Anterior pituitary function in critical illness

Alterations in neuroendocrine axes in brain-dead patients

PURPOSE

To identify changes in anterior pituitary gland hormone levels in brain-dead patients and alterations in free triiodothyronine (fT3), free thyroxine, cortisol, testosterone, and estradiol levels.

METHODS

Ten postmenopausal women and 22 men with brain death (BD) were included. The first blood sample for determination of hormones (pre-BD) was collected when the clinician observed the first signs of BD. The second blood sample (BD day) was drawn after BD certification.

RESULTS

Female patients exhibited lower follicle-stimulating hormone and prolactin levels pre-BD and luteinizing hormone, follicle-stimulating hormone, and prolactin levels on BD day than the age-matched controls. Male patients' sex hormone levels were similar to those of the age-matched controls, except for testosterone levels, which were low in both consecutive measurements. All gonadotropins and prolactin levels were above the tests' lower detection limits (LDLs), except for one male patient with gonadotropin levels below the LDLs of the tests. Estradiol levels in both sexes ranged from normal to elevated. FT3 levels were significantly decreased in the two measurements. Thyroid-stimulating hormone (TSH) levels were low in eight patients and all low TSH levels were above the test's LDL. The remaining patients had normal or elevated TSH levels. The median adrenocorticotropic hormone (ACTH) and cortisol levels were within normal limits. All cortisol and ACTH levels were above the tests' LDLs, except for one patient with ACTH levels below the LDL in both measurements.

CONCLUSION

This study supports the hypothesis that the anterior pituitary gland continues to function in the brain-dead state.

Impact of critical illness on cholesterol and fatty acids: insights into pathophysiology and therapeutic targets

Critical illness is characterized by a hypercatabolic response encompassing endocrine and metabolic alterations. Not only the uptake, synthesis and metabolism of glucose and amino acids is majorly affected, but also the homeostasis of lipids and cholesterol is altered during acute and prolonged critical illness. Patients who suffer from critically ill conditions such as sepsis, major trauma, surgery or burn wounds display an immediate and sustained reduction in low plasma LDL-, HDL- and total cholesterol concentrations, together with a, less pronounced, increase in plasma free fatty acids. The severity of these alterations is associated with severity of illness, but the underlying pathophysiological mechanisms are multifactorial and only partly clarified. This narrative review aims to provide an overview of the current knowledge of how lipid and cholesterol uptake, synthesis and metabolism is affected during critical illness. Reduced nutritional uptake, increased scavenging of lipoproteins as well as an increased conversion to cortisol or other cholesterol-derived metabolites might all play a role in the decrease in plasma cholesterol. The acute stress response to critical illness creates a lipolytic cocktail, which might explain the increase in plasma free fatty acids, although reduced uptake and oxidation, but also increased lipogenesis, especially in prolonged critical illness, will also affect the circulating levels. Whether a disturbed lipid homeostasis warrants intervention or should primarily be interpreted as a signal of severity of illness requires further research.

Prevalence of Hypocortisolemia in Patients with Sepsis or Septic Shock (The HIS Study) Presenting to the Emergency Department

Background

Cortisol response to stressors (hypothalamic-pituitary-adrenal axis, autonomic nervous system, and immune system) plays a vital role in maintaining stable metabolic homeostasis. This study was done to assess the prevalence of hypocortisolemia in patients presenting to ED with sepsis and/or septic shock.

Methods

This prospective observational study was done from July 2020 to April 2021. Serum cortisol levels were measured in patients with sepsis and septic shock, and their clinical and laboratory profile was categorized, coded, and analyzed.

