Free Cortisol in Sepsis and Septic Shock

Hypothalamic-Pituitary Axis Function and Adrenal Insufficiency in COVID-19 Patients

The outbreak of COVID-19 has affected more than half a billion people worldwide and caused more than 6 million deaths since 2019. The responsible virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), primarily affects the lungs, but it has multisystemic effects. It is well known that dysfunction of multiple endocrine organs may occur during or after COVID-19. Impairment of the hypothalamic-pituitary-adrenal (HPA) axis is of utmost importance as it may lead to death if went undiagnosed. SARS-CoV-2 may cause both primary and secondary adrenal insufficiencies (AIs). The clinical manifestations of AI are generally non-specific and might be attributed to the complications caused by the infection itself. The underlying pathogenetic mechanisms were explained by the immunogenic, vascular effects of the infection or the direct effects of the virus. The diagnosis of AI in critically ill patients with COVID-19 is not straightforward. There is lack of consensus on the cut-off values of basal serum cortisol levels and stimulation tests during the disease. Here we review the literature with a special regard on the evaluation of the HPA axis in patients with COVID-19. We conclude that the possibility of AI should always be kept in mind when dealing with patients with COVID-19, and repeated basal cortisol measurements and the ACTH stimulation test results could guide the clinician during the diagnostic process.

Immunotolerance of dairy heifers in response to repeated exposure to bacterial lipopolysaccharide endotoxin

Dairy cattle face a variety of stressful events on a daily basis. More specifically, climate change has resulted in more frequent heat stress events that increase the incidence of chronic bacterial infections by inducing conditions like leaky gut syndrome, whereby the integrity of the intestinal epithelium is compromised allowing for luminal bacterial lipopolysaccharide (LPS) endotoxin to infiltrate the host's bloodstream resulting in acute or chronic systemic stimulation of the innate immune system. Repeated exposure to LPS over a short period of time is reported to induce immunotolerance within the host. This LPS tolerance is an essential immunohomeostatic response that can protect against over activation of the inflammatory response during subsequent exposure to LPS. In the present study, Holstein calves (n = 20) were initially stress challenged with either saline, or 100, 200 or 400 ng/kg of LPS administered intramuscular, and again re-challenged with 200 ng/kg of LPS 2-weeks later. Serum was collected every 2 hr for 6 hr to profile changes in circulatory stress biomarkers after the repeated LPS exposures. Heifers that were initially challenged with 100, 200 and 400 ng/kg of LPS demonstrated significantly attenuated cortisol responses in the second challenge (p < 0.01, 0.01 and 0.05, respectively), whereas control animals who previously received saline demonstrated a strong cortisol response at 2 hr after receiving 200 ng/kg of LPS (p < 0.05). The cytokine/chemokine (IL-6, CCL2, CCL3 and CCL4) responses were also attenuated during the LPS rechallenge (p < 0.05). Finally, microRNA expression profiles were determined to assess the epigenetic response to repeated LPS exposure. Interestingly, miR-31 and miR-223 were downregulated in response to the second LPS challenge. The present study demonstrates the dynamic nature of the stress response in dairy cattle as it relates to the development of LPS tolerance. Understanding the roles of various stress biomarkers in the context of innate immune cell tolerance is essential for evaluating their impact on immune system homeostasis.

Yoga, Meditation, Breathing Exercises, and Inflammatory Biomarkers with Possible Implications in COVID-19: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Introduction

COVID-19, a multisystem disease, has implications for various immunity and infection biomarkers. Yoga (Y), meditation (M), and pranayama (P), and their combinations have shown positive changes on those biomarkers among other than COVID-19 patients and healthy people. So, we aimed to document the evidence of possible implication in a systematic way.

Materials and Methods

We screened 84 full texts, published in the last ten years, from three databases, from which only 44 met the eligibility criteria, and then extracted the data related to demographic characteristics, intervention, results, and strengths and limitations in two MS-Excel grids, and then presented them in tables and figures. Furthermore, we carried out meta-analysis including subgroup and sensitivity analysis using a random effects model of 11 RCTs and reported the mean difference, heterogeneity, and p value with 95% CI and presented them with forest and funnel plots and the tables.

Results

Twenty-five biomarkers of 4023 participants (range, 15-413) from 13 countries, healthy and clinical, from both sexes above 18 years, and from mainly clinical settings, were reported. YMP intervention, in solitary or in different possible combinations with varied durations among clinical and pregnant (range, 960-4800 minutes) and healthy (960-8400 minutes, excluding two studies of 20 minutes only) participants, was reported. It was revealed that 25 biomarkers, nine among the apparently healthy, 14 among the patients, and two among the pregnant, changed favourably (p < 0.05). Furthermore, either in meta- or subgroup-analysis, mean differences of IL-6 (-1.44 pg/ml) (95% CI) (-2.33, -0.55), (p = 0.002, I ²  = 82%), Cortisol (-40.75 pg/ml) (95% CI) (-64.13, -17.38), (p = 0.0006, I ²  = 87%), and TNF-α (-3.40 pg/ml) (95% CI) (-4.83, -1.98), (p < 0.0001, I ²  = 79%) showed statistically significant changes. Nonetheless, considerable heterogeneity and publication bias were observed among the studies.

Conclusion

Although more than two dozens of biomarkers in individual studies showed favourable changes, only IL-6, Cortisol, and TNF-α produced significant combined results, even then with much less certainty. Further meta-analysis of biomarkers of COVID-19 patients is highly recommended. Registration: CRD42021283894.

Chronic stress-driven glucocorticoid receptor activation programs key cell phenotypes and functional epigenomic patterns in human fibroblasts

Chronic environmental stress can profoundly impact cell and body function. Although the underlying mechanisms are poorly understood, epigenetics has emerged as a key link between environment and health. The genomic effects of stress are thought to be mediated by the action of glucocorticoid stress hormones, primarily cortisol in humans, which act via the glucocorticoid receptor (GR). To dissect how chronic stress-driven GR activation influences epigenetic and cell states, human fibroblasts underwent prolonged exposure to physiological stress levels of cortisol and/or a selective GR antagonist. Cortisol was found to drive robust changes in cell proliferation, migration, and morphology, which were abrogated by concomitant GR blockade. The GR-driven cell phenotypes were accompanied by widespread, yet genomic context-dependent, changes in DNA methylation and mRNA expression, including gene loci with known roles in cell proliferation and migration. These findings provide insights into how chronic stress-driven functional epigenomic patterns become established to shape key cell phenotypes.

