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[Myasthenia and pernicious anemia or Biermer's (author's transl)].

The association of myasthenia and Biermer's anemia is very rarely reported. In a series of 138 cases of myasthenia, this association was found in only one patient, in whom the anemia developed 19 years after the discovery of a calcified thymoma and 13 years after the appearance of the first signs of myasthenia. This led the authors to conduct a prospective study for the presence of intrinsic antifactor antibodies. A total of 81 patients (20 men and 61 women) with myasthenia were studied. The myasthenia had appeared after 35 years of age in 40 patients and 19 had a thymoma. The results of the study for the antibodies was positive in 3 women, as was the test of inhibition of leucocyte migration, but none of them had anemia, vitamin B12 malabsorption, achlorhydria, or gastric atrophy. The discovery of these immunological disorders raises the problem of their significance ; two hypotheses can be discussed : pre-Biermer state or immunological disturbance without pathogenetic significance. The problem can probably only be resolved by studying these antibody levels in a very much larger number of patients with myasthenia.

Adult↗

Comparison of diagnostic tests in myasthenia gravis.

Results of 3 tests, intravenous edrophonium chloride, EMG, and acetylcholine receptor antibody testing, were compared in patients with generalised and ocular myasthenia gravis. None of the 3 tests was positive in any patient with a diagnosis other than myasthenia. However, equivocal results were obtained with edrophonium and EMG testing in some patients with myasthenia gravis and in patients with other diseases. It is concluded from this survey that antibody and edrophonium testing were equally efficient in detecting generalised myasthenia gravis. Edrophonium testing was superior in ocular myasthenia gravis. Although the yields from each test varied, all 3 tests were needed for the evaluation of some myasthenia gravis patients as each test may provide additional information.

Autoantibodies↗

[Myasthenia and pregnancy. Two case reports].

OBJECTIVE: Assess obstetrical care in rare cases of pregnant women with myasthenia. METHOD: Two personal cases led to a brief recall of the disease process and the literature and an assessment of proposed optimal care. RESULTS: Both pregnancies were carried to term without aggravation of the myasthenia. According to the data in the literature, pregnancy has a variable effect on myasthenia (1/3 stability, 1/3 improvement, 1/3 aggravation). The risk of decompensation during expulsion is great and the patient's efforts should be limited, although cesarian section is not required (excepting classical surgical indications). Peridural anaesthesia is not required (excepting classical surgical indications). Peridural anaesthesia is recommended because it reduces patient fatigue and facilitates instrumental extraction. Nursing is authorized except in case of severe episodes with a major rise in antibody levels. Pre-eclampsia was reported in only 5 cases: both maternal and fetal risk is high in such cases requiring intensive care. Fetal risks include rare neuro-muscular disease in which prognosis is poor and in 15 to 20% of the cases, neonatal myasthenia. CONCLUSION: Myasthenia is an autoimmune disease rarely occurring in young women of childbearing age. Care for pregnant women with myasthenia requires close collaboration between the different specialists.

Adult↗

[Exacerbation of pseudoparalytic myasthenia gravis following azithromycin (Zithromax)].

We report the case of a 25-year-old female patient with severe aggravation of myasthenia gravis due to azithromycin which was prescribed for an influenza syndrome. One hour after the intake of 500 mg azithromycin the patient developed weakness of the legs and respiratory distress due to respiratory muscle failure. She was hospitalized in a comatose state and required intubation and mechanical ventilation for six days. Acute worsening of myasthenia gravis was observed in this patient in 1986 after parenteral administration of erythromycin. Erythromycin causing aggravation of myasthenia gravis by interfering with neuromuscular transmission is reported in the literature. The close temporal relationship between the intake of azithromycin and severe worsening of myasthenia gravis in our patient suggests that azithromycin, a new azalid-antibiotic of the macrolid group, can exacerbate myasthenia gravis. We conclude that azithromycin should be added to the list of drugs to be used with caution in patients with myasthenia gravis.

Adult↗

Localized thymic Langerhans' cell histiocytosis and its relationship with myasthenia gravis. Immunohistochemical, ultrastructural, and cytometric studies.

