Relief of sleep apnoea after treatment of acromegaly: report of three cases and review of the literature

Sleep-disordered breathing in Australian children with Prader-Willi syndrome following initiation of growth hormone therapy

AIM

In children with Prader-Willi syndrome (PWS), growth hormone (GH) improves height and body composition; however, may be associated with worsening sleep-disordered breathing (SDB). Some studies have reported less SDB after GH initiation, but follow-up with polysomnography is still advised in most clinical guidelines.

METHODS

This retrospective, multicentre study, included children with PWS treated with GH at seven PWS treatment centres in Australia over the last 18 years. A paired analysis comparing polysomnographic measures of central and obstructive SDB in the same child, before and after GH initiation was performed with Wilcoxon signed-rank test. The proportion of children who developed moderate/severe obstructive sleep apnoea (OSA) was calculated with their binomial confidence intervals.

RESULTS

We included 112 patients with available paired data. The median age at start of GH was 1.9 years (range 0.1-13.5 years). Median obstructive apnoea hypopnoea index (AHI) at baseline was 0.43/h (range 0-32.9); 35% had an obstructive AHI above 1.0/h. Follow-up polysomnography within 2 years after the start of GH was available in 94 children who did not receive OSA treatment. After GH initiation, there was no change in central AHI. The median obstructive AHI did not increase significantly (P = 0.13), but 12 children (13%, CI_95% 7-21%) developed moderate/severe OSA, with clinical management implications.

CONCLUSIONS

Our findings of a worsening of OSA severity in 13% of children with PWS support current advice to perform polysomnography after GH initiation. Early identification of worsening OSA may prevent severe sequelae in a subgroup of children.

Obstructive sleep apnea caused by acromegaly: Case report

BACKGROUND

Acromegaly is an uncommon syndrome caused by growth hormone-producing pituitary adenoma or pituitary gland hypertrophy. Acromegaly is known to be characterized by progressive somatic disfigurement and a wide range of systematic manifestations. This case study describes a rare case of severe obstructive sleep apnea (OSA) caused by acromegaly.

CLINICAL PRESENTATION

A female patient presented to the consultant clinic with the chief complaint of progressively worsening sleep and was diagnosed with severe OSA. Because of a peculiar facial appearance of the patient, acromegaly was suspected and confirmed by the findings of hormonal analysis and magnetic resonance imaging (MRI). After transsphenoidal resection of the pituitary adenoma, her OSA was almost cured, with residual AHI of 5.5.

CONCLUSION

This case highlights the importance of a comprehensive clinical examination of OSA patients. In every sleep-related breathing disorder case, sleep clinicians should be aware of alternate problems that could cause upper airway obstruction.

Assessment of sleep apnea syndrome in treated acromegalic patients and correlation of its severity with clinical and laboratory parameters

BACKGROUND

Sleep apnea syndrome (SAS) is a frequent disorder in acromegalic patients and its frequency ranges from 45 to 87.5% of patients. Obstructive SAS is the prevailing form in acromegaly and its pathogenesis is based on craniofacial deformations and thickening of soft tissues and mucosas of upper airways and bronchi. Central and mixed types are less frequent. Respiratory complications, and SAS in particular, may contribute to the increased mortality observed in acromegaly.

AIM

Aim of the present study is to assess the presence of SAS in acromegalic patients, its features and to correlate the severity of SAS with factors such as disease duration, body mass index (BMI), smoking, GH/IGF-I serum levels, associated comorbidities.

SUBJECTS AND METHODS

Polygraphy (SOMNOcheck Effort Weinmann V2.05) was performed in 25 consecutive acromegalic patients (9 men and 16 women). Statistical analysis was performed with Mann-Whitney's test and Spearman coefficient.

