Incidence of adrenal insufficiency after severe traumatic brain injury varies according to definition used: clinical implications

Can Salivary Cortisol be Used in Diagnosing Adrenal Insufficiency During the Acute and Subacute Phases of Traumatic Brain Injury?

INTRODUCTION

The diagnosis of adrenal insufficiency (AI) related to traumatic brain injury (TBI) remains a challenge. We investigated the basal and low-dose adrenocorticotropic hormone (ACTH)-stimulated serum cortisol and salivary cortisol (SaC) levels and the diagnostic utility of SaC levels during 28 days following TBI.

MATERIALS AND METHODS

Blood samples were collected for basal levels [sequentially from day 1 (D1) to D7 and on D28)] and for peak serum cortisol and SaC responses to the low-dose ACTH stimulation test (on D1, D7, and D28). After the patient enrollment period was completed, patients were retrospectively categorized as AI or AS (adrenal sufficiency) for each day separately, based on a basal serum cortisol cut-off level of 11 µg/dL, and data analysis was performed between the groups.

RESULTS

Thirty-seven patients and 40 healthy controls were included. Median basal serum cortisol levels were higher in patients on D1 but were similar on other days. Median basal SaC levels were higher in patients on D1 and D2 but were similar on other days. Median peak serum cortisol and SaC levels were similar on D1 but were lower in patients on D7 and D28. Median basal SaC levels were higher in the AS group than in the AI group on all days.

DISCUSSION AND CONCLUSIONS

When evaluating AI during the course of TBI, the cut-off for basal SaC levels is 0.5-0.6 µg/dL throughout the first week, except for 1.38 µg/dL on D2. SaC levels may serve as a surrogate marker for accurately reflecting circulating glucocorticoid activity.

Management of potential cardiac donors

Heart transplantation (HTx) outcomes have improved with careful donor selection and management; nonetheless, donor shortages remain a major challenge. Optimizing donor management is crucial for improving donor utility rates and post-HTx outcomes. Brain death leads to various pathophysiological changes that can affect multiple organs, including the heart. Understanding these alterations and corresponding management strategies is key to optimizing the donor organ condition. This review assesses several aspects of these pathophysiological changes, including hemodynamic and endocrinological considerations, and emphasizes special consideration for potential cardiac donors, including serial echocardiographic evaluations for reversible cardiac dysfunction and coronary assessments for donors with risk factors.

The ultra-acute steroid response to traumatic injury: a cohort study

OBJECTIVE

Trauma-induced steroid changes have been studied post-hospital admission, resulting in a lack of understanding of the speed and extent of the immediate endocrine response to injury. The Golden Hour study was designed to capture the ultra-acute response to traumatic injury.

DESIGN

We conducted an observational cohort study including adult male trauma patients <60 years, with blood samples drawn ≤1 h of major trauma by pre-hospital emergency responders.

METHODS

We recruited 31 adult male trauma patients (mean age 28 [range 19-59] years) with a mean injury severity score (ISS) of 16 (IQR 10-21). The median time to first sample was 35 (range 14-56) min, with follow-up samples collected 4-12 and 48-72 h post-injury. Serum steroids in patients and age- and sex-matched healthy controls (HCs) (n = 34) were analysed by tandem mass spectrometry.

RESULTS

Within 1 h of injury, we observed an increase in glucocorticoid and adrenal androgen biosynthesis. Cortisol and 11-hydroxyandrostendione increased rapidly, whilst cortisone and 11-ketoandrostenedione decreased, reflective of increased cortisol and 11-oxygenated androgen precursor biosynthesis by 11β-hydroxylase and increased cortisol activation by 11β-hydroxysteroid dehydrogenase type 1. Active classic gonadal androgens testosterone and 5α-dihydrotestosterone decreased, whilst the active 11-oxygenated androgen 11-ketotestosterone maintained pre-injury levels.

CONCLUSIONS

Changes in steroid biosynthesis and metabolism occur within minutes of traumatic injury. Studies that address whether ultra-early changes in steroid metabolism are associated with patient outcomes are now required.

