Overview of the endocrine response to critical illness: how to measure it and when to treat

A Comprehensive Review of the Role of Biomarkers in the Early Detection of Endocrine Disorders in Critical Illnesses

Endocrine disorders pose significant challenges in the management of critically ill patients, contributing to morbidity and mortality in intensive care settings. Timely detection of these disorders is essential to optimizing patient outcomes. Biomarkers, as measurable indicators of biological processes or disease states, play a crucial role in the early identification and monitoring of endocrine dysfunction. This comprehensive review examines the role of biomarkers in the early detection of endocrine disorders in critical illnesses. We provide an overview of common endocrine disorders encountered in the intensive care unit (ICU) and discuss the impact of endocrine dysregulation on patient outcomes. Additionally, we classify biomarkers and explore their significance in diagnosing and monitoring endocrine disorders, including thyroid dysfunction, adrenal insufficiency, and hypopituitarism. Furthermore, we discuss the clinical applications of biomarkers, including their utility in guiding therapeutic interventions, monitoring disease progression, and predicting outcomes in critical illnesses. Emerging trends and future directions in biomarker research are also highlighted, emphasizing the need for continued investigation into novel biomarkers and technological advancements. Finally, we underscore the potential of biomarkers to revolutionize the early detection and management of endocrine disorders in critical illnesses, ultimately improving patient care and outcomes in the ICU.

Vitamin D and acute and severe illness - a mechanistic and pharmacokinetic perspective

The COVID-19 pandemic has generated high interest in factors modulating risk of infection, disease severity and recovery. Vitamin D has received interest since it is known to modulate immune function and vitamin D deficiency is associated with increased risk of respiratory infections and adverse health outcomes in severely ill patients. There are no population representative data on the direct relationship between vitamin D status and SARS-CoV-2 infection risk and severity of COVID-19. Data from intervention studies are limited to 4 studies. Here we summarise findings regarding vitamin D status and metabolism and their alterations during severe illness, relevant to COVID-19 patients. Further, we summarise vitamin D intervention studies with respiratory disease outcomes and in critically ill patients and provide an overview of relevant patient and population guidelines. Vitamin D deficiency is highly prevalent in hospitalised patients, particularly when critically ill including those with COVID-19. Acute and critical illness leads to pronounced changes in vitamin D metabolism and status, suggestive of increased requirements. This needs to be considered in the interpretation of potential links between vitamin D status and disease risk and severity and for patient management. There is some evidence that vitamin D supplementation decreases the risk of respiratory tract infections, while supplementation of ICU patients has shown little effect on disease severity or length of treatment. Considering the high prevalence of deficiency and low risks associated with supplementation, pro-actively applying current population and patient management guidelines to prevent, monitor and correct vitamin D deficiency is appropriate.

Salivary biomarkers may measure stress responses in critically ill children

OBJECTIVE

Measurement of salivary biomarkers can provide important information regarding hypothalamic-pituitary-adrenal axis activity both under normal conditions as well as in response to psychological or physical stress. Our aim was to correlate salivary stress markers, such as cortisol, α-amylase and immunoglobulin A, with the Pediatric Risk Index Score of Mortality, underlying disease (pathologic, trauma and postoperative), need for mechanical ventilation/sedation and time lag between onset of illness and admission in children admitted in the pediatric intensive care unit.

METHODS

We enrolled 79 pediatric intensive care unit patients (2-14 years) over a 2-year period, which satisfy the including criteria, but finally salivary biomarkers were evaluated in 65 patients. Saliva samples were collected within 24 h of admission at 8 a.m., 2 p.m. and 8 p.m. to examine potential disruption of circadian rhythm.

RESULTS

Overall, the salivary biomarkers were increased; specifically, median values were (a) cortisol at 8 a.m.: 50.04 nmol/L, 2 p.m.: 30.69 nmol/L and 8 p.m.: 247.12 nmol/L; (b) α-amylase: at 8 a.m.: 22.567 U/L; 2 p.m.: 22.702 U/L and 8 p.m.: 21.484 U/L and (c) IgA at 8 a.m.: 95.10 mg/dL, 2 p.m.: 88.55 mg/dL and 8 p.m.: 80.80 mg/dL. Significantly higher levels were demonstrated in children younger than 6 years and those with Pediatric Risk Index Score of Mortality ⩾8 upon admission. Disturbances in circadian rhythm were observed. Cortisol circadian rhythm disturbance was observed only in children with Pediatric Risk Index Score of Mortality score ⩾8 upon admission while maintaining normal α-amylase circadian rhythm, which was associated with less than 3 days hospitalization in pediatric intensive care unit. No daily variance in IgA was observed.

CONCLUSION

Salivary biomarkers may serve, in critically ill children, as a sensitive, non-invasive method, important for the early recognition of those at high risk and guiding intervention, before clinical deterioration, promoting the quality of health care in pediatric population.

Evaluation of endocrine function in children admitted to pediatric intensive care unit

BACKGROUND

Although studied widely in adulthood, little is known about endocrinological disorders during critical illnesses in childhood. The aims of this study were to define the endocrinological changes in patients admitted to pediatric intensive care unit (PICU) and to identify their effects on prognosis.