RESULTS

Fourteen out of 25 patients (56%) were affected by SAS. The prevailing form was obstructive SAS (12/14 patients). Smoking, female gender, and presence of lung disease appear to lead to a more severe form. We also found that the prevalence of hypertension was significantly higher in the group of patients with SAS, whereas no correlation was proved among SAS and disease duration, GH/IGF-I serum levels, somatostatin analogs treatment, BMI, and associated comorbidities.

CONCLUSIONS

SAS is a frequent complication of acromegaly. Severe forms seem to be correlated with smoking and lung disease. Therefore, all acromegalic patients should be subjected to a polygraphic study for an early diagnosis and treatment and smoking should be discouraged.

Sleep apnea in acromegaly: a review on prevalence, pathogenetic aspects and treatment

Sleep apnea syndrome is a common complication of acromegaly with a negative impact on quality of life and survival. Obstructive sleep apnea is the prevailing form and is characterized by recurrent episodes of apnea and hypopnea owing to the total or partial collapse of the upper airways during sleep. The craniofacial deformations and the hypertrophy of upper airway soft tissue are responsible for its occurrence. Successful treatment of acromegaly can improve the severity of this complication, but can only seldom reverse it, particularly after a long time of active acromegaly. Thus, it is advisable to evaluate patients for sleep apnea syndrome at diagnosis and during treatment, and also when acromegaly is biochemically controlled. In selected cases, continuous positive airway pressure should be implemented to improve patient outcome.

Craniofacial abnormalities, obesity, and hormonal alterations have similar effects in magnitude on the development of nocturnal hypoxemia in patients with acromegaly

BACKGROUND

In patients with acromegaly, sleep apnea-related hypoxemia results in considerable morbidity and mortality.

AIMS

To evaluate the relative weight of pathogenic factors in predicting such hypoxemia.

METHODS

In this cross-sectional study, 34 acromegaly patients were submitted to clinical evaluation, nocturnal oximetry, and nasolaryngeal airway tomography. GH, IGF-I, and its upper limit normal value were measured. Nocturnal hypoxemia was defined as >5 episodes of desaturation/h of sleep. Craniofacial abnormalities were expressed using a linear parameter index (LPI). Nocturnal hypoxemia was predicted using logistic regression, including the variables markers of craniofacial abnormality, hormonal alteration, and obesity. Coefficients were standardized in order to determine their effect magnitudes relative to the outcome. The best model included the variables gender, age, LPI, body mass index (BMI), and IGFI upper limit normal value.

MAIN RESULTS

In the absence of the age and gender variables, the odds ratio for the LPI (1.60) was slightly higher than those found for BMI (1.49) and upper limit normal value (1.40). When the data were adjusted for age, the hormone upper limit normal value presented little alteration (1.49), although the decrease in the LPI was considerable (1.21), as was the increase in the BMI (2.18). The relative weight of the LPI was age-dependent. The gender variable did not alter the relevance of the others.

CONCLUSIONS

The effects that craniofacial aspect, obesity, and hormonal alterations have on nocturnal hypoxemia are of similar magnitude.

Somatostatin analog treatment is associated with an increased sleep latency in patients with long-term biochemical remission of acromegaly

BACKGROUND

Somatostatin analogs induce alterations in sleep in healthy adults. Presently, it is unknown whether somatostatin analog treatment affects sleep parameters in patients with acromegaly.

DESIGN

Case-control study.

PATIENTS AND MEASUREMENTS

We assessed sleepiness and sleep patterns in 62 adult patients (32 men, age 61 years (33-88 years) controlled by surgery alone or postoperative radiotherapy (69%), and/or somatostatin analogs (31%). We used two validated sleep questionnaires (Epworth sleepiness score and Münchener chronotype questionnaire). Patient outcomes were compared to controls.