Results

Ninety-eight patients were included, of which serum Cortisol <10 μg/dl was noted in 7 (7.2%) patients. The cohort's mean age was 52.9 (SD: 15.3) years with a male predominance (n-61; 62.2%). Most common presenting complaint was fever (n-52; 53.1%), followed by abdominal pain (n-24; 24.5%), and breathing difficulty (n-14; 14.3%). Systolic blood pressure <90 mmHg and tachycardia were seen in 63 patients (64.3%). Assessment of diet and native medication use did not demonstrate a predisposition to hypocortisolemia. The median (IQR) arterial lactate values were lower in the hypocortisolemic group: 2.2 (1.2-2.5) as compared to the non-hypocortisolemic group: 3.7 (2.2-8.0). Patients with septic shock without hypocortisolemia were noted to have a higher mean lactate level (2.6 ± 1.3 Vs 5.4 ± 3.9) and lower platelet counts compared to those with low cortisol levels. Patients with normal cortisol levels (n-38; 38.8%) still had low ACTH values.

Conclusion

The prevalence of hypocortisolemia was lower when compared to other Indian studies. Diet and native medication use do not predispose Indians to hypocortisolemia.

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.

Impact of ß-hydroxy-ß-methylbutyrate (HMB) in critically ill patients on the endocrine axis - A post-hoc cohort study of the HMB-ICU trial

BACKGROUND

β-hydroxy-β-methylbutyrate (HMB) might improve muscle function and maintain its mass in critically ill patients. We aimed to investigate whether the administration of HMB influenced the plasma levels of growth hormone (GH)/insulin-like growth factor-1 (IGF-1), C-peptide, and 25-OH vitamin-D.

METHODS

Post-hoc analysis of the study HMB-ICU, a randomized, placebo-controlled double-blind trial.

INCLUSION CRITERIA

Intensive care unit (ICU) patients depending on mechanical ventilation on day 3 with functional gastrointestinal tract. Patients were randomized to HMB (3 g/day) or placebo (maltodextrin) from day 4 on, for 30 days. Blood samples were collected on days 4 and 15. We determined the GH, C-peptide, 25-OH vitamin-D, and IGF-1. Statistics by ANCOVA.

RESULTS

Blood samples of 26 patients were available on day 4, and 23 on day 15. While age and severity of disease did not differ, diabetes was more frequent in the HMB group (p = 0.041), and obesity was more frequent in the placebo group (p = 0.021). Glucose intake, blood glucose (BG) and amount of insulin to maintain blood glucose between 6 and 8 mM did not differ between groups. There was no difference between groups for C-peptide, GH, IGF-1, and 25-OH vitamin-D. IGF-1 increased significantly from day 4-15 (p = 0.026) in both groups.

CONCLUSION

Subject to possible insufficient power of the study, we did not reach conclusive results. HMB intervention does not affect significantly the plasma concentrations of insulin, GH/IGF axis activity, C-peptide, and 25-OH vitamin-D.

CLINICALTRIALS

GOV IDENTIFIER

NCT03628365.

The Added Value of Serum Random Cortisol and Thyroid Function Tests as Mortality Predictors for Critically Ill Patients: A Prospective Cohort Study

Background: Thyroid hormone and cortisol levels can change during a course of illness. Our study was conducted to assess the ability of the level of these hormones to predict mortality among intensive care unit (ICU) patients. The added predictive value of these hormones with APACHE II scores was also evaluated. Methods: Thyroid hormones and random cortisol levels in adult ICU patients were collected on admission. Multivariate logistic regression analysis was used to assess the relationship between hormone levels and mortality. The added value of the mortality predictive ability was determined by area under the receiver operating characteristic (AuROC). Results: A total of 189 patients were included in the study. Free T3 and serum random cortisol levels were statistically significantly related to ICU mortality with OR 0.51 (0.28, 0.97), p = 0.047 and OR 1.02 (1.01, 1.04), p < 0.002, respectively. Free T3 and serum random cortisol significantly enhanced the predictive performance of APACHE II scores with an AuROC of 0.656 (non-added value model) versus 0.729 (added value model), p = 0.009. The scoring system was created with a total score that ranged from 1 to 14. A score above 7.0 indicated a high mortality rate with a sensitivity of 81.5% and a specificity of 33%. Conclusions: Serum free T3 and cortisol levels are significantly associated with ICU mortality and can enhance the ability of APACHE II scores to predict ICU mortality.

