Acute secondary adrenal insufficiency after traumatic brain injury: a prospective study

Single-dose etomidate for intubation in the trauma patient

BACKGROUND

Concerns over adrenal suppression caused by a single dose of etomidate for intubation led to limiting its use in trauma patients in 2006.

OBJECTIVE

The purpose of this study was to compare mortality, hypotension, and intensive care unit (ICU) and hospital length of stay (LOS) for trauma patients requiring intubation during periods of liberal vs. limited etomidate use.

METHODS

A retrospective review of trauma patients requiring emergent intubation who presented between August 2004 and December 2008, before and after we decided to limit the use of etomidate. Data were collected on patient demographics, induction agents used, episodes of hypotension in the first 24h, ICU and total hospital LOS, and survival.

RESULTS

Of 1325 trauma patients intubated in the Emergency Department during the study period, 443 occurred during the 23 months before July 2006 (liberal etomidate use) and 882 in the 30 months after July 2006 (limited etomidate use). During the liberal use period, 258/443 (58%) were intubated using etomidate, compared to 205/882 (23%, p<0.0001) during the period of limited use. We found no significant differences in mortality (30% vs. 29%, p=0.70), mean ICU days (8.2 vs. 8.8, p=0.356), or mean hospital LOS (13.8 vs. 14.4 days, p=0.55). Episodes of hypotension were more common in the limited etomidate use group (45% vs. 33%, p<0.0001).

CONCLUSIONS

A significant reduction in the use of etomidate in trauma patients was not associated with differences in mortality, ICU days, or hospital LOS, but was associated with an increase in episodes of hypotension within 24h of presentation.

Pathophysiology of hypopituitarism in the setting of brain injury

The complex pathophysiology of traumatic brain injury (TBI) involves not only the primary mechanical event but also secondary insults such as hypotension, hypoxia, raised intracranial pressure and changes in cerebral blood flow and metabolism. It is increasingly evident that these initial insults as well as transient events and treatments during the early injury phase can impact hypothalamic-pituitary function both acutely and chronically after injury. In turn, untreated pituitary hormonal dysfunction itself can further hinder recovery from brain injury. Secondary adrenal insufficiency, although typically reversible, occurs in up to 50% of intubated TBI victims and is associated with lower systemic blood pressure. Chronic anterior hypopituitarism, although reversible in some patients, persists in 25-40% of moderate and severe TBI survivors and likely contributes to long-term neurobehavioral and quality of life impairment. While the rates and risk factors of acute and chronic pituitary dysfunction have been documented for moderate and severe TBI victims in numerous recent studies, the pathophysiology remains ill-defined. Herein we discuss the hypotheses and available data concerning hypothalamic-pituitary vulnerability in the setting of head injury. Four possible pathophysiological mechanisms are considered: (1) the primary brain injury event, (2) secondary brain insults, (3) the stress of critical illness and (4) medication effects. Although each of these factors appears to be important in determining which hormonal axes are affected, the severity of dysfunction, their time course and possible reversibility, this process remains incompletely understood.

Corticotherapy for traumatic brain-injured patients--the Corti-TC trial: study protocol for a randomized controlled trial

Background

Traumatic brain injury (TBI) is a main cause of severe prolonged disability of young patients. Hospital acquired pneumonia (HAP) add to the morbidity and mortality of traumatic brain-injured patients. In one study, hydrocortisone for treatment of traumatic-induced corticosteroid insufficiency (CI) in multiple injured patients has prevented HAP, particularly in the sub-group of patients with severe TBI. Fludrocortisone is recommended in severe brain-injured patients suffering from acute subarachnoid hemorrhage. Whether an association of hydrocortisone with fludrocortisone protects from HAP and improves neurological recovery is uncertain. The aim of the current study is to compare corticotherapy to placebo for TBI patients with CI.

Methods

The CORTI-TC (Corticotherapy in traumatic brain-injured patients) trial is a multicenter, randomized, placebo controlled, double-blind, two-arms study. Three hundred and seventy six patients hospitalized in Intensive Care Unit with a severe traumatic brain injury (Glasgow Coma Scale ≤ 8) are randomized in the first 24 hours following trauma to hydrocortisone (200 mg.day^-1 for 7 days, 100 mg on days 8-9 and 50 mg on day-10) with fludrocortisone (50 μg for 10 days) or double placebo. The treatment is stopped if patients have an appropriate adrenal response. The primary endpoint is HAP on day-28. The endpoint of the ancillary study is the neurological status on 6 and 12 months.

Discussion

The CORTI-TC trial is the first randomized controlled trial powered to investigate whether hydrocortisone with fludrocortisone in TBI patients with CI prevent HAP and improve long term recovery.

Trial registration

NCT01093261

Pituitary dysfunction following traumatic brain injury or subarachnoid haemorrhage - in "Endocrine Management in the Intensive Care Unit"

Traumatic brain injury and subarachnoid haemorrhage are important causes of morbidity and mortality in the developed world. There is a large body of evidence that demonstrates that both conditions may adversely affect pituitary function in both the acute and chronic phases of recovery. Diagnosis of hypopituitarism and accurate treatment of pituitary disorders offers the opportunity to improve mortality and outcome in both traumatic brain injury and subarachnoid haemorrhage. In this article, we will review the history and pathophysiology of pituitary function in the acute phase following traumatic brain injury and subarachnoid haemorrhage, and we will discuss in detail three key aspects of pituitary dysfunction which occur in the early course of TBI; acute cortisol deficiency, diabetes insipidus and SIAD.

Pediatric traumatic brain injury: an update

PURPOSE OF REVIEW

The developing brain is particularly vulnerable to traumatic brain injury (TBI), leading to frequent disability or death. This article is an update of the pediatric specificities of TBI management.

