Sleep apnoea in well-controlled myasthenia gravis and the effect of thymectomy

Sleep in Myasthenia Gravis: A Questionnaire-Based Study

BACKGROUND

Disturbed sleep and its impact on quality of life (QoL) are underrecognized in myasthenia gravis (MG).

AIMS

To evaluate the quality of sleep in MG using standard sleep questionnaires and assess factors that determine sleep.

SETTINGS AND DESIGN

Prospective, cross-sectional, hospital-based study.

PATIENTS AND METHODS

Fifty patients on stable drug therapy for at least 1 month and age- and gender-matched controls were assessed using standard sleep questionnaires [Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI), and NIMHANS Comprehensive Sleep Disorders Questionnaire (NCSDQ)].

RESULTS

Myasthenia Gravis Foundation of America (MGFA) grade was I, IIA, IIB, IIIA, IIIB, and IVA in 11, 19, 3, 10, 6, and 1 respectively. The mean PSQI and ESS scores were similar in patients and controls. Patients with abnormal ESS (>10) were older and had greater neck circumference (P = 0.018 and <0.001). Body mass index was greater in patients with PSQI > 5 (P < 0.05). Age, gender, and clinical severity did not affect PSQI. Compared with ESS and PSQI, NCSDQ showed higher frequency of disturbed sleep, snoring, early morning headache, difficulty in initiation, and maintenance of sleep in MG, although the differences between patients and controls were not significant. No correlation was found between QoL and ESS or PSQI.

CONCLUSION

Patients of MG with stable clinical course with adequate treatment have sleep quality comparable with healthy controls. Longitudinal assessment of sleep quality at multiple time points throughout the disease course and correlating with cross-sectional disease severity may further delineate the impact of disease on sleep and QoL.

[Sleep disorders in patients with myastenia gravis]

This review analyzes publications that present data on sleep disorders in patients with myasthenia gravis (MG). The analysis is based on domestic and foreign publications that are freely available over the past 30 years. Sleep disorders, the most significant of which are sleep-related respiratory disorders, are one of the factors that cause quality of life decreasing and mortality in patients with neuromuscular diseases. The issues of prevalence of breathing disorders during sleep, relationship of these disorders with clinical and immunological characteristics of disease, demographic indicators are studied. The influence of sleep breathing disorders on quality of life and affective sphere of patients is discussed. Most studies prove that sleep-related respiratory disorders occur in patients with MG significantly more often than in general population. Some studies show a high prevalence of poor sleep quality, excessive daytime sleepiness in patients with MG, while others do not report such associations. However, studies that failed to establish an association with MG and sleep disturbances were of small sample sizes. Thus, given the inconclusive evidence and limited literature, further study of sleep disorders in patients with MG is needed. The topic is relevant and requires further development.

Obstructive sleep apnea in late-onset Pompe disease treated by enzyme replacement therapy

Obstructive sleep apnea is a common complication of Pompe disease. Treatment for obstructive sleep apnea in patients with Pompe disease is similar to treatment in the general population, typically involving positive airway pressure therapy. We present a case in which a patient with late-onset Pompe disease was able to discontinue positive airway pressure therapy after treatment with enzyme replacement therapy for his Pompe disease. It is likely that an improvement in muscle tone from the enzyme replacement therapy was sufficient to eliminate his obstructive sleep apnea. Pharmacological therapies for obstructive sleep apnea are lacking but could apply to certain populations, such as Pompe disease.

Home sleep study for patients with myasthenia gravis

OBJECTIVES

The objective of the study was to examine predictors for sleep-disordered breathing (SDB) in patients with myasthenia gravis (MG) using Watch-PAT.

MATERIALS AND METHODS

We prospectively studied 58 consecutive patients with MG without respiratory symptoms for a full-night Watch-PAT with concomitant recording of the MG score and acetylcholine receptor antibody concentration and analyzed potential risk factors of SDB.

RESULTS

Twenty-four patients (41%) had definitive SDB, which was mild in 12 patients, moderate in six, and severe in six. Assessing risk factors with multivariate models, we found four significant predictors (BMI, age, male gender, and use of azathioprine); BMI was the most powerful predictor. The severity and prevalence of sleep-disordered breathing had no significant association with MG score, myasthenia stage, or seropositivity of acetylcholine receptor antibody.