To study thyroid hormone levels (FT3, FT4, and TSH levels) in critically ill children and their correlation with disease severity and clinical outcome in Rajendra Institute of Medical Sciences, Ranchi, Jharkhand

Introduction

There are manifold effects on neuro-endocrine and metabolic systems due to critical illness. Abnormalities in thyroid hormone levels in a critically-ill patient with no pre-existing hypothalamo-pituitary-thyroid dysfunction is seen in Euthyroid sick syndrome or Non thyroidal illness syndrome. The understanding of different endocrinal changes in acute phase of critical illness may help us to intervene early and improve by pharmacological intervention.

Materials and Methods

Critically ill children admitted in PICU, RIMS, Ranchi, aged 29 days to 17 years.

Results

In our study, it was seen that FT3 and FT4 were low at admission at admission in critically ill children. And among them, the non-survivors had significantly lower values compared to survivors.

Discussion

Among this critically ill patient, more than 70% of patients have shown low free T3 (Type I NTIS) and around 50% of low free T4 levels and free T3 levels (Type II NTIS). We have done this study to assess the thyroid dysfunction in critically ill children admitted in our PICU and its correlation with disease severity and clinical outcome.

Is There Any Correlation between Baseline Serum Cortisol Levels and Disease Severity in PCR-Positive COVID-19 Patients with and without Diabetes Mellitus?

Background: COVID-19 has caused a pandemic and is associated with significant mortality. The pathophysiology of COVID-19, affecting many organs and systems, is still being investigated. The hypothalamus, pituitary gland, and possibly adrenal glands are the targets of SARS-CoV-2 because of its angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) receptors expression. Hypocortisolemia can be seen in the postinfection period. COVID-19 infection tends to be severe in diabetic patients due to immune dysfunction. In this study, our aim was to investigate the relationship between basal cortisol levels and the course of COVID-19 infection in diabetic and non-diabetic patients. Methods: Our retrospective study included 311 PCR-positive COVID-19 patients over the age of 18 who were hospitalized in Ankara City Hospital Infectious Diseases Department or Intensive Care Unit (ICU) between 15 March 2020 and 15 May 2020. Serum basal cortisol, fasting plasma glucose (FPG), HbA1c values, and diabetes history were recorded within the first 24 h of hospitalization. The presence of pulmonary involvement was noted from the patients’ imaging records. Pregnant and breastfeeding women, patients with chronic liver disease or chronic kidney disease, and patients who were already using steroids or had started COVID-19 infection treatment within the 72 h before blood collection were excluded from the study. Results: Of the 311 patients, 100 had Type 2 Diabetes Mellitus (T2D), while 211 did not. The age, serum basal cortisol, and glucose levels of the patients with T2D (64.51 ± 12.29, 19.5 ± 13.12, and 143.5 (77−345)) were higher than those of the patients without T2D (46.67 ± 16.38, 15.26 ± 8.75, and 96 (65−202)), and the differences were statistically significant (p = 0.004, p = 0.004, and p < 0.001, respectively). The basal cortisol values of the ICU patients (27.89 (13.91−75)) were significantly higher than those of the ward patients (13.68 (1.48−51.93)) and patients who were transferred to the ICU from the ward due to worsening conditions (19.28 (7.74−55.21)) (p < 0.001 and p = 0.007, respectively). The factors affecting ICU admission were determined to be age, T2D history, basal cortisol, and elevation in FPG using univariate logistic regression analysis. In the multiple logistic regression analysis, age, basal cortisol level, and infiltrative involvement in thorax CT were determined to be the risk factors affecting intensive care admission. Conclusion: High basal cortisol levels in patients with T2D may predict the severity of COVID-19 infection or mortality. Although high basal cortisol levels are among the risk factors affecting ICU admission, patients with COVID-19 should also be evaluated in terms of clinical and laboratory findings and relative adrenal insufficiency.

