Anterior pituitary hormone abnormalities following traumatic brain injury

Traumatic brain injury, abnormal growth hormone secretion, and gut dysbiosis

The gut microbiome has been implicated in a variety of neuropathologies with recent data suggesting direct effects of the microbiome on host metabolism, hormonal regulation, and pathophysiology. Studies have shown that gut bacteria impact host growth, partially mediated through the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis. However, no study to date has examined the specific role of GH on the fecal microbiome (FMB) or the changes in this relationship following a traumatic brain injury (TBI). Current literature has demonstrated that TBI can lead to either temporary or sustained abnormal GH secretion (aGHS). More recent literature has suggested that gut dysbiosis may contribute to aGHS leading to long-term sequelae now known as brain injury associated fatigue and cognition (BIAFAC). The aGHS observed in some TBI patients presents with a symptom complex including profound fatigue and cognitive dysfunction that improves significantly with exogenous recombinant human GH treatment. Notably, GH treatment is not curative as fatigue and cognitive decline typically recur upon treatment cessation, indicating the need for additional studies to address the underlying mechanistic cause.

Biomechanics of Traumatic Head and Neck Injuries on Women: A State-of-the-Art Review and Future Directions

The biomechanics of traumatic injuries of the human body as a consequence of road crashes, falling, contact sports, and military environments have been studied for decades. In particular, traumatic brain injury (TBI), the so-called "silent epidemic", is the traumatic insult responsible for the greatest percentage of death and disability, justifying the relevance of this research topic. Despite its great importance, only recently have research groups started to seriously consider the sex differences regarding the morphology and physiology of women, which differs from men and may result in a specific outcome for a given traumatic event. This work aims to provide a summary of the contributions given in this field so far, from clinical reports to numerical models, covering not only the direct injuries from inertial loading scenarios but also the role sex plays in the conditions that precede an accident, and post-traumatic events, with an emphasis on neuroendocrine dysfunctions and chronic traumatic encephalopathy. A review on finite element head models and finite element neck models for the study of specific traumatic events is also performed, discussing whether sex was a factor in validating them. Based on the information collected, improvement perspectives and future directions are discussed.

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.

Alterations of the GH/IGF-I Axis and Gut Microbiome after Traumatic Brain Injury: A New Clinical Syndrome?

CONTEXT

Pituitary dysfunction with abnormal growth hormone (GH) secretion and neurocognitive deficits are common consequences of traumatic brain injury (TBI). Recognizing the comorbidity of these symptoms is of clinical importance; however, efficacious treatment is currently lacking.

EVIDENCE ACQUISITION

A review of studies in PubMed published between January 1980 to March 2020 and ongoing clinical trials was conducted using the search terms "growth hormone," "traumatic brain injury," and "gut microbiome."

EVIDENCE SYNTHESIS

Increasing evidence has implicated the effects of TBI in promoting an interplay of ischemia, cytotoxicity, and inflammation that renders a subset of patients to develop postinjury hypopituitarism, severe fatigue, and impaired cognition and behavioral processes. Recent data have suggested an association between abnormal GH secretion and altered gut microbiome in TBI patients, thus prompting the description of a hypothesized new clinical syndrome called "brain injury associated fatigue and altered cognition." Notably, these patients demonstrate distinct characteristics from those with GH deficiency from other non-TBI causes in that their symptom complex improves significantly with recombinant human GH treatment, but does not reverse the underlying mechanistic cause as symptoms typically recur upon treatment cessation.

CONCLUSION

The reviewed data describe the importance of alterations of the GH/insulin-like growth factor I axis and gut microbiome after brain injury and its influence in promoting neurocognitive and behavioral deficits in a bidirectional relationship, and highlight a new clinical syndrome that may exist in a subset of TBI patients in whom recombinant human GH therapy could significantly improve symptomatology. More studies are needed to further characterize this clinical syndrome.

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.

Pituitary pathology in traumatic brain injury: a review

PURPOSE

Traumatic brain injury most commonly affects young adults under the age of 35 and frequently results in reduced quality of life, disability, and death. In long-term survivors, hypopituitarism is a common complication.

