Geographical distribution of A seropositive myasthenia gravis population

Epidemiology of myasthenia gravis in the province of Ourense (Galicia, Spain)

INTRODUCTION

Myasthenia gravis (MG) is an autoimmune disease affecting nerve transmission at the level of the neuromuscular junction, and typically causes fluctuating muscle weakness. Epidemiological studies show an increase in MG prevalence, particularly among the older population.

OBJECTIVE

We performed a retrospective epidemiological study to determine the incidence and prevalence of MG in the province of Ourense (Galicia, Spain), characterised by population ageing.

MATERIAL AND METHODS

Patients were selected from our clinical neuromuscular diseases database by searching for patients with an active prescription for pyridostigmine bromide. Incidence was estimated for the period 2009-2018. We calculated prevalence at 31/12/2018. According to census data for the province of Ourense, the population on 1/1/2019 was 307 651, of whom 96 544 (31.4%) were aged ≥ 65 years.

RESULTS

We identified 80 cases of MG, with a prevalence rate of 260 cases/1 000 000 population (95% CI, 202.7-316.4), rising to 517.9/1 000 000 population in those aged ≥ 65 (95% CI, 363.2-672.9). Cumulative incidence in the study period was 15.4 cases per 1 000 000 person-years. Early onset (≤ 50 years) was recorded in 29.1% of cases.

CONCLUSION

The prevalence of MG in our health district is one of the highest published figures, and the disease is highly prevalent in the older population.

Absence of Association between Previous Mycoplasma pneumoniae Infection and Subsequent Myasthenia Gravis: A Nationwide Population-Based Matched Cohort Study

Mycoplasma pneumoniae (M. pneumoniae) is not only one of the most common pathogenic bacteria for respiratory infection but also a trigger for many autoimmune diseases. Its infection process shared many similarities with the pathogenesis of myasthenia gravis (MG) at cellular and cytokine levels. Recent case reports demonstrated patients present with MG after M. pneumoniae infection. However, no epidemiological studies ever looked into the association between the two. Our study aimed to investigate the relationship between M. pneumoniae infection and subsequent development of MG. In this population-based retrospective cohort study, the risk of MG was analyzed in patients who were newly diagnosed with M. pneumoniae infection between 2000 and 2013. A total of 2428 M. pneumoniae patients were included and matched with the non-M. pneumoniae control cohort at a 1:4 ratio by age, sex, and index date. Cox proportional hazards regression analysis was applied to analyze the risk of MG development after adjusting for sex, age, and comorbidities, with hazard ratios and 95% confidence intervals. The incidence rates of MG in the non-M. pneumoniae and M. pneumoniae cohorts were 0.96 and 1.97 per 10,000 person-years, respectively. Another case-control study of patients with MG (n = 515) was conducted to analyze the impact of M. pneumoniae on MG occurrence as a sensitivity analysis. The analysis yielded consistent absence of a link between M. pneumoniae and MG. Although previous studies have reported that M. pneumoniae infection and MG may share associated immunologic pathways, we found no statistical significance between M. pneumoniae infection and subsequent development of MG in this study.

Anti-Muscle Specific Kinase (Anti-MuSK) Positive Myasthenia Gravis Overlapping With Parkinson's Disease: A Challenging Diagnosis

The concomitance between Parkinson's disease (PD) and myasthenia gravis (MG) is rare, with only a few case reports in the literature and only one of them with positive anti-muscle specific kinase (anti-MuSK) MG. The overlap between PD and MG symptoms can cause a diagnostic dilemma for the treating physician. In this report, we present a 73-year-old lady with a history of recurrent falls, dysphagia, and diplopia. She was found to have ptosis, vertical gaze restriction, neck extension, and flexion weakness, as well as features of parkinsonism, including masked face appearance, asymmetrical limbs rigidity, and bradykinesia. She was found to have a high titer antibody for MuSK MG. Her MG symptoms were treated successfully with rituximab.