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

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

Dysfunction of the hypothalamic-pituitary-adrenal axis in critical illness: a narrative review for emergency physicians

The stress response to acute disease is characterized by activation of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathoadrenal system, increased serum cortisol levels, increased percentage of its free fraction and increased nuclear translocation of the glucocorticoid-receptor complex, even though many pathways may be inhibited by poorly understood mechanisms. There is no consensus about the cutoff point of serum cortisol levels for defining adrenal insufficiency. Furthermore, recent data point to the participation of tissue resistance to glucocorticoids in acute systemic inflammatory processes. In this review, we evaluate the evidence on HPA axis dysfunction during critical illness, particularly its action on the inflammatory response, during acute severe injury and some pitfalls surrounding the issue. Critical illness-related corticosteroid insufficiency was defined as a dynamic condition characterized by inappropriate cellular activity of corticosteroids for the severity of the disease, manifested by persistently elevated proinflammatory mediators. There is no consensus regarding the diagnostic criteria and treatment indications of this syndrome. Therefore, the benefits of administering corticosteroids to critically ill patients depend on improvements in our knowledge about the possible disruption of its fragile signalling structure in the short and long term.

[Epidemiological aspects and prognostic factors of severe traumatic brain injuries]

OBJECTIVE

To determine the severity factors in severe traumatic brain injuries.

METHODS

A prospective descriptive study of severe head injuries admitted to the emergency department at Ibn Tofail Hospital at the University Hospital of Marrakech over a period of six months from May to October 2015. The following data was collected: circumstances, clinical, biology, radiology, treatment and evolution.

RESULTS

One hundred and nineteen patients with severe traumatic brain injury were collected (101 males, 84,9%). The mean age was 37,73±15,7 years. Road accidents were the most common cause representing 84%. The median Glasgow coma scale (GCS) was 7±3. We noted 36 cases (30,3%) of anisocoria, 32 cases (26,9%) of bilateral mydriasis and 72 cases (60,5%) of hypoxia. Cerebral contusions (66,1%) and meningeal hemorrhage (66,6%) were the most frequent lesions on CT. Forty-seven patients (42%) had stage VI Marshall lesions. Twenty-four patients (20.1%) required a neurosurgical intervention, 12 extradural hematoma evacuations and 10 craniocerebral wounds. Mortality was 64.7% (77 deaths), the main cause was neurological (64,9%). In the latter group, we observed more frequently an older age (P=0.00001), a management delay (P=0.011), a low initial GCS (P=0.000001), a bilateral nonreactive mydriasis (P=0.0001), a hypoxia (P=0.0002), a subarachnoid hemorrhage (P=0.008), a high Marshall score (P=0.017) and an anemia (P=0.046).

CONCLUSION

Head trauma is a public health problem. The victims are young, and the sequelae are frequently disabling. Several parameters are associated with a poorer prognosis including age, neurological state and the initial delay in management.

Bidirectional Brain-Systemic Interactions and Outcomes After TBI

Traumatic brain injury (TBI) is a debilitating disorder associated with chronic progressive neurodegeneration and long-term neurological decline. Importantly, there is now substantial and increasing evidence that TBI can negatively impact systemic organs, including the pulmonary, gastrointestinal (GI), cardiovascular, renal, and immune system. Less well appreciated, until recently, is that such functional changes can affect both the response to subsequent insults or diseases, as well as contribute to chronic neurodegenerative processes and long-term neurological outcomes. In this review, we summarize evidence showing bidirectional interactions between the brain and systemic organs following TBI and critically assess potential underlying mechanisms.

A Tilted Axis: Maladaptive Inflammation and HPA Axis Dysfunction Contribute to Consequences of TBI