RESULTS

Pituitary dysfunction occurs in approximately 20-40% of patients diagnosed with moderate and severe traumatic brain injury giving rise to growth hormone deficiency, hypogonadism, hypothyroidism, hypocortisolism, and central diabetes insipidus. Varying degrees of hypopituitarism have been identified in patients during both the acute and chronic phase. Anterior pituitary hormone deficiency has been shown to cause morbidity and increase mortality in TBI patients, already encumbered by other complications. Hypopituitarism after childhood traumatic brain injury may cause treatable morbidity in those survivors. Prospective studies indicate that the incidence rate of hypopituitarism may be ten-fold higher than assumed; factors altering reports include case definition, geographic location, variable hospital coding, and lost notes. While the precise pathophysiology of post traumatic hypopituitarism has not yet been elucidated, it has been hypothesized that, apart from the primary mechanical event, secondary insults such as hypotension, hypoxia, increased intracranial pressure, as well as changes in cerebral flow and metabolism may contribute to hypothalamic-pituitary damage. A number of mechanisms have been proposed to clarify the causes of primary mechanical events giving rise to ischemic adenohypophysial infarction and the ensuing development of hypopituitarism.

CONCLUSION

Future research should focus more on experimental and clinical studies to elucidate the exact mechanisms behind post-traumatic pituitary damage. The use of preventive medical measures to limit possible damage in the pituitary gland and hypothalamic pituitary axis in order to maintain or re-establish near normal physiologic functions are crucial to minimize the effects of TBI.

Phase 2 Randomized, Placebo-Controlled Clinical Trial of Recombinant Human Growth Hormone (rhGH) During Rehabilitation From Traumatic Brain Injury

Traumatic brain injury (TBI) is a major cause of death and disability, but there are currently no therapies with proven efficacy for optimizing regeneration of repair during rehabilitation. Using standard stimulation tests, as many as 40-50% of survivors of severe TBI have deficiency of one or more pituitary hormones. Of these, the somatotropic axis is the most commonly affected, with Growth Hormone (GH) deficiency affecting ~20% of persons with severe TBI. Treatment with recombinant human Growth Hormone (rhGH) is generally effective in reversing the effects of acquired GH deficiency, but there is no evidence documenting functional or neurocognitive improvement after GH replacement in TBI patients. As a consequence, screening for GH deficiency and GH replacement when deficiency is found is not routinely performed as part of the rehabilitation of TBI survivors. Given that most of the recovery after TBI occurs within the first 6-12 months after injury and IGF-1 and GH are part of a coordinated restorative neurotrophic system, we hypothesized that patients will optimally benefit from GH therapy during the window of maximal neuroregenerative activity. We performed a Phase IIa, randomized, double-blind, placebo-controlled feasibility trial of recombinant human Growth Hormone (rhGH), starting at discharge from an inpatient rehabilitation unit, with follow up at 6 and 12 months. Our primary hypothesis was that treatment with rhGH in the subacute period would result in improved functional outcomes 6 months after injury. Our secondary hypothesis proposed that treatment with rhGH would increase IGF-1 levels and be well tolerated. Sixty-three subjects were randomized, and 40 completed the trial. At baseline, there was no correlation between IGF-1 levels and peak GH levels after L-arginine stimulation. IGF-1 levels increased after rhGH treatment, but it took longer than 1 month for levels to be higher than for placebo-treated patients. rhGH therapy was well-tolerated. The rhGH group was no different from placebo in the Disability Rating Scale, Glasgow Outcome Scale-Extended, or neuropsychological function. However, a trend toward greater improvement from baseline in Functional Independence Measure (FIM) was noted in the rhGH treated group. Future studies should include longer treatment periods, faster titration of rhGH, and larger sample sizes.

Chronic Hypopituitarism Associated with Increased Postconcussive Symptoms Is Prevalent after Blast-Induced Mild Traumatic Brain Injury

The most frequent injury sustained by US service members deployed to Iraq or Afghanistan is mild traumatic brain injuries (mTBI), or concussion, by far most often caused by blast waves from improvised explosive devices or other explosive ordnance. TBI from all causes gives rise to chronic neuroendocrine disorders with an estimated prevalence of 25-50%. The current study expands upon our earlier finding that chronic pituitary gland dysfunction occurs with a similarly high frequency after blast-related concussions. We measured circulating hormone levels and accessed demographic and testing data from two groups of male veterans with hazardous duty experience in Iraq or Afghanistan. Veterans in the mTBI group had experienced one or more blast-related concussion. Members of the deployment control (DC) group encountered similar deployment conditions but had no history of blast-related mTBI. 12 of 39 (31%) of the mTBI participants and 3 of 20 (15%) veterans in the DC group screened positive for one or more neuroendocrine disorders. Positive screens for growth hormone deficiency occurred most often. Analysis of responses on self-report questionnaires revealed main effects of both mTBI and hypopituitarism on postconcussive and posttraumatic stress disorder (PTSD) symptoms. Symptoms associated with pituitary dysfunction overlap considerably with those of PTSD. They include cognitive deficiencies, mood and anxiety disorders, sleep problems, diminished quality of life, deleterious changes in metabolism and body composition, and increased cardiovascular mortality. When such symptoms are due to hypopituitarism, they may be alleviated by hormone replacement. These findings suggest consideration of routine post-deployment neuroendocrine screening of service members and veterans who have experienced blast-related mTBI and are reporting postconcussive symptoms.