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Physiological stress levels of cortisol drive robust changes in key cell phenotypes

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Stress-driven changes in cell phenotypes are abrogated by concomitant GR blockade

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GR activation induces functional and phenotypically relevant epigenomic changes

[Corticosteroids and metabolic resuscitation (hydrocortisone, ascorbic acid and thiamine) in sepsis and septic shock]

In accordance with the recommendations of, among others, the Surviving Sepsis Campaign, adjunctive therapies may play a role in the treatment and the prognosis in sepsis patients. Corticosteroids, ascorbic acid, and thiamine has been identified as a potential therapy for septic shock alone or in combination. Since many years, low-dosis corticosteroids has been proposed as adjuvant therapies for these patients. However, there are still many controversies regarding the role of systemic low-dose corticosteroids as a part of the treatment of septic shock. In recent clinical and experimental investigations, mitochondrion-target therapy bic acid and thiamine) for sepsis has been suggested to reduce MODS severity and mortality although their clinical results are not yet convincing for their use. In the present article, we have performed a narrative review of the current literature including pathophysiologic rationale and the current evidence for such therapies in septic patients.

Restrained expression of canine glucocorticoid receptor splice variants α and P prognosticates fatal disease outcome in SIRS

Glucocorticoids play a central role in the inflammatory response and alleviate the symptoms in critically ill patients. The glucocorticoid action relies on the glucocorticoid receptor (GR) which translocates into the nucleus upon ligand-binding and regulates transcription of a battery of genes. Although the GR is encoded by a single gene, dozens of its splice variants have been described in diverse species. The GRα isoform encodes the full, functionally active protein that is composed of a transactivation, a DNA-binding, and a C-terminal ligand-binding domain. The second most highly expressed receptor variant, the GR-P, is formed by an intron retention that introduces an early stop codon and results in a probably dysfunctional protein with truncated ligand-binding domain. We described the canine ortholog of GR-P and showed that this splice variant is highly abundant in the peripheral blood of dogs. The level of cGRα and cGR-P transcripts are elevated in patients of SIRS and the survival rate is increased with elevated cGRα and cGR-P expression. The ratio of cGRα and cGR-P mRNA did not differ between the survivor and non-survivor patients; thus, the total GR expression is more pertinent than the relative expression of GR isoforms in assessment of the disease outcome.

Assessment of Plasma-Free Cortisol Concentrations by LC-MS/MS in Patients with Autonomous Cortisol Secretion

Autonomous cortisol secretion (ACS) of an adrenal incidentaloma (AI) is associated with mild cortisol excess that could result in poor metabolic and cardiovascular outcomes. The biological activity of glucocorticoids depends on the unbound, free fraction. We aimed to evaluate plasma free cortisol (FC) concentrations in patients with ACS in this cross-sectional study. One hundred and ten AI patients in 3 groups; non-functioning (NFA, n=33), possible ACS (n=65), ACS (n=12) were enrolled. Following measurements were conducted: Clinical data and total serum cortisol (TC), plasma corticotrophin (ACTH), serum dehydroepiandrosterone sulfate (DHEA-S), cortisol after 1 mg dexamethasone by both immunoassay and LC-MS/MS (DexF), serum corticosteroid binding globulin (CBG), plasma dexamethasone concentration [DEX] and plasma FC by LC-MS/MS. Patients with ACS featured an unfavorable metabolic profile. Plasma [DEX] and serum CBG levels were similar between groups. Plasma FC was significantly higher in ACS when compared to NFA and possible ACS groups p<0.05 and p<0.01, respectively. In multiple regression analysis DexF (beta=0.402, p<0.001) and CBG (beta=-0.257, p=0.03) remained as the independent predictors of plasma FC while age, sex, BMI, smoking habit, and existing cardiovascular disease did not make a significant contribution to the regression model. In conclusion, the magnitude of cortisol excess in ACS could lead to increased plasma FC concentrations. Further studies in AI patients are needed to demonstrate whether any alterations of cortisol affinity for CBG exist and to establish whether plasma FC concentrations predict the unfavorable metabolic profile in ACS.

Could serum total cortisol level at admission predict mortality due to coronavirus disease 2019 in the intensive care unit? A prospective study

BACKGROUND

Critical diseases usually cause hypercortisolemia via activation of the hypothalamic-pituitary-adrenal axis.

OBJECTIVES

To investigate the relationship between serum total cortisol level and mortality among coronavirus disease 2019 (COVID-19) patients in the intensive care unit (ICU), at the time of their admission.

DESIGN AND SETTING

Prospective study developed in a pandemic hospital in the city of Şırnak, Turkey.

METHODS

We compared the serum total cortisol levels of 285 patients (141 COVID-19-negative patients and 144 COVID-19-positive patients) followed up in the ICU.

RESULTS

The median cortisol level of COVID-19-positive patients was higher than that of COVID-19 negative patients (21.84 μg/dl versus 16.47 μg/dl; P < 0.001). In multivariate logistic regression analysis, mortality was associated with higher cortisol level (odds ratio: 1.20; 95% confidence interval: 1.08-1.35; P = 0.001). The cortisol cutoff point was 31 μg/dl (855 nmol/l) for predicting mortality among COVID-19-positive patients (area under the curve 0.932; sensitivity 59%; and specificity 95%). Among the COVID-19 positive patients with cortisol level ≤ 31 μg/dl (79%; 114 patients), the median survival was higher than among those with cortisol level > 31 μg/dl (21%; 30 patients) (32 days versus 19 days; log-rank test P < 0.001).

CONCLUSION

Very high cortisol levels are associated with severe illness and increased risk of death, among COVID-19 patients in the ICU.

Plasma Cortisol, Aldosterone, and Ascorbic Acid Concentrations in Patients with Septic Shock Do Not Predict Treatment Effect of Hydrocortisone on Mortality. A Nested Cohort Study

Rationale: Whether biomarkers can identify subgroups of patients with septic shock with differential treatment responses to hydrocortisone is unknown.Objectives: To determine if there is heterogeneity in effect for hydrocortisone on mortality, shock resolution, and other clinical outcomes based on baseline cortisol, aldosterone, and ascorbic acid concentrations.Methods: From May 2014 to April 2017, we obtained serum samples from 529 patients with septic shock from 22 ICUs in Australia and New Zealand.Measurements and Main Results: There were no significant interactions between the association with 90-day mortality and treatment with either hydrocortisone or placebo for total cortisol (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.02-1.16 vs. OR, 1.07; 95% CI, 1.00-1.13; P = 0.70), free cortisol (OR, 1.20; 95% CI, 1.04-1.38 vs. OR, 1.16; 95% CI, 1.02-1.32; P = 0.75), aldosterone (OR, 1.01; 95% CI, 0.97-1.05 vs. OR, 1.01; 95% CI, 0.98-1.04; P = 0.99), or ascorbic acid (OR, 1.11; 95% CI, 0.89-1.39 vs. OR, 1.05; 95% CI, 0.91-1.22; P = 0.70), respectively. Similar results were observed for the association with shock resolution. Elevated free cortisol was significantly associated with 90-day mortality (OR, 1.13; 95% CI, 1.00-1.27; P = 0.04), but total cortisol, aldosterone, and ascorbic acid were not.Conclusions: In patients with septic shock, there was no heterogeneity in effect of adjunctive hydrocortisone on mortality, shock resolution, or other clinical outcomes based on cortisol, aldosterone, and ascorbic acid concentrations. Plasma aldosterone and ascorbic acid concentrations are not associated with outcome.