RECENT FINDINGS

We review the evidences with regards to general management and therapeutic goals to prevent secondary injuries in pediatric TBI patients. Recent controversies in neurocritical care, such as multimodal neuromonitoring, hyperventilation, barbiturate coma, hypothermia, and decompressive surgery, are also highlighted.

SUMMARY

Many therapeutic modalities in pediatric TBI have a low level of evidence. Further research is needed to establish clear resuscitation goals. Universal objectives may not be suitable for all patients; intensive neuromonitoring may help in identifying individual therapeutic goals and guiding the selection of treatments.

The pathophysiology of concussions in youth

Mild traumatic brain injury, especially sport-related concussion, is common among young persons. Consequences of transient pathophysiologic dysfunction must be considered in the context of a developing or immature brain, as must the potential for an accumulation of damage with repeated exposure. This review summarizes the underlying neurometabolic cascade of concussion, with emphasis on the young brain in terms of acute pathophysiology, vulnerability, alterations in plasticity and activation, axonal injury, and cumulative risk from chronic, repetitive damage, and discusses their implications in the context of clinical care for the concussed youth, highlighting areas for future investigation.

Pituitary dysfunction after traumatic brain injury: screening and hormone replacement

This article highlights the risk of hypopituitarism in survivors of traumatic brain injury (TBI), an underdiagnosed clinical problem. Clinical evidence shows that anterior pituitary dysfunction is common in TBI survivors evaluated at least 6 months after the TBI, with an estimated prevalence of up to 27.5%. Although patients who suffer from moderate-to-severe TBI appear to be at higher risk, the emerging data suggest that mild-intensity trauma can also precede hypopituitarism. Since many of the symptoms of hypopituitarism are similar to those of TBI, it is important for clinicians to be aware of this clinical problem. Moreover, we will address questions such as when to screen and who should be screened, along with a discussion of current management of pituitary dysfunction in patients with TBI.

Acute serum hormone levels: characterization and prognosis after severe traumatic brain injury

Experimental traumatic brain injury (TBI) studies report the neuroprotective effects of female sex steroids on multiple mechanisms of injury, with the clinical assumption that women have hormonally mediated neuroprotection because of the endogenous presence of these hormones. Other literature indicates that testosterone may exacerbate injury. Further, stress hormone abnormalities that accompany critical illness may both amplify or blunt sex steroid levels. To better understand the role of sex steroid exposure in mediating TBI, we 1) characterized temporal profiles of serum gonadal and stress hormones in a population with severe TBI during the acute phases of their injury; and 2) used a biological systems approach to evaluate these hormones as biomarkers predicting global outcome. The study population was 117 adults (28 women; 89 men) with severe TBI. Serum samples (n=536) were collected for 7 days post-TBI for cortisol, progesterone, testosterone, estradiol, luteinizing hormone (LH), and follicle-stimulating hormone (FSH). Hormone data were linked with clinical data, including acute care mortality and Glasgow Outcome Scale (GOS) scores at 6 months. Hormone levels after TBI were compared to those in healthy controls (n=14). Group based trajectory analysis (TRAJ) was used to develop temporal hormone profiles that delineate distinct subpopulations in the cohort. Structural equations models were used to determine inter-relationships between hormones and outcomes within a multivariate model. Compared to controls, acute serum hormone levels were significantly altered after severe TBI. Changes in the post-TBI adrenal response and peripheral aromatization influenced hormone TRAJ profiles and contributed to the abnormalities, including increased estradiol in men and increased testosterone in women. In addition to older age and greater injury severity, increased estradiol and testosterone levels over time were associated with increased mortality and worse global outcome for both men and women. These findings represent a paradigm shift when thinking about the role of sex steroids in neuroprotection clinically after TBI.

The effect of etomidate on adrenal function in critical illness: a systematic review

PURPOSE

Although etomidate is a preferred anesthetic agent for rapid sequence intubation (RSI) in critical illness, as an inhibitor of cortisol synthesis (11β-hydroxylase), it may be associated with adrenal dysfunction. The objectives are to review the effects of etomidate versus comparator anesthetics in critical illness for: primary outcome of mortality and secondary outcome of adrenal insufficiency (AI).

METHODS

Studies were extracted using MEDLINE and SCOPUS, regardless of language, between 1983 and 2010 using the keywords etomidate, intensive care units (ICU), critical illness, intensive care, glucocorticoids, and adrenal insufficiency. Studies of single dose etomidate versus comparator anesthetics with outcomes of adrenal function and/or mortality were included. All reviewers performed electronic data searches. One reviewer extracted data, which were checked by the other reviewers. Authors of trials were contacted for supplemental data. Primary outcome was 28-day mortality. AI was defined per article.

RESULTS

Two hundred sixty-three articles were screened, and 21 articles (19 independent data sets) were evaluated. Meta-analysis comparing etomidate versus non-etomidate anesthesia demonstrated an increased risk ratio (RR) for AI of 1.64 (range 1.52-1.77; 14 studies, 2,854 patients, P<0.0001, I(2)=88%) and an increased RR for mortality of 1.19 (1.10-1.30; 14 studies, 3,516 patients, P<0.0001, I(2)=64%). Significance of re-analysis for mortality within the subset of sepsis was maintained [RR 1.22 (1.11-1.35), 7 studies, n=1,767, I(2)=74%, P<0.0001], but not for trials without sepsis [RR=1.15 (0.97-1.35), 7 studies, n=1,749, I(2)=53%, P=0.10].

CONCLUSIONS

There is an increased rate of AI and mortality in critically ill patients who received etomidate.

