002) and lower T₃/rT₃ (p = 0.0012) than controls. Patients had comparable concentrations of growth hormone, insulin-like growth factor-I (IGF-I) and IGF-binding protein 1 (IGFBP1), but higher IGFBP3 (p = 0.030) than controls. Total and free cortisol, cortisol-binding globulin and albumin concentrations were comparable for patients and controls. A lower T₃/rT₃ was independently associated with lower handgrip strength and shorter 6-min walk distance (p ≤ 0.036), and a higher IGFBP3 was independently associated with higher handgrip strength (p = 0.031).

Conclusions

Five years after ICU admission, most hormones and binding proteins of the thyroid, somatotropic and adrenal axes had recovered. The residual long-term abnormality within the thyroid axis was identified as risk factor for long-term physical impairment, whereas that within the somatotropic axis may be a compensatory protective response. Whether targeting of the residual abnormality in the thyroid axis may improve long-term physical outcome of the patients remains to be investigated.

Trial registration ClinicalTrials.gov: NCT00512122, registered on July 31, 2007 (https://www.clinicaltrials.gov/ct2/show/NCT00512122).

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03858-1.

Menopause, anti-Müllerian hormone and cognition in a cohort of women with persistent symptoms following TBI: a case for future research

Objectives: Primary: To explore anti-Müllerian Hormone (AMH) levels in community dwelling women following TBI. Secondary: To explore the relation of AMH to menstrual cycle, cognition, distress and symptoms of menopause.Setting: Large adult TBI outpatient clinic in Toronto Canada.Research design: Prospective study of 10 women with persistent symptoms who were one or more years post TBI.Methods: Consenting participants provided a serum sample for AMH levels, and completed the Menopause Rating Scale (MRS), Symptom Checklist-90 r (SCL-90 r), Repeatable Battery for the Assessment of Neurological Status (RBANS) and a health questionnaire.Main outcomes and results: This study found lower than expected levels of AMH in 50% of participants relative to age matched norms and 50% of participants experienced new onset of menstrual changes. Also notable were findings of lower-than-expected cognitive scores in women over 35 and reports of menopause-related symptoms across all ages groups.Conclusions: As our understanding of the role of AMH grows, examining changes in this novel biomarker in the long-term post-TBI is warranted. Future research should be sufficiently powered to expand on and validate the study's findings.

Experience of a Pituitary Clinic for US Military Veterans With Traumatic Brain Injury

Context

Traumatic brain injury (TBI) is considered the "signature" injury of veterans returning from wartime conflicts in Iraq and Afghanistan. While moderate/severe TBI is associated with pituitary dysfunction, this association has not been well established in the military setting and in mild TBI (mTBI). Screening for pituitary dysfunction resulting from TBI in veteran populations is inconsistent across Veterans Affairs (VA) institutions, and such dysfunction often goes unrecognized and untreated.

Objective

This work aims to report the experience of a pituitary clinic in screening for and diagnosis of pituitary dysfunction.

Methods

A retrospective analysis was conducted in a US tertiary care center of veterans referred to the VA Puget Sound Healthcare System pituitary clinic with a history of TBI at least 12 months prior. Main outcome measures included demographics, medical history, symptom burden, baseline hormonal evaluation, brain imaging, and provocative testing for adrenal insufficiency (AI) and adult-onset growth hormone deficiency (AGHD).

Results

Fatigue, cognitive/memory problems, insomnia, and posttraumatic stress disorder were reported in at least two-thirds of the 58 patients evaluated. Twenty-two (37.9%) were diagnosed with at least one pituitary hormone deficiency, including 13 (22.4%) AI, 12 (20.7%) AGHD, 2 (3.4%) secondary hypogonadism, and 5 (8.6%) hyperprolactinemia diagnoses; there were no cases of thyrotropin deficiency.

Conclusion

A high prevalence of chronic AI and AGHD was observed among veterans with TBI. Prospective, larger studies are needed to confirm these results and determine the effects of hormone replacement on long-term outcomes in this setting.

Neuroinflammation and Hypothalamo-Pituitary Dysfunction: Focus of Traumatic Brain Injury

The incidence of traumatic brain injury (TBI) has increased over the last years with an important impact on public health. Many preclinical and clinical studies identified multiple and heterogeneous TBI-related pathophysiological mechanisms that are responsible for functional, cognitive, and behavioral alterations. Recent evidence has suggested that post-TBI neuroinflammation is responsible for several long-term clinical consequences, including hypopituitarism. This review aims to summarize current evidence on TBI-induced neuroinflammation and its potential role in determining hypothalamic-pituitary dysfunctions.