Role of neuroendocrine modulation and biochemistry in the sepsis in Piaractus mesopotamicus

Sepsis is a systemic process with multifactorial pathophysiology that affects most animal species. It is responsible for high rates of morbidity and mortality. This work aimed to study the biochemical and neuroendocrine changes of the sepsis process in Piaractus mesopotamicus after Aeromonas hydrophila inoculation analyzing changes in blood leukocyte and differences in neuroendocrine-biochemical modulation using RNA-seq. Fish showed hypercortisolemia, inhibition of glucose absorption, followed by hypocortisolemia and then hyperglycemia. Thyroid hormones (T₃ and T₄) showed immediate decrease in serum and T₄ increased 6 h post-inoculation (HPI). Sepsis-induced hormonal alterations triggered changes in the metabolic pathways increasing protein and lipid catabolism, use of transient anaerobic glycolysis and liver injury. A reference transcriptome was constructed based on blood leukocytes from P. mesopotamicus. The assembly resulted in total 266,272 contigs with a N50 of 2786 bp. There was a reorganization of plasma membrane of leukocytes at the beginning of the septic process with increased expression of neuroendocrine receptors and with continuous flow of neurotransmitters, hormones and solutes with compensatory regulation at 6 HPI. Three and nine HPI seemed to be critical, the expression of a number of transcription factors was increased, including the modulatory DEGs related to glucocorticoid and thyroid hormones induced and suppressed (FDR < 0.05). Neuroendocrine modulation can regulate leukocytes and biochemical parameters of peripheral blood, being important sources for the study of the pathophysiology of sepsis. These finding highlights the importance of further studies focusing on biochemical-neuroendocrine changes in blood leukocytes and systemic sepsis.

Cortisol and adrenal androgens as independent predictors of mortality in septic patients

OBJECTIVE

To determine the prognostic value of cortisol, Dehydroepiandrosterone (DHEA) and Dehydroepiandrosterone-sulfate (DHEAS), together with their ratios (cortisol/DHEA and cortisol/DHEAS), as independent predictors of mortality in septic patients.

METHODS

Prospective cohort study of 139 consecutive patients with a diagnosis of severe sepsis or septic shock. Adrenal hormones were determined within the first 24 hours of the septic process. To determine and compare the predictive ability of each marker for the risk of unfavorable evolution (in-hospital, 28-day and 90-day mortality), ROC (Receiver Operating Characteristic) curves were constructed and the area under the curve (AUC) was determined. As measures of association, adjusted odds ratios (OR) with their 95% confidence intervals (95%CI) were estimated by unconditional logistic regression. Cortisol, DHEA and DHEAS results were compared to lactate, CRP, SOFA and APACHE II Scores.

RESULTS

Cortisol showed the best predictive ability, with AUCs of 0.758, 0.759 and 0.705 for in-hospital mortality, and 28-day and 90-day mortality, respectively; whereas AUCs for 28 days mortality for SOFA and APACHE II scores, and other biomarkers studied, such as Lactate or CRP, were 0.644, 0.618, 0.643 and 0.647, respectively. Associations between high cortisol levels (>17.5 μg/dL) and mortality were strong and statistically significant for in-hospital and 28-day mortality: adjusted ORs 10.13 and 9.45 respectively, and lower for long term mortality (90 days): adjusted OR 4.26 (95% CI 1.34-13.56), p trend 0.014. Regarding adrenal androgens, only positive associations were obtained for DHEAS and most of these positive associations did not yield statistical significance. Regarding Cortisol/DHEA and cortisol/DHEAS ratios, they did not improve the predictive ability of cortisol. The only exception was the cortisol/DHEAS ratio, which was the best predictor of mortality at 90 days (AUC 0.737), adjusted OR for highest cortisol/DHEAS ratio values 6.33 (95%CI 1.77-22.60), p trend 0.002.

CONCLUSION

Basal cortisol measured within the first 24 hours of the septic process was the best prognostic factor for in-hospital and 28-day mortality, even superior to the Sequential Organ Failure Assessment (SOFA) or Acute Physiology and Chronic Health Evaluation II (APACHE II) scores. The cortisol/DHEAS ratio was an independent predictor of long-term mortality.

Prognostic Value of Secretoneurin in Critically Ill Patients With Infections

OBJECTIVES

Secretoneurin is produced in neuroendocrine cells, and the myocardium and circulating secretoneurin levels provide incremental prognostic information to established risk indices in cardiovascular disease. As myocardial dysfunction contributes to poor outcome in critically ill patients, we wanted to assess the prognostic value of secretoneurin in two cohorts of critically ill patients with infections.

DESIGN

Two prospective, observational studies.

SETTING

Twenty-four and twenty-five ICUs in Finland.

PATIENTS

A total of 232 patients with severe sepsis (cohort #1) and 94 patients with infections and respiratory failure (cohort #2).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We measured secretoneurin levels by radioimmunoassay in samples obtained early after ICU admission and compared secretoneurin with other risk indices. In patients with severe sepsis, admission secretoneurin levels (logarithmically transformed) were associated with hospital mortality (odds ratio, 3.17 [95% CI, 1.12-9.00]; p = 0.030) and shock during the hospitalization (odds ratio, 2.17 [1.06-4.46]; p = 0.034) in analyses that adjusted for other risk factors available on ICU admission. Adding secretoneurin levels to age, which was also associated with hospital mortality in the multivariate model, improved the risk prediction as assessed by the category-free net reclassification index: 0.35 (95% CI, 0.06-0.64) (p = 0.02). In contrast, N-terminal pro-B-type natriuretic peptide levels were not associated with mortality in the multivariate model that included secretoneurin measurements, and N-terminal pro-B-type natriuretic peptide did not improve patient classification on top of age. Secretoneurin levels were also associated with hospital mortality after adjusting for other risk factors and improved patient classification in cohort #2. In both cohorts, the optimal cutoff for secretoneurin levels at ICU admission to predict hospital mortality was ≈ 175 pmol/L, and higher levels were associated with mortality also when adjusting for Simplified Acute Physiology Score II and Sequential Organ Failure Assessment scores.

CONCLUSIONS

Secretoneurin levels provide incremental information to established risk indices for the prediction of mortality and shock in critically ill patients with severe infections.

Evaluation of Early Corticosteroid Therapy in Management of Pediatric Septic Shock in Pediatric Intensive Care Patients: A Randomized Clinical Study

BACKGROUND

Septic shock is a major healthcare problem. Adrenal insufficiency (AI) in children with septic shock is a recognized complication, yet is controversial regarding its management and effect on mortality. According to the current guidelines, children with risk factors for AI should receive a stress dose of steroids in step 3 of treatment. This study aimed to evaluate and compare early corticosteroid therapy with the traditional use of steroids among pediatric septic shock patients.