Loss of cortisol circadian rhythm in patients with traumatic brain injury: a microdialysis evaluation

BACKGROUND

Traumatic brain injury (TBI) is commonly associated with disturbances of the hypothalamic-pituitary-adrenal axis secretion. Cerebral microdialysis techniques have been recently applied to measure brain interstitial cortisol levels.

METHODS

We evaluated for the first time the circadian rhythm of cortisol secretion at 08:00, 16:00, and 24:00 h in the acute phase of TBI by determination of total serum and brain interstitial cortisol levels (microdialysis samples) in 10 patients with TBI. Non-parametric Friedman's two way analysis of variance test was used.

RESULTS

Mean age was 29.8 ± 13.6 years. Median Glasgow Coma Scale score after resuscitation was 5 (range 3-10). No differences were found in total serum (P = 0.26) and brain interstitial cortisol (P = 0.77) in the whole sample. Intraindividual analysis showed that circadian variability was lost in all patients, both in serum and brain interstitial cortisol samples in the acute phase after TBI.

CONCLUSION

In our series, circadian variability of cortisol evaluated by serum and cerebral microdialysis samples seems to be lost in TBI patients.

Heightening of the stress response during the first weeks after a mild traumatic brain injury

The effects of a mild traumatic brain injury range from white matter disruption to affective disorders. We set out to determine the response to restraint-induced stress after a mild fluid-percussion injury (FPI), an experimental model for brain injury. Hypothalamic-pituitary-adrenal (HPA) axis regulation of corticosterone (CORT) and adrenocorticotropic hormone (ACTH) was determined during the first post-injury weeks, which corresponds to the same time period when rehabilitative exercise has been shown to be ineffective after a mild FPI. Adult male rats underwent either an FPI or sham injury. Additional rats were only exposed to anesthesia. HPA regulation was evaluated by measuring the effects of dexamethasone (DEX) treatment on CORT and ACTH. Tail vein blood was collected following 30-min restraint stress, at post-injury days (PID) 1, 7 and 14, prior to (0 min) and at 30, 60, 90 and 120 min after stress onset. Results from these studies indicate that the stress response was significantly more pronounced after FPI in that CORT and ACTH restraint-induced increases were more pronounced and longer lasting compared to controls. DEX suppression of CORT and ACTH was observed in all groups, suggesting that stress hyper-responsiveness after mild FPI is not attributable to reduced sensitivity of CORT feedback regulation. The increased sensitivity to stressful events in the first two post-injury weeks after a mild FPI may have a negative impact on early rehabilitative therapies.

Assessment of the hypothalamic-pituitary-adrenal axis in critical illness

Cortisol is the main corticosteroid secreted from the human adrenal cortex, and it has a crucial role for survival in stressful conditions. An adequate increase in levels of cortisol helps patients to cope with the severity of the disease in the acute phase of critical illness. Either higher or lower than expected cortisol levels were found to be related to increased mortality. Prolonged activation of the hypothalamic-pituitary-adrenal (HPA) axis can result in hypercortisolemia or hypocortisolemia; both can be detrimental to recovery from critical illness. Primary and secondary adrenal insufficiency, relative adrenal insufficiency, tissue resistance to glucocorticoids, adrenocorticotrophic hormone deficiency and immune-mediated inhibition of the HPA axis can be the cause of the impairment of the secretion or action of cortisol in critically ill patients. Recently, some authors offered the term 'critical illness-related corticosteroid insufficiency' to better point out the relative adrenal insufficiency that is seen during critical illness. Patients with critical illness-related corticosteroid insufficiency not only have insufficient circulating cortisol but also have impaired cellular utilization of cortisol. In this article, how adrenal dysfunction presents in critical illness and how appropriate diagnosis and management can be achieved in the critical care setting will be discussed.

Injury severity differentially alters sensitivity to dexamethasone after traumatic brain injury

We have reported differential short- and long-term dysregulation of the neuroendocrine stress response after traumatic brain injury (TBI) produced by controlled cortical impact (CCI). We have now investigated three possible mechanisms for this TBI-induced dysregulation: (1) effects on the sensitivity of negative-feedback systems to glucocorticoids; (2) effects on the sensitivity of pituitary corticotrophs to corticotropin-releasing hormone (CRH); and (3) effects on neuronal loss in the hilar region of the dentate gyrus and in the CA3b layer of the dorsal hippocampus. TBI was induced to the left parietal cortex in adult male rats with a pneumatic piston, at two different impact velocities and compression depths, to produce either moderate or mild CCI. At 7 and 35 days after surgery, the rats were injected SC with the synthetic glucocorticoid analog dexamethasone (DEX; 0.01, 0.10, or 1.00 mg/kg) or saline, and 2 h later were subjected to 30 min of restraint stress and tail vein blood collection. Whereas all doses of DEX suppressed corticosterone (CORT) and adrenocorticotropic hormone (ACTH) responses to stress on both days, CORT and ACTH were significantly more suppressed after 0.01 mg/kg DEX in the moderate TBI group than in the mild TBI or sham groups. At both 7 and 35 days post-TBI, CRH (1.0 and 10.0 microg/kg IP) stimulated CORT and ACTH in all rats, regardless of injury condition. Hippocampal cell loss was greatest at 48 days after moderate TBI. Enhanced sensitivity to glucocorticoid negative feedback and greater hippocampal cell loss, but not altered pituitary responses to CRH, contribute to the short- and long-term attenuation of the neuroendocrine stress response following moderate TBI. The role of TBI-induced alterations in glucocorticoid receptors in limbic system sites in enhanced glucocorticoid feedback sensitivity requires further investigation.