CONCLUSIONS

The prevalence of SDB in myasthenic patients with mild and moderate weakness was high when using the Watch-PAT. Both myasthenia-specific factors (use of azathioprine) and general predictors in terms of BMI, age, and male gender predisposed the development of SDB in patients with myasthenia gravis. Careful screening of patients with myasthenia gravis at risk of SDB using Watch-PAT might improve the quality of sleep and cardiovascular health through proper treatment of underlying SDB.

Sleep disorders in patients with myasthenia gravis: a systematic review

[Purpose] This systematic review evaluated the presence of sleep-disordered breathing in patients with myasthenia gravis and clarified the role of physiotherapy. [Subjects and Methods] We followed the PRISMA declaration criteria. The evaluation was performed in accordance with the STROBE statement for observational and cross-sectional studies and the CONSORT checklist for clinical trials. Searches were followed by hand on MEDLINE, EMBASE, SciELO, PubMed Central, and the Cochrane Central Register of Controlled Trials. [Results] Our searches yielded a total of 36 studies published between 1970 and 2014. The number of patients involved ranged from 9–490. Of the 36 studies, 19 articles were excluded because they did not meet the inclusion criteria. Therefore, 17 observational, cross-sectional, or clinical studies assessing the quality of sleep and prevalence of sleep disorders in patients with myasthenia gravis were eligible for our review. [Conclusion] Some studies of patients with MG show that patients with MG are associated with poor sleep quality, excessive daytime sleepiness, presence of restless syndrome, and a higher incidence of SDB, while other studies do not report such associations. Therefore, given the current inconclusive evidence and limited literature, further study of sleep disturbances in patients with MG is needed.

Resolution of severe obstructive sleep apnea after treatment of anti-muscle kinase receptor-positive myasthenia gravis despite 60-pound weight gain

Obstructive sleep apnea (OSA) in patients with myasthenia gravis (MG) may be caused by reduced pharyngeal dilator muscle activity. We report a patient with anti-muscle kinase receptor MG with severe OSA and hypoventilation that resolved upon successful treatment of MG despite a 60-lb weight gain.

Prevalence and profile of sleep disturbances in Guillain-Barre Syndrome: a prospective questionnaire-based study during 10 days of hospitalization

INTRODUCTION

Sleep disturbances in Guillain-Barre Syndrome (GBS), though common, have not received focused attention.

OBJECTIVES

To study frequency and nature of sleep disturbances in patients with GBS, using validated questionnaires, and analyze the contributing factors.

MATERIALS AND METHODS

This prospective study included 60 patients fulfilling National Institute of Neurological and Communicative Diseases and Stroke (NINCDS) criteria for GBS (mean age: 32.7 ± 12.9 years; median: 30 years; M:F = 46:14), evaluated from 2008 to 2010. Data regarding sleep were collected on 10 consecutive days following admission using Richard Campbell Sleep score, St Mary's Hospital Sleep Questionnaire, and Pittsburgh Sleep Quality Index (PSQI) and correlated with various possible contributing factors like pain, paresthesia, anxiety, depression, autonomic dysfunctions, severity of disease, and therapeutic interventions among others.

OBSERVATIONS

Qualitative and quantitative sleep disturbances were rather frequent and involved over 50% patients: abnormal PSQI - 13.3%, abnormal score on Richard scale - 51.6%, abnormal sleep onset latency - 35%, sleep fragmentation - 40%, and reduced sleep duration - 46.6%. The symptoms were severe during the first week of hospitalization and reduced thereafter. Sleep disturbances as scored on Richard scale significantly correlated with anxiety, pain, paresthesia, and severity of immobility (P < 0.05) but not with depression and use of analgesics or antineuritic drugs.

CONCLUSIONS

This study first of its kind suggests that sleep disturbance in GBS is frequent, multi-factorial, often disturbing, and varies during the course of illness. Routine enquiry into the sleep disturbances and timely intervention may reduce morbidity and improve their quality of life.

Myasthenia gravis: sleep quality, quality of life, and disease severity

INTRODUCTION

There is much research on quality of life in myasthenia gravis (MG), and its relationship to disease severity is well-established. However, evidence regarding sleep disturbance in MG is inconclusive.