Analysis of Factors Related to Hypopituitarism in Patients with Nonsellar Intracranial Tumor

OBJECTIVE

Previous studies have suggested that postoperative hypopituitarism in patients with nonsellar intracranial tumors is caused by traumatic surgery. However, with development of minimally invasive and precise neurosurgical techniques, the degree of injury to brain tissue has been reduced significantly, especially for parenchymal tumors. Therefore, understanding preexisting hypopituitarism and related risk factors can improve perioperative management for patients with nonsellar intracranial tumors.

METHODS

Chart data were collected retrospectively from 83 patients with nonsellar intracranial tumors admitted to our hospital from May 2014 to April 2015. Pituitary function of each subject was determined based on results of preoperative serum pituitary hormone analysis. Univariate and multivariate logistic regression methods were used to analyze relationships between preoperative hypopituitarism and factors including age, sex, history of hypertension and secondary epilepsy, course of disease, tumor mass effect, site of tumor, intracranial pressure (ICP), cerebrospinal fluid content, and pituitary morphology.

RESULTS

A total of 30 patients (36.14%) presented with preoperative hypopituitarism in either 1 axis or multiple axes; 23 (27.71%) were affected in 1 axis, and 7 (8.43%) were affected in multiple axes. Univariate analysis showed that risk factors for preoperative hypopituitarism in patients with a nonsellar intracranial tumor include an acute or subacute course (≤3 months), intracranial hypertension (ICP >200 mm H₂O), and mass effect (P < 0.05). Multivariate logistic regression analysis showed that mass effect is an independent risk factor for preoperative hypopituitarism in patients with nonsellar intracranial tumors (P < 0.05; odds ratio, 3.197).

CONCLUSIONS

Prevalence of hypopituitarism is high in patients with nonsellar intracranial tumors. The occurrence of hypopituitarism is correlated with factors including an acute or subacute course (≤3 months), intracranial hypertension (ICP >200 mm H₂O), and mass effect (P < 0.05). Mass effect is an independent risk factor for hypopituitarism.

[Stress adaptive effects after traumatic brain injury]

Neuroendocrine dysfunction, in particular impaired synthesis of anterior pituitary hormones, is a common complication of traumatic brain injury. Deficiency of tropic pituitary hormones entails a hypofunction of the related peripheral endocrine glands and can be accompanied by persistent endocrine and metabolic disorders. In particular, the hypophyseal mechanisms are the key ones in implementation of most stress effects. Adequate implementation of these mechanisms largely determines a favorable outcome in the acute stage of disease. Traumatic brain injury (as well as any significant injury) initiates a stress response that can not develop in full in the case of pituitary gland failure. It is logical to suppose that the course of the acute phase of stress in the presence of hypopituitarism is different to a certain extent from the typical course, which inevitably affects certain adaptation elements. In this review, we analyzed the adaptive effects of stress after traumatic brain injury.

Decreased apparent diffusion coefficient in the pituitary and correlation with hypopituitarism in patients with traumatic brain injury

OBJECT

The relationship between microstructural abnormality in patients with traumatic brain injury (TBI) and hormone-secreting status remains unknown. In this study, the authors aimed to identify the role of the apparent diffusion coefficient (ADC) using a diffusion-weighted imaging (DWI) technique and to evaluate the association of such changes with hypopituitarism in patients with TBI.