METHODS

This prospective randomized interventional clinical study included 3 groups of patients (32 each) and was conducted in Alexandria University pediatric intensive care unit. By protocol, the first group received steroids in step 3 of the treatment according to the current international guidelines (group A), and the second group was managed as group A and was tested for AI by adrenal stimulation test using intramuscular adrenocorticotropic hormone (cosyntropin) (group B). The third group received steroids at the start of fluid therapy (group C). A fourth group (group D) was created by adding patients from groups A and B who needed corticosteroids in the third stage of therapy according to the international protocol in 1 group. All patients were evaluated for basal serum cortisol and plasma adrenocorticotropic hormone concentrations.

RESULTS

The data showed a statistically significant shorter shock reversal time among patients receiving corticosteroids at the start of treatment compared with those who received it at the third step of treatment (P = 0.046); however, mortality was not statistically different among the groups. In addition, there was no superinfection in cases receiving early steroid therapy.

CONCLUSIONS

Early use of corticosteroid in patients with septic shock might shorten the shock reversal time without increase in mortality or superinfection.

Circulating chromogranin B levels in patients with acute respiratory failure: data from the FINNALI Study

PURPOSE

Circulating chromogranin B (CgB) levels are increased in situations characterized by systemic and myocardial stress, but whether CgB provides prognostic information in patients with acute respiratory failure (ARF) is unknown.

METHODS

We included 584 patients with ARF, defined as ventilatory support >6 h, and with blood samples available on Intensive Care Unit (ICU) admission and day 3 (n = 479). CgB levels were measured by radioimmunoassay and follow-up was 90 days.

RESULTS

One-hundred-sixty-nine patients (29%) died during follow-up. Admission CgB levels separated non-survivors from survivors: median 1234 (Q1-3 989-1742) vs. 917 (753-1224) pmol/L, respectively, p < 0.001. CgB levels on ICU admission (logarithmically transformed) were associated with time to death after adjustment for established risk indices available on ICU admission, including N-terminal pro-B-type natriuretic levels: HR 2.62 (95%C.I. 1.82-3.77), p < 0.001. Admission CgB levels also improved prognostication on top of SOFA and SAPS II scores as assessed by Cox regression analyses and the category-free net reclassification index. The area under the curve (AUC) for admission CgB levels to separate survivors and non-survivors was 0.72 (95%CI 0.67-0.76), while the AUC on day 3 was 0.60 (0.54-0.66).

CONCLUSIONS

CgB levels measured on ICU admission provided additional prognostic information to established risk indices in ARF patients.

Cortisol Correlates with Severity of Illness and Poorly Reflects Adrenal Function in Pediatric Acute Respiratory Distress Syndrome

OBJECTIVE

To test the association between random cortisol and severity of illness in a "real-world" application of current guidelines.

STUDY DESIGN

We performed a secondary analysis of a prospective observational cohort of acute respiratory distress syndrome (ARDS). Children with ARDS and vasopressor-dependent shock were identified and random cortisol levels before potential hydrocortisone initiation recorded. The cohort was dichotomized to cortisol < 18 and ≥ 18 μg/dL, and hydrocortisone use and outcomes compared.

RESULTS

Of 357 children with ARDS, 155 (15 nonsurvivors; 10%) had vasopressors initiated with cortisol drawn before possible hydrocortisone use. Patients with cortisol < 18 μg/dL had lower severity of illness scores, fewer organ failures, and lower vasopressor scores (all rank-sum P < .05). No benefit was seen with hydrocortisone in either the entire cohort, or when dichotomized by a cortisol cutoff of 18 μg/dL. In patients with cortisol ≥ 18 μg/dL, hydrocortisone was associated with increased mortality after adjustment for either organ dysfunction or vasopressor score.

CONCLUSIONS

In children with ARDS with vasopressor-dependent shock, low cortisol correlated with lower severity of illness. Random cortisol was a poor method of diagnosing adrenal insufficiency, and a strategy of hydrocortisone replacement for cortisol < 18 μg/dL did not target a population likely to benefit from hydrocortisone. Future guidelines should reconsider using random cortisol levels alone for assessing adrenal function.

Corticosteroid-binding globulin is a biomarker of inflammation onset and severity in female rats

Plasma corticosteroid-binding globulin (CBG) plays a critical role in regulating glucocorticoid bioavailability and is an acute phase 'negative' protein during inflammation. In an adjuvant-induced arthritis model, plasma CBG levels decrease in rats that develop severe inflammation, and we have now determined when and how these reductions in CBG occur. After administering complete Freund's adjuvant or saline intra-dermally at the tail base, blood samples were taken periodically for 16days. In adjuvant-treated rats, decreases in plasma CBG levels matched the severity of inflammation, and decreases were observed 4days before any clinical signs of inflammation. Decreases in CBG levels coincided with an ~5kDa reduction in its apparent size, consistent with proteolytic cleavage, and cleaved CBG lacked steroid-binding activity. At the termination of the experimental period, hepatic Cbg mRNA levels were decreased in rats with severe inflammation. While plasma TNF-α increased in all adjuvant-treated rats, increases in Il-4, IL-6, IL-10, IL-13 and IFN-γ were only observed in rats with cleaved CBG. Rats with cleaved CBG also exhibited increased spleen weights, and strong negative correlations were observed among CBG, IL-6 and spleen weights, respectively. However, there were no differences in hepatic Cbg mRNA levels in relation to the apparent proteolysis of CBG, suggesting that CBG cleavage occurs before changes in hepatic Cbg expression. Our results indicate that the levels and integrity of plasma CBG are biomarkers of the onset and severity of inflammation. Dynamic changes in the levels and function of CBG likely modulate the tissue availability of corticosterone during inflammation.

Sugar or salt? The relative roles of the glucocorticoid and mineralocorticoid axes in traumatic shock

BACKGROUND

Glucocorticoid deficiency (GD) has been proposed as a key contributor to shock states, but the presence and role of acute mineralocorticoid deficiency may be of equal or greater significance. We sought to analyze the incidence and degree of acute mineralocorticoid deficiency and GD in an animal model of severe hemorrhage and shock.

METHODS

Fifty-seven swine underwent 35% volume-controlled hemorrhage followed by aortic cross-clamping for 50 minutes to induce truncal ischemia-reperfusion. Protocol-guided resuscitation was performed. Laboratory analysis included cortisol, aldosterone, and plasma renin activity. The aldosterone-to-renin ratio (ARR) was calculated at each time point, and changes were correlated to markers of perfusion.

RESULTS

Mean baseline cortisol levels were 5.8 μg/dL. Following hemorrhage, there was a significant increase in mean cortisol to 9.2 μg/dL (p < 0.001). After 1 hour of reperfusion, there was no change in mean cortisol levels (9.8 μg/dL, p = 0.12). Mean baseline aldosterone was 13.3 pg/mL. Aldosterone levels before cross-clamp removal increased significantly to 115.1 pg/mL (p < 0.001) and then rapidly declined to 49.2 pg/mL (p < 0.001) after 1 hour of reperfusion. Conversely, baseline plasma renin activity was 0.75 ng/mL per hour and increased significantly before cross-clamp removal (1.8) and at 1 hour (8.9, both p < 0.001). The ARR at baseline was 96.1 and increased to 113.5 (p = 0.68) before cross-clamp removal but significantly declined following 1 hour of reperfusion to 7.6 (p < 0.001). Overall, this represented a 93% reduction in mean ARR following reperfusion. The degree of aldosterone deficiency correlated with degree of systemic shock as measured by arterial base deficit (r = 0.47, p = 0.04), while cortisol showed no correlation.

