Relative adrenal insufficiency in patients with septic shock: comparison of low-dose and conventional corticotropin tests

Critical illness-related corticosteroid insufficiency (CIRCI) in paediatric patients: a diagnostic and therapeutic challenge

Critical illness-related corticosteroid insufficiency or CIRCI is characterized by acute and life-threatening disfunction of hypothalamic-pituitary-adrenal (HPA) axis observed among intensive care unit- staying patients.It is associated with increased circulating levels of biological markers of inflammation and coagulation, morbidity, length of ICU stay, and mortality.Several mechanisms are involved in CIRCI pathogenesis: reduced CRH-stimulated ACTH release, peripheral resistance to glucocorticoids, altered cortisol synthesis, impaired cortisol-free fraction and bioavailability.Diagnostic and therapeutic management of this condition in children is still debated, probably because of the lack of agreement among intensive care specialists and endocrinologists regarding diagnostic criteria and prevalence of CIRCI in paediatric age.In the present narrative review, we focused on definition of CIRCI in paediatric age and we advise on how to diagnose and treat this poorly understood condition, based on current literature data.

PROGNOSTIC VALUE OF LOW-DOSE ADRENOCORTICOTROPIC HORMONE TEST IN CRITICALLY ILL PATIENTS

ABSTRACT

Background: Previous trials evaluated the incidence of critical illness-related corticosteroid insufficiency (CIRCI) using 250 μg adrenocorticotropic hormone (ACTH). However, this supraphysiological dose could result in false-positive levels. We aimed to determine the incidence of CIRCI in septic patients using a 1 μg ACTH stress test. Methods: We conducted a prospective cohort study on 39 patients with septic shock. Critical illness-related corticosteroid insufficiency was defined as a Δ max cortisol <9 μg/dL after 1 μg ACTH stress test. The primary outcome of the study was death. Secondary outcomes included days of vasopressors, days of mechanical ventilation (MV), amount of fluid per day, the incidence of acute kidney injury (AKI), and days of intensive care unit (ICU) stay. Results: The incidence of CIRCI in our cohort was 43.6% using 1 μg ACTH. There were no significant differences between groups in terms of ICU scores, laboratory investigations, vasopressors, MV days, amount of fluid per day, and the ICU stay ( P = > 0.05). The CIRCI group had lower median survival and survival probability rates (5 days and 48.4%, respectively) compared with the non-CIRCI group (7 days and 49.5%, respectively). In addition, the CIRCI group had a shorter time to develop AKI and a higher probability of developing AKI (4 days and 44.6%, respectively) in comparison with the non-CIRCI group (6 days and 45.57%, respectively). Conclusion: We concluded that the CIRCI group had a lower mean survival rate and a higher incidence of AKI. We recommend the use of 1 μg ACTH test in septic shock patients to identify this subgroup of patients.

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.

Combination of vitamin C, thiamine and hydrocortisone added to standard treatment in the management of sepsis: results from an open label randomised controlled clinical trial and a review of the literature

Background: Combination of vitamin C, hydrocortisone and thiamine have recently been used in sepsis but data of efficacy are conflicting and no data are available from developing countries. We sought to study the effect of addition of this combination to standard care in patients with sepsis/septic shock in a north Indian setting.Methods: In a prospective, open label, randomised fashion, 100 patients with sepsis/septic shock were recruited to receive either standard therapy alone (control group, n = 50) or a combination of vitamin C, thiamine and hydrocortisone (treatment group, n = 50) in addition. The patients were followed for various clinical and laboratory parameters, in-hospital and 30-day mortality, duration of vasopressor use, lactate clearance, duration of hospital stay, and change in serum lactate and the SOFA score over the first 4 days.Results: The 2 groups were matched for basic characteristics. The in-hospital mortality (28% in controls and 24% in treatment group, p = .82) and 30-day mortality (42% in controls and 40% in treatment group, p = 1.00) was not significantly different in the 2 groups. However, there was a significant difference in duration of vasopressor use (96.13 ± 40.50 h in control group v/s 75.72 ± 30.29 h in treatment group, p value = .010) and lactate clearance (control group: 41.81% v/s treatment group: 56.83%, p value =.031) between 2 groups.Conclusions: Addition of vitamin C, hydrocortisone, and thiamine into standard care of sepsis does not improve in-hospital or 30 day mortality. However lower vasopressor use and faster lactate clearance is observed with treatment.

Low-dose corticosteroids in septic shock: Has the pendulum shifted?

PURPOSE

The utility of low-dose corticosteroids in septic shock is reviewed.

SUMMARY

Low-dose corticosteroids are suggested as treatment for septic shock patients who remain hemodynamically unstable despite adequate fluid resuscitation and vasopressor therapy. However, the risks and benefits of corticosteroids are unclear in this patient population. Previous multicenter trials have yielded conflicting results on the survival benefits of corticosteroids. The recently published Adjunctive Corticosteroid Treatment in Critically Ill Patients with Septic Shock (ADRENAL) and Activated Protein C and Corticosteroids for Human Septic Shock (APROCCHSS) trials provide valuable but opposing insight into this ongoing debate. Discordant findings related to mortality in these trials are likely related to differences in study design, corticosteroid regimen, and baseline characteristics among enrolled patients. The utility of adding fludrocortisone to hydrocortisone compared with using hydrocortisone alone is unclear. There does not appear to be an advantage to administering corticosteroids as a continuous infusion to reduce the rate of hyperglycemia or providing a taper to prevent rebound hypotension.

CONCLUSION

The mortality benefit of corticosteroids appears to be greatest in septic shock patients with high vasopressor requirements, evidence of multiorgan failure, and primary lung infections. Corticosteroids consistently lead to a faster reversal of shock and may shorten the duration of mechanical ventilation. Corticosteroids do not seem to increase the risk of superinfection at low doses but frequently lead to a higher frequency of hyperglycemia. We recommend the administration of corticosteroids to septic shock patients with escalating doses of vasopressors and evidence of multiorgan dysfunction.

Cosyntropin testing does not predict response to glucocorticoids in community-acquired pneumonia in a randomized controlled trial

OBJECTIVE

Glucocorticoids have been shown to improve outcome in community-acquired pneumonia (CAP). However, glucocorticoids have potential side-effects, and treatment response may vary. It is thus crucial to select patients with high likelihood to respond favourably. In critical illness, cosyntropin testing is recommended to identify patients in need for glucocorticoids. We investigated whether cosyntropin testing predicts treatment response to glucocorticoids in CAP.

DESIGN

Predefined secondary analysis of a randomized controlled trial.

PATIENTS

Hospitalized patients with CAP.

MEASUREMENTS

We performed 1 µg cosyntropin tests in a randomized trial comparing prednisone 50 mg for 7 days to placebo. We investigated whether subgroups based on baseline and stimulated cortisol levels responded differently to glucocorticoids with regard to time to clinical stability (TTCS) and other outcomes by inclusion of interaction terms into statistical models.