METHODS

Diffusion-weighted images were obtained in 164 consecutive patients with TBI within 2 weeks after injury to generate the pituitary ADC as a measure of microstructural change. Patients with TBI were further grouped into those with and those without hypopituitarism based on the secretion status of pituitary hormones at 6 months postinjury. Thirty healthy individuals were enrolled in the study and underwent MRI examinations for comparison. Mean ADC values were compared between this control group, the patients with TBI and hypopituitarism, and the patients with TBI without hypopituitarism; correlational studies were also performed. Neurological outcome was assessed with the Glasgow Outcome Scale (GOS) for all TBI patients 6 months postinjury.

RESULTS

In the TBI group, 84 patients had hypopituitarism and 80 had normal pituitary function. The pituitary ADC in TBI patients was significantly less than that in controls (1.83 ± 0.16 vs 4.13 ± 0.33, p < 0.01). Furthermore, the mean ADC was much lower in TBI patients with hypopituitarism than in those without pituitary dysfunction (1.32 ± 0.09 vs 2.28 ± 0.17, p < 0.05). There was also a significant difference in ADC values between patients with hyperprolactinemia and those with normal prolactin levels (p < 0.05). Additionally, the receiver operating characteristic curve analysis showed that the pituitary ADC could predict hypopituitarism with a sensitivity of 90.0% and a specificity of 90.1% at the level of 1.720 (ADC value). Finally, the ADC value was positively correlated with neurological outcome at 6 months following TBI (r = 0.602, p < 0.05).

CONCLUSIONS

Use of DWI demonstrated that the pituitary ADC is correlated with hormone-secreting status in TBI patients. The authors suggest that pituitary ADC may be a useful biomarker to predict pituitary function in patients with TBI.

Prospective investigation of anterior pituitary function in the acute phase and 12 months after pediatric traumatic brain injury

PURPOSE

Although head trauma is common in childhood, there is no enough prospective study investigating both acute phase and 12 months after injury. Therefore, a prospective clinical trial was planned to evaluate the pituitary function in childhood in the acute and chronic phase after traumatic brain injury (TBI).

METHODS

Forty-one children (27 boys and 14 girls, mean age 7 ± 4.3), who were admitted to neurosurgery intensive care unit due to head trauma, were included. Twenty-one (51.2 %) patients had mild, 10 (24.4 %) had moderate, and 10 (24.4 %) had severe TBI. Twenty-two of them were reevaluated 12 months after TBI. Basal pituitary hormone levels were measured during acute (first 24 h) and chronic phase of TBI. Additionally, in the chronic phase, GHRH-arginine test was used for the diagnosis of growth hormone (GH) deficiency.

RESULTS

In the acute phase, 10 patients (24.4 %) had ACTH deficiency, and the overall 44.3 % of patients had at least one pituitary hormone dysfunction. All the pituitary hormone deficiencies during the acute phase were recovered after 12 months. Two patients (9.1 %) had new-onset GH deficiency in the chronic phase, and in one of them, ACTH deficiency was also present.

CONCLUSIONS

Present prospective data clearly demonstrated that most of the hormonal changes in the early acute phase were transient, suggesting an adaptive response, and these changes did not predict the hormone deficiencies after 1 year. In the chronic phase, although GH deficiency was present, the frequency of TBI-induced hypopituitarism was clearly lower than the adult patients.

Neuropsychological recovery and quality-of-life in children and adolescents with growth hormone deficiency following TBI: a preliminary study

OBJECTIVE

To compare neurocognition and quality-of-life (QoL) in a group of children and adolescents with or without growth hormone deficiency (GHD) following moderate-to-severe traumatic brain injury (TBI).

STUDY DESIGNS

Thirty-two children and adolescents were recruited from the TBI clinic at a children's hospital. Growth hormone (GH) was measured by both spontaneous overnight testing and following arginine/glucagon stimulation administration. Twenty-nine subjects participated in extensive neuropsychological assessment.

RESULTS

GHD as measured on overnight testing was significantly associated with a variety of neurocognitive and QoL measures. Specifically, subjects with GHD had significantly (p < 0.05) lower scores on measures of visual memory and health-related quality-of-life. These scores were not explained by severity of injury or IQ (p > 0.05). GHD noted in response to provocative testing was not associated with any neurocognitive or QoL measures.

CONCLUSIONS

GHD following TBI is common in children and adolescents. Deficits in neurocognition and QoL impact recovery after TBI. It is important to assess potential neurocognitive and QoL changes that may occur as a result of GHD. It is also important to consider the potential added benefit of overnight GH testing as compared to stimulation testing in predicting changes in neurocognition or QoL.