METHODS

To evaluate sleep and quality of life among clinically stable MG patients, 54 subjects were investigated by means of the Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and 15-Item-Quality-Of-Life Instrument for MG (MG-QOL15).

RESULTS

A pathological PSQI score, which was observed in 59% of patients, was increased in subjects with active disease compared with patients in clinical remission [odds ratio = 4.3; confidence interval 95% (1.0-17.6); P = 0.04]. We found a relationship between PSQI and MG-QOL15 scores in patients with clinically active disease (r = 0.62; P < 0.001).

CONCLUSIONS

Our study highlights the high prevalence of sleep disturbance among MG patients. Disease severity may be considered to be a MG-specific risk factor for patient-reported sleep disturbance. The MG-QOL15 and PSQI should be used to estimate the impact of the disease on sleep and quality of life.

Airway limitation and exercise intolerance in well-regulated myasthenia gravis patients

OBJECTIVES

Myasthenia gravis (MG) is an autoimmune disease of neuromuscular synapses, characterized by muscular weakness and reduced endurance. Remission can be obtained in many patients. However, some of these patients complain of fatigue. The aim of this study was to assess exercise capacity and lung function in well-regulated MG patients.

PATIENTS AND METHODS

Ten otherwise healthy MG patients and 10 matched controls underwent dynamic spirometry, and a ramped symptom-limited bicycle exercise test. Spirometric variables included forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and maximum voluntary ventilation (MVV). Exercise variables included maximal oxygen uptake (VO(2) max), anaerobic threshold (VO(2) AT) maximum work load (W), maximum ventilation (VE max), and limiting symptom.

RESULTS

Myasthenia gravis patients had significantly lower FEV1/FVC ratio than controls. This was more marked in patients on acetylcholine esterase inhibitors. On the contrary, patients not using acetylcholine esterase inhibitors had a significantly lower exercise endurance time.

CONCLUSION

Well-regulated MG patients, especially those using pyridostigmine, tend to have an airway obstruction. The modest airway limitation might be a contributing factor to their fatigue. Patients who are not using acetylcholinesterase inhibitor seem to have diminished exercise endurance in spite of their clinically complete remission.

Sleep, sleep disordered breathing, and nocturnal hypoventilation in children with neuromuscular diseases

Sleep disordered breathing (SDB) is now well recognized in children with neuromuscular diseases (NMD) and may lead to significant morbidity and increased mortality. Predisposing factors to SDB in children with NMD include reduced ventilatory responses, reduced activity of respiratory muscles during sleep and poor lung mechanics due to the underlying neuro-muscular disorder. SDB may present long before signs of respiratory failure emerge. When untreated, SDB may contribute to significant cardiovascular morbidities, neuro-cognitive deficits and premature death. One of the problems in detecting SDB in patients with NMD is the lack of correlation between lung function testing and daytime gas exchange. Polysomnography is the preferred method to evaluate for SDB in children with NMD. When the diagnosis of SDB is confirmed, treatment by non-invasive ventilation (NIV) is usually recommended. However, other modalities of mechanical ventilation do exist and may be indicated in combination with or without other supportive measures.

Sleep disordered breathing in medically stable patients with myasthenia gravis

We investigate sleep and breathing in clinically stable myasthenia gravis (MG) patients and ask weather sleep disordered breathing (SDB) is causally linked with MG. Nineteen MG patients with a mean disease duration of 9.7 years underwent sleep studies in two consecutive nights. The primary outcome measure was the respiratory disturbance index (RDI) in terms of snoring and apneas/hypopneas. Further outcome measurements were total sleep time, sleep stage distribution and the number of arousals. A clinically relevant SDB in terms of obstructive sleep apnea (OSA) (defined as RDI > 10/h) was found in four patients. There were only a few central apneas (central apnea index: 0.19 +/- 0.4/h). We did not find a relationship between maximum inspiratory pressure and SDB (r = -0.03). There is no evidence for a causal relationship between medically stable MG and SDB in terms of OSA. The extent of respiratory muscle weakness failed to correlate with SDB. Furthermore, our study does not confirm the high occurrence of central respiratory events during sleep in patients with well-controlled MG.