RESULTS

A total of 326 patients in the prednisone and 309 patients in the placebo group were evaluated. Neither basal cortisol nor a Δcortisol <250 nmol/L after stimulation nor the combination of basal cortisol and Δcortisol predicted treatment response as measured by TTCS (all P for interaction >0.05). Similarly, we found no effect modification with respect to mortality, rehospitalization, antibiotic treatment duration or CAP-related complications (all P for interaction >0.05). However, glucocorticoids had a stronger effect on shortening length of hospital stay in patients with a baseline cortisol of ≥938 nmol/L (P for interaction = 0.015).

CONCLUSIONS

Neither baseline nor stimulated cortisol after low-dose cosyntropin testing at a dose of 1 µg predicted glucocorticoid responsiveness in mild to moderate CAP. A treatment decision for or against adjunct glucocorticoids in CAP should not be made depending on cortisol values or cosyntropin testing results.

Vitamin C, Hydrocortisone, and Thiamine for the Treatment of Severe Sepsis and Septic Shock: A Retrospective Analysis of Real-World Application

A recent study suggested mortality benefits using vitamin C, hydrocortisone, and thiamine combination therapy (triple therapy) in addition to standard care in patients with severe sepsis and septic shock. In order to further evaluate the effects of triple therapy in real-world clinical practice, we conducted a retrospective observational cohort study at an academic tertiary care hospital. A total of 94 patients (47 in triple therapy group and 47 in standard care group) were included in the analysis. Baseline characteristics in both groups were well-matched. No significant difference in the primary outcome, hospital mortality, was seen between triple therapy and standard care groups (40.4% vs. 40.4%; p = 1.000). In addition, there were no significant differences in secondary outcomes, including intensive care unit (ICU) mortality, requirement for renal replacement therapy for acute kidney injury, ICU length of stay, hospital length of stay, and time to vasopressor independence. When compared to standard care, triple therapy did not improve hospital or ICU mortality in patients with septic shock. A randomized controlled trial evaluating the effects of triple therapy is necessary prior to implementing vitamin C, hydrocortisone, and thiamine combination therapy as a standard of care in patients with septic shock.

Neuroendocrine Derangements in Early Septic Shock: Pharmacotherapy for Relative Adrenal and Vasopressin Insufficiency

Septic shock is a leading cause of mortality in intensive care units throughout the world. While this disease state represents a highly complex pathophysiology involving numerous organ systems, the early approach to care includes adequate hemodynamic support traditionally achieved via infusions of vasoactive medications after adequate fluid resuscitation. Relative adrenal and vasopressin deficiencies are a common feature of septic shock that contribute to impaired hemodynamics. Hydrocortisone and vasopressin are endocrine system hormone analogues that target the acute neuroendocrine imbalance associated with septic shock. This clinically focused annotated review describes the pathophysiological mechanisms behind their use and explores the potential clinical roles of early administration and synergy when combined.

Controversies in Corticosteroid use for Sepsis

BACKGROUND

Severe sepsis and septic shock are potentially deadly conditions managed in the emergency department (ED). Management centers on source control, fluid resuscitation, broad-spectrum antimicrobials, and vasopressors as needed. The use of corticosteroids is controversial.

OBJECTIVE

To evaluate the evidence behind corticosteroid therapy in patients with septic shock.

DISCUSSION

Septic shock is associated with severe mortality and morbidity. Cytokine release produces a systemic inflammatory state. Vasopressor-resistant septic shock warrants consideration of the disease state and other pathologies such as adrenal insufficiency. Many studies and meta-analyses have been conducted evaluating corticosteroid therapy for this population. High-dose corticosteroid therapy is associated with increased harm, but physiologic-dose corticosteroids may decrease the need for vasopressors. Mortality benefit is controversial, with much of the literature demonstrating no effect. The risk of superinfection is not suggested by the majority of studies. The Surviving Sepsis Campaign advises consideration of corticosteroids in patients with vasopressor and fluid-resistant septic shock. Patients with vasopressor-resistant septic shock with no contraindications to corticosteroids may benefit from hydrocortisone 100 mg intravenously (i.v.) every 8 h or 50 mg i.v. every 6 h. Fludrocortisone is not recommended at this time.

CONCLUSIONS

Septic shock is associated with higher mortality, specifically for patients with vasopressor and fluid-refractory shock. The use of physiologic-dose steroids can reduce vasopressor requirements and improve time of shock resolution. Current literature suggests corticosteroids do not improve mortality, but further studies are required.

Total and free cortisol responses and their relation to outcomes after cardiopulmonary bypass in infants

BACKGROUND

Hypothalamic-pituitary-adrenal (HPA) axis dysfunction may be partially responsible for the hemodynamic instability experienced by infants after cardiopulmonary bypass (CPB). We report the full spectrum of the HPA response surrounding CPB for infant congenital cardiac surgery.

METHODS

We enrolled 84 infants who received 1 mg/kg of dexamethasone before initiation of CPB. Total cortisol (TC), free cortisol (FC), adrenocorticotropic hormone (ACTH), and corticosteroid-binding globulin (CBG) were measured at 3 time points: immediately before CPB (TP1), on intensive care unit arrival (TP2), and at 24 hours after surgery (TP3). A 1-μg ACTH stimulation test was performed at each time point to evaluate adrenal responsiveness.

RESULTS

Sixty-eight infants completed all study procedures. Levels of TC, FC, CBG, and ACTH decreased significantly between the preoperative and 24-hour postoperative measurements. There were no significant associations between preoperative FC responses and clinical outcomes after adjusting for weight and Risk-Adjusted Scores for Congenital Heart Surgery. Infants with subnormal TC responses to ACTH stimulation (<9 μg/dL) at TP2 had greater fluid requirements (P < .001) and greater chest tube output (P < .001) during the first 24 hours, as well as longer length of stay (LOS) (P = .007). Except for LOS, these differences persisted for infants with subnormal stimulation tests at TP3.

CONCLUSIONS

We observed a significant decline in all aspects of the HPA axis throughout the first 24 hours after infant CPB. TC and FC levels were not associated with clinical outcomes. Subnormal (Δ <9 μg/dL) TC response to cosyntropin stimulation during the postoperative period was associated with increased fluid resuscitation and greater LOS.

Steroids Improve Hemodynamics in Infants With Adrenal Insufficiency After Cardiac Surgery

OBJECTIVE

To investigate whether steroid replacement therapy improved hemodynamics in infants after surgery for congenital heart disease only when they develop adrenal insufficiency. The authors retrospectively investigated adrenal function and evaluated hemodynamic responses to steroid replacement therapy in infants after surgery for congenital heart disease.

DESIGN

Retrospective, cohort study.

SETTING

Intensive care unit in the National Cerebral and Cardiovascular Center Hospital in Japan.

PATIENTS

Thirty-two neonates and infants<3 months old who underwent cardiovascular surgery.

INTERVENTIONS

The patients were divided into 2 groups based on corticotropin stimulation test results: group AI with adrenal insufficiency (baseline cortisol<15 µg/dL or incremental increase after testing of<9 µg/dL, with baseline cortisol of 15-34 µg/dL); and group N with normal adrenal function. The corticotropin stimulation test was performed by injecting 3.5 µg/kg of tetracosactide acetate. Hydrocortisone (1 mg/kg) was administered every 6 hours, and hemodynamics were compared before and after steroid administration between the groups.

