Hypothalamic-Pituitary Adrenal Axis Status 3 Months After Recovery From COVID-19 Infection

Seven-tesla magnetic resonance imaging of the nervus terminalis, olfactory tracts, and olfactory bulbs in COVID-19 patients with anosmia and hypogeusia

Introduction

Linking olfactory epithelium to the central nervous system are cranial nerve 1, the olfactory nerve, and cranial nerve "0," and the nervus terminalis (NT). Since there is minimal expression of angiotensin-converting enzyme-2 (ACE-2) in the olfactory nerve, it is unclear how SARS-CoV-2 causes anosmia (loss of smell) and hypogeusia (reduction of taste). In animal models, NT expresses ACE-2 receptors, suggesting a possible SARS-CoV-2 viral entry site in humans. The purpose of this study was to determine whether ultra-high-field 7 T magnetic resonance imaging (MRI) could visualize the NT, olfactory bulbs (OB), and olfactory tract (OT) in healthy controls and COVID-19 anosmia or hypogeusia and to qualitatively assess for volume loss and T2 alterations.

Methods

In this study, 7 T MRI was used to evaluate the brain and olfactory regions in 45 COVID-19 patients and 29 healthy controls. Neuroimaging was qualitatively assessed by four board-certified neuroradiologists who were blinded to outcome assignments: for the presence or absence of NT; for OB, OT, and brain volume loss; and altered T2 signal, white matter T2 hyperintensities, microhemorrhages, enlarged perivascular spaces, and brainstem involvement.

Results

NT was identifiable in all COVID-19 patients and controls. T2 hyperintensity in the NT, OB, and OT in COVID-19 patients with anosmia or hypogeusia was statistically significant compared to controls and COVID-19 patients without anosmia or hypogeusia.

Discussion

On 7 T MRI, NT was radiographically identifiable, adjacent to OB and OT. In COVID-19 anosmia and hypogeusia, T2 hyperintensity of NT, OB, and OT was statistically significant compared to COVID-19 patients without anosmia or hypogeusia and controls. The NT may be a potential entry site for SARs-CoV-2 and may play a role in the pathophysiology of COVID-19 anosmia.

Implications of Dysnatremia and Endocrine Disturbances in COVID-19 Patients

Sodium imbalance is a common electrolyte disturbance in COVID-19, often linked to disruptions in hormonal regulation. This review explores the relationship between sodium dysregulation and endocrine disturbances, particularly focusing on primary and secondary hypothyroidism, hypocortisolism, and the renin-angiotensin-aldosterone system (RAAS). Hypocortisolism in COVID-19, due to adrenal insufficiency or secondary to pituitary dysfunction, can lead to hyponatremia through inadequate cortisol levels, which impair renal free water excretion and enhance antidiuretic hormone (ADH) secretion. Similarly, hypothyroidism is associated with decreased renal blood flow and the glomerular filtration rate (GFR), which also increases ADH activity, leading to water retention and dilutional hyponatremia. Furthermore, COVID-19 can disrupt RAAS (primarily through its interaction with the angiotensin-converting enzyme 2 (ACE2) receptor), diminishing aldosterone secretion and further contributing to sodium loss and hyponatremia. These hormonal disruptions suggest that sodium imbalance in COVID-19 is multifactorial and warrants further investigation into the complex interplay between COVID-19, endocrine function, and sodium homeostasis. Future research should focus on understanding these mechanisms to develop management algorithms that address both sodium imbalance and underlying hormonal disturbances in order to improve prognosis and outcomes in COVID-19 patients.

Long COVID and pituitary dysfunctions: a bidirectional relationship?