Sleep disorders in neuromuscular diseases

PURPOSE OF REVIEW

Patients with neuromuscular disorders (NMD) are especially vulnerable to sleep-related dysfunction. Sleep-disordered breathing often precedes diurnal respiratory failure in NMD patients, requiring timely recognition and management with noninvasive ventilation (NIV). This paper reviews the mechanisms, diagnostic evaluation, and management of sleep disorders in various neuromuscular diseases.

RECENT FINDINGS

The severity, duration, and type of NMD influence the pattern of sleep disturbance. Several investigators have addressed other clinical aspects including rating scales for sleep complaints, hypocretin-1 deficiency, excessive daytime somnolence, and relation of sleep disorder with length of CTG trinucleotide repeats in myotonic dystrophy. Benefits of NIV on quality of life and survival in adults and children with chronic NMD are well established, and recently have been documented even in patients with nocturnal hypoventilation and daytime normocapnia. In contrast, the timing for investigation with polysomnography and for initiation of NIV is debated.

SUMMARY

Patients with chronic NMD should be routinely assessed for sleep-disordered breathing and sleep complaints, because these are treatable complications in an otherwise progressive disease process. Further research is needed to establish the indications for polysomnography and to determine the optimal timing for initiating NIV to treat sleep-disordered breathing in patients with neuromuscular diseases.

Sleep and Neuromuscular Disorders

Nocturnal sleep-related ventilatory alterations may occur in dis-proportion to the severity of the neuromuscular disorder. Diaphragm paralysis occurring with a neuromuscular disorder is an overlooked complication. Failure to thrive, daytime tiredness, and incapacitating fatigue may be the result of a correctable sleep-related abnormality, not the result of relentless progression of a neuromuscular condition. Polysomnographic evaluation is recommended for patients who have neuromuscular disorder who develop symptoms and signs of sleep-wake abnormality or nocturnal respiratory failure. Application of noninvasive positive airway ventilation and, in some cases, administration of supple-mental oxygen may improve quality of life and prolong survival of patients who have neuromuscular disorder.

Excessive daytime sleepiness and sleep disturbances in patients with neurological diseases: epidemiology and management

Up to 12% of the general population experience excessive daytime sleepiness (EDS), with increasing prevalence in the elderly. EDS may lead to cognitive impairment, resulting in inattentiveness, poor memory, mood disorders and an increased risk of accidents. As a result, quality of life is reduced in most patients with EDS as well as in their caregiving spouses. There are a variety of causes leading to EDS, including CNS pathology, neurological dysfunction, associated sleep disorders with insufficient or fragmented sleep, and drug therapy. Since EDS accompanies many neurological disorders, such as neurodegenerative and neuromuscular diseases, neurologists should be familiar with the diagnosis, its major causes and with treatment options. The main focus of this article is on movement disorders, neuromuscular diseases, multiple sclerosis, dementia, cerebrovascular diseases, head and brain trauma, pain and epilepsy. General management strategies for EDS in all these neurological diseases include sleep hygiene aspects such as extensions of noctural time in bed and frequent naps during the day. Pharmacological treatment is generally achieved with stimulants such as amphetamine, methylphenidate and pemoline, or newer compounds such as modafinil.

A review of sleep in selected immune and autoimmune disorders

Evidence for the reciprocal role of the immune system in sleep is growing. Sleep disturbances are believed to be both a cause and a consequence of various immune and autoimmune conditions.

Age-related changes in upper airway muscles morphological and oxidative properties

Obstructive sleep apnea (OSA) is a common disorder of the middle aged and elderly. It results from the decrease in upper airway muscle (UAM) tone that occurs during sleep. It is unclear whether age-related changes in UAM could constitute a contributory mechanism to the increased prevalence of OSA with increasing age, and previous papers evaluating the effects of aging on UAM in rats reported conflicting results. In the present study, we compared, in four age groups of Wistar rats (6-24 months), fiber-type distribution, mean cross-sectional fiber area and succinate dehydrogenase optical density of dilating and non-dilating UAM, and the diaphragm. Succinate dehydrogenase optical density, a marker of oxidative capacity, decreased significantly after the age of 6 months in all muscles (except for the sternohyoid), particularly in the genioglossus, the main tongue protrudor. In this muscle, we also found a significant decrease in type IIa and an increase in IIb fibers after the age of 18 months. Age-related changes in fiber-type distribution in other muscles were mostly insignificant. Dilating UAM could not be distinguished from their non-dilating neighboring muscles by their histochemical properties or aging-related changes. The aging-related changes observed in the present study may decrease UAM endurance, particularly that of the main tongue protrudor, the genioglossus.