Novel insights in endocrine and metabolic pathways in sepsis and gaps for future research

Sepsis is defined as any life-threatening organ dysfunction caused by a dysregulated host response to infection. It remains an important cause of critical illness and has considerable short- and long-term morbidity and mortality. In the last decades, preclinical and clinical research has revealed a biphasic pattern in the (neuro-)endocrine responses to sepsis as to other forms of critical illness, contributing to development of severe metabolic alterations. Immediately after the critical illness-inducing insult, fasting- and stress-induced neuroendocrine and cellular responses evoke a catabolic state in order to provide energy substrates for vital tissues, and to concomitantly activate cellular repair pathways while energy-consuming anabolism is postponed. Large randomized controlled trials have shown that providing early full feeding in this acute phase induced harm and reversed some of the neuro-endocrine alterations, which suggested that the acute fasting- and stress-induced responses to critical illness are likely interlinked and benefical. However, it remains unclear whether, in the context of accepting virtual fasting in the acute phase of illness, metabolic alterations such as hyperglycemia are harmful or beneficial. When patients enter a prolonged phase of critical illness, a central suppression of most neuroendocrine axes follows. Prolonged fasting and central neuroendocrine suppression may no longer be beneficial. Although pilot studies have suggested benefit of fasting-mimicking diets and interventions that reactivate the central neuroendocrine suppression selectively in the prolonged phase of illness, further study is needed to investigate patient-oriented outcomes in larger randomized trials.

Euthyroid sick syndrome as an early surrogate marker of poor outcome in mild SARS-CoV-2 disease

BACKGROUND

The new coronavirus 19 disease (COVID-19) represents the current worldwide emergency. According to past evidence, a simple biomarker, such as low free triiodothyronine (fT3) levels, within the framework of euthyroid sick syndrome (ESS), might help to identify patients with unfavourable outcomes.

OBJECTIVE

Evaluation of ESS significance in hospitalized mild COVID-19 patients.

DESIGN

Prospective study, from 1 April 2020 to 31 May 2021.

PARTICIPANTS

COVID-19 patients with mild disease at hospital admission.

MAIN MEASURES

At hospital admission, eligible patients underwent a complete thyroid function evaluation. Subjects with previous thyroid disease or with thyroid-interfering medications were excluded. Levels of fT3 were correlated to biochemical markers and to patient outcome, the latter considered as favourable in the event of infection recovery and unfavourable in the event of death or transfer to an intensive care unit (ICU).

KEY RESULTS

Of 600 screened patients, 506 were eligible for this study. Of those, 94 (19%) died during hospitalization and 80 (18%) required a transfer to ICU. The most frequent thyroid disorder was ESS (57%). Admission levels of fT3 were significantly lower within the unfavourable outcome subgroup (p < 0.001) and were negatively associated with several poor prognostic markers, including IL-6 (p < 0.001). In Kaplan-Meier and Cox regression analyses, fT3 was independently associated with poor outcome and death (p = 0.005 and p = 0.037, respectively). A critical fT3 threshold for levels < 2.7 pmol/l (sensitivity 69%, specificity 61%) was associated with a 3.5-fold increased risk of negative outcome (95%CI 2.34-5.34).

CONCLUSION

Low fT3 levels, in the framework of ESS, resulted as being a valid predictor of unfavourable outcomes in a very early stage population of COVID-19.

Recovery of serum testosterone levels is an accurate predictor of survival from COVID-19 in male patients

BACKGROUND

SARS-CoV-2 infection portends a broad range of outcomes, from a majority of asymptomatic cases to a lethal disease. Robust correlates of severe COVID-19 include old age, male sex, poverty, and co-morbidities such as obesity, diabetes, and cardiovascular disease. A precise knowledge of the molecular and biological mechanisms that may explain the association of severe disease with male sex is still lacking. Here, we analyzed the relationship of serum testosterone levels and the immune cell skewing with disease severity in male COVID-19 patients.

METHODS

Biochemical and hematological parameters of admission samples in 497 hospitalized male and female COVID-19 patients, analyzed for associations with outcome and sex. Longitudinal (in-hospital course) analyses of a subcohort of 114 male patients were analyzed for associations with outcome. Longitudinal analyses of immune populations by flow cytometry in 24 male patients were studied for associations with outcome.

