Myasthenia gravis in Ceará, Brazil: clinical and epidemiological aspects

Isolated dysarthria as the sole manifestation of myasthenia gravis: a case report

Myasthenia gravis (MG) is an acquired autoimmune disease. Its clinical manifestations comprise ptosis, diplopia, dysarthria, dysphagia, limb weakness, and in severe cases, respiratory muscle involvement. Dysarthria as an exclusive initial and primary complaint in MG is rare and seldom reported. In this paper, we report a case of type IIIb MG with isolated dysarthria as the only clinical manifestation and we review the relevant literature. The patient was a 62-year-old man who presented with episodes of slurred speech for 20 days that had worsened in the previous 9 days. His medical history comprised hypertension, diabetes mellitus, and coronary heart disease. The initial diagnosis on admission was transient ischemic attack. Careful re-examination of the patient’s history revealed that his symptoms mainly involved increasingly worse slurred speech episodes without drinking or swallowing difficulties, and no significant improvement with rest was observed. Electromyography and autoantibody profiling led to a diagnosis of type IIIb MG. His symptoms improved after the oral administration of pyridostigmine bromide 60 mg. Laryngeal MG is important to differentiate from stroke. It is necessary to perform a computerized voice analysis when encountering patients with atypical symptoms of MG.

Myasthenia gravis during pregnancy: what care should be taken?

Myasthenia gravis (MG) is an autoimmune disease in which the peak incidence is among women of childbearing age. For this reason, there is an overlap between the occurrence of this disease and pregnancy. It is known that MG symptoms can worsen during pregnancy and postpartum, and that pregnancy has special characteristics in MG patients. Children born to myasthenic mothers are at risk of having transient neonatal myasthenia. We briefly review the main relationships between MG and pregnancy, and we make recommendations for MG therapy, pregnancy, delivery, breastfeeding and newborns.

Myasthenia Gravis with Elderly Onset at Advanced Age

Myasthenia gravis (MG) in older adults has not been extensively studied. The prevalence of this disease in older people seems to be higher in recent epidemiological studies. In patients with disease onset after the age of 70, the diagnosis is more difficult as other conditions are more easily taken to be the causal element. The mortality is higher than in young patients, so prompt specific treatment can improve prognosis. We present an 85-year-old female patient with speech disturbance and difficulty in swallowing solids, and neurological examination with palpebral ptosis, disphonia, convergent strabismus and weakness and mild progressive fatigue in arms, with electroneuromyography and acetylcholine receptor antibody who was diagnosed with MG, emphasizing the importance of this entity in geriatric patients.

Molecular and clinical relationship between live-attenuated Japanese encephalitis vaccination and childhood onset myasthenia gravis

Objective

The incidence of childhood onset myasthenia gravis (CMG) in China is higher than that in other countries; however, the reasons for this are unclear.

Methods

We investigated the clinical and immunological profiles of CMG, and assessed the potential precipitating factors. For the mouse studies, the possible implication of vaccination in the pathogenesis was explored.

Results

In our retrospective study, 51.22% of the 4,219 cases of myasthenia gravis (MG) were of the childhood onset type. The cohort study uncovered that the pathophysiology of CMG was mediated by immune deviation, rather than through gene mutations or virus infections. The administration of the live‐attenuated Japanese encephalitis vaccine (LA‐JEV), but not the inactivated vaccine or other vaccines, in mice induced serum acetylcholine receptor (AChR) antibody production, reduced the AChR density at the endplates, and decreased both muscle strength and response to repetitive nerve stimulation. We found a peptide (containing 7 amino acids) of LA‐JEV similar to the AChR‐α subunit, and immunization with a synthesized protein containing this peptide reproduced the MG‐like phenotype in mice.

Interpretation

Our results describe the immunological profile of CMG. Immunization with LA‐JEV induced an autoimmune reaction against the AChR through molecular mimicry. These findings might explain the higher occurrence rate of CMG in China, where children are routinely vaccinated with LA‐JEV, compared with that in countries, where this vaccination is not as common. Efforts should be made to optimize immunization strategies and reduce the risk for developing autoimmune disorders among children. Ann Neurol 2018;84:386–400

Clinical characteristics of autoimmune disorders in the central nervous system associated with myasthenia gravis

Myasthenia gravis (MG) is occasionally associated with autoimmune diseases in the central nervous system (CNS), such as neuromyelitis optica spectrum disorder (NMOSD), multiple sclerosis (MS), Morvan syndrome, and anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. Here, we report five original cases associated with autoimmune disorders in the CNS among 42 patients with MG in a single tertiary hospital in Japan (11.9%). In four of these five cases, the second disease developed when the preceding disease was unstable. Accurate diagnosis of the newly developing disease may be difficult in such cases, because some neurological symptoms can be seen in both disorders. This implies the great importance of recognizing the possible co-occurrence of MG and disorders in the CNS. In addition, a comprehensive review of the literature revealed distinct clinical characteristics depending on the associated disease in the CNS, including thymic pathology and temporal relationship between MG and associated CNS disorders. Notably, NMOSD usually develops after the onset of MG and thymectomy, in clear contrast to MS. Thymoma is highly prevalent among patients with Morvan syndrome, in contract to cases with NMOSD and MS. The analysis of clinical characteristics, representing the first such investigation to the best of our knowledge, suggests different pathogeneses of these autoimmune diseases in the CNS, and provides significant implications for clinical practice.