CONCLUSION

Hemorrhagic shock with ischemia-reperfusion injury resulted in only modest impact on the glucocorticoid axis, but major dysfunction of the mineralocorticoid axis and severe hyperreninemic hypoaldosteronism. The degree of aldosterone deficiency may provide prognostic information or offer potential targets for pharmacologic intervention.

LEVEL OF EVIDENCE

Diagnostic study, level III.

Three calculations of free cortisol versus measured values in the critically ill

OBJECTIVES

To investigate the agreement between the calculated free cortisol levels according to widely applied Coolens and adjusted Södergård equations with measured levels in the critically ill.

DESIGN AND METHODS

A prospective study in a mixed intensive care unit. We consecutively included 103 patients with treatment-insensitive hypotension in whom an adrenocorticotropic hormone (ACTH) test (250μg) was performed. Serum total and free cortisol (equilibrium dialysis), corticosteroid-binding globulin and albumin were assessed. Free cortisol was estimated by the Coolens method (C) and two adjusted Södergård (S1 and S2) equations. Bland Altman plots were made.

RESULTS

The bias for absolute (t=0, 30 and 60min after ACTH injection) cortisol levels was 38, -24, 41nmol/L when the C, S1 and S2 equations were used, with 95% limits of agreement between -65-142, -182-135, and -57-139nmol/L and percentage errors of 66, 85, and 64%, respectively. Bias for delta (peak-baseline) cortisol was 14, -31 and 16nmol/L, with 95% limits of agreement between -80-108, -157-95, and -74-105nmol/L, and percentage errors of 107, 114, and 100% for C, S1 and S2 equations, respectively.

CONCLUSIONS

Calculated free cortisol levels have too high bias and imprecision to allow for acceptable use in the critically ill.

Postoperative Sudden Hypotension Due to Relative Adrenal Insufficiency

Systemic blood pressure is regulated by three mechanisms: the sympathetic nervous system, the renin-angiotensin system, and the arginine-vasopressin system. Hypotension is a condition that can occur at any stage of management of general anaesthesia, including induction, extubation, and maintenance. Many of the medications used for anaesthesia produce a mild to moderate decrease in systemic vascular resistance (SVR) with a subsequent decrease in arterial blood pressure. Profound and sustained hypotension, however, can have a global impact, resulting in a failure to adequately perfuse systemic capillary networks. The following report describes the case of a 69-year-old man undergoing surgery for total hip replacement who had hypotension that was refractory to fluid administration and inotropic agents at the end of the surgery. In this case study, the role of methylprednisolone therapy in catecholamine-resistant hypotension is also discussed.

Etomidate, adrenal function, and mortality in critically ill patients

BACKGROUND

In critically ill patients, induction with etomidate is hypothesized to be associated with an increased risk of mortality. Previous randomized studies suggest a modest trend toward an increased risk of death among etomidate recipients; however, this relationship has not been measured with great statistical precision. We aimed to test whether etomidate is associated with risk of hospital mortality and other clinical outcomes in critically ill patients.

METHODS

We conducted a retrospective cohort study from January 1, 2001, to December 31, 2005, of 824 subjects requiring mechanical ventilation, who underwent adrenal function testing in the ICUs of 2 academic medical centers. The primary outcome was in-hospital mortality, comparing subjects given etomidate (n = 452) to those given an alternative induction agent (n = 372). The secondary outcome was diagnosis of critical illness-related corticosteroid insufficiency following etomidate exposure.

RESULTS

Overall mortality was 34.3%. After adjustment for age, sex, and baseline illness severity, the relative risk of death among the etomidate recipients was higher than that of subjects given an alternative agent (relative risk 1.20, 95% CI 0.99-1.45). Among subjects whose adrenal function was assessed within the 48 hours following intubation, the adjusted risk of meeting the criteria for critical illness-related corticosteroid insufficiency was 1.37 (95% CI 1.12-1.66), comparing etomidate recipients to subjects given another induction agent.

CONCLUSIONS

In this study of critically ill patients requiring endotracheal intubation, etomidate administration was associated with a trend toward a relative increase in mortality, similar to the collective results of smaller randomized trials conducted to date. If a small relative increased risk is truly present, though previous trials have been underpowered to detect it, in absolute terms the number of deaths associated with etomidate in this high-risk population would be considerable. Large, prospective controlled trials are needed to finalize the role of etomidate in critically ill patients.

Cortisol levels are influenced by sedation in the acute phase after subarachnoid haemorrhage

BACKGROUND

Subarachnoid haemorrhage (SAH) is a life-threatening condition that may be aggravated by acute pituitary damage and cortisol insufficiency. Robust diagnostic criteria for critical illness-related corticosteroid insufficiency (CIRCI) are lacking. The aim of this study was to assess the frequency of CIRCI in the acute phase (0-240 h) after SAH and to evaluate associations between cortisol levels and clinical parameters (sedation, circulatory failure, gender, age, severity of disease, treatment). CIRCI was defined as a single morning serum cortisol (mSC) < 200 nmol/L. The lower limit for calculated free cortisol (cFC) was set at < 22 nmol/L, and for saliva cortisol at < 7.7 nmol/L.

METHODS

Fifty patients were included. Serum/saliva cortisol and corticosteroid-binding globulin were obtained every second morning. A logistic regression model was used for multivariate analysis comparing cortisol levels with clinical parameters.

RESULTS

Of the patients, 21/50 (42%) had an mSC < 200 nmol/L and 30/50 (60%) had a cFC < 22 nmol/L. In patients with continuous intravenous sedation, the odds ratio for a mSC to be < 200 nmol/L was 18 times higher (95% confidence interval 4.2-85.0, P < 0.001), and the odds ratio for a cFC to be < 22 nmol/L was 2.4 times higher (95% confidence interval 1.2-4.7, P < 0.05) compared with patients with no continuous intravenous sedation.

CONCLUSIONS

Continuous intravenous sedation was significantly associated with cortisol values under defined limits (mSC < 200, cFC < 22 nmol/L). The possibility that sedating drugs per se may influence cortisol levels should be taken into consideration before CIRCI is diagnosed.

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.

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.

Prognostic value of chromogranin A in severe sepsis: data from the FINNSEPSIS study

PURPOSE

To assess the prognostic information of chromogranin A (CgA), a marker associated with adrenergic tone and myocardial function, in patients with severe sepsis.

METHODS

CgA levels were measured at the time of study inclusion and 72 h later in 232 patients with severe sepsis recruited from 24 ICUs in Finland (FINNSEPSIS study).