RESULTS

We have found quantitative differences in biochemical predictors of disease outcome in male vs. female patients. Longitudinal analyses in a subcohort of male COVID-19 patients identified serum testosterone trajectories as the strongest predictor of survival (AUC of ROC = 92.8%, p < 0.0001) in these patients among all biochemical parameters studied, including single-point admission serum testosterone values. In lethal cases, longitudinal determinations of serum luteinizing hormone (LH) and androstenedione levels did not follow physiological feedback patterns. Failure to reinstate physiological testosterone levels was associated with evidence of impaired T helper differentiation and augmented circulating classical monocytes.

CONCLUSIONS

Recovery or failure to reinstate testosterone levels is strongly associated with survival or death, respectively, from COVID-19 in male patients. Our data suggest an early inhibition of the central LH-androgen biosynthesis axis in a majority of patients, followed by full recovery in survivors or a peripheral failure in lethal cases. These observations are suggestive of a significant role of testosterone status in the immune responses to COVID-19 and warrant future experimental explorations of mechanistic relationships between testosterone status and SARS-CoV-2 infection outcomes, with potential prophylactic or therapeutic implications.

PREVALÊNCIA E FATORES ASSOCIADOS À DOENÇA CRÍTICA CRÔNICA EM HOSPITALIZADOS POR TRAUMA EM TERAPIA INTENSIVA

RESUMO Objetivo identificar a prevalência de doença crítica crônica e fatores associados em pacientes hospitalizados por trauma em Unidade de Terapia Intensiva. Método estudo de caso-controle, com dados de prontuários de adultos hospitalizados por trauma em uma Unidade de Terapia Intensiva, entre 2013 e 2019. Os dados foram coletados do livro de admissão de pacientes, do prontuário eletrônico e das fichas do Serviço de Controle de Infecção Hospitalar. A variável dependente foi a ocorrência de doença crítica crônica e as variáveis independentes relacionavam-se às características sociodemográficas, comorbidades, trauma, atendimento pré-hospitalar, índices prognósticos, procedimentos e complicações. Realizou-se análise de regressão logística múltipla, que estimou o Ods Ratio (OR) e respectivos intervalos de confiança (IC). Resultados a doença crítica crônica ocorreu em 150 pacientes (24,2%), dos 619 estudados. Os fatores associados à DCC foram disfunção orgânica (OR=1,09) e complicações gastrointestinais (OR=2,71). Os pacientes com doença crítica crônica, além de demandarem por procedimentos cirúrgicos, desenvolveram disfunções orgânicas em diferentes sistemas, apresentando altas pontuações nos índices de prognósticos, ou seja, um pior prognóstico, além de desenvolverem complicações. Conclusão a identificação das complicações gastrointestinais e o aumento da disfunção orgânica como fatores associados ao paciente crítico crônico tornam-se úteis para compor perfil clínico de pacientes e para planejar a assistência intensiva ao traumatizado, contribuindo, assim, para a prevenção e o manejo desses pacientes pelo enfermeiro.

PREVALENCE AND FACTORS ASSOCIATED WITH CHRONIC CRITICAL DISEASE IN HOSPITALIZED FOR TRAUMA IN INTENSIVE CARE

ABSTRACT Objective to identify the prevalence of chronic critical disease and associated factors in patients hospitalized for trauma in the Intensive Care Unit. Method case-control study, with data from medical records of adults hospitalized for trauma in an Intensive Care Unit, between 2013 and 2019. Data were collected from the patient admission book, the electroni cmedical records and the records of the Hospital Infection Control Service. The dependent variable was the occurrence of chronic critical disease, and the independent variables were related to sociodemographic characteristics, comorbidities, trauma, pre-hospital care, prognostic indices, procedures and complications. Multiple logistic regression analysis was performed, which estimated the Ods Ratio (OR) and respective confidence intervals (CI). Results chronic critical disease occurred in 150 patients (24.2%), of the 619 patients studied. The factors associated with CCD were organic dysfunction (OR=1.09) and gastrointestinal complications (OR=2.71). Patients with chronic critical disease, in addition to proseeding for surgical procedures, developed organic dysfunctions in different systems, presenting high scores in prognostic indexes, i.e., a worse prognosis, in addition to developing complications. Conclusion the identification of gastrointestinal complications and the increase in organic dysfunction as factors associated with chronic critical patients become useful to compose the clinical profile of patients and to plan intensive care for the traumatized patients, thus contributing to the prevention and management of these patients by nurses.