Each year approximately 1.7 million people sustain a traumatic brain injury (TBI) in the US alone. Associated with these head injuries is a high prevalence of neuropsychiatric symptoms including irritability, depression, and anxiety. Neuroinflammation, due in part to microglia, can worsen or even cause neuropsychiatric disorders after TBI. For example, mounting evidence demonstrates that microglia become “primed” or hyper-reactive with an exaggerated pro-inflammatory phenotype following multiple immune challenges. Microglial priming occurs after experimental TBI and correlates with the emergence of depressive-like behavior as well as cognitive dysfunction. Critically, immune challenges are various and include illness, aging, and stress. The collective influence of any combination of these immune challenges shapes the neuroimmune environment and the response to TBI. For example, stress reliably induces inflammation and could therefore be a gateway to altered neuropathology and behavioral decline following TBI. Given the increasing incidence of stress-related psychiatric disorders after TBI, the degree in which stress affects outcome is of particular interest. This review aims to highlight the role of the hypothalamic-pituitary-adrenal (HPA) axis as a key mediator of stress-immune pathway communication following TBI. We will first describe maladaptive neuroinflammation after TBI and how stress contributes to inflammation through both anti- and pro-inflammatory mechanisms. Clinical and experimental data describing HPA-axis dysfunction and consequences of altered stress responses after TBI will be discussed. Lastly, we will review common stress models used after TBI that could better elucidate the relationship between HPA axis dysfunction and maladaptive inflammation following TBI. Together, the studies described in this review suggest that HPA axis dysfunction after brain injury is prevalent and contributes to the dynamic nature of the neuroinflammatory response to brain injury. Experimental stressors that directly engage the HPA axis represent important areas for future research to better define the role of stress-immune pathways in mediating outcome following TBI.

Effect of acute restraint stress in a polytrauma rat model

INTRODUCTION

A stressful environment may contribute to poor outcomes after TBI. The current study evaluates the impact of acute stress in a polytrauma rat model.

METHODS

Rats were stressed by a 45-minute immobilization period before instrumentation under ketamine (t1). Polytrauma was produced by blast overpressure and controlled hemorrhage (t2). Rats were euthanized immediately after a 3 h simulated Medevac-transport time (t3) or after 72 h post-trauma (t4). Corticosterone, ACTH, and ACTH receptor gene expression were measured at these time points. Physiological parameters were monitored throughout the study.

RESULTS

HR was higher in stressed compared to unstressed animals at t1. Corticosterone and ACTH levels were similar for all conditions at t1 and t2; ACTH and corticosterone became elevated in all groups at t3 and at t4, respectively. The ACTH receptor gene expression trended towards higher values at t4 for the stressed animals whether being injured or not. Survival after injury was 83% in both unstressed and stressed animals.

CONCLUSION

Overall, corticosterone was not significantly affected following acute stress in ketamine-anesthetized rats. Early mortality was primarily due to polytrauma and change in the animal's biochemical parameters appeared at t4 post trauma. The findings indicate that ketamine-anesthesia and/or surgery may have overshadowed the effect of the initial stress.

Comparison of Etomidate and Ketamine for Induction During Rapid Sequence Intubation of Adult Trauma Patients

STUDY OBJECTIVE

Induction doses of etomidate during rapid sequence intubation cause transient adrenal dysfunction, but its clinical significance on trauma patients is uncertain. Ketamine has emerged as an alternative for rapid sequence intubation induction. Among adult trauma patients intubated in the emergency department, we compare clinical outcomes among those induced with etomidate and ketamine.

METHODS

The study entailed a retrospective evaluation of a 4-year (January 2011 to December 2014) period spanning an institutional protocol switch from etomidate to ketamine as the standard induction agent for adult trauma patients undergoing rapid sequence intubation in the emergency department of an academic Level I trauma center. The primary outcome was hospital mortality evaluated with multivariable logistic regression, adjusted for age, vital signs, and injury severity and mechanism. Secondary outcomes included ICU-free days and ventilator-free days evaluated with multivariable ordered logistic regression using the same covariates.

RESULTS

The analysis included 968 patients, including 526 with etomidate and 442 with ketamine. Hospital mortality was 20.4% among patients induced with ketamine compared with 17.3% among those induced with etomidate (adjusted odds ratio [OR] 1.41; 95% confidence interval [CI] 0.92 to 2.16). Patients induced with ketamine had ICU-free days (adjusted OR 0.80; 95% CI 0.63 to 1.00) and ventilator-free days (adjusted OR 0.96; 95% CI 0.76 to 1.20) similar to those of patients induced with etomidate.