Innovations in organ donation

The growing disparity between organ availability for transplantation and the number of patients in need has challenged the donation and transplantation community of practice to develop innovative processes, ideas, and techniques to bridge the gaps. Advances in the sharing of best practices in the donation community have contributed greatly over the last 8 years. Broader sharing of updated guidelines for declaration of brain death in conjunction with improvements in deceased donor management have increased opportunities for organ donation. New techniques for organ preservation and organ resuscitation have allowed for better utilization of the potential donor pool. This review will highlight processes, ideas, and techniques in organ donation.

Hypopituitarism following brain injury: when does it occur and how best to test?

Aim of this review is to highlight how and when Traumatic Brain Injury (TBI) as well as Subarachnoid Haemorrhage (SAH) and primary Brain Tumours (pBT) of the Central Nervous System (CNS) can induce hypopituitarism, an under-diagnosed clinical problem. Moreover, this review aims to clarify, on the basis of the recent evidences, how these patients have to be tested for pituitary-function. Both retrospective and prospective studies recommended that patients with more severe form of Brain Injuries (BI) and in particular, those with fractures of the base of the skull or early diabetes insipidus, have to be closely monitored for signs and symptoms of endocrine dysfunction. Further studies will be crucial to raise awareness and remind physicians on the prevalence of hypopituitarism in patients with BI and to elucidate any incremental benefits these patients may receive from hormone replacement.

High prevalence of chronic pituitary and target-organ hormone abnormalities after blast-related mild traumatic brain injury

Studies of traumatic brain injury from all causes have found evidence of chronic hypopituitarism, defined by deficient production of one or more pituitary hormones at least 1 year after injury, in 25–50% of cases. Most studies found the occurrence of posttraumatic hypopituitarism (PTHP) to be unrelated to injury severity. Growth hormone deficiency (GHD) and hypogonadism were reported most frequently. Hypopituitarism, and in particular adult GHD, is associated with symptoms that resemble those of PTSD, including fatigue, anxiety, depression, irritability, insomnia, sexual dysfunction, cognitive deficiencies, and decreased quality of life. However, the prevalence of PTHP after blast-related mild TBI (mTBI), an extremely common injury in modern military operations, has not been characterized. We measured concentrations of 12 pituitary and target-organ hormones in two groups of male US Veterans of combat in Iraq or Afghanistan. One group consisted of participants with blast-related mTBI whose last blast exposure was at least 1 year prior to the study. The other consisted of Veterans with similar military deployment histories but without blast exposure. Eleven of 26, or 42% of participants with blast concussions were found to have abnormal hormone levels in one or more pituitary axes, a prevalence similar to that found in other forms of TBI. Five members of the mTBI group were found with markedly low age-adjusted insulin-like growth factor-I (IGF-I) levels indicative of probable GHD, and three had testosterone and gonadotropin concentrations consistent with hypogonadism. If symptoms characteristic of both PTHP and PTSD can be linked to pituitary dysfunction, they may be amenable to treatment with hormone replacement. Routine screening for chronic hypopituitarism after blast concussion shows promise for appropriately directing diagnostic and therapeutic decisions that otherwise may remain unconsidered and for markedly facilitating recovery and rehabilitation.

Assessment of endocrine abnormalities in severe traumatic brain injury: a prospective study

OBJECTIVE

The frequency and pattern of endocrine abnormalities among patients with traumatic brain injury have been the subject matter of very few studies. This study was intended to assess the pattern of endocrine dysfunction following severe head injury.

METHODS

Severe head injury patients admitted to the Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, from January to December in 1 year formed the study group. Apart from clinical assessment, NCCT of the head was performed on all patients on admission. A complete anterior pituitary hormone analysis was performed within 24 h of injury and was repeated at 2 weeks, 3 months and 6 months amongst patients who survived.

RESULTS

A total of 99 patients were included in the study. Forty of our patients succumbed in the hospital. Rest of the patients were followed up for 6 months. Elevations of cortisol followed by prolactin were the most common hormonal derangements at admission. Midline shift on CT scans was inversely related to cortisol elevation and directly related to GH elevation. Infarct on CT scans was inversely related to cortisol and LH elevation. A significant alteration was found in the decreasing trend of the mean T4 values and normalisation or a decreasing trend from initially elevated mean cortisol and GH levels during follow-up (p < 0.05).