Acute gonadotroph and somatotroph hormonal suppression after traumatic brain injury

Hormonal dysfunction is a known consequence of moderate and severe traumatic brain injury (TBI). In this study we determined the incidence, time course, and clinical correlates of acute post-TBI gonadotroph and somatotroph dysfunction. Patients had daily measurement of serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, estradiol, growth hormone, and insulin-like growth factor-1 (IGF-1) for up to 10 days post-injury. Values below the fifth percentile of a healthy cohort were considered abnormal, as were non-measurable growth hormone (GH) values. Outcome measures were frequency and time course of hormonal suppression, injury characteristics, and Glasgow Outcome Scale (GOS) score. The cohort consisted of 101 patients (82% males; mean age 35 years; Glasgow Coma Scale [GCS] score <or=8 in 87%). In men, 100% had at least one low testosterone value, and 93% of all values were low; in premenopausal women, 43% had at least one low estradiol value, and 39% of all values were low. Non-measurable GH levels occurred in 38% of patients, while low IGF-1 levels were observed in 77% of patients, but tended to normalize within 10 days. Multivariate analysis revealed associations of younger age with low FSH and low IGF-1, acute anemia with low IGF-1, and older age and higher body mass index (BMI) with low GH. Hormonal suppression was not predictive of GOS score. These results indicate that within 10 days of complicated mild, moderate, and severe TBI, testosterone suppression occurs in all men and estrogen suppression occurs in over 40% of women. Transient somatotroph suppression occurs in over 75% of patients. Although this acute neuroendocrine dysfunction may not be TBI-specific, low gonadal steroids, IGF-1, and GH may be important given their putative neuroprotective functions.

Dysfunction of hypothalamic-hypophysial axis after traumatic brain injury in adults

Object

Traumatic brain injury (TBI) is a major cause of serious morbidity and mortality. The incidence is 100–500/100,000 inhabitants/year. Chronic pituitary dysfunction is increasingly recognized after TBI. To define the incidence of endocrine dysfunction and risk factors, the authors describe a prospectively assessed group of patients in whom they documented hormonal functions, early diagnosis, and treatment of neuroendocrine dysfunction after TBI.

Methods

Patients aged 18–65 years were prospectively observed from the time of injury to 1 year postinjury; the Glasgow Coma Scale score ranged from 3 to 14. Patients underwent evaluation of hormonal function at the time of injury and at 3, 6, and 12 months postinjury. Magnetic resonance imaging was also conducted at 1 year postinjury.

Results

During the study period, 89 patients were observed. The mean age of the patients was 36 years, there were 23 women, and the median Glasgow Coma Scale score was 7. Nineteen patients (21%) had primary hormonal dysfunction. Major deficits included growth hormone dysfunction, hypogonadism, and diabetes insipidus. Patients in whom the deficiency was major had a worse Glasgow Outcome Scale score, and MR imaging demonstrated empty sella syndrome more often than in patients without a deficit.

Conclusions

To the authors' knowledge, this is the third largest study of its kind worldwide. The incidence of chronic hypopituitarism after TBI was higher than the authors expected. After TBI, patients are usually observed on the neurological and rehabilitative wards, and endocrine dysfunction can be overlooked. This dysfunction can be life threatening and other clinical symptoms can worsen the neurological deficit, extend the duration of physiotherapy, and lead to mental illness. The authors recommend routine pituitary hormone testing after moderate or severe TBI within 6 months and 1 year of injury.

Drug-induced endocrine disorders in the intensive care unit

The neuroendocrine response to critical illness is key to the maintenance of homeostasis. Many of the drugs administered routinely in the intensive care unit significantly impact the neuroendocrine system. These agents can disrupt the hypothalamic-pituitary-adrenal axis, cause thyroid abnormalities, and result in dysglycemia. Herein, we review major drug-induced endocrine disorders and highlight some of the controversies that remain in this area. We also discuss some of the more rare drug-induced syndromes that have been described in the intensive care unit. Drugs that may result in an intensive care unit admission secondary to an endocrine-related adverse event are also included. Unfortunately, very few studies have systematically addressed drug-induced endocrine disorders in the critically ill. Timely identification and appropriate management of drug-induced endocrine adverse events may potentially improve outcomes in the critically ill. However, more research is needed to fully understand the impact of medications on endocrine function in the intensive care unit.

Contemporary pharmacologic issues in the management of traumatic brain injury

Traumatic brain injury (TBI) is a major cause of death and disability in the United States. While there are no pharmacotherapeutic options currently available for attenuating the neurologic injury cascade after TBI, numerous pharmacologic issues are encountered in these critically ill patients. Adequate fluid resuscitation, reversal of coagulopathy, maintenance of cerebral perfusion, and treatment of intracranial hypertension are common interventions early in the treatment of TBI. Other deleterious complications such as venous thromboembolism, extremes in glucose concentrations, and stress-related mucosal disease should be anticipated and avoided. Early provision of nutrition and prevention of drug or alcohol withdrawal are also cornerstones of routine care in TBI patients. Prevention of infections and seizures may also be helpful. Clinicians caring for TBI patients should be familiar with the pharmacologic issues typical of this vulnerable population in order to develop optimal strategies of care to anticipate and prevent common complications.

Correlation between brain interstitial and total serum cortisol levels in traumatic brain injury. A preliminary study

INTRODUCTION

Brain cortisol availability has never been evaluated in patients with traumatic brain injury (TBI). Cerebral microdialysis is a well-established technique for monitoring brain metabolism in neurocritically ill patients, which may be used to measure interstitial cortisol. The objective of this preliminary study was to measure brain interstitial cortisol and its correlation with total serum cortisol in patients with TBI.