CONCLUSION

In this analysis spanning an institutional protocol switch from etomidate to ketamine as the standard rapid sequence intubation induction agent for adult trauma patients, patient-centered outcomes were similar for patients who received etomidate and ketamine.

Adrenal inhibition following a single dose of etomidate in intubated traumatic brain injury victims

Background:

Etomidate is frequently used to intubate traumatic brain injury (TBI) victims, even though it has been linked to adrenal insufficiency (AI) in some populations. Few studies have explored the risk of prolonged etomidateinduced AI among TBI victims.

Objective:

To determine the risk and the length of AI induced by etomidate in patients intubated for moderate and severe TBI.

Methods:

Participants in this observational study were moderate to severe intubated TBI victims aged ≥ 16 years. The anesthetic used (etomidate versus others) was determined solely by the treating emergency physician. Adrenocorticotropic hormone (ACTH) stimulation tests (250 µg) were performed 24, 48, and 168 hours after intubation. AI was defined as an increase in serumcortisol 1 hour post–ACTH test (delta cortisol) of less than 248.4 nmol/L.

Results:

Forty subjects (participation 42.6%) underwent ACTH testing. Fifteen received etomidate, and 25 received another anesthetic. There were no statistically significant differences between groups as to the cumulative incidence of AI at any measurement time. However, at 24 hours, exploratory post hoc analyses showed a significant decrease in delta cortisol (adjusted means: etomidate group: 305.1 nmol/L, 95% CI 214.7–384.8 versus other anesthetics: 500.5 nmol/L, 95% CI 441.8–565.7). This decrease was not present at 48 and 168 hours.

Conclusion:

In TBI victims, although a single dose of etomidate does not increase the cumulative incidence of AI as defined, it seems to decrease the adrenal response to an ACTH test for 24 hours. The clinical impacts of this finding remain to be determined.

Traumatic brain injury and adrenal insufficiency: morning cortisol and cosyntropin stimulation tests

INTRODUCTION

Adrenal insufficiency (AI) has a great impact on the prognosis of patients with traumatic brain injury. There is a lack of consensus regarding the diagnostic criteria of AI. In these patients with acute stress we compared fasting cortisol, low and high dose cosyntropin stimulation tests to assess adrenal function in patients with moderate to severe traumatic brain injury.

MATERIAL AND METHODS

This multicenter, cross-sectional study recruited 50 consecutive patients (aged between 15 and 70 years old) with moderate to severe traumatic brain injury who survived more than 5 days after the event. The patients' adrenal function was assessed using the fasting cortisol, 1 and 250-µg ACTH stimulation tests.

RESULTS

More cases of AI were detected by the 1-µg ACTH stimulation test compared to those detected by the basal serum cortisol level and 250-µg ACTH stimulation test. The κ test showed no agreement between these tests. The incidence of AI in the first 10 days after traumatic brain injury varied from 34% to 82% according to the various definitions of AI. The incidence of hypotension and need for vasopressors was higher in the patients diagnosed by the 250-µg ACTH stimulation test (p < 0.0001).

CONCLUSIONS

The incidence of secondary AI in moderate to severe traumatic brain injury seems to be high. A combination of stimulation test (either 250 or 1 µg) and basal cortisol level may improve diagnostic ability compared to either test alone. Hence performing both tests for the assessment of adrenal function in patients with traumatic brain injury is recommended.

Hypocortisolism in noncomatose patients during the acute phase of subarachnoid hemorrhage

BACKGROUND

Hypopituitarism represents a common long-term complication of subarachnoid hemorrhage (SAH). The incidence of hypocortisolism may be higher during the acute phase of SAH. Although hypocortisolism may be harmful in critically ill SAH patients, data are still lacking. The primary objective of this study was to investigate the incidence of hypocortisolism during the acute phase of SAH (15 days). Secondary objectives included an analysis of the relationship between hypocortisolism and outcome and the computation of the cortisol-time secretion curve.

METHODS

Clinical data of a consecutive series of 26 noncomatose patients with aneurysmal SAH were collected prospectively. The sample size was calculated considering an expected proportion of hypocortisolism of 30%, a confidence level of 95%, and a total width of confidence interval of 0.35. The definition of hypocortisolism (as taken from a statement from the critical care medicine task forces) includes random total cortisol <10 μg/dL or a Δtotal serum cortisol <9 μg/dL after 1 μg of corticotrophin hormone.