MEASUREMENTS AND MAIN RESULTS

Seven patients were classified into group AI, and demonstrated a mean blood pressure increase from 53±8 mmHg before treatment to 68±9 mmHg 18 hours after steroid administration (p<0.01). Urine output also increased, from 2.7±1.0 mL/kg/h to 4.8±1.9 mL/kg/h (p<0.05). In group N, neither mean blood pressure nor urine output increased after steroid administration.

CONCLUSIONS

After surgery for congenital heart disease, one-fifth of infants developed adrenal insufficiency. Steroid replacement therapy improved hemodynamics only in the subgroup with adrenal insufficiency.

The utility of the corticotropin test to diagnose adrenal insufficiency in critical illness: an update

OBJECTIVE

One of the most common dynamic testing procedures for assessment of adrenocortical function is the standard corticotropin or the cosyntropin test. The aim of this review was to examine the evidence base underlying the corticotropin test in the management of the critically ill patient.

DATA SYNTHESIS

The principle behind the corticotropin test is the demonstration of an inappropriately low cortisol production in response to exogenous ACTH, a situation analogous to physiological stress. The corticotropin test was originally described in nonstressed subjects, and its applicability and interpretation in the setting of critical illness continues to generate controversy. Attempting to determine the prevalence of an abnormal corticotropin test in critical illness is complicated by the use of different end-points and different populations. Moreover, the test result is also influenced by the assay used for measurement of plasma cortisol. Trials assessing the relationship between corticotropin response and severity of stress and organ dysfunction have produced divergent results, which may reflect differences in the methodology and the association being measured. Moreover, controversy exists with respect to the methodology and the interpretation with respect to the following variables: dose of corticotropin, end-points for assessment of total or free cortisol, effect of plasma cortisol variability, adrenal blood flow and its equivalence with other tests of adrenocortical function.

CONCLUSIONS

The corticotropin test is used widely in the evaluation of adrenocortical function in the endocrine clinics. Its role in the critically ill patient is less well established. Several confounding variables exist and to have a 'one-size-fits-all' approach with a single end-point in the face of several methodological and pathophysiological confounders may be flawed and may result in the institution of inappropriate therapy. The current evidence does not support the use of the corticotrophin test in critical illness to assess adrenocortical function and guiding steroid therapy in critical illness.

Hypothalamic-pituitary-adrenal axis in lethal canine Staphylococcus aureus pneumonia

The clinical significance and even existence of critical illness-related corticosteroid insufficiency is controversial. Here, hypothalamic-pituitary-adrenal (HPA) function was characterized in severe canine Staphylococcus aureus pneumonia. Animals received antibiotics and titrated life-supportive measures. Treatment with dexamethasone, a glucocorticoid, but not desoxycorticosterone, a mineralocorticoid, improves outcome in this model. Total and free cortisol, adrenocorticotropic hormone (ACTH). and aldosterone levels, as well as responses to exogenous ACTH were measured serially. At 10 h after the onset of infection, the acute HPA axis stress response, as measured by cortisol levels, exceeded that seen with high-dose ACTH stimulation but was not predictive of outcome. In contrast to cortisol, aldosterone was largely autonomous from HPA axis control, elevated longer, and more closely associated with survival in early septic shock. Importantly, dexamethasone suppressed cortisol and ACTH levels and restored ACTH responsiveness in survivors. Differing strikingly, nonsurvivors, sepsis-induced hypercortisolemia, and high ACTH levels as well as ACTH hyporesponsiveness were not influenced by dexamethasone. During septic shock, only serial measurements and provocative testing over a well-defined timeline were able to demonstrate a strong relationship between HPA axis function and prognosis. HPA axis unresponsiveness and high aldosterone levels identify a septic shock subpopulation with poor outcomes that may have the greatest potential to benefit from new therapies.

CBS and CSE are critical for maintenance of mitochondrial function and glucocorticoid production in adrenal cortex

AIMS

Mitochondria are known to play a central role in adrenocortical steroidogenesis. Recently, hydrogen sulfide (H2S), a gaseous transmitter endogenously produced by cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE), has been found to improve mitochondrial function. The present study aimed at examining whether CBS and CSE are expressed in adrenal glands, and investigated the role of these enzymes in the maintenance of mitochondrial function and the production of glucocorticoids in adrenocortical cells.

RESULTS

Both CBS and CSE are present in murine adrenocortical cells and account for H2S generation in adrenal glands. Using a combination of both in vivo and in vitro approaches, we demonstrated that either CBS/CSE inhibitors or small interfering RNAs led to mitochondrial oxidative stress and dysfunction, which meanwhile resulted in blunted corticosterone responses to adrenocorticotropic hormone (ACTH). These effects were significantly attenuated by the treatment of H2S donor GYY4137. Lipopolysaccharide (LPS) also caused mitochondrial damage, thereby resulting in adrenal insufficiency. Moreover, LPS inhibited CBS/CSE expression and H2S production in adrenal glands, while H₂S donor GYY4137 protected against LPS-induced mitochondrial damage and hyporesponsiveness to ACTH. Local suppression of CBS or CSE in adrenal glands significantly increased the mortality in endotoxemic mice, which was also improved by GYY4137.

INNOVATION

The identification of endogenous H2S generation as critical regulators of adrenocortical responsiveness might result in the development of new therapeutic approaches for the treatment of relative adrenal insufficiency during sepsis.

CONCLUSIONS

Endogenous H₂S plays a critical role in the maintenance of mitochondrial function in the adrenal cortex, thereby resulting in an adequate adrenocortical response to ACTH.

Longitudinal assessment of adrenal function in the early and prolonged phases of critical illness in septic patients: relations to cytokine levels and outcome

CONTEXT

Adrenal dysfunction remains a controversial issue in critical care. The long-stay intensive care unit (ICU) population may be at increased risk of adrenal insufficiency.

OBJECTIVE

We aimed to determine whether adrenal dysfunction develops during the course of sepsis.

DESIGN

This is a prospective observational longitudinal study.

SETTING

The study was conducted in the ICU of a secondary/tertiary care hospital.

PATIENTS

We studied 51 consecutive mechanically ventilated patients with sepsis.

INTERVENTION

We measured cortisol, ACTH, cortisol-binding globulin, cytokines, and cortisol 30 minutes after 1 μg ACTH(1-24), upon sepsis diagnosis and every 3 to 4 days, until Day 30 or until recovery or death.

MAIN OUTCOME MEASURES

We looked for changes in baseline and stimulated cortisol levels and its relationship to ACTH levels, sepsis severity or survival.