RESULTS

Sixty-five patients (28%) died during the index hospitalization. CgA levels at inclusion and after 72 h correlated with several established indices of risk in sepsis. Patients who died during the hospitalization had higher baseline CgA levels than hospital survivors: 14.0 (Q1-3, 7.4-27.4) versus 9.1 (5.9-15.8) nmol/l, P = 0.002, and after 72 h: 16.2 (9.0-31.1) versus 9.8 (6.0-18.0) nmol/l, P = 0.001. Prior cardiovascular disease (P = 0.04) and cardiovascular SOFA levels on day 3 (P = 0.03) were associated with higher CgA levels after 72 h by linear regression. CgA levels on study inclusion and after 72 h were independently associated with hospital mortality by logistic regression: OR (logarithmically transformed CgA levels) 1.95 (95% CI 1.01-3.77), P = 0.046 and OR 2.03 (95% CI 1.18-3.49), P = 0.01, respectively. The prognostic accuracy was comparable for CgA measurements and SAPS II score, and the addition of CgA measurements to the SAPS II score improved risk stratification of the patients as assessed by the category-free net reclassification index. A CgA level >6.6 nmol/l on study inclusion was associated with septic shock during the hospitalization.

CONCLUSION

CgA levels measured during hospitalization for severe sepsis are associated with cardiovascular dysfunction and may provide additional prognostic information in patients with severe sepsis.

Real-time free cortisol quantification among critically ill children

OBJECTIVES

Ascertainment of adrenal function assessing free rather that total cortisol may be beneficial for the diagnosis of critical illness-related cortisol insufficiency. We hypothesized that centrifugal ultrafiltration would provide timely free cortisol data that highly correlated with the gold standard, but logistically cumbersome, equilibrium dialysis technique when the free cortisol fractions were identically quantified by chemiluminescence immunoassay. We also hypothesized that free cortisol would correlate with illness severity in a large cohort of critically ill children.

DESIGN

Prospective, multi-institutional, observational cohort investigation.

SETTING

Seven pediatric intensive care units within the Eunice Kennedy Shriver National Institute of Child Health and Human Development Collaborative Pediatric Critical Care Research Network.

PATIENTS

One hundred sixty-five critically ill children across the spectrum of illness severity.

INTERVENTIONS

Blood sampling.

MEASUREMENTS AND MAIN RESULTS

Time to derive plasma free cortisol concentrations after centrifugal ultrafiltration or equilibrium dialysis fractionation with chemiluminescence immunoassay was approximately 2 vs. approximately 24 hrs, respectively. Using centrifugal ultrafiltration, mean plasma free cortisol was 4.1 ± 6.7 μg/dL (median, 1.6 μg/dL; range, 0.2-43.6 μg/L), representing an average of 15.2 ± 9.4% of total cortisol. Nearly 60% of subjects exhibited free cortisol <2 and 30% <0.8 μg/dL, previously suggested threshold concentrations for defining critical illness-related cortisol insufficiency. Plasma-free cortisol concentrations comparing centrifugal ultrafiltration vs. equilibrium dialysis fractionation demonstrated a strong correlation (R2 = 0.97). For free cortisol <2 μg/dL, Bland-Altman analysis revealed minimal negative bias for the centrifugal ultrafiltration technique. Illness severity assessed by Pediatric Risk of Mortality III correlated moderately with free cortisol and percent total cortisol as free cortisol.

CONCLUSIONS

Determination of centrifugal ultrafiltration fractionated free cortisol was fast and results correlated highly with equilibrium dialysis fractionated free cortisol. Many children exhibited free cortisol <2 and <0.8 μg/dL but did not demonstrate clinical evidence of critical illness-related cortisol insufficiency. This study ascertains that real-time free cortisol quantification is feasible to potentially help guide clinical decision-making for cortisol replacement therapy in the pediatric intensive care unit.

Assessing adrenal insufficiency of corticosteroid secretion using free versus total cortisol levels in critical illness

PURPOSE

To study the value of free versus total cortisol levels in assessing relative adrenal insufficiency during critical illness-related corticosteroid insufficiency.

METHODS

A prospective study in a mixed intensive care unit from 2004 to 2007. We consecutively included 49 septic and 63 non-septic patients with treatment-insensitive hypotension in whom an adrenocorticotropic hormone (ACTH) test (250 μg) was performed. Serum total and free cortisol (equilibrium dialysis), corticosteroid-binding globulin (CBG) and albumin were assessed.

RESULTS

Although a low CBG resulted in a high free cortisol level relative to total cortisol, free and total cortisol and their increases were well correlated (r = 0.77-0.79, P < 0.001). In sepsis, hypoalbuminemia did not affect total and free cortisol, and increases in total cortisol upon ACTH predicted increases in free cortisol regardless of low binding proteins. In non-sepsis, total cortisol was lower with than without hypoalbuminemia; free cortisol did not differ, since hypoalbuminemia concurred with a low CBG. Increases in total cortisol depended less on binding proteins than on raw levels. The areas under the receiver operating characteristic curve for predicting increases in free from total cortisol were 0.93-0.97 in sepsis and 0.79-0.85 in non-sepsis (P = 0.044 or lower for sepsis vs. non-sepsis).

CONCLUSIONS

Although the biologically active free cortisol fraction depends on binding proteins, total cortisol correlates to free cortisol in treatment-insensitive hypotension during critical illness. In sepsis, albumin is not an important binding molecule. Subnormal increments in total cortisol upon ACTH suffice in assessing relative adrenal insufficiency, particularly in sepsis.

The effect of cardiopulmonary bypass on the hypothalamic-pituitary-adrenal axis in children

OBJECTIVE

The pathophysiology of low-cardiac-output syndrome after cardiopulmonary bypass is incompletely understood, but adrenal insufficiency has been proposed as a contributing factor. Our objective was to examine the effect of cardiopulmonary bypass on the hypothalamic-pituitary-adrenal axis, specifically adrenal responsiveness, in patients with congenital heart disease undergoing surgery. We hoped to correlate bound and free cortisol values both postoperatively and after adrenocorticotropic hormone stimulation, in conjunction with corticosteroid-binding globulin levels, with clinical outcomes to determine whether these variables are sensitive indicators of adrenal axis function.

DESIGN

Prospective cohort study.

SETTING

A children's hospital.

PATIENTS

Fifty-two pediatric heart surgery patients undergoing cardiopulmonary bypass.

INTERVENTION

Total cortisol and corticosteroid-binding globulin levels were obtained pre- and postoperatively and after a postoperative cosyntropin stimulation test. Free cortisol was calculated by using Coolens' method.

MEASUREMENTS AND MAIN RESULTS

Nine of 51 (17.6%) patients had low (<3 μg/dL) baseline postoperative total cortisol, median 1.6 μg/dL, yet all nine had normal (>9 μg/dL increase from postoperative baseline) stimulation tests. The corticosteroid-binding globulin levels declined from a mean of 29 mg/L preoperatively to 22 mg/L postoperatively (p < .001) and showed marked variability between patients. Patients with free cortisol δ >6 μg/dL (n = 18, 35%) had a longer length of stay (median 9 vs. 5 days; p = .002), higher inotrope scores (median 13.3 vs. 10.8; p = .05), greater fluid requirement (median 73.5 vs. 55.6 mL/kg; p = .007), and longer ventilator times (median 41.5 vs. 20 hrs; p = .013).