OBJECTIVE: It has been suggested that localized Langerhans cell histiocytosis may represent an exaggerated form of a proliferative process that has been reported in a few patients with myasthenia gravis. To evaluate the relationship between thymic Langerhans' cell proliferation and myasthenia gravis, we analyzed a rare case of localized thymic Langerhans' cell histiocytosis and examined thymic Langerhans' cell distribution in myasthenic and control patients. DESIGN: Immunohistochemical, ultrastructural, and image cytometric DNA analyses were performed on the index case. Immunostaining for S100 was performed on 20 additional thymuses, 10 from patients with myasthenia gravis and 10 from control patients. RESULTS: Immunohistochemical studies revealed no increase in Langerhans' cells in the surrounding thymic tissue of the index case. No difference was found between the number of Langerhans' cells in the remaining thymuses of myasthenia patients compared with the control group, and no micronodular proliferations were identified in either group. CONCLUSIONS: Localized thymic Langerhans' cell histiocytosis is an unusual lesion that is associated with myasthenia gravis in some patients. In the few cases reported at present, however, the lesion does not appear to be related pathogenetically to myasthenia gravis.

Adult↗

[Clinical analysis of familial forms of myasthenia].

Having studied 29 cases of myasthenia observed in 12 families, as well as 578 relatives of 59 patients with myasthenia, the authors have identified clinical characteristics of familial forms of myasthenia and the frequency of familial myasthenia among patient's relatives. It has been shown that familial forms of myasthenia are characterized by the appearance of a number of symptoms that are not typical of the common sporadic forms of myasthenia, which indicates the involvement, in addition to synaptic structures, of distal portions of peripheral nerves and/or muscle fibers. In families of myasthenic patients there is an extremely high rate of collagenoses, allergic diseases, diabetes, thyroid disease and malignant tumors.

Adolescent↗

[Various diagnostic and therapeutic aspects of myasthenia in children and adolescents].

Data of examining 32 patients with myasthenia treated at the Institute of Children's Neurology and Psychiatry in Belgrade are presented. Among these patients there were no children with the neonatal transitory form of myasthenia. In two children being treated, the disease symptoms appeared since the birth or soon after it and had been then persisting for a long time (the neonatal persistent form of myasthenia). In 30 children, the disease began before or soon after the age of 10 year. The juvenile form of myasthenia gravis could be divided into the early and the late ones, with regard to the patients' age and the disease clinical course. Modern diagnostic tests and their significance in diagnosing myasthenia gravis and myasthenic syndromes in children and adolescents are considered, and present-day aspects of treating myasthenia gravis in the patients mentioned are discussed.

Adolescent↗

The natural history and ophthalmic involvement in childhood myasthenia gravis at the hospital for sick children.

OBJECTIVE: To characterize signs, symptoms, and the natural history of myasthenic syndromes in pediatric patients. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: Thirty-four patients with a diagnosis of myasthenia were identified from either the hospital's or treating physician's database. METHODS: Retrospective chart review, clinical examination, and telephone interview. MAIN OUTCOME MEASURES: Information pertaining to the ophthalmologic and neurologic examination, diagnostic interventions, and treatment was noted. Patients with active disease, attending during the study period, were examined at their outpatient visits. Those who no longer attended the hospital were contacted by means of a telephone interview to complete their follow-up. RESULTS: Thirty-four children were found to have myasthenia. Two had transient neonatal myasthenia, which resolved quickly. Seven (20.6%) patients had congenital myasthenic syndromes (CMS) and 25 (73.5%, 19 females) were affected with autoimmune myasthenia gravis (AMG). In those patients with severe CMS, three showed signs of generalized weakness, including failure to thrive, frequent apneas, and aspirations. In four patients with mild CMS, eye signs were relatively more prominent. In all patients with CMS, strabismus, ophthalmoplegia, and ptosis were the main ophthalmologic signs and remained relatively constant. Fourteen (56%) patients with AMG had ocular signs and symptoms, and five of them progressed to systemic involvement in 7.8 months on average (range, 1-23). The remaining nine patients with ocular AMG had either strabismus or ptosis and were treated with pyridostigmine (nine patients) and prednisone (two patients). Patients with ocular AMG were seen at 78 months on average, those with systemic AMG at 85.6 months. Systemic AMG was seen in 16 patients. No thymomas were found in 14 patients who underwent thymectomy. Of the 25 patients with AMG, 8 are still being treated, 8 are in remission for an average of 65.2 months and are asymptomatic, 4 patients are receiving long-term immunosuppressants (1 has likely sustained permanent damage to her extraocular muscles with complete ophthalmoplegia and ptosis), and 4 have been lost to follow-up. Finally, one patient died after aspiration because of bulbar weakness. CONCLUSIONS: Patients with CMS varied in the degree of severity. Apneic attacks, aspiration, and failure to thrive may obscure the diagnosis. Compared with AMG, their ophthalmologic signs and symptoms were usually permanent. Visual signs and symptoms were usually prominent in those patients with active AMG, but those in remission were asymptomatic. More than half of the patients with juvenile AMG had ocular symptoms. Generalization occurred in a minority in an average of 7.8 months. Patients entered remission after approximately 2 years of treatment and were visually asymptomatic. This study suggests that long-term permanent damage to the extraocular muscles as a result of juvenile AMG is rare. Myasthenia gravis is a life-threatening disease as evidenced by the death of one of our patients. Many of these patients are first seen by the ophthalmologist who can aid the diagnosis, screen for amblyopia, and monitor the patient's response to therapy.