RESULTS

Hypocortisolism was diagnosed in 11 patients (42.3%). Cortisol increment after stimulation test was always >9 μg/dl, suggesting a hypothalamic-pituitary impairment. Hypocortisolism was independently associated with a higher risk of poor outcome (P = .046) even after adjusting for age and Hunt and Hess grade. The cortisol-time secretion curve showed a peak at day 5 and a minimum at day 8. The peak at day 5 correlated with the risk of delayed cerebral ischemia (P = .001), and the cortisol concentration slope between days 1 and 8 correlated with the risk of poor outcome (P = .033).

CONCLUSIONS

Patients with SAH are at high risk of secondary hypocortisolism during the first 15 days after bleeding. Hypocortisolism independently increases the risk of poor outcome. The acute phase of hypothalamo-pituitary dysfunction, as reflected by an abnormal day-by-day cortisol secretion pattern, may affect the risk of delayed cerebral ischemia.

Incidence and Outcomes of Critical Illness-Related Corticosteroid Insufficiency in Trauma Patients

The spectrum of critical illness-related corticosteroid insufficiency (CIRCI) in trauma is not fully defined. This study describes our trauma experience with hydrocortisone-treated patients experiencing CIRCI. We conducted a 5-year retrospective analysis from a Level II trauma center using biochemical and clinical criteria for adrenal insufficiency. Seventy patients met the inclusion criteria for CIRCI. There was a 34 per cent mortality rate despite therapy. Nonsurvivors were older with larger admission base deficits and experienced higher rates of sepsis, bacteremia, and pneumonia. Nonsurvivors had prolonged vent days (mean 53 ± 64 days) when compared with survivors (mean 30 ± 22 days; P = 0.029). Renal replacement therapy was a strong predictor of mortality. Spinal cord-injured patients had high Injury Severity Scores (mean 34 ± 18), elevated baseline Cortisol levels (mean 56 ± 84 vs 18 ± 14; P = 0.004), and required prolonged duration of steroid therapy (30 ± 52 vs 15 ± 15 days; P = 0.080) when compared with the nonspinal cord-injured group. Our data suggest that CIRCI in trauma is associated with significant mortality and morbidity even when patients are treated appropriately.

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.

Low-dose and high-dose synacthen tests and the hemodynamic response to hydrocortisone in acute traumatic brain injury

INTRODUCTION

In order to identify whether low-dose (1 microg) tetracosactide (Synacthen) testing may be preferable to high-dose (250 microg) testing in the diagnosis of adrenal insufficiency in traumatic brain injury (TBI), as suggested by studies in other forms of critical illness.

METHODS

We retrospectively reviewed the results of modified tetracosactide tests (involving administration of both low-dose and high-dose tetracosactide) conducted for clinical indications in patients in a neurocritical care unit within 10 days of TBI. Sixty-three modified tests were included and cortisol concentrations before and after administration of tetracosactide were extracted from the hospital records. Data were also extracted regarding hemodynamic response to empirical corticosteroid therapy, based on rapid weaning from vasoactive drugs.

RESULTS

Cortisol increments at 30 and 60 min following tetracosactide correlated well in the low-dose test (r(2) = 0.875, P < 0.0001). The mean cortisol concentration was 581 nmol/l at 30 min and 556 nmol/l at 60 min in the low-dose test. Cortisol increments following low-dose and high-dose testing correlated well overall (r(2) = 0.839, P < 0.0001), but results were discordant in 27 of 63 cases (43%) when the same diagnostic threshold was used. ROC curve analysis showed that both tests performed poorly in identifying hemodynamic steroid responsiveness (AUC 0.553 and 0.502, respectively).

CONCLUSIONS

In the low-dose tetracosactide test, it is sufficient to determine cortisol concentrations at baseline and at 30 min. Low-dose and high-dose tests give discordant results in a significant proportion of cases when using the same diagnostic threshold. Neither test can be used to guide the initiation of corticosteroid therapy in acute TBI.

[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.