RESULTS

Baseline and stimulated cortisol levels did not vary significantly. Septic patients with shock had higher baseline (20 ± 6 vs 17 ± 5 μg/dL, P = .03) and stimulated cortisol levels (26 ± 5 vs 23 ± 6 μg/dL, P = .04), compared with those without shock. On Day 1, ACTH levels could not predict cortisol levels (R(2) = 0.06, P = .08). ACTH levels increased significantly after Day 10 and, at this time point, they related to cortisol levels (R(2) = 0.35, P < .001). Development of septic shock, or resolution from it, was not associated with changes in baseline, stimulated cortisol levels, or the cortisol increment. There was much inpatient variability in the diagnosis of adrenal dysfunction at different time points.

CONCLUSIONS

Total cortisol levels relate both to the severity and outcome of sepsis and remain fairly unchanged during the course of illness. Initially, cortisol levels are largely ACTH independent, whereas ACTH increases and correlates with cortisol levels later on. Adrenal dysfunction does not seem to be a major problem during the prolonged phase of sepsis. Although not significant, the variation in cortisol levels may be such that classification of patients varies, questioning the utility of arbitrary cut-offs to define adrenal dysfunction in septic patients.

Secondary adrenal insufficiency after glucocorticosteroid administration in acute spinal cord injury: a case report

CONTEXT/BACKGROUND

A 61-year-old female with cervical stenosis underwent an elective cervical laminectomy with post-op worsening upper extremity weakness. Over the first 3 weeks post-op, she received two separate courses of intravenous steroids. Two days after cessation of steroids, she presented with non-specific symptoms of adrenal insufficiency (AI). Initial formal diagnostic tests of random cortisol level and 250 µg cosyntropin challenge were non-diagnostic; however, symptoms resolved with the initiation of empiric treatment with hydrocortisone. Ten days later, repeat cosyntropin (adrenocortocotropic hormone stimulation) test confirmed the diagnosis of AI.

FINDINGS

AI is a potentially life-threatening complication of acute spinal cord injury (ASCI), especially in those receiving steroids acutely. Only three cases have been reported to date of AI occurring in ASCI after steroid treatment. The presenting symptoms can be non-specific (as in this patient) and easily confused with other common sequelae of ASCI such as orthostasis and diffuse weakness. The 250 µg cosyntropin simulation test may not the most sensitive test to diagnose AI in ASCI.

CONCLUSION

The non-specific presentations and variability of diagnosis criteria make diagnosis more difficult. One microgram cosyntropin simulation test may be more sensitive than higher dose. Clinicians should be aware that AI can be a potential life-threatening complication of ASCI post-steroid treatment. Prompt diagnosis and treatment can reverse symptoms and minimize mortality.

Serum cortisol concentrations in horses with colic

Few studies have evaluated cortisol concentrations in horses with colic. In humans with septic shock, high cortisol levels are associated with an increased risk of death. The objectives of this study were to compare the serum total cortisol concentrations (STCCs) in horses with colic to those without colic, and to assess whether the STCC relates to the pathological nature or outcome of the disease. STCCs were determined at presentation in horses with colic and in systemically healthy 'control' horses. Horses with colic were grouped based on clinical and clinico-pathological parameters at admission, treatment, lesion type and location, and outcome. Univariable and multivariable logistic regression were performed using two different outcome measures: (a) whether the horse had colic or not (yes vs. no), and (b) horse STCC (≥200 nmol/L vs. <200 nmol/L). Horses were more likely to have colic if they presented with high STCCs (≥200 nmol/L compared with <200 nmol/L). Horses with colic and with STCCs ≥200nmol/L were more likely to have moderate or severe colic signs (compared with mild colic) and heart rates >45 beats per min (compared with ≤45 beats per min). It was concluded that colic in horses is associated with elevated STCCs, and increased STCC in horses with colic appears to relate to the severity of the disease. STCCs may provide additional decision-making and prognostic information in horses with colic but further studies are required to avoid misinterpretations associated with the wide variation in STCCs.

Anesthetic induction with etomidate, rather than propofol, is associated with increased 30-day mortality and cardiovascular morbidity after noncardiac surgery

BACKGROUND

Because etomidate impairs adrenal function and blunts the cortisol release associated with surgical stimulus, we hypothesized that patients induced with etomidate suffer greater mortality and morbidity than comparable patients induced with propofol.

METHODS

We evaluated the electronic records of 31,148 ASA physical status III and IV patients who had noncardiac surgery at the Cleveland Clinic. Among these, anesthesia was induced with etomidate and maintained with volatile anesthetics in 2616 patients whereas 28,532 were given propofol for induction and maintained with volatile anesthetics. Two thousand one hundred forty-four patients given etomidate were propensity matched with 5233 patients given propofol and the groups compared on 30-day postoperative mortality, length of hospital stay, cardiovascular and infectious morbidities, vasopressor requirement, and intraoperative hemodynamics.

RESULTS

Patients given etomidate had 2.5 (98% confidence interval [CI], 1.9-3.4) times the odds of dying than those given propofol. Etomidate patients also had significantly greater odds of having cardiovascular morbidity (odds ratio [OR] [98% CI]: 1.5 [1.2-2.0]), and significantly longer hospital stay (hazard ratio [95% CI]: 0.82 [0.78-0.87]). However, infectious morbidity (OR [98% CI]: 1.0 [0.8-1.2]) and intraoperative vasopressor use (OR [95% CI] 0.92: [0.82-1.0]) did not differ between the agents.

CONCLUSION

Etomidate was associated with a substantially increased risk for 30-day mortality, cardiovascular morbidity, and prolonged hospital stay. Our conclusions, especially on 30-day mortality, are robust to a strong unmeasured binary confounding variable. Although our study showed only an association between etomidate use and worse patients' outcomes but not causal relationship, clinicians should use etomidate judiciously, considering that improved hemodynamic stability at induction may be accompanied by substantially worse longer-term outcomes.

Detection of critical illness-related corticosteroid insufficiency using 1 μg adrenocorticotropic hormone test

Our objectives were to determine the incidence of critical illness-related corticosteroid insufficiency (CIRCI) in patients with septic shock using a 1 μg corticotropin (ACTH) test and to describe their clinical outcomes. We retrospectively identified 219 consecutive patients with septic shock assessed for CIRCI with a 1 μg ACTH test. Standardized testing involved plasma cortisol measurements at baseline (T0) and at 30 min (T30) and 60 min (T60) after ACTH administration. The maximal increase in cortisol (Δ max) was calculated as the difference between T0 and the highest cortisol value at T30 or T60. Critical illness-related corticosteroid insufficiency was defined as Δ max less than 9 μg/dL after ACTH administration. The mean age of the cohort was 63.0 ± 15.8 years, mean Acute Physiology and Chronic Health Evaluation II score was 26.3 ± 8.1, 85.6% were mechanically ventilated, and the mean number of organ failures was 3.0 ± 1.2. Critical illness-related corticosteroid insufficiency was diagnosed in 70.8% of patients. Twenty-eight-day mortality was highest in patients with baseline cortisol greater than 65 μg/dL (62.5%) and in those with baseline cortisol 34 μg/dL or greater and Δ max less than 9 μg/dL (50.0%). There was no difference in mortality in patients with and without CIRCI (53.9% vs. 36.4%, P = 0.08). Corticosteroids were administered to 69.4% of patients for 5.3 ± 3.6 days. For patients with CIRCI, intensive care unit mortality was similar for those who received corticosteroids compared with those who did not (46.0% vs. 25.0%, P = 0.166). The incidence of CIRCI based on 1 μg ACTH was high in this septic shock cohort. The highest mortality rates were observed in patients with high baseline cortisol and in those who failed to respond appropriately to ACTH. The administration of corticosteroids was not associated with a reduction in mortality.