METHODS

We prospectively studied 6 patients with severe TBI admitted to the Intensive Care Unit of our tertiary University Hospital in which multimodal neuromonitoring including cerebral microdialysis with a high cut-off of 100 k-Da and 20-mm long membrane was used. Serum and brain interstitial cortisol microdialysis samples were obtained every 8 h and analyzed afterwards.

RESULTS

Linear regression analysis of total serum cortisol and brain interstitial cortisol in the whole population showed a moderate correlation (R2=0.538, p<0.001, no.=118). However, intra-individual correlation showed a great variability, with correlation coefficients ranging from a R2=0.091 to R2=0.680.

CONCLUSION

Our prospective and preliminary study showed a moderate correlation of brain interstitial cortisol and total serum cortisol values in patients with diffuse TBI. However, intra-individual analysis showed a great variability. These results suggest that total serum cortisol may not reflect brain cortisol availability in half of TBI patients.

Pituitary function in subjects with mild traumatic brain injury: a review of literature and proposal of a screening strategy

Traumatic brain injury (TBI) is an important public health problem all over the world. The level of consciousness of the patients and the severity of the brain injury is commonly evaluated by the Glascow Coma Scale as mild, moderate and severe TBI. When we consider the high frequency of mild TBI (MTBI) among the all TBI patients the burden of the pituitary dysfunction problem in this group could not be ignored. However, one of the most important and still unresolved questions is which patients with MTBI should be screened for hypopituitarism? Another type of head trauma which could be considered as the subgroup of MTBI is sports related chronic repetitive head trauma. Therefore, in this review we will discuss the frequency, characteristics and current management of pituitary dysfunction in patients with MTBI including the subjects exposed to sports related chronic mild head trauma.

Cosyntropin as a diagnostic agent in the screening of patients for adrenocortical insufficiency

Adrenocortical insufficiency occurs when there is inadequate release of cortisol from the adrenal cortex. Disturbances of the hypothalamic-pituitary-adrenal axis are common following trauma, surgical stress, and critical illness. While this is often a protective mechanism, these responses may become "uncoupled" or maladaptive resulting in an exacerbation of organ failure and higher mortality rates. In these clinical settings, the patient presents with a persistent systemic inflammation state, a hyperdynamic cardiovascular response, and vasopressor dependent shock. As such, the occurrence of adrenal insufficiency in the setting of critical illness is most appropriately termed critical illness-related corticosteroid insufficiency. In these settings, recent data suggests that these patients may benefit from a short course of low-dose steroid replacement therapy. Cosyntropin, a synthetic derivative of adrenocorticotropic hormone, is being used with increased frequency in the evaluation and diagnosis of adrenocortical insufficiency in this patient population. A random cortisol level is checked before a 250-μg injection of cosyntropin and then 30-60 minutes later. The cortisol levels and response to cosyntropin may be interpreted to identify an insufficient adrenal response. Of note, the setting of critical illness can greatly affect the cosyntropin test sensitivity on identifying adrenal insufficiency. Changes in the stress response during critical illness combined with the resuscitation and management of these patients greatly disturbs serum protein levels, especially those of albumin and transcortin. Common intensive care unit (ICU) diagnoses such as sepsis and malnutrition can increase baseline levels and blunt the cortisol response to cosyntropin stimulation, respectively. As well, numerous pharmacological agents routinely used in the ICU have been shown to interfere with cortisol levels and cosyntropin responsiveness. While steroids have a place in the ICU, specific dosing and length of administration remain inconsistent.

Relative adrenal insufficiency and hemodynamic status in cardiopulmonary bypass surgery patients. A prospective cohort study

Background

The objectives of this study were to determine the risk factors for relative adrenal insufficiency in cardiopulmonary bypass patients and the impact on postoperative vasopressor requirements.

Methods

Prospective cohort study on cardiopulmonary bypass patients who received etomidate or not during anesthetic induction. Relative adrenal insufficiency was defined as a rise in serum cortisol ≤ 9 μg/dl after the administration of 250 μg of consyntropin. Plasma cortisol levels were measured preoperatively, immediately before, 30, 60, and 90 minutes after the administration of cosyntropin, and at 24 hours after surgery.

Results

120 elective cardiopulmonary bypass patients were included. Relative adrenal insufficiency (Δcortisol ≤9 μg/dl) incidence was 77.5%. 78 patients received etomidate and 69 (88%) of them developed relative adrenal insufficiency, (P < 0.001). Controlling for clinical characteristics with a propensity analysis, etomidate was the only independent risk factor associated with relative adrenal insufficiency (OR 6.55, CI 95%: 2.47-17.4; P < 0.001). Relative adrenal insufficiency patients showed more vasopressor requirements just after surgery (P = 0.04), and at 4 hours after surgery (P = 0.01). Pre and post-test plasma cortisol levels were inversely associated with maximum norepinephrine dose (ρ = -0.22, P = 0.02; ρ = -0.18, P = 0.05; ρ = -0.21, P = 0.02; and ρ = -0.22, P = 0.02, respectively).

Conclusions

Relative adrenal insufficiency in elective cardiopulmonary bypass patients may induce postoperative vasopressor dependency. Use of etomidate in these patients is a modifiable risk factor for the development of relative adrenal insufficiency that should be avoided.