CONCLUSIONS

Although hypothalamic-pituitary-adrenal axis dysfunction may play a role in low-cardiac-output syndrome among children undergoing congenital heart surgery, using total cortisol to investigate such dysfunction may be inadequate. Decreased corticosteroid-binding globulin levels and marked free cortisol increase after stimulation were associated with worse clinical outcomes. Further investigation into the cortisol-corticosteroid-binding globulin complex and its relationship to free cortisol is necessary to examine the problem of adrenal insufficiency from a more integrated perspective.

Methylprednisolone exacerbates acute critical illness-related corticosteroid insufficiency associated with traumatic brain injury in rats

Emerging evidence demonstrates that severe illness could induce critical illness-related corticosteroid insufficiency (CIRCI) and cause poor prognosis. The purpose of this study was to test the hypothesis that methylprednisolone (MP), a synthetic glucocorticoid, promotes post-traumatic apoptosis in both the hypothalamus and pituitary, resulting in acute CIRCI and increased mortality in the acute phase of traumatic brain injury (TBI). We tested this hypothesis by measuring acute CIRCI in rats subjected to fluid percussion injury (FPI) and treated with MP (5-30mg/kg). The corticosteroid response to TBI was evaluated using the corticosterone increase index (CII), where values less than 2.5 were considered indicative of acute CIRCI. The CII of MP treated rats was comparable to that of saline treated control rats before injury but was significantly decreased in injured rats receiving high-dose MP on post-injury day 7. Similarly, the incidence of acute CIRCI was significantly higher in the high-dose MP group on post-injury day 7. Furthermore, the CII of rats that did not survive post-injury was significantly lower compared to that of survival and was indicative of acute CIRCI. We also examined apoptosis in the paraventricular nucleus (PVN) of the hypothalamus and the adenohypophysis of the pituitary, using a TUNEL assay and transmission electron microscopy (TEM). The number of TUNEL-positive cells was significantly higher in injured rats treated with high-dose MP. No TUNEL-positive cells were detected in the adenohypophysis across experimental groups at either 7 or 14days after TBI. However, autopsies performed on rats that did not survive post-injury revealed obvious apoptotic cells in the adenohypophysis. Moreover, TEM revealed morphological changes characteristic of apoptosis in both the PVN and adenohypophysis of high-dose MP treated rats. These data suggest that MP therapy for TBI could increase neuronal apoptosis in both the hypothalamus and pituitary and consequently exacerbate acute CIRCI and mortality induced by TBI.

Circulating high sensitivity troponin T in severe sepsis and septic shock: distribution, associated factors, and relation to outcome

PURPOSE

To assess the clinical utility of a recently developed highly sensitive cardiac troponin T (hs-cTnT) assay for providing prognostic information on patients with sepsis.

METHODS

cTnT levels were measured by the novel hs-cTnT assay at two time points (inclusion and 72 h thereafter) in a subgroup of patients from the FINNSEPSIS study and associations with clinical outcomes were examined. Results for the hs-cTnT assay were compared to those of the established fourth-generation cTnT assay.

RESULTS

cTnT measured by the fourth-generation and hs-cTnT assay was detectable in 124 (60%) and 207 (100%) patients, respectively, on inclusion in this study. hs-cTnT levels on inclusion correlated with several indices of risk in sepsis, including the simplified acute physiology score (SAPS) II and sequential organ failure assessment (SOFA) scores. The level of hs-cTnT on inclusion was higher in hospital non-survivors (n = 47) than survivors (n = 160) (median 0.054 [Q1-3, 0.022-0.227] versus 0.035 [0.015-0.111] μg/L, P = 0.047), but hs-cTnT level was not an independent predictor of in-hospital mortality. hs-cTnT levels on inclusion were also higher in patients with septic shock during the hospitalization (0.044 [0.024-0.171] versus 0.033 [0.012-0.103] μg/L, P = 0.03), while this was not the case for the fourth-generation cTnT assay or NT-proBNP levels.

CONCLUSIONS

Circulating hs-cTnT is present in patients with severe sepsis and septic shock, associates with disease severity and survival, but does not add to SAPS II score for prediction of mortality. hs-cTnT measurement could still have a role in sepsis as an early marker of shock.

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.

Proven infection-related sepsis induces a differential stress response early after ICU admission

INTRODUCTION

Neuropeptides arginine-vasopressin (AVP), apelin (APL), and stromal-derived factor-1α (SDF-1α) are involved in the dysfunction of the corticotropic axis observed in septic ICU patients. Study aims were: (i) to portray a distinctive stress-related neuro-corticotropic systemic profile of early sepsis, (ii) to propose a combination data score, for aiding ICU physicians in diagnosing sepsis on admission.

METHODS

This prospective one-center observational study was carried out in a medical intensive care unit (MICU), tertiary teaching hospital. Seventy-four out of 112 critically ill patients exhibiting systemic inflammatory response syndrome (SIRS) were divided into two groups: proven sepsis and non sepsis, based on post hoc analysis of microbiological criteria and final diagnosis, and compared to healthy volunteers (n = 14). A single blood sampling was performed on admission for measurements of AVP, copeptin, APL, SDF-1α, adrenocorticotropic hormone (ACTH), cortisol baseline and post-stimulation, and procalcitonin (PCT).

RESULTS

Blood baseline ACTH/cortisol ratio was lower and copeptin higher in septic vs. nonseptic patients. SDF-1α was further increased in septic patients vs. normal patients. Cortisol baseline, ACTH, PCT, APACHE II and sepsis scores, and shock on admission, were independent predictors of sepsis diagnosis upon admission. Using the three first aforementioned categorical bio-parameters, a probability score for predicting sepsis yielded an area under the Receiver Operating Curve (ROC) curves better than sepsis score or PCT alone (0.903 vs 0.727 and 0.726: P = 0.005 and P < 0.04, respectively).

CONCLUSIONS

The stress response of early admitted ICU patients is different in septic vs. non-septic conditions. A proposed combination of variable score analyses will tentatively help in refining bedside diagnostic tools to efficiently diagnose sepsis after further validation.

Relative adrenal insufficiency in the intensive care population; background and critical appraisal of the evidence

Dysfunction of the hypothalamo-pituitary adrenal axis has become a central feature in descriptions of the pathophysiology of sepsis. However; despite hundreds of published articles including literature reviews and consensus statements, controversy still exists regarding the fundamental nature of the disorder and its relevance to clinical management. Often referred to as 'relative adrenal insufficiency', a recent consensus conference has proposed the alternate term 'critical illness related corticosteroid insufficiency' and suggested diagnostic criteria of a delta serum cortisol of less than 9 microg/l after adrenocorticotrophic hormone administration or a random total cortisol of under 10 microg/l. This review attempts to establish a critical reappraisal of the evidence for the existence of relative adrenal insufficiency/critical illness related corticosteroid insufficiency in patients with sepsis and examines the background, controversies and possibilities for future research into the condition.

