Dysfunction of the hypothalamic-pituitary-adrenal axis in critical illness: a narrative review for emergency physicians

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.

Neuroimmunoendocrinology of SARS-CoV 2 Infection

This review is aimed at illustrating and discussing the neuroimmune endocrinological aspects of the SARS-CoV-2 infection in light of the studies on this topic that have so far appeared in the literature. The most characteristic findings and pending controversies were derived by PubMed and Scopus databases. We included original and observational studies, reviews, meta-analysis, and case reports. The entry of the coronavirus into susceptible cells is allowed by the interaction with an ecto-enzyme located on human cells, the angiotensin-converting enzyme 2 (ACE2). SARS-CoV-2 also targets the central nervous system (CNS), including hypothalamic-pituitary structures, as their tissues express ACE2, and ACE2 mRNA expression in hypothalamus and pituitary gland cells has been confirmed in an autoptic study on patients who died of COVID 19. SARS-CoV-2 infection may cause central endocrine disorders in acute phase and in post-COVID period, particularly due to the effects of this virus at CNS level involving the hypothalamic-pituitary axis. The aggression to the hypothalamus-pituitary region may also elicit an autoimmune process involving this axis, responsible consequently for functional disorders of the satellite glands. Adrenal, thyroid and gonadal dysfunctions, as well as pituitary alterations involving GH and prolactin secretions, have so far been reported. However, the extent to which COVID-19 contributes to short- and long-term effects of infection to the endocrine system is currently being discussed and deserves further detailed research.

Association of thyroid hormones and thyroid-stimulating hormone with mortality in adults admitted to the intensive care unit: A systematic review and meta-analysis

BACKGROUND

Thyroid hormones (THs) and thyroid-stimulating hormone (TSH) seem to show high potential in predicting the clinical death outcome of patients admitted to the intensive care unit (ICU). However, diverse studies on this topic are conflicting.

METHODS

A search was conducted by two investigators involved in this research in the PubMed, Embase, and Cochrane databases (all last launched on July 12, 2021). The quality of the included studies was evaluated using the Newcastle-Ottawa Quality Assessment Scale (NOS). Subgroup analyses were performed to determine the sources of heterogeneity. Sensitivity and publication bias analyses were also assessed.

RESULTS

A total of 27 studies (4970 participants) were included based on the eligibility criteria. Compared with survivors, nonsurvivors were found to have lower levels of THs (T3, T4, fT3, and fT4), whereas no significant difference was found in TSH levels (13 studies for T3: standardized mean differences [SMD], -0.78; 95% CI, -1.36 to -0.20; I2 = 96%; p = 0.008; 11 studies for T4: SMD = -0.79; 95% CI, -1.31 to -0.28; I2 =95%; p = 0.0002; 14 studies for fT3: SMD = -0.76; 95% CI, -1.21 to -0.32; I2 = 95%; p = 0.0008; 17 studies for fT4: SMD = -0.60; 95% CI, -0.99 to -0.22; I2 = 95%; p = 0.002; 20 studies for TSH: SMD = 0.00; 93% CI, -0.29 to 0.29; I2 = 93%; p = 0.98).

CONCLUSION

Nonsurvivors were associated with lower levels of THs (T3, T4, fT3, and fT4) than survivors. THs show great application potential in predicting ICU patients' death outcomes and improving already widely used prognostic scores in the ICU (ie, Acute Physiological and Chronic Health Evaluation [APACHE] II and Therapeutic Intervention Scoring System).