Myasthenia Gravis in Poland: National Healthcare Database Epidemiological Study

INTRODUCTION

Myasthenia gravis (MG) is a rare autoimmune disorder of the neuromuscular junction. MG epidemiology has not been studied in Poland in a nationwide study before.

METHODS

Our epidemiological data were drawn from the National Health Fund (Narodowy Fundusz Zdrowia, NFZ) database; an MG patient was defined as a person who received at least once medical service coded in ICD-10 as MG (G70) and at least 2 reimbursed prescriptions for pyridostigmine bromide (Mestinon®) or ambenonium chloride (Mytelase®) in 2 consecutive years.

RESULTS

On 1st of January 2019, 8,702 patients with MG were receiving symptomatic treatment (female:male ratio: 1.65:1). MG incidence was 2.36/100,000. The mean age of incident cases in 2018 was 61.37 years, 59.17 years for women and 64.12 years for men. Incidence of early-onset MG (<50 years) was 0.80/100,000 and 4.98/100,000 for late-onset MG (LOMG), with male predominance in LOMG. Prevalence was 22.65/100,000. In women, there was a constant increase in prevalence of symptomatic MG from the first decade of life up to 80-89 years. In men, an increase in prevalence appeared in the 6th decade. The highest prevalence was observed in the age group of 80-89 years: 59.65/100,000 in women and 96.25/100,000 in men.

CONCLUSIONS

Our findings provide information on epidemiology of MG in Poland and can serve as a tool to evaluate healthcare resources needed for MG patients.

Epidemiology of myasthenia gravis in the province of Ourense (Galicia, Spain)

INTRODUCTION

Myasthenia gravis (MG) is an autoimmune disease affecting nerve transmission at the level of the neuromuscular junction, and typically causes fluctuating muscle weakness. Epidemiological studies show an increase in MG prevalence, particularly among the older population.

OBJECTIVE

We performed a retrospective epidemiological study to determine the incidence and prevalence of MG in the province of Ourense (Galicia, Spain), characterised by population ageing.

MATERIAL AND METHODS

Patients were selected from our clinical neuromuscular diseases database by searching for patients with an active prescription for pyridostigmine bromide. Incidence was estimated for the period 2009-2018. We calculated prevalence at 31/12/2018. According to census data for the province of Ourense, the population on 1/1/2019 was 307,651, of whom 96,544 (31.4%) were aged ≥ 65 years.

RESULTS

We identified 80 cases of MG, with a prevalence rate of 260 cases/1 000 000 population (95% CI, 202.7-316.4), rising to 517.9/1 000 000 population in those aged ≥ 65 (95% CI, 363.2-672.9). Cumulative incidence in the study period was 15.4 cases per 1 000 000 person-years. Early onset (≤ 50 years) was recorded in 29.1% of cases.

CONCLUSION

The prevalence of MG in our health district is one of the highest published figures, and the disease is highly prevalent in the older population.

Patients with Parkinson's Disease and Myasthenia Gravis-A Report of Three New Cases and Review of the Literature

Neurodegenerative diseases such as Parkinson's disease (PD)have increasing incidence, due to lifespan expansion. The association between PD and Myasthenia Gravis (MG) is uncommon, and so far, since 1987, 26 cases have been reported. We report here a series of three new cases, two men and one woman with this peculiar combination of conditions, identified in the Neurology Department of Colentina Clinical Hospital. In this article, the pathogenesis of MG in patients with PD is discussed, along with a literature review regarding the co-occurrence of these two neurological diseases.

Myasthenia gravis and pregnancy: retrospective evaluation of 27 pregnancies in a tertiary center and comparison with previous studies

BACKGROUND AND AIM

To share our experience with the management of pregnancies in women with myasthenia gravis (MG) in a tertiary center.