Adrenal insufficiency: etiology, diagnosis and treatment

PURPOSE OF REVIEW

Adrenal insufficiency, first codified in 1855 by Thomas Addison, remains relevant in 2010 because of its lethal nature.

RECENT FINDINGS

Reports illuminate features of adrenal insufficiency cause, diagnosis and treatment, and the role of glucocorticoids in critical illness.

SUMMARY

Progress has been made in identifying human leukocyte antigen and major histocompatability complex alleles that predispose to the development of adrenal insufficiency in patients with antibodies to 21-hydroxylase, but their role in clinical care is not established. Reports of HIV-associated infections and medication-induced hypocortisolism are reminders that autoimmune adrenal destruction does not underlie all cases. The diagnosis is adequately established by the 250 microg adrenocortocotropin hormone stimulation test in most patients; the 1 microg test carries the risk of misdiagnosis of healthy individuals as adrenally insufficient. Glucocorticoids provide life-saving treatment, but long-term quality of life is impaired, perhaps because therapy is not given in a physiologic way. The current recommended total daily dose is lower than that often prescribed. Dehydroepiandrosterone replacement may be useful in pubertal girls with hypopituitarism, but not in adults. Supraphysiologic hydrocortisone doses may aid in the reversal of septic shock independent of underlying adrenal function.

Corticosteroid-binding globulin: the clinical significance of altered levels and heritable mutations

Corticosteroid-binding globulin (CBG) is the specific high-affinity plasma transport glycoprotein for cortisol. Stress-induced falls in CBG levels may heighten hypothalamic-pituitary-adrenal axis responses and CBG:tissue interactions may allow targeted cortisol delivery. Three genetic variants of CBG have been identified that reduce cortisol binding affinity and/or CBG levels. These include the Leuven and Lyon mutations which reduce CBG:cortisol binding affinity 3- and 4-fold, respectively, and the null mutation resulting in a 50% (heterozygote) or 100% (homozygote) reduction in CBG levels. The three reported null homozygotes demonstrate that complete CBG deficiency is not lethal, although it may be associated with hypotension and fatigue. The phenotype of a CBG null murine model included fatigue and immune defects. One community-based study revealed that severe CBG mutations are rare in idiopathic fatigue disorders. The mechanisms by which CBG mutations may cause fatigue are unknown. There are preliminary data of altered CBG levels in hypertension and in the metabolic syndrome; however, the nature of these associations is uncertain. Further studies may clarify the functions of CBG, and clinical observations may validate and/or extend the phenotypic features of various CBG mutations.

"Relative" adrenal insufficiency in critical illness

OBJECTIVE

To present a recommended approach to the problem of "relative" adrenal insufficiency (RAI) in the intensive care unit (ICU).

METHODS

We examine historical data that support the traditional concepts of adrenal insufficiency and the idea that the increase in cortisol secretion during stress is needed to survive the stress. The controversial use of treatment with glucocorticoids (GCs) in patients with sepsis and septic shock in the ICU (and thus survival benefit) is also briefly discussed.

RESULTS

During the past decade, the concept of RAI as the failure of cortisol secretion to increase in response to stress to sustain the patient through that stress has gained strength. In some studies, it has been suggested that as many as 75% of patients in an ICU setting have RAI. Experimental support for the concept is not possible because there is no clinically useful laboratory measure of GC action. Therefore, diagnosis is generally based on interpretation of the cosyntropin stimulation test.

CONCLUSION

The best clinical judgment should always guide interpretation of any test results, and sharp categorization of patients on the basis of a single cutoff criterion should be avoided. Overall, the concept of RAI has no clinical utility. In these cases, administration of GCs adds cost without benefit and with increased risk.

Pretreatment with stress cortisol enhances the human systemic inflammatory response to bacterial endotoxin

OBJECTIVE

There is continuing controversy regarding the effect of glucocorticoids on a systemic inflammatory process. Based ona model of glucocorticoid action that includes both pro- and anti-inflammatory effects, we used the human experimental endotoxemia model to test the hypothesis that a transient elevation of plasma cortisol to stress-associated levels would enhance a subsequent (delayed) systemic inflammatory response to bacterial endotoxin.

DESIGN

Prospective, randomized, double-blind, placebo-controlled clinical investigation.

SETTING

Academic medical center.

SUBJECTS

Thirty-six healthy human volunteers.

INTERVENTIONS

Participants were randomized to receive a 6-hr intravenous infusion of saline (control), an intermediate dose of cortisol (Cort80; 6.3 mg/hr/70 kg), or a high dose of cortisol (Cort160; 12.6 mg/hr/70 kg) on day 1. On day 2, participants received an intravenous injection of 2 ng/kg Escherichia coli endotoxin followed by serial measurements of plasma cytokine concentrations.

MEASUREMENTS AND MAIN RESULTS

Baseline participant characteristics and cortisol and cytokine concentrations were similar in all three groups. The plasma cortisol response to endotoxemia on day 2 was similar in all three groups. The interleukin-6 response to endotoxemia was significantly increased in the Cort80 Group compared with the control Group (p = .004), whereas the interleukin-10 response was significantly suppressed (p = .034). Corresponding results for the Cort160 Group were not significantly different from control Group values.

CONCLUSIONS

In this study, transient elevation of in vivo cortisol concentrations to levels that are observed during major systemic stress enhanced a subsequent, delayed in vivo inflammatory response to endotoxin. This appeared to be a dose-dependent effect that was more prominent at intermediate concentrations of cortisol than at higher concentrations of cortisol.

Sex defines the age dependence of endogenous ACTH-cortisol dose responsiveness

Sex influences adrenal glucocorticoid responses to ACTH in experimental animals. Whether similar sex differences operate in humans is unknown. To test this notion, we estimated ACTH-cortisol dose-response properties analytically in 48 healthy adults (n = 22 women, n = 26 men), ages 18-77 yr, body mass index (BMI) 18-32 kg/m(2), previously studied at two medical centers. Plasma ACTH and cortisol concentrations were measured every 10 min for 24 h. The 145 sample pairs were used in each subject to estimate ACTH-cortisol drive via a logistic function. Statistical analyses revealed that 24-h cortisol secretion (>82% pulsatile) fell in men (r = -0.38, P = 0.028) and rose in women (r = +0.37, P = 0.045) with age (P = 0.01 sex effect). The mechanisms involved decreased ACTH efficacy with age in men (r = -0.35, P = 0.04), and increased ACTH efficacy with age in women (r = +0.42, P = 0.025) [P = 0.009 sex effect]. ACTH potency diminished with higher BMI in men (r = +0.38, P = 0.029) and in the cohort as a whole (r = 0.34, P = 0.0085). These outcomes demonstrate that sex, age, and BMI modulate selective properties of endogenous ACTH-cortisol drive in humans, thereby indicating the need to control these three major variables in experimental comparisons.

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.