Sleep, lung function, and quality of life in patients with myasthenia gravis: A cross-sectional study

Office-based respiratory assessment in patients with generalized myasthenia gravis

Patients with myasthenia gravis (MG) can present with respiratory dysfunction, ranging from exercise intolerance to overt respiratory failure, increased fatigue, or sleep-disordered breathing. To investigate the value of multiple respiratory tests in MG, we performed clinical and respiratory assessments in patients with mild to moderate generalized disease. One-hundred and thirty-six patients completed the myasthenia gravis quality-of-life score(MG-QOL-15), myasthenia gravis impairment index(MGII), Epworth sleepiness scale(ESS), University of California-San Diego Shortness of Breath Questionnaire(UCSD-SOB), Modified Medical Research Council Dyspnea Scales(MRC-DS), supine and upright forced vital capacity(FVC), maximal inspiratory pressures(MIPs) and sniff nasal inspiratory pressures(SNIP). Seventy-three (54 %) had respiratory and/or bulbar symptoms and 45 (33 %) had baseline abnormal FVC, with no significant postural changes (p = 0.89); 55 (40.4 %) had abnormal MIPs and 50 (37 %) had abnormal SNIPs. Overall, there were low scores on respiratory and disability scales. Females had increased odds of presenting with abnormal FVC (OR 2.89, p = 0.01) and MIPs (OR 2.48, p = 0.022). There were significant correlations between MIPs, FVC and SNIPs; between MGII/MG-QOL15 and UCSD-SOB/MRC-DS and between ESS and respiratory scales in the whole group. Our data suggests that office-based respiratory measurements are a useful screening method for stable MG patients, even when presenting with minimal respiratory symptoms and no significant disability.

Impaired cerebral microvascular endothelial cells integrity due to elevated dopamine in myasthenic model

Myasthenia gravis is an autoimmune disease characterized by pathogenic antibodies that target structures of the neuromuscular junction. However, some patients also experience autonomic dysfunction, anxiety, depression, and other neurological symptoms, suggesting the complex nature of the neurological manifestations. With the aim of explaining the symptoms related to the central nervous system, we utilized a rat model to investigate the impact of dopamine signaling in the central nervous and peripheral circulation. We adopted several screening methods, including western blot, quantitative PCR, mass spectrum technique, immunohistochemistry, immunofluorescence staining, and flow cytometry. In this study, we observed increased and activated dopamine signaling in both the central nervous system and peripheral circulation of myasthenia gravis rats. Furthermore, changes in the expression of two key molecules, Claudin5 and CD31, in endothelial cells of the blood-brain barrier were also examined in these rats. We also confirmed that dopamine incubation reduced the expression of ZO1, Claudin5, and CD31 in endothelial cells by inhibiting the Wnt/β-catenin signaling pathway. Overall, this study provides novel evidence suggesting that pathologically elevated dopamine in both the central nervous and peripheral circulation of myasthenia gravis rats impair brain-blood barrier integrity by inhibiting junction protein expression in brain microvascular endothelial cells through the Wnt/β-catenin pathway.

The influence of symptom severity and fatigue on sleep quality in patients with myasthenia gravis

INTRODUCTION

Myasthenia gravis is a rare and chronic autoimmune disease. The study aimed to evaluate the influence of symptom severity and fatigue on sleep quality in patients with myasthenia gravis.

METHODS

This was a cross-sectional study, and the population consisted of patients with MG throughout Turkey. The study was completed with 163 patients on 1 April and 31 July 2022.

RESULTS

 It was found that the mean Myasthenia Gravis-Activities of Daily Living Scale score was 6.32 ± 3.9, the Fatigue Severity Scale score was 37.01 ± 23.26, and the total Pittsburgh Sleep Quality Index score was 9.04 ± 2.69. The variables affecting the Pittsburgh Sleep Quality Index scores were age, Body Mass Index, Fatigue Severity Scale ≥ 4, Myasthenia Gravis-Activities of Daily Living Scale ≥ 5.5, duration of diagnosis, and income level; a multiple regression model was created with these variables, and the variables in the resulting model explained 26.4% of the Pittsburgh Sleep Quality Index scores. In addition, those with clinically significant symptom severity (MG-ADL ≥5.5) in daily living and those with severe fatigue (FSS ≥4) explained 17.2% of the PSQI scores, and the model was statistically significant (p < 0.001).

CONCLUSION

The study determined that the participants had clinically significant symptom severity in daily living, severe fatigue, and poor sleep quality. The participants with clinically significant severe symptoms in daily living and fatigue had higher sleep disturbances, daytime dysfunction, and poor sleep quality.

The Burden Patients with Myasthenia Gravis Experience in Terms of Breathing, Fatigue, Sleep, Mental Health, Discomfort and Usual Activities in Comparison to the General Population

INTRODUCTION

Myasthenia gravis (MG) is a rare neuromuscular disorder marked by a variable combination of weakness of eye, bulbar, respiratory, axial, and limb muscles. This study compared the experience of people with MG regarding breathing, fatigue, sleep, pain/discomfort, mental health, and usual activities with the general population.

