Evaluation of long-term pituitary functions in patients with severe ventricular arrhythmia: a pilot study

A, Baba MS, Tramboo NA, Shah ZA, Lone AA, Hafeez I. Anterior pituitary hormone dysfunction among individuals with complete heart block requiring pacemaker

Background & objectives Neuronal hypoxia associated with conditions like traumatic brain injury and cardiac tachyarrhythmia has been implicated in causing hypopituitarism. Individuals with complete heart block (CHB) may be predisposed to develop anterior pituitary hormone dysfunction in the long term. The objective of this study was to investigate anterior pituitary hormone functions in individuals after CHB. Methods This prospective cohort study included 30 individuals (21 men and 9 women) with CHB requiring pacemaker implantation, who were evaluated at admission and then at a mean follow up of 12.4 ± 2.2 months to look for development of any degree of hypopituitarism. In addition to the measurement of hormones like follicle-stimulating hormone (FSH), luteinising hormone (LH), thyroid stimulating hormone (TSH), total tetra iodothyronines (TT4), free tetraiodothyronines (FT4), cortisol, insulin-like growth factor-1 (IGF-1), testosterone and estradiol, a fixed-dose glucagon stimulation test (GST) was performed to assess growth hormone (GH) and adrenocorticotrophic hormone (ACTH) axis. Results The mean age of the participants was 64.9 ± 11.3 yr. At follow up evaluation, 17 (56.7%) had low serum IGF-1, and among them, seven (23%) had growth hormone deficiency (GHD) (peak GH <1.0 ng/ml after GST). Six participants (20%) had ACTH deficiency (peak cortisol <9 ug/dl after GST) and one had TSH deficiency. None had prolactin (PRL) or gonadotropin deficiency. Overall, hormone deficiencies were observed in nine patients (30%). Interpretation & conclusions This pilot study detected loss of anterior pituitary hormones in a significant number of individuals of CHB at 12 months follow up. Unrecognised hypopituitarism may have resulted in significant morbidity and mortality in these individuals.

Investigation of pituitary functions after acute coronavirus disease 2019

Although coronavirus disease 2019 (COVID-19) mainly involves the lungs, it also affects many systems. The hypothalamic/pituitary axis is vulnerable to hypoxia, hypercoagulation, endothelial dysfunction and autoimmune changes induced by COVID-19 infection. Given that there is no extensive investigation on this issue, we investigated the pituitary functions three to seven months after acute COVID-19 infection. Forty-three patients after diagnosis of COVID-19 infection and 11 healthy volunteers were included in the study. In addition to the basal pituitary hormone levels, growth hormone (GH) and hypothalamo-pituitary adrenal (HPA) axes were evaluated by glucagon stimulation test (GST) and low-dose adrenocorticotropic hormone (ACTH) stimulation test, respectively. The peak cortisol responses to low-dose ACTH test were insufficient in seven (16.2%) patients. Twenty (46.5%) and four (9.3%) patients had inadequate GH and cortisol responses to GST, respectively. Serum insulin-like growth factor-1 (IGF-1) values were also lower than age and sex-matched references in four (9.3%) patients. The peak GH responses to GST were lower in the patient group when compared to the control group. Other abnormalities were mild thyroid-stimulating hormone elevation in four (9.3%) patients, mild prolactin elevation in two (4.6%) patients and central hypogonadism in four (9.3%) patients. Mean total testosterone values were lower in male patients when compared to male controls; however, the difference was not significant. These findings suggest that COVID-19 infection may affect pituitary functions, particularly the HPA and GH axes. These insufficiencies should be kept in mind in post-COVID follow-up. Long-term data are needed to determine whether these deficiencies are permanent or not.

Classical and non-classical causes of GH deficiency in adults

Growth hormone deficiency (GHD) can develop due to a variety of conditions, and may occur either as isolated or multiple pituitary hormone deficiencies. It has been previously demonstrated that GH is one of the most frequent hormonal deficiencies in adult patients with hypopituitarism. The most frequent classical causes of adult-onset GHD (AO-GHD) are pituitary adenomas and/or their treatment. However, during the last decade an increasing number of studies from different parts of the world have revealed that non-tumoural causes of hypopituitarism are more common than previously known. Therefore, in this review our aim is to briefly summarize the classical and non-classical acquired causes of GHD in adults.

GH and Pituitary Hormone Alterations After Traumatic Brain Injury

Traumatic brain injury (TBI) is a crucially important public health problem around the world, which gives rise to increased mortality and is the leading cause of physical and psychological disability in young adults, in particular. Pituitary dysfunction due to TBI was first described 95 years ago. However, until recently, only a few papers have been published in the literature and for this reason, TBI-induced hypopituitarism has been neglected for a long time. Recent studies have revealed that TBI is one of the leading causes of hypopituitarism. TBI which causes hypopituitarism may be characterized by a single head injury such as from a traffic accident or by chronic repetitive head trauma as seen in combative sports including boxing, kickboxing, and football. Vascular damage, hypoxic insult, direct trauma, genetic predisposition, autoimmunity, and neuroinflammatory changes may have a role in the development of hypopituitarism after TBI. Because of the exceptional structure of the hypothalamo-pituitary vasculature and the special anatomic location of anterior pituitary cells, GH is the most commonly lost hormone after TBI, and the frequency of isolated GHD is considerably high. TBI-induced pituitary dysfunction remains undiagnosed and therefore untreated in most patients because of the nonspecific and subtle clinical manifestations of hypopituitarism. Treatment of TBI-induced hypopituitarism depends on the deficient anterior pituitary hormones. GH replacement therapy has some beneficial effects on metabolic parameters and neurocognitive dysfunction. Patients with TBI without neuroendocrine changes and those with TBI-induced hypopituitarism share the same clinical manifestations, such as attention deficits, impulsion impairment, depression, sleep abnormalities, and cognitive disorders. For this reason, TBI-induced hypopituitarism may be neglected in TBI victims and it would be expected that underlying hypopituitarism would aggravate the clinical picture of TBI itself. Therefore, the diagnosis and treatment of unrecognized hypopituitarism due to TBI are very important not only to decrease morbidity and mortality due to hypopituitarism but also to alleviate the chronic sequelae caused by TBI.