RESULTS

Sleep duration and timing of sleep were not different in patients compared to controls. However, sleepiness score was increased in all patients compared to controls: 6 (1-20) vs. 4 (0-14), P=0.014 (median (range)), reflecting increased daytime sleepiness. Snoring was reported in 68% of both patients and controls (P=0.996), observed apnoea's and restless legs in 23% and 37% of patients compared to 12% and 21% of controls (P=0.062 and P=0.031, resp.). In addition, sleep latency was increased in patients treated by somatostatin analogs compared to patients cured by surgery and/ or radiotherapy (52+/-48 min vs. 26+/-40 min, P=0.005), resulting in a delayed sleep onset (24:08+/-1:26 h vs. 23:25+/-0:43 h, P=0.053). Sleep duration was unaffected.

CONCLUSIONS

Daytime sleepiness is increased in a homogeneous cohort of patients in long-term remission from acromegaly. In addition, somatostatin analog treatment increases sleep latency and delays sleep onset in patients with long-term biochemical control of growth hormone overproduction without altering total sleep duration.

Prevalence of sleep apnea and metabolic abnormalities in patients with acromegaly and analysis of cephalometric parameters by magnetic resonance imaging

OBJECTIVES

To determine the prevalence of sleep apnea (SA) and SA syndrome (SAS) in patients with acromegaly and correlate SA with clinical, laboratory, and cephalometric parameters.

DESIGN AND METHODS

Prospective and cross-sectional study of 24 patients with active acromegaly evaluated by clinical and laboratory (GH, IGF-I) parameters, polysomnography and magnetic resonance imaging (MRI) of the pharynx.

RESULTS

Out of 24 patients, 21 had SA (87.5%), of which 20 (95.3%) had the predominant obstructive type. Median age of these 21 patients was 54 years (range 23-75) and median estimated disease duration was 60 months (range 24-300). The frequency in SA patients of impaired glucose tolerance, diabetes mellitus (DM), and hypertension was 19, 33.3, and 71.4% respectively. Goiter was found in 10 patients (47.6%) and obesity in 18 (90%). Median GH level was 14 mug/l (1.4-198) and median %IGF-I (percentage above the upper limit of normal range of IGF-I) was 181% (-31.6 to 571.2). The prevalence of SAS was 52.4%. Apnea-hypopnea index (AHI) correlated significantly with age, waist circumference, body mass index, and hypopharynx area. The AHI was significantly higher in patients with hypertension and DM.

CONCLUSIONS

The prevalence of SA and SAS in acromegaly was similar to the one previously described in other series. Age was a significant risk factor, and hypertension and DM were significantly associated complications of SA. Obesity was also significantly related to SA, as a risk factor, a complication or both. Overall, cephalometric parameters by MRI did not correlate with SA.

Acromegaly presented as a cause of laryngeal dyspnea

Acromegalic patients can develop obstructive sleep apnea syndrome or upper airflow obstruction. The development of dyspnea is unusual and the fixation of both vocal cords is exceptional. We report the case of a patient with bilateral vocal cord paralysis. Fiberoptic laryngoscopy and computed tomography (CT) of the neck showed a supra-glottic stenosis due to a swelling of the soft tissue. A tracheostomy was first performed. Thereafter, micro-laryngoscopy using laser vaporisation of the supra-glottic soft tissue was attempted but failed to remove the tracheostomy canula. Finally, blood tests and cerebral MRI revealed an acromegaly. The patient underwent a trans-sphenoidal resection of the pituitary adenoma. Fifteen months later, fiberoptic laryngoscopy showed bilateral restoration of vocal cord mobility and the tracheostomy canula was successfully removed after 18 months. Vocal cord fixation is probably due to hypopharyngeal and laryngeal soft tissue swelling and can be reversible after successful treatment of the adenoma.

Sleep-related breathing disorders in prepubertal children with Prader-Willi syndrome and effects of growth hormone treatment

CONTEXT

Recently, several cases of sudden death in GH-treated and non-GH-treated, mainly young Prader-Willi syndrome (PWS), patients were reported. GH treatment in PWS results in a remarkable growth response and an improvement of body composition and muscle strength. Data concerning effects on respiratory parameters, are however, limited.