METHODS

Forty patients with a mean age of 5.1 years admitted to PICU were enrolled in the study. Blood samples were taken at admission and at 24 and 48 h to measure cortisol, adrenocorticotropic hormone (ACTH), prolactin, growth hormone (GH), GH binding protein (GHBP), insulin-like growth factor-binding protein-3 (IGFBP-3) and interleukin-6 (IL-6). The severity of the patient's condition was assessed using pediatric risk of mortality (PRISM) and pediatric logistic organ dysfunction (PELOD) scores.

RESULTS

PRISM and PELOD scores were significantly higher in non-survivors. Cortisol, ACTH, prolactin, GH, GHBP, IGFBP-3 and IL-6 were not significantly different between the survivors and non-survivors. There was a negative correlation between baseline IGFBP-3 and PRISM scores. A positive correlation was seen between cortisol level at 24 h and PRISM score. On multivariate linear regression analysis, PRISM score was best explained by ACTH and cortisol at 24 h. A positive weak correlation was detected between IL-6 at 24 h and PELOD scores.

CONCLUSIONS

Although there was no difference between survivors and non-survivors regarding the studied endocrine parameters, there were associations between cortisol, ACTH, IL-6 and IGFBP-3 and risk assessment scores, and, given that these scores correlated with mortality, these parameters might be useful as prognostic factors.

Acute neuro-endocrine profile and prediction of outcome after severe brain injury

OBJECT

The aim of the study was to evaluate the early changes in pituitary hormone levels after severe traumatic brain injury (sTBI) and compare hormone levels to basic neuro-intensive care data, a systematic scoring of the CT-findings and to evaluate whether hormone changes are related to outcome.

METHODS

Prospective study, including consecutive patients, 15-70 years, with sTBI, Glasgow Coma Scale (GCS) score ≤ 8, initial cerebral perfusion pressure > 10 mm Hg, and arrival to our level one trauma university hospital within 24 hours after head trauma (n = 48). Serum samples were collected in the morning (08-10 am) day 1 and day 4 after sTBI for analysis of cortisol, growth hormone (GH), prolactin, insulin-like growth factor 1 (IGF-1), thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), free thyroxine (fT4), follicular stimulating hormone (FSH), luteinizing hormone (LH), testosterone and sex hormone-binding globulin (SHBG) (men). Serum for cortisol and GH was also obtained in the evening (17-19 pm) at day 1 and day 4. The first CT of the brain was classified according to Marshall. Independent staff evaluated outcome at 3 months using GOS-E.

RESULTS

Profound changes were found for most pituitary-dependent hormones in the acute phase after sTBI, i.e. low levels of thyroid hormones, strong suppression of the pituitary-gonadal axis and increased levels of prolactin. The main findings of this study were: 1) A large proportion (54% day 1 and 70% day 4) of the patients showed morning s-cortisol levels below the proposed cut-off levels for critical illness related corticosteroid insufficiency (CIRCI), i.e. <276 nmol/L (=10 ug/dL), 2) Low s-cortisol was not associated with higher mortality or worse outcome at 3 months, 3) There was a significant association between early (day 1) and strong suppression of the pituitary-gonadal axis and improved survival and favorable functional outcome 3 months after sTBI, 4) Significantly lower levels of fT3 and TSH at day 4 in patients with a poor outcome at 3 months. 5) A higher Marshall CT score was associated with higher day 1 LH/FSH- and lower day 4 TSH levels 6) In general no significant correlation between GCS, ICP or CPP and hormone levels were detected. Only ICPmax and LH day 1 in men was significantly correlated.

CONCLUSION

Profound dynamic changes in hormone levels are found in the acute phase of sTBI. This is consistent with previous findings in different groups of critically ill patients, most of which are likely to be attributed to physiological adaptation to acute illness. Low cortisol levels were a common finding, and not associated with unfavorable outcome. A retained ability to a dynamic hormonal response, i.e. fast and strong suppression of the pituitary-gonadal axis (day 1) and ability to restore activity in the pituitary-thyroid axis (day 4) was associated with less severe injury according to CT-findings and favorable outcome.

Perioperative glucose control in neurosurgical patients

Many neurosurgery patients may have unrecognized diabetes or may develop stress-related hyperglycemia in the perioperative period. Diabetes patients have a higher perioperative risk of complications and have longer hospital stays than individuals without diabetes. Maintenance of euglycemia using intensive insulin therapy (IIT) continues to be investigated as a therapeutic tool to decrease morbidity and mortality associated with derangements in glucose metabolism due to surgery. Suboptimal perioperative glucose control may contribute to increased morbidity, mortality, and aggravate concomitant illnesses. The challenge is to minimize the effects of metabolic derangements on surgical outcomes, reduce blood glucose excursions, and prevent hypoglycemia. Differences in cerebral versus systemic glucose metabolism, time course of cerebral response to injury, and heterogeneity of pathophysiology in the neurosurgical patient populations are important to consider in evaluating the risks and benefits of IIT. While extremes of glucose levels are to be avoided, there are little data to support an optimal blood glucose level or recommend a specific use of IIT for euglycemia maintenance in the perioperative management of neurosurgical patients. Individualized treatment should be based on the local level of blood glucose control, outpatient treatment regimen, presence of complications, nature of the surgical procedure, and type of anesthesia administered.