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

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.

Endocrine consequences of adult traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is the most common cause of death and disability in young adults living in industrialised countries. Over the last few years, there has been an increasing awareness that hypopituitarism can complicate TBI in a significant proportion of survivors: at least 25% of TBI survivors develop one or more pituitary hormone deficiencies. This remarkably high frequency has changed the traditional concept that hypopituitarism was a rare complication of TBI and suggests that most cases of posttraumatic hypopituitarism remain undiagnosed and untreated in clinical practice. It is therefore reasonable to infer that posttraumatic hypopituitarism may make an important contribution to the high rates of physical and neuropsychiatric morbidity in patients with head injury.

CONCLUSIONS

There is clearly a need for identification as well as appropriate and timely management of hormone deficiencies in TBI patients to reduce morbidity, aid recovery and rehabilitation and avoid the long-term complications of pituitary failure.

Hyponatremia in patients with traumatic brain injury: incidence, mechanism, and response to sodium supplementation or retention therapy with hydrocortisone

BACKGROUND

Hyponatremia is a frequently observed electrolyte abnormality in patients with central nervous system disease. Several mechanisms, such as SIADH, hypopituitarism, and CSWS, have been proposed with varied incidences among several studies. We attempted to clarify the incidence and mechanism of hyponatremia for each type of TBI. We also assessed the efficacy of sodium supplementation and retention therapy. For sodium retention therapy, hydrocortisone was administered, expecting its mineralocorticoid effect, when the hyponatremia was associated with excess natriuresis.

METHODS

Retrospective analysis of 298 patients with TBI between January 2003 and December 2004 was performed. The incidence, background, clinical data, and outcome were evaluated.

RESULTS

Of the 298 patients, 50 (16.8%) presented hyponatremia during the time course. Hyponatremia was associated with longer hospital stay (P < .001) and bad outcome (P = .02). Among these 50 patients, 37 recovered from the hyponatremia with simple sodium supplementation. The remaining 13 patients presented massive natriuresis and required additional sodium retention therapy. Hydrocortisone statistically reduced the amount of sodium excretion (P = .002) and returned the serum sodium level to a normal value.

CONCLUSIONS

A high rate of hyponatremia after TBI was observed. Further studies are required to establish the precise mechanism of hyponatremia after TBI. Clear definition of CSWS is required to avoid confusion of the pathophysiology that causes hyponatremia. Hydrocortisone was useful to prevent excess natriuresis.

Traumatic brain injury in horses: 34 cases (1994-2004)

OBJECTIVE

To investigate the clinical, clinicopathologic, and diagnostic characteristics; treatment; and outcome associated with acute traumatic brain injury (TBI) in horses and assess risk factors for nonsurvival in TBI-affected horses.

DESIGN

Retrospective case series.

ANIMALS

34 horses with TBI. Procedures-Medical records of horses that had sustained trauma to the head and developed neurologic signs were reviewed. Data that included signalment, clinicopathologic findings, diagnosis, treatment, and outcome were analyzed. Clinicopathologic variables among horses in survivor and nonsurvivor groups were compared, and risk factors for nonsurvival were determined.

RESULTS

Median age of affected horses was 12 months. Findings of conventional survey radiography of the head alone failed to identify all horses with fractures of the calvarium. Horses with basilar bone fractures were 7.5 times as likely not to survive as horses without this type of fracture. Depending on clinical signs, horses received supportive care, osmotic or diuretic treatments, antimicrobials, anti-inflammatory drugs, analgesics, or anticonvulsants. Twenty-one (62%) horses survived to discharge from the hospital. In the nonsurvivor group, mean PCV was significantly higher, compared with the value in the survivor group (40% vs 33%). Risk factors associated with nonsurvival included recumbency of more than 4 hours' duration after initial evaluation (odds ratio, 18) and fracture of the basilar bone (odds ratio, 7.5).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that prognosis for survival in horses with acute TBI may be more favorable than previously reported. Among horses with TBI, persistent recumbency and fractures involving the basilar bones were associated with a poor prognosis.