OBJECTIVE

The objective of the study was to evaluate effects of GH on respiratory parameters in prepubertal PWS children.

DESIGN

Polysomnography was performed before GH in 53 children and repeated after 6 months of GH treatment in 35 of them.

PATIENTS

Fifty-three prepubertal PWS children (30 boys), with median (interquartile range) age of 5.4 (2.1-7.2) yr and body mass index of +1.0 sd score (-0.1-1.7).

INTERVENTION

Intervention included treatment with GH 1 mg/m2.d.

RESULTS

Apnea hypopnea index (AHI) was 5.1 per hour (2.8-8.7) (normal 0-1 per hour). Of these, 2.8 per hour (1.5-5.4) were central apneas and the rest mainly hypopneas. Duration of apneas was 15.0 sec (13.0-28.0). AHI did not correlate with age and body mass index, but central apneas decreased with age (r = -0.34, P = 0.01). During 6 months of GH treatment, AHI did not significantly change from 4.8 (2.6-7.9) at baseline to 4.0 (2.7-6.2; P = 0.36). One patient died unexpectedly during a mild upper respiratory tract infection, although he had a nearly normal polysomnography.

CONCLUSIONS

PWS children have a high AHI, mainly due to central apneas. Six months of GH treatment does not aggravate the sleep-related breathing disorders in young PWS children. Our study also shows that monitoring during upper respiratory tract infection in PWS children should be considered.

Cardiopulmonary and metabolic functions, aerobic capacity, fatigue and quality of life in patients with multiple sclerosis

OBJECTIVES

The objectives of this study were to evaluate cardiopulmonary and metabolic functions in patients with multiple sclerosis (MS) and to clarify the relationship between these functions and neurological deficits, respiratory involvement, fatigue and quality of life.

MATERIALS AND METHODS

Twenty-five patients with MS and 15 healthy controls were included in the study. Cardiopulmonary and metabolic responses to maximum exercise were investigated with an electronically braked arm crank ergometer. A computerized gas analysis system collected and analysed expired gases during exercise.

RESULTS

In the present study, significant respiratory muscle weakness, and decreased aerobic performance and cardiopulmonary and metabolic responses to maximum exercise were determined in patients with MS.

CONCLUSIONS

As respiratory muscle function plays a strong role in aerobic capacity and in most of the cardiopulmonary and metabolic responses to exercise, measurement of respiratory muscle strength and endurance should also be carried out in the MS population.

Etiologic aspects and management of acromegaly

Acromegaly is a systemic disease with various etiologies. It can occur as a sporadic or, more rarely, as a familial disease. Numerous complications such as endocrine, cardiovascular, respiratory, metabolic, osteoarticular and neoplastic disturbances occur and must be taken into account when establishing a therapeutic strategy. For this reason, the decision as to a treatment modality of acromegaly must be followed by a thorough evaluation of the patient and once the diagnosis of complications is settled, adequate treatment should be instituted. Follow up of the patients requires periodical re-assessment of complications’ status.

Long-term treatment outcome in acromegaly

A number of groups have developed guidelines to indicate whether an individual with acromegaly has been cured by treatment. However, studies to date do not provide a robust definition of biochemical remission of the disorder based on correlation with long-term outcome. Available data suggest that those with a random serum growth hormone (GH) level of <2.5 microg/l, or a glucose-suppressed GH level of <1 microg/l following treatment have mortality figures indistinguishable from the general population. However, the confidence limits for these mortality estimates are quite wide. It remains possible that growth hormone levels lower than 1 microg/l for random samples, or even lower when using ultrasensitive GH assays, may indicate superior outcome, but this remains to be confirmed. There are limited data relating serum insulin-like growth factor-I (IGF-I) levels to outcome, although normalisation of serum IGF-I clearly improves outcome compared with continued elevation of measurements after treatment. Current evidence suggests that a post-treatment random serum GH <2.5 microg/l and a normal serum IGF-I value defines biochemical cure. Available data suggest that achieving similar growth hormone levels after treatment also reduces the prevalence of chronic complications of the disorder, which is subsequently reflected in improved mortality.