Interleukin-2 Transiently Inhibits Pulsatile Growth Hormone Secretion in Young but not Older Healthy Men

CONTEXT

Interleukin-2 (IL-2), a proinflammatory cytokine, has been used to treat malignancies. Increased cortisol and adrenocorticotropin (ACTH) were noted, but growth hormone (GH) secretion was not investigated in detail.

OBJECTIVE

We quantified GH secretion after a single subcutaneous injection of IL-2 in 17 young and 18 older healthy men in relation to dose, age, and body composition.

METHODS

This was a placebo-controlled, blinded, prospectively randomized, crossover study. At 20:00 hours IL-2 (3 or 6 million units/m2) or saline was injected subcutaneously. Lights were off between 23:00 and 07:00 hours. Blood was sampled at 10-minute intervals for 24 hours. Outcome measures included convolution analysis of GH secretion.

RESULTS

GH profiles were pulsatile under both experimental conditions and lower in older than young volunteers. Since the effect of IL-2 might be time limited, GH analyses were performed on the complete 24-hour series and the 6 hours after IL-2 administration. Total and pulsatile 24-hour GH secretion decreased nonsignificantly. Pulsatile secretion fell over the first 6 hours after IL-2 (P = .03), with visceral fat as a covariate (P = .003), but not age (P = .10). Plots of cumulative 2-hour bins of GH pulse mass showed a distinction by treatment and age groups: A temporary GH decrease of 32% and 28% occurred in the first 2-hour bins after midnight (P = .02 and .04) in young participants, whereas in older individuals no differences were present at any time point.

CONCLUSION

This study demonstrates that IL-2 temporarily diminishes GH secretion in young, but not older, men.

Challenges in parenteral nutrition in adult ultrashort gut: A case of cachexia

Patients with ultrashort gut have inadequate nutrient absorption. Parenteral nutrition (PN) is required to meet nutrition requirements caused by chronic intestinal failure (IF). We present a case of cachexia and IF caused by ultrashort gut following an extensive small-bowel resection caused by volvulus that was complicated by small-bowel ischemia. Targeting energy prescriptions to optimize PN using indirect calorimetry in this population with ultrashort gut has not been reported in adults. This case serves to outline the challenges in optimizing PN, including factors such as anabolic status, to meet nutrition requirements in patients with ultrashort gut and cachexia.

An update on non-thyroidal illness syndrome

The non-thyroidal illness syndrome (NTIS) was first reported in the 1970s as a remarkable ensemble of changes in serum TH (TH) concentrations occurring in probably any severe illness. Ever since, NTIS has remained an intriguing phenomenon not only because of the robustness of the decrease in serum triiodothyronine (T3), but also by its clear correlation with morbidity and mortality. In recent years, it has become clear that (parenteral) feeding in patients with critical illness should be taken into account as a major determinant not only of NTIS but also of clinical outcome. Moreover, both experimental animal and clinical studies have shown that tissue TH concentrations during NTIS do not necessarily reflect serum low TH concentrations and may decrease, remain unaltered, or even increase according to the organ and type of illness studied. These differential changes now have a solid basis in molecular studies on organ-specific TH transporters, receptors and deiodinases. Finally, the role of inflammatory pathways in these non-systemic changes has begun to be clarified. A fascinating role for TH metabolism in innate immune cells, including neutrophils and monocytes/macrophages, was reported in recent years, but there is no evidence at this early stage that this may be a determinant of susceptibility to infections. Although endocrinologists have been tempted to correct NTIS by TH supplementation, there is at present insufficient evidence that this is beneficial. Thus, there is a clear need for adequately powered randomized clinical trials (RCT) with clinically relevant endpoints to fill this knowledge gap.