Insights into non-classic and emerging causes of hypopituitarism

Hypopituitarism is defined as one or more partial or complete pituitary hormone deficiencies, which are related to the anterior and/or posterior gland and can have an onset in childhood or adulthood. The most common aetiology is a sellar or suprasellar lesion, often an adenoma, which causes hypopituitarism due to tumour mass effects, or the effects of surgery and/or radiation therapy. However, other clinical conditions, such as traumatic brain injury, and autoimmune and inflammatory diseases, can result in hypopituitarism, and there are also genetic causes of hypopituitarism. Furthermore, the use of immune checkpoint inhibitors to treat cancer is increasing the risk of hypopituitarism, with a pattern of hormone defects that is different from the classic patterns and depends on mechanisms that are specific for each drug. Moreover, autoantibody production against the pituitary and hypothalamus has been demonstrated in studies investigating the development or worsening of some cases of hypopituitarism. Finally, evidence suggests that posterior pituitary damage can affect oxytocin secretion. The aim of this Review is to summarize current knowledge on non-classic and emerging causes of hypopituitarism, so as to help clinicians improve early identification, avoid life-threatening events and improve the clinical care and quality of life of patients at risk of hypopituitarism.

Antibodies against the pituitary and hypothalamus in boxers

Traumatic brain injury (TBI), a growing public health problem worldwide, has recently been recognized as one of the leading causes of hypopituitarism. The main causes of TBI-induced pituitary dysfunction are car accidents, falls, violence, sports-related brain injury, and war accidents, including blast-related brain injuries. Car accidents and falls are the most common causes of TBI and pituitary dysfunction among the younger generation and elderly population, respectively. The prevalence of hypopituitarism after TBI is about 30%. GH is the most common hormone lost. The mechanisms underlying hypopituitarism are still unclear; however, recent studies have demonstrated that hypoxic insult, increased intracranial pressure, axonal injury, genetic predisposition, neuroinflammation, and autoimmunity may be responsible for the development of pituitary dysfunction. Neuroendocrine abnormalities are recently described in athletes dealing with contact sports, including boxing and kickboxing, which are characterized by chronic repetitive head trauma. Mild TBI and concussion are accepted in boxing and kickboxing. The positivity of antipituitary and antihypothalamic antibodies is also a significant risk factor in the development of neuroendocrine abnormalities. Autoimmune reaction may also be responsible for the reduction in pituitary volume in boxers with hypopituitarism. In this chapter, the role of autoimmunity in the occurrence of pituitary dysfunction among boxers is discussed.

Traumatic Brain Injury as Frequent Cause of Hypopituitarism and Growth Hormone Deficiency: Epidemiology, Diagnosis, and Treatment

Traumatic brain injury (TBI)-related hypopituitarism has been recognized as a clinical entity for more than a century, with the first case being reported in 1918. However, during the 20^th century hypopituitarism was considered only a rare sequela of TBI. Since 2000 several studies strongly suggest that TBI-mediated pituitary hormones deficiency may be more frequent than previously thought. Growth hormone deficiency (GHD) is the most common abnormality, followed by hypogonadism, hypothyroidism, hypocortisolism, and diabetes insipidus. The pathophysiological mechanisms underlying pituitary damage in TBI patients include a primary injury that may lead to the direct trauma of the hypothalamus or pituitary gland; on the other hand, secondary injuries are mainly related to an interplay of a complex and ongoing cascade of specific molecular/biochemical events. The available data describe the importance of GHD after TBI and its influence in promoting neurocognitive and behavioral deficits. The poor outcomes that are seen with long standing GHD in post TBI patients could be improved by GH treatment, but to date literature data on the possible beneficial effects of GH replacement therapy in post-TBI GHD patients are currently scarce and fragmented. More studies are needed to further characterize this clinical syndrome with the purpose of establishing appropriate standards of care. The purpose of this review is to summarize the current state of knowledge about post-traumatic GH deficiency.

Distant Organ Damage in Acute Brain Injury

Acute brain injuries pose a great threat to global health, having significant impact on mortality and disability. Patients with acute brain injury may develop distant organ failure, even if no systemic diseases or infection is present. The severity of non-neurologic organs' dysfunction depends on the extremity of the insult to the brain. In this comprehensive review we sought to describe the organ-related consequences of acute brain injuries. The clinician should always be aware of the interplay between central nervous system and non-neurological organs, that is constantly present. Cerebral injury is not only a brain disease, but also affects the body as whole, and thus requires holistic therapeutical approach.