METHODS

The study retrospectively evaluated 27 pregnancies in 12 patients. The pregnancies were divided into 3 groups on the basis of the clinical course of MG during pregnancy: improvement (n = 7), disease-stable (n = 9), and deterioration (n = 11). The groups were compared with respect to patient characteristics, clinical features, and obstetric outcomes.

RESULTS

There were 4 miscarriages (14.8%), 3 preterm births (11.1%), and 4 cases of preterm premature rupture of the membranes (PPROM) (14.8%). Exacerbation was observed in 25.9% of the cases; the remission rate during the postpartum period and after miscarriage was 37%. The cesarean section (CS) rate was 78.3%. Pregnancies with deterioration of MG were statistically more likely to have higher miscarriage, preterm birth, PPROM, CS, and transient neonatal MG rates, in addition to a lower gestational age at birth, birth weight, and 5-min Apgar score than pregnancies with improved or stable disease (p values < 0.001, 0.04, 0.03, 0.009, 0.02, < 0.001, 0.002, and 0.043, respectively).

CONCLUSION

Physicians who manage pregnant women with MG must be familiar with the clinical features of the condition; a multidisciplinary approach is necessary for a better prognosis.

The association between scabies and myasthenia gravis: A nationwide population-based cohort study

Scabies is an infectious inflammatory pruritic skin disease. Cytokine-mediated inflammatory processes contribute to the pathologic mechanism in scabies. Myasthenia gravis (MG) is also an autoimmune disease that is mediated by cytokines. The study aimed to investigate the association between scabies and myasthenia gravis. We conducted a nationwide population-based cohort study utilized data from the National Health Insurance Research Database (NHIRD) of Taiwan. Patients with scabies (n=5429) and control subjects without scabies (n=20,176) were enrolled. We tracked the subjects in both groups for a 7-year period to identify new onset MG. Cox regression analysis was performed to calculate the hazard ratio (HR) for MG. A total of 25,605 patients were enrolled in the study, including 5429 patients in the scabies group and 20,176 in the control group. There were 40 (0.7%) patients from the scabies group and 84 (0.4%) subjects from the control group who were newly diagnosed with MG during the 7-year follow-up period. The scabies patients had a significantly increased risk of MG, with an adjusted HR of 1.27 (95% confidence interval [CI] 1.01-1.89). As such, prompt diagnosis and treatment of scabies may decrease the risk of subsequent MG.

Mechanisms of Autoantibody-Induced Pathology

Autoantibodies are frequently observed in healthy individuals. In a minority of these individuals, they lead to manifestation of autoimmune diseases, such as rheumatoid arthritis or Graves' disease. Overall, more than 2.5% of the population is affected by autoantibody-driven autoimmune disease. Pathways leading to autoantibody-induced pathology greatly differ among different diseases, and autoantibodies directed against the same antigen, depending on the targeted epitope, can have diverse effects. To foster knowledge in autoantibody-induced pathology and to encourage development of urgently needed novel therapeutic strategies, we here categorized autoantibodies according to their effects. According to our algorithm, autoantibodies can be classified into the following categories: (1) mimic receptor stimulation, (2) blocking of neural transmission, (3) induction of altered signaling, triggering uncontrolled (4) microthrombosis, (5) cell lysis, (6) neutrophil activation, and (7) induction of inflammation. These mechanisms in relation to disease, as well as principles of autoantibody generation and detection, are reviewed herein.

[The quality of life in patients with a different types of myasthenia gravis]

AIM

Researching quality of life in patients with myasthenia gravis at different clinical variants of disease.

MATERIAL AND METHODS

We studied 103 patients with myasthenia gravis. A battery of tests and scales for assessment of neurological deficit and quality of life was used.

RESULTS AND CONCLUSION

Two types of disease have been identified in myasthenia gravis: favorable and unfavorable. The minimal duration of disease before thymectomy is the main determinant of the best outcome. Favorable clinical type of myasthenia gravis was found in patients with weakness in extraocular and limb muscles. Factors associated with a poor quality of life included following: weakness in bulbar and respiratory muscles (p<0.003), endocrine comorbidities (p<0.01) or thymoma (p<0.005).