Sleep apnea syndrome in endocrine diseases

It is increasingly recognized that sleep-disordered breathing (SDB) - from snoring to apnea-hypopnea syndrome (SAHS) - can affect patients with various endocrine diseases (ED). Different mechanisms are implied in SDB, promoting either central or, more frequently, obstructive apnea in different ED. In the past, acromegaly and hypothyroidism were first associated with both central and obstructive SAHS. Today, great attention is placed on the complex cause-effect relationship between diabetes mellitus and obstructive SAHS (and vice versa). Symptoms and signs of SAHS may complicate the clinical course of these diseases and should be promptly suspected to detect and possibly treat the accompanying SDB.

CLINICAL REVIEW ARTICLE: Epidemiology of sleep-related obstructive breathing

The diagnosis of obstructive sleep apnoea syndrome (OSAS) and upper airway resistance syndrome (UARS) is based both on a combination of laboratory findings from whole-night sleep recordings and daytime symptoms. Due to the recent interest in breathing disturbances during sleep many prevalence studies have been performed within this field. There are, however, methodological difficulties in characterizing these syndromes in large populations; many of the studies have therefore been unable to present an overview of the complete syndromes but rather have focused on specific characteristics. In epidemiological research snoring and/or daytime sleepiness have often been used as markers of OSAS, while other studies have looked only on the respiratory disturbances or oxygen desaturation. Studies on the prevalence of OSAS based on polysomnography are reviewed here, as well as investigations where associated factors such as cardiovascular diseases and mortality were analysed. The interrelationships between snoring, daytime symptoms and laboratory findings are discussed. Gender, age, obesity, smoking, alcohol and ethnicity are all factors that influence the prevalence of OSAS. The data on associations between OSAS and cardiovascular disease or mortality are sometimes unrelated. Much of the discrepancy between different studies can be explained by the methodological difficulties connected with the definition of OSAS and also by the fact that the association between sleep-disordered breathing and cardiovascular outcome seems to be age-dependent.

Epidemiology of acromegaly

Acromegaly is a consequence of chronic growth hormone (GH) excess, due in the majority of cases to a GH-secreting pituitary adenoma, and occurring with a population prevalence of 60 per million and an incidence of 3-4 per million per year. Males and females appear to be equally affected with an average age of presentation of 44 years. Younger patients may have more aggressive tumours and higher GH concentrations. There is co-existent hyperprolactinaemia in about one third of cases, and a variable proportion of [figure: see text] tumours appear to have activating mutations of the gsp gene or other genetic abnormalities. Acute complications such as carpal tunnel syndrome, sweating and obstructive sleep apnoea are usually readily reversible with treatment of the condition, but chronic complications such as hypertension, diabetes and heart disease are less readily corrected and post-treatment GH levels of < 2.5 ug/L (5 mU/L) are needed to achieve the prevalence found in the general community. Such 'curative' levels of GH are achieved in only about 50% of patients with current therapies, and as a result there is an ongoing excess of patients with chronic complications of acromegaly leading to increased morbidity and mortality from the disorder, with observed-to-expected mortality ratios ranging from 1.6-3.3 and only approaching unity in those with growth hormone levels < 2.5 ug/L following treatment. Prognostic factors include in some studies the presence of diabetes and [table: see text] hypertension prior to diagnosis as well as measures of exposure to excessive growth hormone derived from the product of preoperative serum GH and the time from first symptoms to treatment. Overall, however, the most important prognostic variable appears to be the serum GH concentration achieved by treatment, with an increasing consensus that this needs to be < 2.5 ug/L (5 mU/L) to achieve cure of the condition.