Sex as a Biological Variable in Preclinical Modeling of Blast-Related Traumatic Brain Injury

Approaches to furthering our understanding of the bioeffects, behavioral changes, and treatment options following exposure to blast are a worldwide priority. Of particular need is a more concerted effort to employ animal models to determine possible sex differences, which have been reported in the clinical literature. In this review, clinical and preclinical reports concerning blast injury effects are summarized in relation to sex as a biological variable (SABV). The review outlines approaches that explore the pertinent role of sex chromosomes and gonadal steroids for delineating sex as a biological independent variable. Next, underlying biological factors that need exploration for blast effects in light of SABV are outlined, including pituitary, autonomic, vascular, and inflammation factors that all have evidence as having important SABV relevance. A major second consideration for the study of SABV and preclinical blast effects is the notable lack of consistent model design—a wide range of devices have been employed with questionable relevance to real-life scenarios—as well as poor standardization for reporting of blast parameters. Hence, the review also provides current views regarding optimal design of shock tubes for approaching the problem of primary blast effects and sex differences and outlines a plan for the regularization of reporting. Standardization and clear description of blast parameters will provide greater comparability across models, as well as unify consensus for important sex difference bioeffects.

Traumatic brain injuries induced pituitary dysfunction: a call for algorithms

Traumatic brain injury affects many people each year, resulting in a serious burden of devastating health consequences. Motor-vehicle and work-related accidents, falls, assaults, as well as sport activities are the most common causes of traumatic brain injuries. Consequently, they may lead to permanent or transient pituitary insufficiency that causes adverse changes in body composition, worrisome metabolic function, reduced bone density, and a significant decrease in one's quality of life. The prevalence of post-traumatic hypopituitarism is difficult to determine, and the exact mechanisms lying behind it remain unclear. Several probable hypotheses have been suggested. The diagnosis of pituitary dysfunction is very challenging both due to the common occurrence of brain injuries, the subtle character of clinical manifestations, the variable course of the disease, as well as the lack of proper diagnostic algorithms. Insufficiency of somatotropic axis is the most common abnormality, followed by presence of hypogonadism, hypothyroidism, hypocortisolism, and diabetes insipidus. The purpose of this review is to summarize the current state of knowledge about post-traumatic hypopituitarism. Moreover, based on available data and on our own clinical experience, we suggest an algorithm for the evaluation of post-traumatic hypopituitarism. In addition, well-designed studies are needed to further investigate the pathophysiology, epidemiology, and timing of pituitary dysfunction after a traumatic brain injury with the purpose of establishing appropriate standards of care.

Long-term neuroendocrine consequences of traumatic brain injury and strategies for management

Introduction: Traumatic brain injuries (TBI) are reported to cause neuroendocrine impairment with a prevalence of 15% with confirmatory testing. Pituitary dysfunction (PD) may have detrimental effects on vital parameters as well as on body composition, cardiovascular functions, cognition, and quality of life. Therefore, much effort has been made to identify predictive factors for post-TBI PD and various screening strategies have been offered.Areas covered: We searched PubMed and reviewed the recent data on clinical perspectives and long-term outcomes as well as predictive factors and screening modalities of post-TBI PD. Inconsistencies in the literature are overviewed and new areas of research are discussed.Expert opinion: Studies investigating biomarkers that will accurately predict TBI patients with a high risk of PD are generally pilot studies with a small number of participants. Anti-pituitary and anti-hypothalamic antibodies, neural proteins, micro-RNAs are promising in this field. As severity of TBI has been the most commonly associated risk factor for post-TBI PD, we suggest prospective screening based on severity of head trauma until new evidence emerges. There is also a need for more studies investigating the clinical effects of hormone replacement in TBI patients with PD.

Disease-directed engineering for physiology-driven treatment interventions in neurological disorders

Neurological disease is killing us. While there have long been attempts to develop therapies for both acute and chronic neurological diseases, no current treatments are curative. Additionally, therapeutic development for neurological disease takes 15 years and often costs several billion dollars. More than 96% of these therapies will fail in late stage clinical trials. Engineering novel treatment interventions for neurological disease can improve outcomes and quality of life for millions; however, therapeutics should be designed with the underlying physiology and pathology in mind. In this perspective, we aim to unpack the importance of, and need to understand, the physiology of neurological disease. We first dive into the normal physiological considerations that should guide experimental design, and then assess the pathophysiological factors of acute and chronic neurological disease that should direct treatment design. We provide an analysis of a nanobased therapeutic intervention that proved successful in translation due to incorporation of physiology at all stages of the research process. We also provide an opinion on the importance of keeping a high-level view to designing and administering treatment interventions. Finally, we close with an implementation strategy for applying a disease-directed engineering approach. Our assessment encourages embracing the complexity of neurological disease, as well as increasing efforts to provide system-level thinking in our development of therapeutics for neurological disease.