CONCLUSIONS

This study reveals that abnormalities in hormonal profiles appear to be relatively common in severe traumatic brain injury and fluctuate significantly over at least 6 months; there is a correlation with age and radiological findings. Performance of hormonal analysis evaluation should be considered in patients with severe brain injury so that appropriate hormonal replacement can be done to optimise the clinical outcome.

Cognitive deterioration due to GH deficiency in patients with traumatic brain injury: A preliminary report

PRIMARY OBJECTIVE

To determine whether cognitive and behavioural disorders observed in TBI patients are due to hormonal deficits or to the brain injury itself.

RESEARCH DESIGN

Transversal, between-group design.

METHODS AND PROCEDURES

Studied 22 severe TBI patients (GCS < 8): 11 had isolated GH deficiency and 11 did not. Prepared detailed clinical reports on patients and performed physical examinations, standard biochemical and full blood count analysis. Patients underwent neuropsychological assessment and hormonal evaluation 6 months after TBI diagnosis.

RESULTS

TBI patients with GH deficiency show greater deficits in attention, executive functioning, memory and emotion than those without GH deficiency.

CONCLUSIONS

Results show GH-related cognitive impairment in patients who develop GH deficiency after TBI and suggest that treatment of GH deficiency would improve cognition. The clinical importance of these findings should be established to better understand the nature, magnitude and meaning of GH-related cognitive impairment in patients who develop GH deficiency after TBI.

[Assessment of hypothalamo-pituitary axis in early phase of severe cranioencephalic brain injury]

OBJECTIVE

To assess early pituitary function in a sequential cohort of critical care patients after severe traumatic brain injury (TBI).

DESIGN

This was a prospective observational study. The pituitary function was always tested on the third day after TBI.

SETTING

Neurocritical intensive care unit (ICU) in a University hospital.

PATIENTS

A total of 136 adult patients with severe TBI (range, 16-65 years) enrolled over a 2 year and 9 month period having a stay in the ICU treated than 48 hours.

INTERVENTION

None. MEASUREMENTS AND DATA COLLECTED: The following data were recorded within the first 72 hours after injury: demographic variables, injury severity, neuromonitoring data, systemic secondary brain insults, use of vasoactive drugs and type of TBI according to the computerized tomography (CT) scan findings. Pituitary function was evaluated by measurement of both the pituitary and target organ hormones, with the exception of the somatotrophic function, which was assessed by measurement of basal serum values of insulin-like growth factor-I (IGF-I).

RESULTS

Pituitary dysfunction was observed in 101 patients (74.2%). Seventy-nine patients (58%) had impairment of only one pituitary axis, the axes being affected as follows: gonadotropic 63.7% (87 patients), thyrotropic 8.8% (12 patients) and corticotropic 0.7% (1 patient). Low IGF-1 plasmatic levels in accordance to the patient's age were observed in 90 patients (66.7%). However, only 26 of them had a value below 90 ng/ml.

CONCLUSIONS

Our data show that pituitary dysfunction occurs early and with high frequency after severe TBI, but the real significance of these findings still needs to be elucidated.

Histologic study of the human pituitary gland in acute traumatic brain injury

PURPOSE

Approximately 25% of patients with traumatic brain injury (TBI) may develop partial or complete hypopituitarism. The causative mechanisms involved in its development are not clear. To the authors' knowledge, there have been no recent morphologic studies of the pituitary following TBI.

METHODS

To characterize the resultant histologic changes, this study investigated the pituitaries of 42 patients who died following a motor vehicle accident, all from the Mayo Tissue Registry. Twelve patients died instantly at the scene of the accident (Group I) whereas 30 survived between 3 hours and 7 days (Group II). All pituitary specimens were obtained at autopsy, formalin-fixed and paraffin-embedded. Hematoxylin-eosin sections cut in horizontal or sagittal plane were examined light-microscopically.

RESULTS

No infarction was noted in the pituitary specimens from group I. In group II, 13 of 30 (43%) showed acute infarcts of varying size. The extent of infarction in group II ranged from focal to sub-total necrosis involving 90% of the adenohypophysis.

CONCLUSIONS

Underlying adenohypophysial pathology in patients dying after TBI is acute infarction. Loss of large numbers of adenohypophysial cells causes reduced secretion of adenohypophysial hormones and may contribute to post-traumatic hypopituitarism.