Hypopituitarism following traumatic brain injury (TBI)

Traumatic brain injury (TBI) is the commonest cause of death and disability in young adults living in industrialised countries. Recently, several studies have shown that hypopituitarism is a common complication of head trauma, with a prevalence of at least 25% among patients who were studied months or years following injury. This remarkably high frequency has changed the traditional concept of hypopituitarism being a rare complication of TBI, and suggests that most cases of posttraumatic hypopituitarism remain undiagnosed and untreated in clinical practice. It is therefore reasonable to infer that posttraumatic hypopituitarism may have an important contribution to the high physical and neuropsychiatric morbidity seen in patients with head injury. This article discusses the published reports on neuroendocrine dysfunction in TBI patients and the natural history of this disorder. The potential impact of posttraumatic hypopituitarism on recovery and rehabilitation after injury will also be examined, as well as the need for the identification, and appropriate and timely management of hormone deficiencies in order to reduce morbidity, aid recovery, and avoid the long-term complications of pituitary failure.

Current approach on spinal cord monitoring: the point of view of the neurologist, the anesthesiologist and the spine surgeon

Optimal outcome in spine surgery is dependent of the coordination of efforts by the surgeon, anesthesiologist, and neurophysiologist. This is perhaps best illustrated by the rising use of intraoperative spinal cord monitoring for complex spine surgery. The challenges presented by neurophysiologic monitoring, in particular the use of somatosensory and motor evoked potentials, requires an understanding by each member for the team of the proposed operative procedure as well as an ability to help differentiate clinically important signal changes from false positive changes. Surgical, anesthetic, and monitoring issues need to be addressed when relying on this form of monitoring to reduce the potential of negative outcomes in spine surgery. This article provides a practical overview from the perspective of the neurophysiologist, the anesthesiologist, and the surgeon on the requirements which must be understood by these participants in order to successfully contribute to a positive outcome when a patient is undergoing complex spine surgery.

Relationship between plasma adrenocorticotropin hormone and intensive care unit survival in early traumatic brain injury

BACKGROUND

Hypothalamic pituitary adrenal response has been recently evaluated in patients with traumatic brain injury (TBI) with different results. Our objective was to study this response and its relationship with outcome in the early stage after TBI.

METHODS

We conducted a prospective observational clinical study in the intensive care unit of a tertiary level university hospital. The study included 50 consecutive patients who suffered isolated TBI. Intracranial pressure (ICP) was measured by an intraparenchymal probe. All patients were sedated and mechanically ventilated. Second-level measures were provided as per protocol, when needed. We measured plasma adrenocorticotropin hormone (ACTH) levels, as well as baseline and stimulated serum cortisol after a high-dose corticotrophin stimulation test, within 2 days after TBI for all patients.

RESULTS

Mean age was 36 +/- 18 (range 16-77) years. Forty-four (88%) were male. Median Glasgow Coma Scale score was 7. Mean ACTH was 15.4 +/- 19.8 pg/mL. Mean baseline cortisol was 14.8 +/- 9.0 microg/dL and mean stimulated cortisol was 27.1 +/- 7.3 microg/dL and 30.5 +/- 7.2 microg/dL at 30 and 60 minutes, respectively. Baseline and stimulated cortisol were not correlated with mortality. Logistic regression analysis revealed that, either plasma ACTH levels <9 pg/mL or lack of indication to provide second-level measures to control ICP were significant independent predictors of survival.

CONCLUSIONS

The presence of a low plasma ACTH concentration at an early stage of TBI and lack of indication to provide second-level measures to control ICP were associated with a higher intensive care unit survival.

Traumatic brain injury: assessment, resuscitation and early management

This review examines the evidence base for the early management of head-injured patients. Traumatic brain injury (TBI) is common, carries a high morbidity and mortality, and has no specific treatment. The pathology of head injury is increasingly well understood. Mechanical forces result in shearing and compression of neuronal and vascular tissue at the time of impact. A series of pathological events may then ensue leading to further brain injury. This secondary injury may be amenable to intervention and is worsened by secondary physiological insults. Various risk factors for poor outcome after TBI have been identified. Most of these are fixed at the time of injury such as age, gender, mechanism of injury, and presenting signs (Glasgow Coma Scale and pupillary signs), but some such as hypotension and hypoxia are potential areas for medical intervention. There is very little evidence positively in favour of any treatments or packages of early care; however, prompt, specialist neurocritical care is associated with improved outcome. Various drugs that target specific pathways in the pathophysiology of brain injury have been the subject of animal and human research, but, to date, none has been proved to be successful in improving outcome.

