Growth hormone excess and sternohyoid muscle mechanics in rats

Updates in rare and not-so-rare complications of acromegaly: focus on respiratory function and quality of life in acromegaly

Acromegaly is a complex disease with excessive growth hormone and insulin-like growth factor 1 (IGF-1) causing multisystem effects, particularly cardiovascular, respiratory, and metabolic. Psychological concerns and poor quality of life (QoL) are also major disease consequences. This review is intended for clinicians and focuses on the latest developments related to respiratory and QoL effects of long-term growth hormone excess. Along with biochemical disease control, patient treatment satisfaction and outcomes have become major treatment objectives; current knowledge and tools to evaluate and manage this aspect of the disease are described. Sleep apnea syndrome and other derangements of lung function and apparatus, from pathophysiology to treatment, and evaluation tools and determinants of QoL in patients with acromegaly are discussed.

[Assessment of treatment effect for acromegaly with sleep disordered breathing]

Acromegaly is caused by excessive secretion of growth hormone (GH) and presents with a variety of clinical manifestations, including facial disfigurement and abnormally large hands and feet, as well as diabetes mellitus, hypertension, and sleep-disordered breathing (SDB). Although SDB is known to be associated with serious symptoms, there have been few study reports, and no clear consensus has been reached regarding the method of assessment of individual treatments. We report herein on the results of surgical intervention with transsphenoidal surgery (TSS) for acromegaly and assessment of the treatment effect after the intervention. We studied 6 patients who received a diagnosis of acromegaly complicated with SDB and underwent TSS at our hospital. Polysomnography (PSG) was performed before and after TSS, and the polysomnograms were analyzed. We also examined changes in the levels of GH and insulin-like growth factor-1 (IGF-1) on blood biochemistry. In 6 cases of acromegaly with SDB, we were able to confirm endocrinologic improvement of TSS with blood biochemistry. However there was no meaningful improvement in the PSG index for SDB.

[Characteristics of sleep apnea syndrome in a cohort of patients with acromegaly]

INTRODUCTION

Sleep apnoea syndrome (SAS) has a prevalence of between 40 and 80 % in patients with acromegaly. The objective of our study was to focus on the occurrence of SAS and its relation with acromegalic characteristics in this population as well as to study patients' comorbidities.

METHODOLOGY

This study was retrospective, monocentric and related to a cohort of 106 acromegalic patients of whom 55 patients had performed ventilatory polygraphic recordings looking for SAS in addition to assessment of comorbidities.

RESULTS

Within the screened patients, 42 had sleep apnoea syndrome with a majority of them having severe SAS. In this population, SAS was associated with hypertension, diabetes and a longer duration of acromegaly but acromegaly control was not a risk factor. Patients with severe SAS were older (mean 64 years) than the ones without SAS (47 years) (P=0.01).

CONCLUSION

SAS prevalence is twenty times higher in the acromegalic population than for the normal population, even more so if patients are diabetic, hypertensive, older and if acromegaly has had a long evolution. Knowing this high prevalence, systematic screening for SAS may be justified in this population.

Endocrine aspects of obstructive sleep apnea

CONTEXT

Some endocrine and metabolic disorders are associated with a high frequency of obstructive sleep apnea (OSA), and treatment of the underlying endocrine disorder can improve and occasionally cure OSA. On the other hand, epidemiological and interventional studies suggest that OSA increases the cardiovascular risk, and a link between OSA and glucose metabolism has been suggested, via reduced sleep duration and/or quality.

EVIDENCE ACQUISITION

We reviewed the medical literature for key articles through June 2009.

EVIDENCE SYNTHESIS

Some endocrine and metabolic conditions (obesity, acromegaly, hypothyroidism, polycystic ovary disease, etc.) can be associated with OSA. The pathophysiological mechanisms of OSA in these cases are reviewed. In rare instances, OSA may be improved or even cured by treatment of underlying endocrine disorders: this is the case of hypothyroidism and acromegaly, situations in which OSA is mainly related to upper airways narrowing due to reversible thickening of the pharyngeal walls. However, when irreversible skeletal defects and/or obesity are present, OSA may persist despite treatment of endocrine disorders and may thus require complementary therapy. This is also frequently the case in patients with obesity, even after substantial weight reduction.

CONCLUSIONS

Given the potential neurocognitive consequences and increased cardiovascular risk associated with OSA, specific therapy such as continuous positive airway pressure is recommended if OSA persists despite effective treatment of its potential endocrine and metabolic causes. "Apropos of sleep, that sinister adventure of all our nights, we might say that men go to bed daily with an audacity that would be incomprehensible if we did not know that it is the result of ignorance of the danger." Charles Baudelaire, in "Fusées, IX"