Predictors of anterior pituitary insufficiency after traumatic brain injury

BACKGROUND

Several studies have reported a high prevalence of hypopituitarism after traumatic brain injury (TBI). Risk stratification is a prerequisite for cost-effective hormonal screening of these patients. However, it is still unclear which risk factors predispose patients to develop anterior hypopituitarism after TBI.

OBJECTIVE

To assess clinical and radiological risk factors for post-traumatic hypopituitarism.

PATIENTS AND METHODS

Seventy-eight consecutive patients (52 men, 26 women; mean age 36.0 years, range 18-65 years) with mild, moderate or severe TBI were studied. Endocrine and clinical parameters were assessed 3 and 12 months after TBI.

RESULTS

We found diffuse axonal injury, basal skull fracture and older age to be major risk factors of post-traumatic hypopituitarism.

CONCLUSIONS

We have defined specific risk factors for the development of post-traumatic hypopituitarism that are consistent with pathophysiological considerations. These findings might help to identify at-risk patients.

Acute and long-term pituitary insufficiency in traumatic brain injury: a prospective single-centre study

OBJECTIVE

To assess the prevalence of hypopituitarism following traumatic brain injury (TBI), describe the time-course and assess the association with trauma-related parameters and early post-traumatic hormone alterations.

DESIGN

A 12-month prospective study.

PATIENTS

Forty-six consecutive patients with TBI (mild: N = 22; moderate: N = 9; severe: N = 15).

MEASUREMENTS

Baseline and stimulated hormone concentrations were assessed in the early phase (0-12 days post-traumatically), and at 3, 6 and 12 months postinjury. Pituitary tests included the Synacthen-test (acute +6 months) and the insulin tolerance test (ITT) or the GHRH + arginine test if the ITT was contraindicated (3 + 12 months). Insufficiencies were confirmed by retesting.

RESULTS

Early post-traumatic hormone alterations mimicking central hypogonadism or hypothyroidism were present in 35 of the 46 (76%) patients. Three months post-traumatically, 6 of the 46 patients failed anterior pituitary testing. At 12 months, one patient had recovered, whereas none developed new insufficiencies. All insufficient patients had GH deficiency (5 out of 46), followed by ACTH- (3 out of 46), TSH- (1 out of 46), LH/FSH- (1 out of 46) and ADH deficiency (1 out of 46). Hypopituitary patients had more frequently been exposed to severe TBI (4 out of 15) than to mild or moderate TBI (1 out of 31) (P = 0.02). Early endocrine alterations including lowered thyroid and gonadal hormones, and increased total cortisol, free cortisol and copeptin were positively associated to TBI severity (P < 0.05), but not to long-term development of hypopituitarism (P > 0.1), although it was indicative in some.

CONCLUSION

Long-term hypopituitarism was frequent only in severe TBI. During the 3-12 months follow-up, recovery but no new insufficiencies were recorded, indicating manifest hypothalamic or pituitary damage already a few months postinjury. Very early hormone alterations were not associated to long-term post-traumatic hypopituitarism. Clinicians should, nonetheless, be aware of potential ACTH deficiency in the early post-traumatic period.

Hypopituitarism

Incidence and prevalence of hypopituitarism are estimated to be 4.2 per 100,000 per year and 45.5 per 100,000, respectively. Although the clinical symptoms of this disorder are usually unspecific, it can cause life-threatening events and lead to increased mortality. Current research has refined the diagnosis of hypopituitarism. Identification of growth hormone and corticotropin deficiency generally requires a stimulation test, whereas other deficiencies can be detected by basal hormones in combination with clinical judgment. Newly developed formulations of replacement hormones are convenient and physiological. Work has shown that many patients with brain damage--such as traumatic brain injury or aneurysmal subarachnoid haemorrhage--are at high risk of (sometimes unrecognised) hypopituitarism. Thus, a much increased true prevalence of this disorder needs to be assumed. As a result, hypopituitarism is not a rare disease and should be recognised by the general practitioner.