METHODS

The MyRealWorld-MG digital, multinational study enrolled patients with MG and collected demographics, PROMIS-Dyspnea, PROMIS-Sleep Disturbance, FACIT-Fatigue, EQ-5D-5L, Health Utilities Index (HUI-3), Hospital Anxiety and Depression Scale (HADS), MG-Activities of Daily Living (MG-ADL), and MG-Quality-of-Life (MG-QoL-15r). Comparisons with the general population were based on PROMIS population norms, published literature, or on data from a digital, multinational, observational study which enrolled a representative sample of the general population (POPUP).

RESULTS

In MyRealWorld-MG (N = 2074), patients experienced higher intensity, frequency, and duration of PROMIS shortness of breath than a US population (p < 0.0001). Patients with MG had higher PROMIS-Sleep Disturbance scores than POPUP (53.7 vs 50.0, p < 0.0001), and 54.9% of patients had clinically severe FACIT-Fatigue scores vs 6.8% in POPUP (p < 0.0001). Among patients with MG, 69.6% and 18.5% had moderate-to-severe HADS-Anxiety and HADS-Depression compared to 20.3% and 6.9% in POPUP (p < 0.001). Statistically significant and strong associations were found between fatigue, sleep, dyspnea, usual activities, and emotions. All outcomes worsened with more severe disease.

CONCLUSION

A considerable burden was observed in this comparison of breathing, sleep, fatigue, mental health, and usual activities between patients with MG and the general population, using data from two international studies and published population norms. Even mildly affected patients had significantly worse outcomes than the general population.

Correlation between Cardiovascular Autonomic and Pulmonary Ventilation Functions in Myasthenia Gravis Patients

This study aimed to investigate the relationship between pulmonary function and cardiac autonomic function parameters in clinically stable myasthenia gravis (MG) patients. A total of 22 MG patients and 22 healthy controls (HCs) were evaluated. Pulmonary function test parameters, heart rate variability (HRV), baroreflex sensitivity (BRS), and cardiovascular autonomic function test parameters (the Valsalva ratio, expiration/inspiration (E/I) ratio) were assessed. Compared with the HCs, the patients demonstrated a similar diffusion capacity for carbon monoxide (DLCO); a lower forced vital capacity (FVC%pred); a lower forced expiratory volume in 1 s (FEV1%pred); lower BRS and HRV, including high-frequency and total power spectral density; and a higher percentage of abnormal cardiovagal function test results (p < 0.05). A lower BRS in the patient group was associated with worse clinical disease outcomes and reduced pulmonary function (DLCO%pred, R = 0.59; TLC%pred, R = 0.48). Age, forced vital capacity, and total lung capacity predicted the E/I ratio (R2 values ranging from 0.48 to 0.49). Our study demonstrated a significant relationship between a reduced pulmonary ventilation function and respiratory mechanics with cardiovascular autonomic parameters, including the E/I ratio, BRS, and HRV measures at rest, as shown in the MG group. Future studies should focus on the interplay between respiratory and autonomic function testing, as well as pulmonary rehabilitation, to mitigate cardiovascular risk in these patients.

A late diagnosis of myasthenia gravis at the respiratory practice: back to basics

Myasthenia gravis may affect respiratory muscles. To differentiate between other neuromuscular diseases, evaluation for muscle fatigability can be demonstrated by cardiopulmonary exercise testing and the maximal voluntary ventilation test.https://bit.ly/3qMeWFd

[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.

Myasthenia Symptom Burden, Fatigue, and Sleep: Are They Related?

OBJECTIVE

Our aim is to explore the relationship between myasthenia gravis (MG)-related symptom burden, sleep quality, and fatigue in a diverse group of self-identified MG patients.

METHODS

Patients provided relevant myasthenia disease data and completed the MG QOL-15, Epworth sleepiness scale, Pittsburgh Sleep Quality Index, and fatigue severity score (FSS) online. MG activities of daily living scale (MG-ADL) was completed on a follow-up telephone interview.

RESULTS

One hundred ninety-six patients completed the online survey and 99 provided MG-ADL data. The mean age was 52 ± 15.34 years, 88 were acetylcholine receptor antibody positive, and 21 were muscle specific kinase positive. The mean MG-ADL was 6.81, indicating a moderate MG disease burden. Forty-seven (24%) reported high Epworth sleepiness scale scores, 152 (77%) reported high Pittsburgh Sleep Quality Index scores, and 162 (82%) reported high FSS scores. Correlation analysis correcting for body mass index and sleep apnea revealed a moderate positive correlation between MGQOL-15, MG-ADL, and FSS.