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.

Duration of adrenal inhibition following a single dose of etomidate in critically ill patients

OBJECTIVE

To determine the incidence and duration of adrenal inhibition induced by a single dose of etomidate in critically ill patients.

DESIGN

Prospective, observational cohort study.

SETTING

Three intensive care units in a university hospital.

PATIENTS

Forty critically ill patients without sepsis who received a single dose of etomidate for facilitating endotracheal intubation.

MEASUREMENTS AND MAIN RESULTS

Serial serum cortisol and 11beta-deoxycortisol samples were taken at baseline and 60 min after corticotropin stimulation test (250 microg 1-24 ACTH) at 12, 24, 48, and 72 h after etomidate administration. Etomidate-related adrenal inhibition was defined by the combination of a rise in cortisol less than 250 nmol/l (9 microg/dl) after ACTH stimulation and an excessive accumulation of serum 11beta-deoxycortisol concentrations at baseline. At 12 h after etomidate administration, 32/40 (80%) patients fulfilled the diagnosis criteria for etomidate-related adrenal insufficiency. This incidence was significantly lower at 48 h (9%) and 72 h (7%). The cortisol to 11beta-deoxycortisol ratio (F/S ratio), reflecting the intensity of the 11beta-hydroxylase enzyme blockade, improved significantly over time.

CONCLUSIONS

A single bolus infusion of etomidate resulted in wide adrenal inhibition in critically ill patients. However, this alteration was reversible by 48 h following the drug administration. The empirical use of steroid supplementation for 48 h following a single dose of etomidate in ICU patients without septic shock should thus be considered. Concomitant serum cortisol and 11beta-deoxycortisol dosages are needed to provide evidence for adrenal insufficiency induced by etomidate in critically ill patients.

Traumatic brain injury: intensive care management

Traumatic brain injury (TBI) is a major cause of morbidity and mortality worldwide. The modern management of severe TBI has fallen into the domain of a multidisciplinary team led by neurointensivists, neuroanaesthetists, and neurosurgeons and is based on the avoidance of secondary injury, maintenance of cerebral perfusion pressure (CPP), and optimization of cerebral oxygenation. In this review, we will discuss the intensive care management of severe TBI with emphasis on the specific measures directed at the control of intracranial pressure and CPP.

Hemodynamic steroid responsiveness is predictive of neurological outcome after traumatic brain injury

INTRODUCTION

To determine the impact of physiologic doses of hydrocortisone on neurologic outcome after traumatic brain injury (TBI).

METHODS

We conducted a retrospective study in a neurocritical care unit at a university teaching hospital. We included 29 patients with moderate and severe TBI requiring vasoactive drugs to maintain adequate arterial blood pressure who received corticosteroid. Infected patients were excluded. Blood cortisol levels were measured before and 30 and 60 minutes after the administration of a high-dose corticotropin stimulation test (HDST). Patients received hydrocortisone replacement therapy (200-300 mg/day) and vasoactive drugs requirements were noted. Intracranial pressure was managed according to a predefined protocol.

RESULTS

A total of 14 out of 29 (48%) of patients were classified as responders to hydrocortisone (stopping vasoactive drugs within 3 days of starting hydrocortisone). The Glasgow Outcome Score (GOS) was used to assess neurologic outcome at 6 months. A favorable outcome (GOS 4 and 5) was observed in 11 out of 14 (79%) of responders and five out of 15 (33%) of nonresponders (p = 0.03). Of the responders, 12 out of 14 (85%) had a baseline cortisol below 414 nmol/L, and five out of 14 (36%) had primary adrenal insufficiency (AI) (primary AI: low baseline cortisol, and poor response to the HDST). Age, severity of injury, and response to hydrocortisone were predictive of outcome in multiple logistic regression analysis.

CONCLUSIONS

Adrenal insufficiency is frequent after TBI, and hydrocortisone replacement therapy seems to be associated with a favorable neurologic outcome.