Abnormalities of pituitary function after traumatic brain injury in children

Traumatic brain injury (TBI) is a frequent cause of neuroendocrine dysfunction typically in male adults. Head injuries are also common in childhood, but only a few case reports outlined the endocrine consequences. The aim of this study was to reveal anterior pituitary function in children with history of hospitalization due to mild to severe head trauma. Our endocrine follow-up study was performed between October 2003 and February 2004 in the Pediatric Department of Petz Aladár County Teaching Hospital, Gyor, Hungary. Twenty-six children (17 boys and nine girls, aged 11.47 +/- 0.75 years) at 30.6 +/- 8.3 months after head injury and 21 age-matched controls were enrolled. Basal and stimulated anterior pituitary and peripheral hormone concentrations were measured by routine laboratory methods. Pituitary dysfunction was detected in 61% of patients with TBI history. All growth hormone (GH) parameters measured and calculated were significantly (p < 0.05) lower in TBI group than in controls after L-DOPA stimulation. Similar difference was detected 60 min after insulin provocation. Forty-two percent of all TBI children showed insufficient growth hormone (GH) response in both stimulation tests, 73% of these cases were boys. Cortisol levels of TBI patients were significantly (p < 0.05) lower all through the insulin test than values measured in control group. The degree of pituitary dysfunction was independent from the severity of TBI. Our study confirms the high risk for hypopituitarism in children with TBI despite the lack of obvious clinical symptoms. We suggest screening of pituitary function after any kind of brain trauma requiring hospitalization in childhood.

Anterior pituitary hormone replacement therapy--a clinical review

This clinical review summarizes current approaches to diagnosis and treatment of anterior pituitary hormone deficiency. The diagnostic value of endocrine function tests and replacement strategies for hydrocortisone, thyroxine, sex steroids, and growth hormone replacement are reviewed. Female androgen deficiency syndrome and the current role of DHEA and testosterone replacement in women are also discussed.

Neurobehavioral and quality of life changes associated with growth hormone insufficiency after complicated mild, moderate, or severe traumatic brain injury

Adult-onset growth hormone deficiency (GHD) has been associated with reduced quality of life (QOL) and neurobehavioral (NB) deficits. This prospective study tested the hypothesis that traumatic brain injury (TBI) patients with GHD or GH insufficiency (GHI) would exhibit greater NB/QOL impairment than patients without GHD/GHI. Complicated mild, moderate, and severe adult TBI patients (GCS score 3-14) had pituitary function and NB/QOL testing performed 6-9 months postinjury. GH-secretory capacity was assessed with a GHRH-arginine stimulation test and GHD and GHI were defined as peak GH<6 or <or=12 ng/mL (5th and 10th percentiles of healthy control subjects, respectively). Of 44 patients (mean age, 32+/-18 years; median GCS, 7), one (2%) was GHD, seven (16%) were GHI, and 36 (82%) were GH-sufficient at 6-9 months post-injury. Mean peak GH was 8.2+/-2.1 ng/mL in the GHD/GHI group versus 45.7+/-29 ng/mL in the GHsufficient group. The two groups were well-matched in injury characteristics, except that one patient with GHD had central hypogonadism treated with testosterone prior to NB/QOL testing. At 6-9 months postinjury, patients with GHD/GHI had higher rates of at least one marker of depression (p<0.01), and reduced QOL (by SF-36 Health Survey) in the domains of limitations due to physical health (p=0.02), energy and fatigue (p=0.05), emotional well-being (p=0.02), pain (p=0.01), and general health (p=0.05). Chronic GHI develops in approximately 18% of patients with complicated mild, moderate, or severe TBI, and is associated with depression and diminished QOL. The impact of GH replacement therapy on NB function and QOL in these TBI patients is being tested in a randomized placebo-controlled trial.

Hypopituitarism after acute brain injury

Acute brain injury has many causes, but the most common is trauma. There are 1.5-2.0 million traumatic brain injuries (TBI) in the United States yearly, with an associated cost exceeding 10 billion dollars. TBI is the most common cause of death and disability in young adults less than 35 years of age. The consequences of TBI can be severe, including disability in motor function, speech, cognition, and psychosocial and emotional skills. Recently, clinical studies have documented the occurrence of pituitary dysfunction after TBI and another cause of acute brain injury, subarachnoid hemorrhage (SAH). These studies have consistently demonstrated a 30-40% occurrence of pituitary dysfunction involving at least one anterior pituitary hormone following a moderate to severe TBI or SAH. Growth hormone (GH) deficiency is the most common pituitary hormone disorder, occurring in approximately 20% of patients when multiple tests of GH deficiency are used. Within 7-21 days of acute brain injury, adrenal insufficiency is the primary concern. Pituitary function can fluctuate over the first year after TBI, but it is well established by 1 year. Studies are ongoing to assess the effects of hormone replacement on motor function and cognition in TBI patients. Any subject with a moderate to severe acute brain injury should be screened for pituitary dysfunction.