CONCLUSIONS

There is a moderate positive correlation between various MG-specific outcome measures and fatigue severity.

Diagnosis of sleepiness, fatigue and depression in patients with myasthenia gravis

Introduction. Examination of excessive daytime sleepiness, fatigue and depression in patients with myasthenia gravis is important for differential diagnosis of other disorders, and adds to a comprehensive clinical assessment.

Objective. The aim is a comprehensive assessment of sleepiness, fatigue and depression and evaluation of the impact of autoimmune comorbidity on these symptoms in myasthenia gravis patients, using newly validated Russian versions of international questionnaires. The present article aims at familiarizing a wider Russian-speaking audience of specialists in the field of neuromuscular disease and sleep medicine with the main findings of our previously published work.

Materials and methods. The study included 73 patients with MG and 230 control subjects. For sleepiness, fatigue and depression evaluation were used: Fatigue Severity Scale (FSS), Fatigue Impact Scale (FIS) (cognitive / physical / psychosocial subscales), Epworth Sleepiness Scale (ESS), Beck Depression Inventory (BDI) (cognitive-affective and somatic domains), Spielberger–Khanin State Trait Anxiety Inventory (STAI).

Results. The Fatigue Severity Scale and Fatigue Impact Scale showed good psychometric properties and can be used to identify distinct aspects of fatigue in patients with myasthenia gravis. The studied patient cohort revealed clinically significant fatigue (69.9 %), excessive daytime sleepiness (15.1 %), moderate to severe depression (20.5 %), a high level of personal (64.4 %) and situational anxiety (27.4 %). Among 13 patients with myasthenia gravis and additional autoimmune comorbidity, there were no significant differences in the severity of sleepiness, fatigue and depression compared with the main group.

Conclusion. The use of self-reported scale of sleepiness, fatigue and depression combined with careful clinical-neurological characterization adds to a more comprehensive view of the patient. The identification of sleepiness, fatigue and depression can guide therapeutic decisions and contributes to a better patient care. The presence of concomitant autoimmune pathology in patients with myasthenia gravis does not seem to increase the severity of sleepiness, fatigue and depression.

Evidence-Based Practice in Rehabilitation of Myasthenia Gravis. A Systematic Review of the Literature

Myasthenia gravis is a rare neuromuscular disorder characterized by muscle weakness and fatigue. This review analyzes the most recent evidence regarding the effectiveness and safety of different rehabilitative approaches to the disease. The review was carried out in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A total of 365 articles were found in the main scientific databases. Applying the inclusion/exclusion criteria, 11 studies were admitted to the final phase of the review. Three different rehabilitative approaches were identified: physical training, respiratory training, and balance training. All rehabilitative modalities contributed to enhancing functional outcomes, reducing fatigue, and improving quality of life, but currently none can be recommended over another for the lack of cross-comparative studies. The included studies showed methodological quality from low to fair. Despite the range of rehabilitative interventions available, there is a lack of high-quality evidence. However, this review suggests that a multidisciplinary rehabilitation approach should be recommended to people with myasthenia gravis, and above all, for those with mild to moderate symptomatology.

Effects of long-term respiratory muscle endurance training on respiratory and functional outcomes in patients with Myasthenia gravis

BACKGROUND

Myasthenia gravis (MG) is characterized by reduced muscle endurance and often leads to respiratory complications.

OBJECTIVE

A long-term respiratory muscle endurance training (RMET) based on normocapnic hyperpnea was introduced for the first time in MG patients. We investigated RMET effects on respiratory endurance (RE), MG symptoms, lung function and physical fitness and compared the results with a control group (CG).

METHODS

The training period consisted of four weeks intensive training (IT; five 30-min training sessions per week) followed by twelve months maintenance training (MT; five 30-min training sessions over two weeks). Eighteen patients with mild to moderate MG participated as the training group (TG), six patients served as CG. RE, lung function, MG score and physical fitness were tested before and after IT and after three to twelve months of MT.

RESULTS

Only 12 TG patients completed the entire training period. Thirteen months of training significantly increased RE measured as time until exhaustion (T_lim) to 412% of baseline (P < 0.001). The MG score improved from 0.67±0.09 to 0.41 ± 0.1 (p = 0.004), and the number of squats per minute as a measure of physical fitness increased in the TG to 160% of baseline (p = 0.015). While lung function did not change during the training period, we observed a modulation in the breathing pattern at rest with prolonged expiration (122% of baseline, p = 0.028). In addition, TG reported subjective improvements in MG symptoms, respiratory symptoms and physical fitness by 49%, 58% and 64%, respectively (P < 0.001). No significant changes were observed in the CG.

CONCLUSION AND SIGNIFICANCE

This is the first controlled long-term RMET study in MG patients. The results demonstrated that this normocapnic hyperpnea training is feasible and beneficial for patients with mild to moderate MG and is a valuable supplement to conventional drug treatment.