Adolescent↗

Anti-MuSK myasthenia gravis presenting with purely ocular findings.

BACKGROUND: Antibodies to a muscle-specific receptor tyrosine kinase (MuSK) have been found in approximately 40% of patients with generalized myasthenia gravis who are seronegative for the antiacetylcholine receptor antibody. Many of the patients with anti-MuSK antibodies have prominent oculobulbar symptoms or weakness of the neck and respiratory muscles, but patients with ocular myasthenia have not been described. OBJECTIVE: To report a case of ocular myasthenia due to anti-MuSK antibodies. PATIENT: A young woman with ocular myasthenia and antibodies to MuSK. RESULTS: Anti-MuSK antibody was detected by radioimmunoassay using highly purified MuSK recombinant antigen. CONCLUSION: Ocular myasthenia gravis is a presentation of the anti-MuSK antibody syndrome.

Adolescent↗

Corticosteroids for myasthenia gravis.

BACKGROUND: Although widely accepted as an appropriate immunosuppressive therapy, the efficacy of glucocorticosteroid treatment has only rarely been tested in controlled studies. OBJECTIVES: To assess the efficacy of glucocorticosteroids or adrenocorticotrophic hormone (ACTH) medication in autoimmune myasthenia gravis. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group Trials Register in July 2004, MEDLINE (from January 1966 to June 2004) and EMBASE (from January 1980 to June 2004). We also checked the bibliographies in reviews and the randomised trials and contacted their authors to identify additional published and unpublished data. SELECTION CRITERIA: From the articles identified we selected those open or controlled studies which allowed us to assess the outcome of treated and untreated patients at definite endpoints. Types of studies: quasi-randomised or randomised controlled trials. TYPES OF PARTICIPANTS: patients with myasthenia gravis of all ages and all degrees of severity. Types of interventions: any form of glucocorticosteroids or adrenocorticotrophic hormone treatment. Types of outcome measures:Primary outcome(1) improvement after at least three months in either the weakest muscles or all muscles. Secondary outcomes(1) proportion of patients improved after at least six months(2) proportion of patients in remission(3) number of episodes of worsening during the first six months(4) acetylcholine receptor antibody titres after at least three months of therapy. DATA COLLECTION AND ANALYSIS: Three authors extracted the data from the selected articles and one other checked them. MAIN RESULTS: A trial of adrenocorticotrophic hormone (43 patients) did not show any advantage compared with placebo for the treatment of ocular myasthenia gravis. Two double-blind trials compared prednisone with placebo for generalised myasthenia gravis. In the first (13 patients), the improvement was slightly greater in the prednisone group at six months. In the second (20 patients) which was a short-term trial, the improvement was significantly greater at two weeks. Two trials compared glucocorticosteroids with azathioprine (41 and 10 patients respectively). In one of these the rate of treatment failure was greater in the prednisone group. In a trial of glucocorticosteroids versus intravenous immunoglobulin (33 patients) no differences in treatment responses were encountered during a treatment period of 14 days. An open trial (39 patients) evaluating different corticosteroid doses revealed a shorter time to improvement in the high-dose group. However only limited evidence can be drawn from the available randomised controlled trials due to numerous and important methodological flaws. AUTHORS' CONCLUSIONS: Limited evidence from randomised controlled trials suggests that corticosteroid treatment offers significant short-term benefit in myasthenia gravis compared with placebo. This supports the conclusions of observational studies and expert opinion. Limited evidence from randomised controlled trials does not show any difference in efficacy between corticosteroids and either azathioprine or intravenous immunoglobulin.