What have we learned about cognition in myasthenia gravis?: a review of methods and results

Most individuals with myasthenia gravis (MG) complain of cognitive impairment, but empirical studies of cognition in MG have produced mixed results. In the present review, we critically examined the methodology and results of previous studies that investigated cognition in MG. Results from our review revealed that none of the studies met at least 50% of criteria under review. The most common shortcomings of previous studies included small sample size, no exclusion for visual difficulties in patients, inadequate assessment of mood, and poor control for prednisone use. Despite these methodological difficulties, mild impairments on measures of learning have been identified. These findings need to be replicated with adequate control of potential confounds before any conclusions can be made regarding cognition in this disease. Suggestions for design of future studies are provided.

Cognitive dysfunction in individuals with myasthenia gravis

In the present study we administered a battery of cognitive measures that examined attention, response fluency, information processing, and verbal and visual learning and retention to 28 individuals with generalized myasthenia gravis (MG) and 18 demographically similar control subjects. Results revealed that MG patients performed significantly more poorly than control subjects on the measures of response fluency, information processing and most measures of verbal and visual learning. Significant group differences were not evident on the measure of attention span or on the indices of retention of information. Cognitive performances of the MG group were not related to mood disturbance, disease duration, or daily dose of prednisone. While these results suggest central involvement in MG, previous studies have not provided evidence that MG antibodies bind to central nicotinic receptors. Possible alternative mechanisms underlying cognitive dysfunction in MG are discussed.

Sleep-related disorders in neurologic disease during childhood

Sleep disorders commonly are associated with neurologic disorders in childhood. This review discusses primary sleep disorders that affect children with primary neurologic diseases. Primary sleep disorders are discussed as they relate to the primary neurologic disease. In addition, sleep disorders secondary to neurologic disorders commonly seen in the practice of pediatric neurology are reviewed. A useful sleep history to improve diagnostic and therapeutic interventions is outlined.

Does myasthenia gravis affect the brain?

Associations between myasthenia gravis (MG) and CNS functions have been made for over 80 years. An increased incidence of psychiatric disorders, epilepsy and multiple sclerosis as well as electroencephalographic (EEG) abnormalities and abnormal evoked responses have been noted in patients with MG. Descriptions of sleep and memory disturbances in MG patients appeared as knowledge accumulated about the role of brain cholinergic systems in sleep and memory. The inference of many of these studies has been that the alleged central cholinergic effects in MG were caused either by the anticholinesterases used to treat MG or by antibodies to muscle nicotinic acetylcholine receptor (nAchR) present in the serum and cerebrospinal fluid (CSF) of MG patients. The antigenic differences between muscle nAchR and neuronal nAchRs, together with the very low concentrations of muscle nAchR antibodies in the CSF, make highly unlikely the claims that CNS cholinergic systems are affected by these muscle antibodies in MG patients. Evoked response abnormalities, if indeed present, are more likely caused by peripheral than central mechanisms, and sleep abnormalities in MG also probably originate in the periphery rather than in the CNS, the result of hypoxia caused by oropharyngeal, intercostal and diaphragmatic muscle weakness which may worsen during sleep, especially during REM sleep. Such hypoxia may account for some of the EEG abnormalities noted in MG patients, but the association of MG with epilepsy appears to be either coincidental or the result of uncontrolled MG. Significant excessive daytime sleepiness resulting from sleep disturbances can also impair memory and the performance of MG patients on neuropsychological tests, as can the presence of mental depression. The psychological aspects of MG can be attributed to the expected consequences of a chronic but unpredictable neuromuscular disease involving weakness of breathing, swallowing, talking, limb and eye movement. Considering the number and variety of claims for direct CNS involvement in MG, the evidence for this is remarkably unconvincing. The quality of MG treatment, both physical and psychological, is a presently undefined variable which might help explain the diametrically opposed results which have been obtained in some of the studies reviewed. Adequate respiratory muscle strength during sleep is an often overlooked peripheral influence upon mental functioning and general well-being of MG patients.