Neuroendocrine function following traumatic brain injury and subsequent intensive care treatment: a prospective longitudinal evaluation

Neuroendocrine dysfunction following traumatic brain injury (TBI) has been described extensively. However, few studies are longitudinal and most lack subtle radiological, clinical, and repetitive endocrine assessment in the acute phase. Accordingly, we prospectively assessed neuroendocrine function in 71 patients after TBI. Injury was documented by a computed tomography (CT). During the first week, critical clinical data (Glasgow Coma Score, APACHE score), treatment variables such as duration of analgosedation for mechanical ventilation, were related to basal pituitary function. More than 2 years later, a subgroup of patients was re-evaluated using dynamic testing with ACTH and GHRH-arginine tests. The Pearson's correlation analysis and Mann-Whitney rank sum test for group differences were used for statistical analysis. None of the CT findings predicted neuroendocrine dysfunction following TBI. The adaptive response to critical illness with significantly elevated cortisol levels on admission and decreased levels thereafter in patients ventilated for more than 24 h (p < 0.05) was attenuated following severe TBI (p < 0.05). However, the coincidence of low serum cortisol and increased urinary excretion of glucocorticoid metabolites in about 80% of patients challenges the relevance of basal hormone measurements. In ventilated patients, total T3 and free T4 were decreased (p < 0.05), TSH was low on day 3 (p < 0.05), and a gonadotropic insufficiency was present (p < 0.05). The thyrotropic and gonadotropic system recovered completely within the follow-up period. With regard to the somatotropic system, neither brain injury severity nor mechanical ventilation was associated with an insufficiency during the acute phase post-injury. However, initially low GH levels predicted a persistent deficiency (r = 0.731, p < 0.001). We conclude that both severe TBI and prolonged mechanical ventilation result in hormonal disturbances early after injury, suggesting a pathophysiological response to brain injury and subsequent intensive care treatment rather than morphological damage.

Hypothalamic-pituitary axis deficiency following traumatic brain injury in a dog

OBJECTIVE

To describe endocrine dysfunction associated with traumatic brain injury in a dog.

SUMMARY

A 12-week-old dog presented with traumatic brain injury and did not respond to traditional supportive care. Continued hypothermia, electrolyte derangements, hypotension, and hyposthenuria prompted screening for and detection of several hypothalamic-pituitary disorders including: hypoadrenocorticism, central diabetes insipidus, hypothyroidism, and growth hormone deficiency. Electrolyte abnormalities, urine osmolarity, and blood pressure improved with treatment for the associated disorders.

NEW OR UNIQUE INFORMATION PROVIDED

This is the first report of generalized hypothalamic-pituitary dysfunction or panhypopituitarism following traumatic brain injury in a dog.

Hypogonadism after traumatic brain injury

Traumatic brain injury (TBI) is the most common cause of death and disability in young adults. Post-TBI neuroendocrine disorders have been increasingly acknowledged in recent years due to their potential contribution to morbidity and, probably, to mortality after trauma. Marked alterations of the hypothalamic-pituitary axis during the post-TBI acute and chronic phases have been reported. Prospective and longitudinal studies have shown that some abnormalities are transitory. On the other hand, there is a high frequency (15% to 68%) of pituitary hormone deficiency among TBI survivors in a long term setting. Post-TBI hypogonadism is a common finding after cranial trauma, and it is predicted to develop in 16% of the survivors in the long term. Post-TBI hypogonadism has been associated with adverse results in the acute and chronic phases after injury. These data reinforce the need for identification of hormonal deficiencies and their proper treatment, in order to optimize patient recovery, improve their life quality, and avoid the negative consequences of non-treated hypogonadism in the long term.

[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.

Reduced medial temporal lobe functionality in stroke patients: a functional magnetic resonance imaging study

Stroke is a leading cause of disability, not only because of motor limitations, but also because of the frequent occurrence of post-stroke cognitive impairment. This is illustrated by the fact that the risk of post-stroke dementia is reportedly higher than a recurrent stroke. The loss of subcortical and cortical functions in the post-stroke cognitive dysfunction spectrum is usually well explained by the size and location of the infarction. However, this does not apply for post-stroke memory dysfunction (especially episodic memory dysfunction), as there is almost never an infarction in the medial temporal lobe. Involvement of the medial temporal lobe in post-stroke memory dysfunction seems likely since this structure is essential for memory encoding and retrieval. For a proper episodic memory function, the medial temporal lobe depends on intact connections with virtually the whole brain. Disconnection from other brain areas due to the infarction could lead to a reduced medial temporal lobe function and the attendant reduced episodic memory function. We investigated medial temporal lobe functionality in 28 'first-ever' stroke patients and 22 healthy controls with the aid of functional magnetic resonance imaging. Stroke patients with a reduced episodic memory function 6-8 weeks after infarction had reduced medial temporal lobe functionality. Post-stroke reduced medial temporal lobe functionality may be responsible for the frequent observation of impaired post-stroke episodic memory function. Insight into this mechanism could be helpful in identifying which stroke patients may be at increased risk for developing post-stroke dementia and those who could benefit from early cognitive rehabilitation.

[Should etomidate still be used?]

Etomidate blocks the cortisol synthesis by specifically inhibiting the activity of 11 beta-hydroxylase, resulting in a primary adrenal insufficiency. Therefore, a serum accumulation of 11 beta-deoxycortisol and a low secretion of serum cortisol must be required as diagnostic criteria to assign that adrenal impairment to the drug. These requirements have been rarely fulfilled in studies exploring the contribution of etomidate to the adrenal insufficiency despite numerous causes of adrenal derangement. In critically ill patients without sepsis, a single dose of etomidate results in a wide adrenal inhibition, reversible in 48 h after etomidate administration. Although there are still uncertainties as to whether etomidate directly affects mortality and morbidity, it seems preferable to avoid the use of etomidate in patients with severe sepsis and septic shock. In patients with severe traumatic brain injury, arterial hypotension is one of major factors of poor outcome and can be prevented with the use of etomidate for facilitating tracheal intubation. Substitutive opotherapy with low doses of hydrocortisone should be assessed after a single dose of etomidate for critically ill patients.