Relative adrenal insufficiency as a predictor of disease severity and mortality in severe septic shock

OBJECTIVE

To evaluate if cortisol responses to 250 µg of intravenously administered adrenocorticotropic hormone are related to disease severity and, hence, mortality.

METHODS

This is a retrospective study in a medical-surgical intensive care unit of a university hospital. We studied 69 consecutive patients with septic shock over a 1-yr period; these patients underwent a short 250-µg adrenocorticotropic hormone test because they exhibited >6 hours of progressive hemodynamic instability requiring repeated fluid challenges and vasopressor treatment to maintain blood pressure. The test was performed by intravenously injecting 250 µg of synthetic adrenocorticotropic hormone and measuring cortisol immediately before injection, 30 minutes post-injection and 60 minutes post-injection.

RESULTS

The mean APACHE II score was 22±7. The intensive care unit mortality rate at day 28 was 55%. Median baseline cortisol levels (19 [11-27] µg/dL versus 24 [18-34] µg/dL, p=0.047) and median baseline cortisol/albumin ratios (7.6 [4.6-12.3] versus 13.9 [8.8-18.5]; p=0.01) were lower in survivors than in non-survivors. Responders and non-responders had similar baseline clinical data and outcomes. The variables that were significantly correlated with outcome based on the area under the ROC curves (AUC) were APACHE II (AUC=0.67 [0.535 to 0.781]), baseline cortisol (µg/dl) (AUC=0.662 [0.536 to 0.773], peak cortisol (µg/dl) (AUC=0.642 [0.515 to 0.755]) and baseline cortisol/albumin (AUC=0.75 [0.621 to 0.849]).

CONCLUSIONS

Increased basal cortisol is associated with mortality and disease severity. Cortisol responses upon adrenocorticotropic hormone stimulation were not related to outcome. The cortisol/albumin ratio does not predict unfavorable outcomes better than total cortisol levels or help to improve the accuracy of the adrenocorticotropic hormone test.

The effects of three specific conditions related to critical care on adrenal function in children

PURPOSE

To evaluate the effects of three specific conditions related to critical care on adrenal function with special regard to the levels of serum cortisol, corticotropin (ACTH), dehydroepiandrosterone sulfate, and cytokines.

METHODS

The study enrolled a total of 74 children who were divided into three groups. Group 1 comprised 23 patients who had acute critical illness (ACI) associated with severe sepsis/septic shock. Group 2 comprised 27 patients who had ACI without sepsis. Group 3 comprised 24 patients who underwent major surgery. Blood samples were obtained for baseline measurements and a low-dose ACTH stimulation test (LD-ST) was performed. Serial ACTH and cortisol levels were measured with an interval of 3 days and LD-ST was repeated on day 14 for all groups.

RESULTS

Baseline cortisol, ACTH, and dehydroepiandrosterone sulfate levels were significantly higher in patients with adrenal insufficiency (AI) than those of without AI. AI was detected in four patients in group 1, seven in group 2, and ten in group 3. Consecutive cortisol and ACTH levels did not differ significantly among the groups. On day 14, the recovery rate in patients with AI was 82 % in the whole group. Patient's age and interleukin-10 level were found to be independent predictors of AI.

CONCLUSIONS

A considerable proportion of patients in these three groups had AI with a high spontaneous recovery rate in 2 weeks. The presence of sepsis was not associated with an increased risk of AI. Our serial cortisol and ACTH values in these different groups could be used as reference values for further studies.

Diagnosis of adrenal failure in critically ill patients

In the last two decades there was important evolution on the knowledge of the function of the hypothalamic-pituitary-adrenal axis. In the last decade, the expression "relative adrenal insufficiency" (RAI) was created, and more recently "critical illness-related corticosteroid insufficiency" (CIRCI) was used to designate those patients in which cortisol production was not sufficiently increased in stress situations. Patients with CIRCI have elevated hospital morbidity and mortality. Currently, there is a wide discussion about diagnostic criteria for this dysfunction. Besides basal cortisol, some publications now study the role of other tests, such as cortrosyn test - either in low (1 μg) or high doses (250 μg); free cortisol, salivary cortisol, metyrapone test and others. With this review, we aimed at summarizing the results of the most influent papers that intended to define diagnostic criteria for CIRCI. We also suggest an approach for CIRCI diagnosis and make it clear that the decision about steroid therapy in septic shock patients is matter apart from RAI.

Serial changes in plasma total cortisol, plasma free cortisol, and tissue cortisol activity in patients with septic shock: an observational study

Published data on adrenocortical function in septic shock have enrolled patients at various stages of critical illness and predominantly used plasma total cortisol, with minimal information on serial changes. Moreover, plasma free cortisol and tissue corticosteroid activity may not be strongly associated; however, few published data exist. The aim of this prospective observational study was to investigate serial changes in plasma total and free cortisol and tissue cortisol activity in septic shock. Twenty-nine adult patients admitted with septic shock to a tertiary-level intensive care unit were enrolled. A low-dose corticotropin test was performed on day 1. Plasma total and free cortisol, cortisone, transcortin, and urinary free cortisol and cortisone were analyzed on days 1 to 5, 7, and 10. Urinary and plasma cortisol-cortisone ratios (F:E ratio) were calculated as indices of 11-β hydroxysteroid dehydrogenase 2 and global 11-β hydroxysteroid dehydrogenase activity, respectively. Baseline total and free plasma cortisol values from 10 healthy control subjects were obtained for comparative analysis. Baseline plasma total and free cortisol levels were significantly higher than controls (457.8 ± 193 vs. 252 ± 66 nmol/L, P = 0.0002; and 50.83 ± 43.19 vs. 6.4 ± 3.2, P < 0.0001, respectively). Plasma free cortisol rose proportionately higher than total cortisol (124% ± 217.3% vs. 40% ± 33.2%, P = 0.007) following corticotropin. Baseline plasma and urinary F:E ratios were elevated over the reference ranges (13.13 ± 1.5, 1.69 ± 2.8) and were not correlated with plasma free cortisol values (r = 0.2, 0.3 respectively). Over the study period, total cortisol levels and plasma F:E ratios remained elevated, whereas plasma free cortisol levels and urinary F:E ratio declined. At baseline, plasma free cortisol levels were higher in patients who subsequently survived (23.7 ± 10.5 vs. 57.9 ± 45.8 nmol/L, P = 0.04). In septic shock, there is a differential response of plasma total and free cortisol over time and in response to corticotropin. Changes in plasma and urinary F:E ratios suggest tissue modulation of 11-β hydroxysteroid dehydrogenase activity. Total plasma cortisol measurements may not reflect the global adrenal response in septic shock.