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.

Identification of adrenal insufficiency in pediatric critical illness

OBJECTIVE

To determine physicians' beliefs and practices regarding adrenal dysfunction in pediatric critical illness.

DESIGN

Cross-sectional mail survey.

SETTING

Canada.

PARTICIPANTS

All members of the Canadian Pediatric Endocrine Group and all physicians identified as practicing pediatric intensive care medicine in any of 16 tertiary care teaching centers in Canada.

INTERVENTIONS

Three pediatric intensive care physicians and three pediatric endocrinologists reviewed the questionnaire before administration to ensure clarity. We asked participants to report their views on the following: a) the frequency of adrenal insufficiency in pediatric critical illness; b) diagnosis/definition of adrenal insufficiency in pediatric critical illness; and c) the use of empirical glucocorticoids in fluid/vasopressor-resistant hypotension in pediatric critical illness.

MEASUREMENTS AND MAIN RESULTS

Forty-six of 57 (80.7%) endocrinologists responded, with 43 participating (75.4%). Among intensivists, 59 of 70 (84.3%) responded with no refusals. Of intensivists, 81.4% believe that adrenal insufficiency occurs sometimes or often in critically ill pediatric intensive care unit patients, whereas 41.8% of endocrinologists believe adrenal insufficiency occurs never or rarely in these patients. Six definitions of adrenal insufficiency were proposed (varying cortisol level vs. peak/increment of cortisol in response to corticotropin), with no consensus on the definition of adrenal insufficiency from the endocrinologists or intensivists. Half (50.9%) of intensivists said they would sometimes or often empirically treat hypotensive pediatric patients with glucocorticoids, whereas 81.0% of endocrinologists would occasionally or never recommend glucocorticoids on this basis.

CONCLUSIONS

There is no consensus among pediatric intensivists or endocrinologists as to how often adrenal insufficiency occurs in pediatric critical illness or how to diagnose this condition. Despite this lack of consensus, however, many pediatric intensivists would empirically treat hypotensive patients who they suspect may have adrenal insufficiency. Prospective studies are required to determine the definition, frequency, and appropriate treatment of adrenal insufficiency in critically ill pediatric patients.

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.

Abnormalities of pituitary function after traumatic brain injury in children

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

[Management of severe traumatic brain injury]

Severe brain injuries, most often occurring in young subjects, are a major source of lost work years. These injuries are medical and surgical emergencies. Prehospital management of severe brain injuries requires intubation and mechanical ventilation aimed at normal arterial carbon dioxide pressure. Signs of transtentorial herniation: Uni- or bilateral mydriasis requires immediate perfusion of 20% mannitol or hypertonic sodium chloride. Neurological disorders after head injury justify emergency cerebral computed tomography. The presence of a mass syndrome or signs of transtentorial herniation are in principle indications for surgery. Specialized hospital management is essential. In the case of refractory intracranial hypertension, the cerebral perfusion pressure and osmotherapy should be adapted to the volume of the cerebral contusion. The use of deep hypothermia and barbiturates should be minimized as much as possible. Magnetic resonance imaging makes it possible to identify the cerebral lesions.

Adrenal insufficiency: still a cause of morbidity and death in childhood

Adrenal insufficiency is relatively rare in childhood and adolescence. Signs and symptoms may be nonspecific; therefore, the diagnosis may not be suspected early in the course. If unrecognized, adrenal insufficiency may present with life-threatening cardiovascular collapse. Adrenal crisis continues to occur in children with known primary or secondary adrenal insufficiency during intercurrent illness because of failure to increase glucocorticoid dosage. In this article, current knowledge of the incidence, diagnosis, and treatment of adrenal insufficiency in children and factors precipitating adrenal crisis are summarized. Suggestions for prevention of adrenal crisis in patients at risk are provided for health care professionals and families.