Clinical follow-up of pregnancy in myasthenia gravis patients

This study aimed to analyze the outcome and impact of pregnancy in women with myasthenia gravis (MG). Obstetric and clinical data were retrospectively analyzed before, during and after pregnancy. Predictors of outcome were studied. We included 35 pregnancies from 21 MG patients. In the course of MG symptoms in 30 pregnancies with live births, 50% deteriorated (mainly during the second trimester, p = 0.028), 30% improved, and 20% remained unchanged. The deterioration group had more frequent abnormal repetitive nerve stimulation (RNS) (p = 0.028) and lower myasthenia gravis composite (MGC) scores (p = 0.045) before pregnancy. The improvement group was associated with higher MGC scores (p = 0.012) before pregnancy. The no-change group was associated with longer duration of MG (p = 0.026) and normal RNS (p = 0.008) before pregnancy. The course of MG in the second pregnancy was different from that in the previous pregnancy in 65.3% of cases. Obstetric complications were reported in 20 pregnancies; the most common was preterm premature rupture of membranes (PPROM) (25.8%), and the most severe were abortion (11.4%) and fetal death (2.9%). Most of the patients delivered via caesarean section (66.7%). Spinal anesthesia was performed in 73.3%. Transient neonatal myasthenia gravis occurred in 12.9% of live-born infants, and no predictors were found. In conclusion, severity and duration of MG, RNS and treatment influence MG and pregnancy. Pregnant MG patients have greater rates of PPROM and caesarean delivery. Our data suggest that duration of MG, MGC and RNS before pregnancy may be useful in helping to predict the course of MG during pregnancy.

"Warming yang and invigorating qi" acupuncture alters acetylcholine receptor expression in the neuromuscular junction of rats with experimental autoimmune myasthenia gravis

Myasthenia gravis is an autoimmune disorder in which antibodies have been shown to form against the nicotinic acetylcholine nicotinic postsynaptic receptors located at the neuromuscular junction. “Warming yang and invigorating qi” acupuncture treatment has been shown to reduce serum inflammatory cytokine expression and increase transforming growth factor beta expression in rats with experimental autoimmune myasthenia gravis. However, few studies have addressed the effects of this type of acupuncture on the acetylcholine receptors at the neuromuscular junction. Here, we used confocal laser scanning microscopy to examine the area and density of immunoreactivity for an antibody to the nicotinic acetylcholine receptor at the neuromuscular junction in the phrenic nerve of rats with experimental autoimmune myasthenia gravis following “warming yang and invigorating qi” acupuncture therapy. Needles were inserted at acupressure points Shousanli (LI10), Zusanli (ST36), Pishu (BL20), and Shenshu (BL23) once daily for 7 consecutive days. The treatment was repeated after 1 day of rest. We found that area and the integrated optical density of the immunoreactivity for the acetylcholine receptor at the neuromuscular junction of the phrenic nerve was significantly increased following acupuncture treatment. This outcome of the acupuncture therapy was similar to that of the cholinesterase inhibitor pyridostigmine bromide. These findings suggest that “warming yang and invigorating qi” acupuncture treatment increases acetylcholine receptor expression at the neuromuscular junction in a rat model of autoimmune myasthenia gravis.

Clinical profile of patients with myasthenia gravis followed at the University Hospital, Federal University of Minas Gerais

OBJECTIVE

to determine the clinical profile of patients with myasthenia gravis (MG); followed at the Neuromuscular Diseases Clinic of the University Hospital, Federal University of Minas Gerais, Brazil, and to compare it with other Brazilian case series.

METHODS

sociodemographic and clinical data were collected from patients, and a systematic literature review performed, focusing on national studies on the clinical profile of MG patients.

RESULTS

sixty nine patients were enrolled in the study. Fifty five (91%) subjects were female and the mean age (SD) was 37.6 (± 11.4) years. The mean disease duration was 14.1 years. Regarding treatment, prednisone was the most used strategy (64%), followed by the use of azathioprine (43%). There was no difference between thymectomized (42) and non-thymectomized (27) patients regarding disease severity and medication use.

CONCLUSION

clinical and socio-demographic features of this MG sample from a University-based clinic resemble those reported in other Brazilian series and in the international literature.

Disfonia como principal queixa num quadro de miastenia grave: diagnóstico e fonoterapia

Miastenia grave é uma doença autoimune que se manifesta por fraqueza e fadiga muscular progressivas. São frequentes os sintomas oculares e bulbares, dentre eles, a disfonia. Este artigo relata um caso de disfonia, cuja avaliação fonoaudiológica contribuiu com o diagnóstico de miastenia grave e seu tratamento. A paciente em questão procurou o atendimento fonoaudiológico com diagnóstico otorrinolaringológico de presbifonia. A avaliação perceptivo-auditiva e acústica da voz identificou alterações em respiração, fonte glótica e filtro/ressonância. Como alguns dados obtidos com a anamnese e observados nas provas vocais não se relacionavam diretamente com a presença de presbifonia, houve a necessidade de discussão do caso com o médico, quando ambos concluíram a necessidade de encaminhar a paciente para avaliação neurológica. O neurologista consultado levantou a hipótese diagnóstica de miastenia grave e solicitou exames. A paciente seguiu em acompanhamento fonoaudiológico e medicamentoso. Na reavaliação vocal, ocorrida cerca de dois meses após o início do tratamento, foi constatada melhora na qualidade vocal, com grande impacto na qualidade de vida. Este trabalho evidencia a importância da avaliação fonoaudiológica detalhada e da participação do fonoaudiólogo na equipe interdisciplinar.