Long COVID is a novel emerging syndrome known to affect multiple health areas in patients previously infected by SARS-CoV-2 markedly impairing their quality of life. The pathophysiology of Long COVID is still largely poorly understood and multiple mechanisms were proposed to underlie its occurrence, including alterations in the hormonal hypothalamic-pituitary axes. Aim of this review is to present and discuss the potential negative implications of these hormonal dysfunctions in promoting and influencing the Long COVID syndrome. To date, the hypothalamic-pituitary-adrenal axis is the mostly investigated and several studies have reported a prolonged impairment leading to mild and subclinical forms of central adrenal insufficiency. Few data are also available regarding central hypogonadism, central hypothyroidism and growth hormone (GH) deficiency. A high prevalence of central hypogonadism in COVID-19 survivors several months after recovery was consistently reported in different cohorts. Conversely, very few data are available on the hypothalamic-pituitary-thyroid axis function that was mainly shown to be preserved in COVID-19 survivors. Finally, a potential impairment of the hypothalamic-GH axis in Long COVID has also been reported. These data altogether may suggest a novel possible pituitary-centred pathophysiological view of Long COVID syndrome which if confirmed by large clinical studies may have relevant implication for the diagnostic and therapeutic approach at least in a subset of patients with the syndrome.

Male Hypogonadism After Recovery from Acute COVID-19 Infection: A Prospective Observational Study

BACKGROUND

The severe acute respiratory syndrome coronavirus 2 can affect the hypothalamic-pituitary-gonadal axis (HPG) due to the expression of the angiotensin-converting enzyme 2 receptor.

OBJECTIVES

To assess the prevalence of hypogonadism and Sertoli cell dysfunction in coronavirus disease 2019 (COVID-19) male survivors.

METHOD

Male subjects recovered from acute COVID-19 infection were prospectively observed. The primary outcomes included the proportion of hypogonadism, defined biochemically as serum testosterone<230 ng/dL or CFT of<6.4 ng/mL if the total testosterone is between 230-320 ng/m. Sertoli cell dysfunction was defined as inhibin-B level<54.5 pg/mL. Subjects with hypogonadism were followed up at 12 months to assess the recovery of the HPG axis.

RESULTS

Eighty-three subjects aged≥18 years were evaluated at a median of 120 (±35) days post-recovery. Their mean age was 49.50±12.73 years, and the mean BMI was 26.84±5.62 kg/m2. Low testosterone was detected in 21 (24.71%) and low inhibin-B was detected in 14 (19.71%) out of 71 subjects at 3 months. Subjects with low testosterone were younger, with a mean age of 43.29±12.03 years (P-0.08) and higher BMI (P-0.012). The severity of COVID-19 infection, duration of hospitalization, and other factors were not significantly associated with low testosterone. At 12 months, 18 out of 21 subjects came for follow-up, of which 9 (50%) showed persistently low testosterone, suggestive of hypogonadism.

CONCLUSION

Following COVID-19 infection, testosterone levels recovered over time; however, a significant proportion of subjects had low levels at 12-month follow-up. These findings have long-term implications for the management of COVID-19 subjects.

COVID-19 and Adrenal Insufficiency: Unmasking the Link

We describe a case of a 28-year-old male who presented with general malaise, fatigue, anorexia, occasional epigastric pain, and vomiting a few days after a mild severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Clinical evolution led to weight loss (6 kg in six months) and craving for salty foods. Physical examination revealed dehydration, hypotension, and hyperpigmentation of the skin and mucosal surfaces. Laboratory tests demonstrated normocytic normochromic anemia, acute kidney injury, hyperkalemia, hyponatremia, and compensated metabolic acidosis. Adrenal workup allowed us to establish a diagnosis of adrenal insufficiency (AI) due to autoimmune adrenalitis, considering findings of a low cortisol and positive 21-hydroxylase antibodies (21OH-Abs), as well as high serum renin and adrenocorticotropic hormone (ACTH). Atypical presentations and comorbidities may appear regarding coronavirus disease 2019 (COVID-19), such as the association between COVID-19 and the hypothalamic-pituitary-adrenal (HPA) axis, which may be affected in any patient with SARS-CoV-2 infection, thus making adrenal insufficiency a diagnosis to consider.