Association of adrenocorticotrophin and cortisol concentrations with peripheral blood leukocyte cytokine gene expression in septic and nonseptic neonatal foals

BACKGROUND

The hypothalamic-pituitary-adrenal (HPA) is influenced by the proinflammatory cytokines IL-6, IL-1β, and TNF-α in critically ill humans. Information about the association of cytokines with the HPA axis in neonatal foals is lacking.

HYPOTHESIS/OBJECTIVES

The objectives were to describe for hospitalized septic and nonseptic foals (1) temporal changes in blood concentrations of ACTH, and cortisol, and leukocyte cytokine gene expression, and (2) coassociation of these HPA axis hormones with blood leukocyte cytokine gene expression.

ANIMALS

Hospitalized septic foals (N = 15) and hospitalized nonseptic foals (N = 11).

METHODS

Blood samples, obtained from study foals at admission (T = 0), and 24 (T = 1), 48 (T = 2), 72 (T = 3), and 96 (T = 4) hours after admission, were processed to isolate RNA from leukocytes and to harvest plasma and serum for hormone assays. Plasma ACTH and serum cortisol concentrations were determined by radioimmunoassay. Leukocyte mRNA expression of IL-1β IL-6, IL-8, IL-10, and TNF-α was determined using RT-PCR.

RESULTS

Cortisol concentrations were greater (P < .05) in foals at admission than at other time points. The expressions of IL-8 and IL-10 mRNA were lower (P < .05) at each time point in septic than in nonseptic foals. Among septic foals, ACTH was positively associated (P = .0026) with IL-6 mRNA expression.

CONCLUSIONS

Sepsis influences secretion of the HPA axis hormones and expression of cytokines in foals. A positive association with the HPA axis and IL-6 expression was detected. The clinical importance of these findings requires additional study.

Adrenal insufficiency in cardiothoracic patients: an evaluation of the corticotrophin stimulation test and other diagnostic methods

PURPOSE

The purposes of the study were to determine the incidence of adrenal insufficiency (AI) using several published techniques, compare the response rates using a low-dose (LD) corticotropin (ACTH) stimulation test vs a standard dose (SD), and identify the technique that is most closely related to vasopressor use.

MATERIALS AND METHODS

Consecutive adult patients who were undergoing open heart surgery for CAD or valvular disease were prospectively enrolled. Exclusion criteria included history of steroid use, operative steroid, or etomidate administration. Postoperatively, each patient underwent ACTH stimulation with 1 μg (LD) and 249 μg (SD), 60 minutes apart. Agreement among the tests was evaluated, and vasopressor use was compared between groups.

RESULTS

There were 40 patients evaluated. The incidence of AI based on operative change, postoperative values, and LD-ACTH and SD-ACTH tests was 53%, 38%, 60%, and 38%, respectively. Agreement between the LD- and SD-ACTH tests was 73% (κ = 0.476, P = .001). There was a significant difference in the need for (93% vs 52%, P = .013) and duration (18.9 [0-180.6] vs 0.6 [0-73.2] hours, P = .003) of vasopressor therapy in patients with and without AI but only using the SD-ACTH definition.

CONCLUSION

The incidence of AI will vary greatly based on technique used for diagnosis. The SD-ACTH stimulation test should be used to determine AI in open heart patients postoperatively because of the close association with vasopressor usage.

Post-cardiac arrest syndrome: Mechanisms and evaluation of adrenal insufficiency

Cardiac arrest is one of the leading causes of death and represents maximal stress in humans. After restoration of spontaneous circulation, post-cardiac arrest syndrome is the predominant disorder in survivors. Besides the post-arrest brain injury, the post-resuscitation myocardial stunning, and the systemic ischemia/reperfusion response, this syndrome is characterized by adrenal insufficiency, a disorder that often remains undiagnosed. The pathophysiology of adrenal insufficiency has not been elucidated. We performed a comprehensive search of three medical databases in order to describe the major pathophysiological disturbances which are responsible for the occurrence of the disorder. Based on the available evidence, this article will help physicians to better evaluate and understand the hidden yet deadly post-cardiac arrest adrenal insufficiency.

Adrenocortical (dys)function in septic shock - a sick euadrenal state

A central feature of the endocrine pathophysiology of septic shock is thought to be the existence of adrenal dysfunction. Based on changes in glucocorticoid secretion and responsiveness, protein binding, and activity. These changes have been described by the terms "Relative Adrenal Insufficiency" (RAI), or "Critical Illness Related Corticosteroid Insufficiency" (CIRCI), and form part of the rationale for trials of glucocorticoid treatment in septic shock. Diagnostic criteria for these conditions have been based on plasma cortisol profiles and have proven notoriously difficult to establish. The uncertainty in this area arises from the inability of current tests to clearly identify who is truly glucocorticoid "deficient" at a cellular level, and hence who requires supplemental glucocorticoid administration. Emerging data suggest that there may be abnormalities in the tissue activity of glucocorticoids in patients with severe sepsis and plasma profiles may not be reliable indicators of tissue glucocorticoid activity, We put forward an alternative point of view, that is the spectrum of adrenocortical dysfunction in sepsis - plasma and tissue, can be grouped under the umbrella of a "sick euadrenal syndrome" rather than an adrenocortical insufficiency.

Response to the high-dose corticotrophin stimulation test depends on plasma adrenocotropin hormone levels in septic shock

PURPOSE

The use of the high-dose corticotrophin stimulation test (HDCST) as a guide to use low-dose steroid therapy in septic shock is controversial. The adrenocotropin hormone (ACTH) constitutes the immediate stimuli to produce cortisol. We evaluated the correlation of the response to the HDCST with plasma ACTH levels in patients with septic shock.

METHODS

This is a retrospective review of 102 patients with septic shock in which adrenal function was evaluated using the HDCST and plasma ACTH levels were measured. Patients with a δ cortisol of 9 μg/dL or less were considered as nonresponders or with subnormal response. The association between plasma ACTH levels and the response to the HDCST was investigated.

RESULTS

Sixty-four patients (62.7%) had a subnormal response. Plasma ACTH levels were higher in patients with subnormal response (19.8 [11.7-31.4] vs 10.0 [7.0-21.2] pg/mL; P = .002). Patients in the highest quartile of plasma ACTH had lower δ cortisol (P = .014) and higher percentage of subnormal response (P = .005). The optimal cutoff point of plasma ACTH level with fewest false classifications was 10 pg/mL (sensitivity, 0.83 [95% confidence interval, 074-0.90] and specificity, 0.50 [95% confidence interval, 0.74-0.90]).

CONCLUSION

Patients with septic shock with higher plasma ACTH values presented a subnormal response to the HDCST. The number of patients who failed to the HDCST was higher as plasma ACTH increased.