Pituitary-adrenal function in patients with acute subarachnoid haemorrhage: a prospective cohort study

INTRODUCTION

Subarachnoid haemorrhage (SAH) may damage the hypothalamo-pituitary-adrenal gland (HPA) axis and disturb cortisol metabolism. There are no available data that relates to the response of the HPA axis in the acute phase of SAH. We aimed to characterise the behavior of serum adrenocorticotropic hormone (ACTH), total cortisol, stimulated total cortisol and free cortisol concentrations in acute aneurysmal SAH.

METHODS

A prospective cohort study was conducted of patients with acute aneurysmal SAH (n = 30) admitted to a tertiary university hospital. Patients admitted for elective aneurysmal surgery (n = 16) served as the control group. An ACTH stimulation test was performed twice during the first week and at three months. The main outcome measure was description of the ACTH-cortisol response by calculating serum free cortisol and measuring total cortisol and ACTH concentrations. A mixed models method was used for testing between the groups, allowing heterogeneity between the groups.

RESULTS

Patients with SAH had higher initial serum total cortisol (mean +/- SD; 793 +/- 312 nmol/L) and free cortisol concentrations (83 +/- 55 nmol/L) than control patients (535 +/- 193 nmol/L, p = 0.001 and 33 +/- 18 nmol/L, p < 0.001, respectively). Thereafter, there were no differences in this respect. Serum free and total cortisol concentrations correlated but were unaffected by the severity of SAH. ACTH concentrations were comparable between SAH and control groups. Patients with Hunt-Hess grades IV to V had higher ACTH concentrations at day one (10.7 +/- 7.1 pmol/l/L) and day five (8.2 +/- 7.7 pmol/L) than patients with grade I-III (day one: 3.8 +/- 2.0 pmol/L, p = 0.002; day five: 4.7 +/- 1.8 pmol/L, p = 0.04).

CONCLUSIONS

Calculation of serum free cortisol concentration was not helpful in identifying patients with potential hypocortisolism. SAH severity did not affect cortisol concentrations, possibly indicating relative pituitary-adrenal insufficiency in patients with more severe bleeding.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT00614887.

ACUTE RELATIVE ADRENAL INSUFFICIENCY AFTER ANEURYSMAL SUBARACHNOID HEMORRHAGE

OBJECTIVE

The hypothalamic-pituitary-adrenal axis is an important part of the body's natural response to acute illness. Adrenal insufficiency has the potential to lead to hemodynamic instability and electrolyte imbalances, limit the body's ability to respond to stress, and worsen overall clinical outcome. In this case series, we describe 16 patients evaluated for acute adrenal insufficiency after aneurysmal subarachnoid hemorrhage.

CLINICAL PRESENTATION

Over a 2-year period, the medical records of 16 patients admitted to the adult neurosurgery service for aneurysmal subarachnoid hemorrhage who were nonresponsive to vasopressor therapy and received cosyntropin for the evaluation of adrenal insufficiency within 14 days of their event were reviewed.

INTERVENTION

The median baseline cortisol in this population was 22.5 μg/dL, with a poststimulation cortisol level of 31 μg/dL. Of the population surveyed, a total of 11 patients met the preestablished criteria for adrenal insufficiency, 3 with baseline cortisol levels of less than 15 μg/dL and 11 with poststimulation concentration changes of less than 9 μg/dL. Baseline serum cortisol concentrations were significantly correlated with hospital stay (P = 0.045), intensive care unit stay (P = 0.005), and ventilator days (P = 0.006).

CONCLUSION

To date, this is the only investigation evaluating the incidence of acute relative adrenal insufficiency in this population. In our cohort, 69% of the patients met the preestablished criteria for relative adrenal insufficiency. The impact of low-dose corticosteroid therapy in this population also needs review, as it could have significant implications for the management of cerebral vasospasm.

Chronic hypopituitarism after traumatic brain injury: risk assessment and relationship to outcome

OBJECTIVE

Chronic pituitary dysfunction is increasingly recognized as a sequela of traumatic brain injury. We sought to define the incidence, risk factors, and neurobehavioral consequences of chronic hormonal deficiencies after complicated mild, moderate, or severe traumatic brain injury.

METHODS

Patients aged 14 to 80 years were prospectively enrolled at the time of injury and assessed at 3 and 6 to 9 months after injury for hormonal function and neurobehavioral consequences. Major and minor (subclinical) hormonal deficiencies, including growth hormone deficiency (GHD) and growth hormone insufficiency (GHI), were identified. Acute injury characteristics, neurobehavioral, and quality of life measures were compared in patients with and without major hormonal deficits by the use of multivariate analysis.

RESULTS

Out of 70 patients (mean age, 32 yr; median Glasgow Coma Scale score, 7; 19% women) tested at 6 to 9 months after injury, 15 (21%) had at least one major hormonal deficiency, 20 (29%) had minor deficiencies, and 30 (43%) had major and/or minor deficiencies. Patients with major deficiencies included 16% with GHD or GHI, 10.5% with hypogonadism, and 1.4% with diabetes insipidus. None of the patients required adrenal or thyroid replacement. At 6 to 9 months after injury, patients with major hormonal deficits had more abnormal acute computed tomographic findings (P = 0.014), greater acute and chronic body mass index (P < 0.01), and a worse Disability Rating Scale score (multivariate P = 0.04). Compared with the 59 growth hormone-sufficient patients, the 11 patients with GHD or GHI had worse Disability Rating Scale scores (multivariate P = 0.04), greater rates of depression, (90 versus 53%; multivariate P = 0.06), and worse quality of life in the Short Form-36 domains of energy and fatigue (multivariate P = 0.03), emotional well-being (multivariate P = 0.02), and general health (multivariate P = 0.07).