Juvenile myasthenia gravis in Norway: A nationwide epidemiological study

BACKGROUND

The aim of this study was to assess the incidence rate and prevalence of autoimmune myasthenia gravis (MG) among children in Norway.

METHODS

This retrospective population-based study was performed in Norway from January 2012 to December 2013. Cases of juvenile MG (JMG) with onset < 18 years were identified through searches in coding systems of electronic patient records at the 15 main hospitals in Norway from 1989 to 2013. In addition, the acetylcholine receptor antibody database at Haukeland University Hospital and the clinical nationwide MG database at Oslo University Hospital were searched for cases of JMG. Diagnosis and age at onset were verified through medical records. Incidence and prevalence rates were calculated using the Norwegian population as reference.

RESULTS

In total 63 unique JMG cases were identified. This corresponds to an average annual incidence rate of 1.6 per million. Incidence rate was stable over the study period. Prevalence of JMG was 3.6-13.8 per million. Females constituted the majority of JMG cases (55 vs 8 males). The risk of JMG was higher among females both in the postpubertal and prepubertal group (p < 0.001 and p = 0.02, respectively).

CONCLUSION

This study confirms the rarity of JMG in Norway, especially among males, and shows a stable incidence rate over the last 25 years.

Epidemiology of myasthenia gravis in Northern Portugal: Frequency estimates and clinical epidemiological distribution of cases

INTRODUCTION

In this study we estimated the prevalence, incidence, and mortality of myasthenia gravis (MG) in northern Portugal and characterized the clinical features of the patients identified.

METHODS

We used 2 data sources: clinical records from the hospitals and pyridostigmine prescription registers.

RESULTS

On December 31, 2013, we estimated a point prevalence of 111.7 patients per million population. The highest prevalence was observed in the group >65 years of age, especially in men (288.1 per million). During 2013, we estimated an incidence rate of 6.3 per million per year. Among women, the incidence rate was highest in the 15-49-year age group; in men, incidence increased with age up to 22.1 per million in those >65 years old. The MG-related mortality rate was 0.5 per million.

CONCLUSIONS

These figures are in keeping with similar studies and emphasize the importance of diagnosis and management of MG in elderly populations. Muscle Nerve 54: 413-421, 2016.

Myasthenia gravis epidemiology in a national cohort; combining multiple disease registries

OBJECTIVES

There is a wide variation in reported prevalence and incidence of myasthenia gravis (MG). In this study, we aimed to evaluate the validity of two nationwide databases by comparing prevalence and incidence rates reported from three recent studies using the two databases as case-finding method.

MATERIALS AND METHODS

Two different Norwegian nationwide databases were used: the acetylcholine receptor antibody database (reference cohort) and the Norwegian Prescription Database (NorPD) (study cohort). Presence of acetylcholine receptor antibodies (AChR) is specific for MG. Up to 85% of MG patients are AChR antibody-positive. All samples from the whole country were tested at one laboratory. NorPD contains patient information on all prescriptions of pyridostigmine.

RESULTS

Prevalence was 131 per million in the study cohort and 145 per million estimated from the reference cohort (Jan 1, 2008). No significant difference in prevalence between the study cohort and the reference cohort was found (SIR 1.1, 95% CI 1.0-1.2). The annual incidence rate was 16.0 per million in the study cohort and 8.8 per million estimated from the reference cohort, twofold more new MG patients were found in the study cohort compared to estimated figures from the reference cohort (SIR 1.8; 1.4-2.3).

CONCLUSIONS

This study confirms an optimal and unbiased case finding in both databases. Our calculated prevalence and incidence rates are in line with previous population-based studies. There was good agreement in prevalence reported from the two databases. The discrepancy in incidence is expected to diminish as years of study are increasing in NorPD.