Lasting Neuroendocrine-Immune Effects of Traumatic Brain Injury in Rats

Traumatic brain injury (TBI) is a principal cause of long-term physical, cognitive, behavioral, and social deficits in young adults, which frequently coexist with a high incidence of substance abuse disorders. However, few studies have examined the long-term effects of TBI on the neuroendocrine-immune system. TBI was induced in adult male rats under isoflurane anesthesia by cortical contusion injury with a pneumatic piston positioned stereotaxically over the left parietal cortex. Controls underwent sham surgery without injury. At 4 weeks post-injury, the plasma corticosterone response to 30-min restraint stress was significantly blunted in TBI rats compared to the sham controls. One week later, transmitters were implanted for continuous biotelemetric recording of body temperature and spontaneous locomotor activity. At 6 weeks post-injury, the febrile response to i.p. injection of the bacterial endotoxin, lipopolysaccharide (LPS; 50 microg/kg), was significantly lower in TBI than in sham rats. At 8 weeks, swimming in the forced swim test was significantly less in TBI than sham rats. At 9 weeks, rats were rendered ethanol (EtOH) dependent by feeding an EtOH-containing liquid diet for 14 days. Cosine rhythmometry analysis of circadian body temperature Midline Estimating Statistic of Rhythm (MESOR), amplitudes, and acrophases indicated differential effects of EtOH and withdrawal in the two groups. Light- and dark-phase activity analysis indicated that TBI rats were significantly more active than the sham group, and that EtOH and withdrawal differentially affected their activity. Given the extensive interactions of the neuroendocrine-immune systems, these results demonstrate that TBI produces lasting dysregulation amidst the central substrates for allostasis and circadian rhythmicity.

Relative adrenal insufficiency after cardiac arrest: impact on postresuscitation disease outcome

The purpose of this study is to prospectively evaluate the cortisol response and determine the relative adrenal insufficiency after return of spontaneous circulation (ROSC).

METHODS

This is a prospective cohort study describing the prevalence of relative adrenal insufficiency in consecutive patients admitted to an intensive care unit following ROSC (>24 hours) after cardiac arrest. The study institution is a 1,300-bed urban hospital with an annual intensive care unit census of 80. Descriptive statistics is used to report results.

RESULTS

This study included 30 patients over a 1-year period. The mean patient age was 52 years, and there were 15 (50%) males. The most common etiology for cardiac arrest was unknown, and the most common initial rhythm was asystole. There were 16 (53%) witnessed arrests. The mean time from arrest to cardiopulmonary resuscitation was 8 minutes, and the mean time from arrest to ROSC was 23 minutes. Relative adrenal insufficiency (incremental response to corticotrophin test < 9 microg/dL) at initial 12 to 24 hours and >24 to 48 hours occurred in 13 (43%) and 10 (33%) patients, respectively. All basal cortisol values were normal to high. Nineteen (58%) patients survived. The mean cortisol values at the initial 12 to 24 hours and >24 to 48 hours were similar among survivors and nonsurvivors. Relative adrenal insufficiency was present in only 5 (26%) survivors.

CONCLUSION

Relative adrenal insufficiency may be associated with the increased mortality rate in patients with return of circulation after cardiac arrest. Although basal cortisol values were normal to high, treatment of relative adrenal insufficiency with corticosteroids may decrease the mortality rate. Additional studies are needed to confirm this association and to determine the effectiveness of treating relative adrenal insufficiency.

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

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

Corticosteroid replacement in critically ill patients

This review addresses the use of corticosteroid replacement in critically ill patients. Low-dose corticosteroid replacement for critically ill patients with septic shock has been shown to reduce the duration of vasopressor-dependent shock, to shorten ICU length of stay, and, in recent trials, to reduce mortality. Numerous questions remain to be fully answered about patient selection, corticotropin-stimulation testing methods, and interpretation of results.

Relative Adrenal Failure in the ICU: An Identifiable Problem Requiring Treatment

Critically ill patients at some stage may develop adrenal insufficiency (AI). This article reviews the mechanisms, diagnosis criteria, consequences, and treatment of AI in various ICU conditions. Glucocorticoid insufficiency may be related to a decrease in glucocorticoid synthesis (ie, adrenal insufficiency) or to a reduced delivery of glucocorticoid to target tissues and cells. Diagnosis relies on clinical suspicion and ACTH test results. The length of cortisol replacement therapy should be at least 7 days and the adjunction of fludrocortisone is recommended.