CONCLUSION

Chronic hypopituitarism warranting hormone replacement occurs in approximately 20% of patients after complicated mild, moderate, or severe traumatic brain injury and is associated with more severe brain injuries and increased disability. GHD and GHI are also associated with increased disability, poor quality of life, and a greater likelihood of depression. The clinical significance of minor hormonal deficits, which occur in almost 30% of patients, warrants further study. Given that major deficiencies are readily treatable, routine pituitary hormonal testing within 6 months of injury is indicated for this patient population.

Adrenal insufficiency following traumatic brain injury in adults

PURPOSE OF REVIEW

Hypoadrenalism occurs in approximately 25% of patients soon after traumatic brain injury. Neurosurgeons or critical care physicians should be prepared to diagnose and treat this and other related hormonal deficiencies.

RECENT FINDINGS

The severity of traumatic brain injury, location of basilar skull fractures and edema or hemorrhage within the hypothalamic-pituitary axis appear correlated with secondary adrenal failure. Primary hypoadrenalism also may occur due to injury-related systemic inflammation. Hypotension requiring vasoactive drug support, hyponatremia and hypoglycemia may be corresponding clinical signs. Evaluation of either primary or secondary hypoadrenalism should include measurement of basal and post-adrenocorticotropin stimulation cortisol blood concentrations. If the basal cortisol is under 15 microg/dl or increases by over 9 microg/dl after stimulation treatment should be considered. Intravenous hydrocortisone at 50-100 mg every 8 h or by continuous infusion is usually sufficient but may be supplemented with a mineralocorticoid if hyponatremia persists. All patients sustaining severe traumatic brain injury should be tested for endocrine failure (adrenal, thyroid and growth hormone) 3 months after injury.

SUMMARY

Adrenal gland failure or the inability to produce adrenocorticotropin and other pituitary hormones may occur early after traumatic brain injury. Acute treatment of either cause of hypoadrenalism may correct associated hypotension, hypoglycemia, or hyponatremia.

[Sedation and analgesia for the brain-injured patient]

Sedation-analgesia occupies an essential place in the specific therapeutic arsenal of the brain-injured patients. The maintenance of the perfusion of the brain, its relaxation and its protection are the fundamental objectives whose finality is to avoid the extension of the lesions and to preserve the neuronal capital. Sedation is instituted when patients are severely agitated or present a deterioration of their state of consciousness (GCS< or =8). Under cover of mechanical ventilation, sedation is the first line treatment of intracranial hypertension, a common pathway of various acute brain diseases of traumatic, vascular or other origin. The use of the combination of hypnotic and opioids is the rule. The combined action of these two classes reinforces and improves their sedative effects. Midazolam is the 2 benzodiazepine of reference. Propofol is more and more frequently added to the combination of hypnotic and opioids. The "propofol infusion syndrome" is a severe limitation to its long term administration in particular among patients presenting a severe septic or inflammatory state. Propofol will be imperatively stopped in the event of metabolic acidosis, rhabdomyolysis, acute renal insufficiency, hyperkaliemia or increase in the blood triglyceride levels. The use of thiopental is restricted to the most severe cases. Its use as a monotherapy at high doses is abandoned to the profit of a co-administration with midazolam or even with the combination of midazolam and propofol. Thiopental overdose is very frequent in the event of associated hypothermia. Etomidate does not have its place apart from induction in fast sequence. The neuro-protective effects of ketamine require to be demonstrated in man before being recommended routinely. Withdrawal of sedation can be responsible for a state of agitation which can be controlled by neuroleptics.

Medication-related complications in the trauma patient

Trauma patients are twice as likely to have adverse reactions to medication as nontrauma patients. The need for medication in trauma patients is high. Surgery is often necessary, and immunosuppression and hypercoagulability may be present. Adverse drug events can be caused in part by altered pharmacokinetics, drug interactions, and polypharmacy. Medications may also have serious long-term adverse effects, which must be considered. It is not the purpose of this review article to discuss all adverse effects of all medications. This article will discuss the more common adverse effects of medications for trauma patients in the acute care setting, in the following categories: pain control, sedation, antibiotics, seizure prophylaxis in head trauma, atrial fibrillation, deep vein thrombosis and pulmonary embolism prophylaxis, hemodynamic support, adrenal insufficiency, factor VIIa.

Relative adrenal insufficiency in patients with acute spinal cord injury

INTRODUCTION

Relative adrenal insufficiency has been shown to occur in the settings of critical illness and septic shock, impairing the body's ability to respond to stress. Studies have demonstrated that the treatment of adrenal insufficiency (AI) results in shock reversal, hemodynamic stability, and a subsequent decrease in mortality. Endocrine changes and AI have been reported in patients with spinal cord injuries during their extended courses of rehabilitation.

DISCUSSION

We describe two cases of patients with cervical spine injuries who presented with acute adrenal insufficiency following their injuries. With the addition of low-dose corticosteroids, each patient had symptom resolution and demonstrated clinical improvement.

CONCLUSION

Patients with spinal cord injuries are at risk for AI, both in the acute and chronic settings following injury prompting the need for an increased awareness of this condition. Although variability exists in the exact criteria for the diagnosis of AI, the combination of clinical symptoms, depressed serum cortisol concentrations, and responsiveness to exogenous steroid therapy should all contribute to the diagnosis of this condition.