Endocrine interventions in the intensive care unit

Following the onset of any life-threatening illness that requires intensive medical care, alterations within the neuroendocrine axes occur which are thought to be essential for survival, as they postpone energy-consuming anabolism, activate energy-producing catabolic pathways, and optimize immunological and cardiovascular functions. The hormonal changes present in the acute phase of critical illness at least partially resemble those of the fasting state, and recent evidence suggests that they are part of a beneficial, evolutionary-conserved adaptive stress response. However, a fraction of patients who survive the acute phase of critical illness remain dependent on vital organ support and enter the prolonged phase of critical illness. In these patients, the hypothalamic-pituitary-peripheral axes are functionally suppressed, which may have negative consequences by which recovery may be hampered and the risk of morbidity and mortality in the long-term increased. Most randomized controlled trials of critically ill patients that investigated the impact on the outcome of treatment with peripheral hormones did not reveal a robust morbidity or mortality benefit. In contrast, small studies of patients in the prolonged phase of critical illness documented promising results with the infusion of hypothalamic-releasing hormones. The currently available data corroborate the need for well-designed and adequately powered RCTs to further investigate the impact of these releasing factors on patient-centered outcomes.

Could Exogenous Insulin Ameliorate the Metabolic Dysfunction Induced by Glucocorticoids and COVID-19?

The finding that high-dose dexamethasone improves survival in those requiring critical care due to COVID-19 will mean much greater usage of glucocorticoids in the subsequent waves of coronavirus infection. Furthermore, the consistent finding of adverse outcomes from COVID-19 in individuals with obesity, hypertension and diabetes has focussed attention on the metabolic dysfunction that may arise with critical illness. The SARS coronavirus itself may promote relative insulin deficiency, ketogenesis and hyperglycaemia in susceptible individuals. In conjunction with prolonged critical care, these components will promote a catabolic state. Insulin infusion is the mainstay of therapy for treatment of hyperglycaemia in acute illness but what is the effect of insulin on the admixture of glucocorticoids and COVID-19? This article reviews the evidence for the effect of insulin on clinical outcomes and intermediary metabolism in critical illness.

Serum leptin level as a diagnostic and prognostic marker in infectious diseases and sepsis: A comprehensive literature review

BACKGROUND

Infections and sepsis are common causes of morbidity and mortality, with an increasing incidence worldwide. Leptin is involved in the inflammatory process and may modulate the cytokine production, immune cell proliferation and endothelial function. There are conflicting results regarding alterations of leptin levels in infectious diseases and the outcome from sepsis.The aim of the current article is to provide an overview of the medical literature on the correlations between variations of leptin levels and infectious diseases and sepsis.

METHODS

We performed an extensive literature search in PubMed and Google Scholar databases, using keywords to identify articles related to leptin in infectious diseases and sepsis. Searches were referenced using medical subject headings that included "leptin," "adipokines," "sepsis," "infectious diseases," "leptin deficiency," "leptin resistance" or "hyperleptinemia." The language of publication, journal, or country were not included as limitation criteria.Articles or abstracts containing adequate information, such as age, sex, anthropometric indices, clinical presentation, comorbidities, and management were included in the study, whereas articles with insufficient clinical and demographic data were excluded. We assessed the quality of the studies selected.The final review of all databases was conducted on June 18, 2020.

RESULTS

We find the results from the current review to be of great importance due to the possible therapeutic role of leptin analogs in states of leptin deficiency associated with infectious diseases or sepsis.In hyperleptinemia, a therapeutic plan for obtaining leptin neutralization also needs further investigations. This could lead to the reduction of proinflammatory responses.There is a need for further studies to demonstrate the specificity and sensitivity of leptin in the early diagnosis of sepsis and the need to measure serum leptin levels in routine evaluation of the critical patient.

CONCLUSION

The multiple effects of leptin are of growing interest, but further studies are needed to elucidate the role of leptin signalling in infectious diseases and sepsis. Because very few human studies are reported, we recommend the need for further research.Better understanding of the pathophysiology of sepsis and the implication of circulating total leptin in this process could help physicians in managing this life-threatening condition.