Intensive care unit management of patients with stroke

Patients admitted with the diagnosis of "stroke" have a variety of different disorders that require specific treatment approaches in the critical care unit. Early thrombolysis for ischemic stroke and improvements in surgical and neurointerventional techniques for the treatment of aneurysms and arteriovenous malformations in patients with subarachnoid hemorrhage have been milestones in the past decade, but the evolvement of general management principles in critical care and the dedication of neurointensivists are equally important for improved outcomes. Strategies, which have been developed in other areas of intensive care medicine (eg, in patients with septic shock, acute respiratory distress syndrome, or trauma), need to be adopted and modified for the stroke patient. Prevention of iatrogenic complications and nosocomial infections is of utmost importance and requires sufficient numbers of trained personnel and high-quality equipment. Although the focus of attention in stroke patients is "brain resuscitation," comorbidities often limit the diagnostic and therapeutic options, and overall cardiopulmonary and metabolic functions need to be optimized in order to prevent secondary injury and allow the brain to recover. As part of a holistic approach to the rehabilitation process, psychologic and spiritual support for the patient must start early on in the intensive care unit, and family members should be involved in the patient's care and provided with special support as well.

Systemic steroids in severe sepsis and septic shock

Despite more than 5 decades of study and debate, the role of corticosteroid treatment in patients with severe sepsis and septic shock remains controversial. Data support a beneficial effect on systemic blood pressure in patients with septic shock. However, the ability of corticosteroid therapy to improve mortality in patients with severe sepsis and septic shock remains controversial, with contradictory results from recent large multicenter clinical trials. Although it appears clear that high-dose corticosteroid treatment provides no benefit and possibly harm in septic patients, the experimental design flaws and biases of recent low-dose (physiologic) steroid treatment trials limit their ability to provide adequate answers to the important questions of which septic patients should be treated, how much steroid to give, and the optimum duration of treatment. Unfortunately, the answer to these important questions is not readily evident based on the current evidence or the application of metaanalysis to the available clinical data. This concise evidence-based review highlights the strengths and weaknesses of the current data to inform the practicing clinician as to which patients are likely to derive significant benefit from corticosteroid treatment, while we await more definitive guidance from future multicenter, prospective, randomized, controlled trials designed to better answer these important therapeutic questions.

Critical illness-related corticosteroid insufficiency in cancer patients

PURPOSE

Critically ill cancer patients with sepsis represent a high-risk sub-group for the development of critical illness-related corticosteroid insufficiency (CIRCI); however, the incidence of CIRCI in this population is unknown. The purpose of this study was to determine the incidence of CIRCI in cancer patients with severe sepsis or septic shock.

METHODS

A single-center, retrospective, observational study was conducted in a 52-bed medical-surgical intensive care unit of a National Cancer Institute-recognized academic oncology institution. Eighty-six consecutive patients with a diagnosis of severe sepsis or septic shock who received a high-dose 250-μg cosyntropin stimulation test were included. CIRCI was identified by a maximum delta serum cortisol of 9 μg/dL or less post cosyntropin.

RESULTS

Overall, 59% (95% CI, 48-70%) of cancer patients with severe sepsis or septic shock were determined to have CIRCI. When compared to patients without CIRCI, patients with CIRCI had higher baseline serum cortisol (median, 26.3 versus 14.7 μg/dL; p = 0.002) and lower delta cortisol levels (median, 3.1 versus 12.5 μg/dL; p < 0.001). Mortality did not differ between the two groups. An inverse relationship was identified between baseline serum cortisol and maximum delta cortisol (maximum delta cortisol = -0.27 × baseline cortisol + 14.30; R (2) = 0.208, p < 0.001).

CONCLUSIONS

The incidence of CIRCI in cancer patients with severe sepsis or septic shock appears high. Further large-scale prospective trials are needed to confirm these findings.

Adrenocortical insufficiency in horses and foals

The adrenal cortices produce various steroid hormones that play vital roles in several physiologic processes. Although permanent adrenocortical insufficiency is rare in all species, emerging evidence in both human and equine medicine suggests that transient reversible adrenocortical dysfunction resulting in cortisol insufficiency frequently develops during critical illness. This syndrome is termed relative adrenal insufficiency (RAI) or critical illness-related corticosteroid insufficiency (CIRCI) and can contribute substantially to morbidity and mortality associated with the primary disease. This review discusses the mechanisms, diagnosis, and clinical consequences of adrenocortical insufficiency, with particular focus on the current understanding of RAI/CIRCI in horses and foals.

Risk factors and outcome of changes in adrenal response to ACTH in the course of critical illness

BACKGROUND

To evaluate the concept of critical illness-related corticosteroid insufficiency (CIRCI) by studying the clinical significance, in terms of risk factors and outcome, of changes in the cortisol response to repeated adrenocorticotropic hormone (ACTH) testing in the course of critical illness.

PATIENTS AND METHODS

In a retrospective study in a medical-surgical intensive care unit (ICU) of a university hospital, we retrospectively included 54 consecutive patients during a 3-year period, who underwent 2 conventional 250 μg ACTH tests at an interval >24 hours, because of ≥6 hours hypotension requiring repeated fluid challenges or vasopressor/inotropic treatment, while corticosteroid treatment was not (yet) initiated. Serum cortisol was measured immediately before and 30 and 60 minutes after intravenous injection of 250 μg of ACTH. Patients were divided into those with an increase (≥0, n = 27) or a decrease (n = 27) in time in delta (Δ) cortisol in response to ACTH and with a Δcortisol <100 (n = 11) and ≥100 nmol/L (n = 43) at the second ACTH test.

RESULTS

Changes in Δcortisol in time were paralleled by changes in Δcortisol/albumin, with a higher frequency of septic shock, persistently high disease severity, increased renal replacement therapy, and decreased platelet counts in the course of disease with a decrease in Δcortisol in time. Similar trends in increased disease severity were observed when Δcortisol remained or fell to <100 nmol/L. A decrease in Δcortisol between the 2 tests, particularly to <100 nmol/L, was associated with increased mortality (18 nonsurvivors in the ICU).

CONCLUSIONS

The findings favor the concept of dynamic adrenal function rather than poor reproducibility of the ACTH test, so that development of CIRCI, particularly in complicated septic shock and indicated by a fall in Δcortisol (to <100 nmol/L) upon ACTH, correlates to a poor prognosis, independently of baseline cortisol, cortisol binding in blood, and disease severity.

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.

Effects of endogenous and exogenous hypercortisolemia on low-dose adrenocorticotropin test outcome in humans

BACKGROUND

The results of low-dose ACTH testing may be impaired during endogenous or exogenous hypercortisolemia in various clinical situations.

AIM

The hypothesized inhibitory effects of hypercortisolemia on adrenal responsiveness to low-dose ACTH were tested in two model situations in healthy humans.

SUBJECTS AND METHODS

Nine young healthy women underwent low-dose ACTH test in 5 modifications. In ACTH-ACTH test, ACTH (1 microg iv) was given at 09:00 h and 10:00 h. Two control tests consisted of single ACTH bolus at 09:00 h or at 10:00 h. In hydrocortisone (HC)-ACTH test, HC (20 mg po) was given at 08:30 h and ACTH was injected at 10:00 h. Control test consisted of single HC administration at 08:30 h.