Effect of barbiturate coma on adrenal response in patients with traumatic brain injury

INTRODUCTION

Barbiturate coma is the second tier measure recommended by guidelines to treat post-traumatic refractory intracranial pressure. Systemic hypotension is its most important side effect. Recent evidence suggests that low-dose corticosteroid therapy may be used in a subset of patients with traumatic brain injury (TBI) to avoid hypotension. We evaluated adrenal function in TBI patients undergoing barbiturate coma, as treatment of their refractory intracranial hypertension.

MATERIALS AND METHODS

We prospectively studied 40 patients with moderate to severe TBI. Group A (17 patients) were treated with barbiturate coma. Group B (23 patients) presented intracranial hypertension controlled with first tier measures, and acted as a control. Adrenal function was evaluated by using the high-dose corticotropin stimulation test within 24 h after brain injury and after barbiturate coma induction.

RESULTS

Within 24 h after TBI, adrenal function was similar in both groups. Once barbiturate coma was induced, patients in group A treated with barbiturate coma presented a higher incidence of adrenal insufficiency compared with the control group B (53% vs 22%, p=0.03). Patients treated with barbiturates, who developed adrenal impairment, required higher doses of norepinephrine to maintain cerebral perfusion pressure than patients treated with barbiturates without adrenal impairment (1.07+/-1.04 microg/kg/min vs 0.31+/-0.32 mug/kg/min, p=0.03).

CONCLUSIONS

Patients with TBI treated with barbiturate coma are at higher risk of developing adrenal insufficiency. This subset of patients presented higher requirements of vasoactive support to avoid hypotension. In these patients corticosteroid therapy may have potential therapeutic implications to treat hemodynamic instability.

Adrenal function testing in patients with septic shock

INTRODUCTION

Adrenal failure (AF) is associated with increased mortality in septic patients. Nonetheless, there is no agreement regarding the best diagnostic criteria for AF. We compared the diagnosis of AF considering different baseline total cortisol cutoff values and Deltamax values after low (1 microg) and high (249 microg) doses of corticotropin, we analyzed the impact of serum albumin on AF identification and we correlated laboratorial AF with norepinephrine removal.

METHODS

A prospective noninterventional study was performed in an intensive care unit from May 2002 to May 2005, including septic shock patients over 18 years old without previous steroid usage. After measurement of serum albumin and baseline total cortisol, the patients were sequentially submitted to 1 microg and 249 microg corticotropin tests with a 60-minute interval between doses. Post-stimuli cortisol levels were drawn 60 minutes after each test (cortisol 60 and cortisol 120). The cortisol 60 and cortisol 120 values minus baseline were called Deltamax1 and Deltamax249, respectively. Adrenal failure was defined as Deltamax249 < or = 9 microg/dl or baseline cortisol < or = 10 microg/dl. Other baseline cortisol cutoff values referred to as AF in other studies (< or =15, < or =20, < or =25 and < or =34 mug/dl) were compared with Deltamax249 < or = 9 microg/dl and serum albumin influence. Norepinephrine removal was compared with the baseline cortisol values and Deltamax249 values.

RESULTS

We enrolled 102 patients (43 male). AF was diagnosed in 22.5% (23/102). Patients with albumin < or =2.5 g/dl presented a lower baseline total cortisol level (15.5 microg/dl vs 22.4 microg/dl, P = 0.04) and a higher frequency of baseline cortisol < or =25 microg/dl (84% vs 58.3%, P = 0.05) than those with albumin > 2.5 g/dl. The Deltamax249 levels and Deltamax249 < or = 9, however, were not affected by serum albumin (14.5 microg/dl vs 18.8 microg/dl, P = 0.48 and 24% vs 25%, P = 1.0). Baseline cortisol < or = 23.6 microg/dl was the most accurate diagnostic threshold to determine norepinephrine removal according to the receiver operating characteristic curve.

CONCLUSION

AF was identified in 22.5% of the studied population. Since Deltamax249 < or = 9 microg/dl results were not affected by serum albumin and since the baseline serum total cortisol varied directly with albumin levels, we propose that Deltamax249 < or = 9 microg/dl, which means Deltamax after high corticotropin dose may be a better option for AF diagnosis whenever measurement of free cortisol is not available. Baseline cortisol < or =23.6 microg/dl was the best value for predicting norepinephrine removal in patients without corticosteroid treatment.