HIV and the Pituitary Gland: Clinical and Biochemical Presentations

Human immunodeficiency virus (HIV) can have profound impact on the function of the pituitary gland. We have performed an electronic literature search using the following database: PubMed, Medline, Scopus, and Google Scholar. These databases were searched using the keywords HIV, pituitary glands, cancer, pituitary apoplexy, and infertility. HIV can cause hypopituitarism and also can lead to diabetes insipidus. The impact can be slow and insidious, and diagnosis depends on high index of clinical suspicion. The effect on anterior pituitary gland can be associated with growth hormone deficiency, hypothyroidism, adrenal insufficiency, premature menopause, erectile dysfunction, and infertility. HIV can cause pituitary apoplexy, and this should be treated as an endocrine emergency. Importantly, HIV can be associated with pituitary lymphoma and pituitary cancer. Therefore, joined management between HIV physicians, clinical biochemists and endocrinologists may help in establishing pituitary dysfunction.

Critical Illness and the Frailty Syndrome: Mechanisms and Potential Therapeutic Targets

Frailty is a syndrome characterized by decreased reserves across multiple physiologic systems resulting in functional limitations and vulnerability to new stressors. Physical frailty develops over years in community-dwelling older adults but presents or worsens within days in the intensive care unit (ICU) because common mechanisms governing age-related physical frailty are often exacerbated by critical illness. The hallmark of physical frailty is a combined loss of muscle mass, force, and endurance. About one-third of ICU patients have frailty before hospitalization, which increases their risk for both short- and long-term disability and mortality. While there are several valid ways to measure clinical frailty in patients before or after an ICU admission, the mechanistic underpinnings of frailty in critically ill patients and ICU survivors have not been thoroughly investigated. Furthermore, therapeutic interventions to treat frailty during and after time in the ICU are lacking. In this narrative review, we examine studies that identify potential biological mechanisms underlying the development and propagation of physical frailty in both aging and critical illness (eg, inflammation, mitochondrial myopathy, and neuroendocrinopathy). We discuss specific aspects of these frailty mechanisms in older adults, critically ill patients, and ICU survivors that may represent therapeutic targets. Consistent with complexity underlying frailty, this syndrome is unlikely to result from an excess of a single harmful mediator or deficit of a single protective mediator. Rather, frailty occurs in the presence of an incompletely understood state of multisystem dysregulation. We further describe knowledge gaps that warrant clinical and translational research in frailty and critical care with an overall goal of developing effective frailty treatments in critically ill patients and ICU survivors.

Perioperative Low Tetraiodothyronine Levels and Adverse Outcomes After Heart Transplantation: A Retrospective, Observational Study

OBJECTIVES

Thyroid dysfunction has been shown to be associated with increased all-cause mortality and severity of chronic heart failure in critical illness and severe cardiac diseases. The present study was conducted to ascertain the relationship between perioperative free triiodothyronine and free tetraiodothyronine (fT4) levels and postoperative adverse outcomes after heart transplantation (HTX).

DESIGN

Retrospective, observational study.

SETTING

Single-center study in a quaternary care university clinical center.

PARTICIPANTS

The study comprised adult patients who underwent HTX between 2015 and 2019 and had at least 1 perioperative thyroid hormone laboratory test on the day of surgery or in the 24 hours before/after the procedure (free triiodothyronine, fT4, and thyroid-stimulating hormone).

INTERVENTIONS

No interventions were applied.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was primary graft dysfunction (PGD), defined by the consensus conference of the International Society for Heart and Lung Transplantation. A total of 151 patients were included in the final analyses. Twenty-nine (19.2%) patients had PGD. Fourteen (9.3%) patients had low fT4 levels. An independent association was found between fT4 and PGD (odds ratio 6.49; 95% confidence interval 2.26-18.61; p = 0.001), with adjusted multivariate Cox regression models.

CONCLUSION

The perioperative fT4 level could be a prognostic marker of adverse outcomes in HTX. The authors suggest appropriate perioperative monitoring of fT4 levels. Additional research is warranted to examine the optimal timing, dosage, and method of replacement.