RESULTS

Cortisol response after the 2nd ACTH test was significantly lower vs the 1st ACTH bolus (Deltamax: 166+/-32 nmol/l vs 276+/-15 nmol/l, p<0.05) in ACTH-ACTH test. Responses of other steroids after both ACTH injections were comparable. ACTH bolus during HC-induced hypercortisolemia caused a slight increase in cortisol level and prevented its decrease, seen after HC administration alone. Adrenal cortisol production in response to ACTH bolus under different incipient conditions (baseline, physiological, and pharmacological hypercortisolemia; 180+/-16, 173+/-21, and 177+/-53 nmol.min.l-1, respectively) did not significantly differ (p=0.8).

CONCLUSIONS

Endogenous and exogenous hypercortisolemia did not influence adrenal cortisol response to low-dose ACTH test indicating lack of its negative feedback at adrenal level.

Sympathetic overstimulation during critical illness: adverse effects of adrenergic stress

The term ''adrenergic'' originates from ''adrenaline'' and describes hormones or drugs whose effects are similar to those of epinephrine. Adrenergic stress is mediated by stimulation of adrenergic receptors and activation of post-receptor pathways. Critical illness is a potent stimulus of the sympathetic nervous system. It is undisputable that the adrenergic-driven ''fight-flight response'' is a physiologically meaningful reaction allowing humans to survive during evolution. However, in critical illness an overshooting stimulation of the sympathetic nervous system may well exceed in time and scope its beneficial effects. Comparable to the overwhelming immune response during sepsis, adrenergic stress in critical illness may get out of control and cause adverse effects. Several organ systems may be affected. The heart seems to be most susceptible to sympathetic overstimulation. Detrimental effects include impaired diastolic function, tachycardia and tachyarrhythmia, myocardial ischemia, stunning, apoptosis and necrosis. Adverse catecholamine effects have been observed in other organs such as the lungs (pulmonary edema, elevated pulmonary arterial pressures), the coagulation (hypercoagulability, thrombus formation), gastrointestinal (hypoperfusion, inhibition of peristalsis), endocrinologic (decreased prolactin, thyroid and growth hormone secretion) and immune systems (immunomodulation, stimulation of bacterial growth), and metabolism (increase in cell energy expenditure, hyperglycemia, catabolism, lipolysis, hyperlactatemia, electrolyte changes), bone marrow (anemia), and skeletal muscles (apoptosis). Potential therapeutic options to reduce excessive adrenergic stress comprise temperature and heart rate control, adequate use of sedative/analgesic drugs, and aiming for reasonable cardiovascular targets, adequate fluid therapy, use of levosimendan, hydrocortisone or supplementary arginine vasopressin.

Effects of hydrocortisone on microcirculatory alterations in patients with septic shock

OBJECTIVE

To evaluate the effects of hydrocortisone on microcirculatory blood flow alterations in patients with septic shock.

DESIGN

Prospective, open-label study.

SETTING

A 31-bed, medico-surgical intensive care unit of a university hospital.

PATIENTS

Twenty patients with septic shock.

INTERVENTIONS

Intravenous hydrocortisone (50 mg/6 hr).

MEASUREMENTS AND MAIN RESULTS

An orthogonal polarization spectral device (Cytoscan ARII, Cytometrics; Philadelphia, PA) was used to investigate the sublingual microcirculation in 20 patients who received so-called "stress doses" of hydrocortisone as part of their management for septic shock. Hemodynamic measurements and orthogonal polarization spectral images were obtained before administration of the first dose (50 mg) of hydrocortisone and 1, 2, 4, and 24 hours later. Measurements were also made before an adrenocorticotropic hormone (ACTH) test, whenever performed. Global hemodynamic variables were similar at all study time points. Microcirculatory variables improved slightly already at 1 hour after the start of hydrocortisone administration. In particular, perfused vessel density increased from 5.7 (4.8-6.4) to 7.2 (6.5-9.0)n/mm, p < 0.01, which was due to combined increases in small vessel density from 5.2 (4.6-6.2) to 6.0 (5.1-7.5)n/mm, p < 0.01, and in the proportion of perfused vessels from 82.1 (68.7-88.0) to 89.2 (83.4-92.6)%, p < 0.01. There were no differences in microcirculatory variables during hydrocortisone administration between ACTH test responders and nonresponders.

CONCLUSIONS

The administration of moderate doses of hydrocortisone in septic shock results in a modest but consistent improvement in capillary perfusion, independent of the response to the ACTH test. The mechanisms underlying this effect need to be elucidated.

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.

Baseline plasma cortisol and ACTH concentrations and response to low-dose ACTH stimulation testing in ill foals

OBJECTIVE

To evaluate baseline plasma cortisol and ACTH concentrations and responses to low-dose ACTH stimulation testing in ill foals.

DESIGN

Cross-sectional study.

ANIMALS

58 ill foals.

PROCEDURES

Baseline cortisol and ACTH concentrations and cortisol concentrations after administration of a low dose of cosyntropin were determined within 6 hours after admission. Foals were assigned to 4 groups on the basis of age (<or=24 hours vs 1 to 56 days) and presence of septicemia (yes vs no). Values were compared among groups and with values previously reported for healthy foals.

RESULTS

Plasma cortisol concentrations 30 and 60 minutes after cosyntropin administration in foals<or=24 hours old were significantly higher than corresponding cortisol concentrations in older foals. In all 4 groups, plasma cortisol concentration 30 minutes after cosyntropin administration was significantly higher than baseline cortisol concentration or concentration 60 minutes after cosyntropin administration. No differences in baseline cortisol or ACTH concentration or in the ACTH-to-cortisol ratio were detected between groups or when ill foals were compared with healthy foals. A small number of ill foals had low baseline cortisol and ACTH concentrations or low responses to cosyntropin administration, compared with healthy foals.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that most ill foals in the present study population had adequate responses to cosyntropin administration. However, a small subset of ill foals appeared to have dysfunction of the hypothalamic-pituitary-adrenal axis.

The altered adrenal axis and treatment with glucocorticoids during critical illness

Critical illness is generally hallmarked by activation of the hypothalamic-pituitary-adrenal axis. The development of very high levels of cortisol has been associated with severe illness and a raised risk of death. Likewise, a response that is inadequate relative to the degree of stress, termed relative adrenal insufficiency (also known as critical-illness-related corticosteroid insufficiency) has been associated with increased mortality. Much controversy exists with regard to the definition and biochemical testing of an adequate adrenal response to critical illness, which hampers diagnosis. High doses of glucocorticoids have been shown to have no effect in this setting and might be harmful. Moderate doses have been advocated, however, for critically ill patients with inflammatory conditions, such as acute respiratory distress syndrome and septic shock syndrome. Initial results from proof-of-concept studies were promising but thus far have not been reproduced in large, multicenter trials, although the latter were underpowered to yield definite conclusions. The role of glucocorticoid therapy in intensive care, therefore, remains uncertain. Until the debate has been settled, we recommend that use of glucocorticoid therapy in critically ill patients should continue to be based on the clinician's judgment and that routine adjuvant use should be avoided.