Adrenal Cortex Hormones↗

Heterogeneity in myasthenia gravis: HLA phenotypes and autoantibody responses in ocular and generalized types.

HLA phenotypes and autoantibody responses were studied in 71 Japanese patients with myasthenia gravis. HLA-A2, Bw61, and DRw9 were associated with ocular myasthenia gravis (corrected p [CP] less than 0.05 relative risk [RR] = 2.88; CP less than 0.02, RR = 3.60; and CP less than 0.001, RR = 4.63, respectively) and HLA-DRw8 was associated with generalized myasthenia gravis (CP less than 0.001, RR = 5.40). Neither HLA-B8 nor DR3 was found in Japanese patients. The titer of antiacetylcholine receptor antibody (AChR Ab) and the incidence of autoantibodies other than AChR Ab were higher in patients with generalized myasthenia gravis than in those with the ocular type (2.77 +/- 0.62 versus 0.17 +/- 0.03 pmol/ml, p less than 0.001; and 60.6 versus 29.0%, p less than 0.02, respectively). Patients with a high titer of AChR Ab or with autoantibodies had an increased frequency of HLA-DRw8 (CP less than 0.02, RR = 4.61, and CP less than 0.005, RR = 4.53, respectively); whereas patients with a low titer of AChR Ab or without autoantibodies had an increased frequency of HLA-DRw9 (CP less than 0.001, RR = 8.26, and CP less than 0.005, RR = 4.08, respectively). These findings suggest that ocular and generalized myasthenia gravis might have different immunogenetic backgrounds.

Adolescent↗

HLA class II antigens and DNA restriction fragment length polymorphism in myasthenia gravis in Japan.

Human leukocyte phenotypes and genes in the HLA class II regions were studied in 46 Japanese patients with myasthenia gravis. When the HLA phenotypes of the patients with myasthenia gravis were compared with the controls, an increased frequency of HLA-DRw53 was observed in females less than 30 years of age. The genomic DNAs of the HLA-DRw53-positive patients and DRw53-positive controls were analyzed by using four complementary DNA probes for HLA class II genes. With DQB complementary DNA as the probe, a higher incidence of the 6.5-kb or 8.2-kb BamHI fragment was observed in the patients (76.0%) compared with the controls (19.0%). In contrast, no significant difference was observed between patients and controls when complementary DNAs for DRB, DQA, and DPB were used as probes. These results indicate that the genetic background of Japanese females with early-onset myasthenia gravis is different from other patients with myasthenia gravis, and that DQB genes can greatly influence the onset of myasthenia gravis.

Adolescent↗

The human-severe combined immunodeficiency myasthenic mouse model: a new approach for the study of myasthenia gravis.

We have established a new chimeric human-mouse model of myasthenia gravis in severe combined immunodeficiency mice, using human peripheral blood lymphocytes that survive in the mouse and produce specific antibodies that mediate pathological changes typical of human myasthenia gravis. Mice given peripheral blood lymphocytes from both anti-acetylcholine receptor (AChR) antibody-positive and -negative patients with myasthenia gravis showed circulating anti-acetylcholine receptor antibodies, deposition of human IgG at muscle end-plates, and simplification of the postsynaptic membrane, findings characteristic of human myasthenia gravis. Mice given human peripheral blood lymphocytes from healthy donors and simultaneously immunized with Torpedo acetylcholine receptor showed the same changes. This chimeric model, utilizing human cells to reproduce the immunopathological findings of human myasthenia gravis in a nonhuman environment, offers new opportunities to study immune regulation in autoimmunity.

Adult↗

["Seronegative" myasthenia with antibodies against muscle-specific tyrosine-kinase].

About 10-20% of patients with generalized myasthenia gravis do not have acetylcholin receptor (AChR) antibodies and are referred to as having "seronegative" myasthenia. Recently, antibodies to muscle-specific kinase (MuSK), which mediates aggregation of AChR, were detected in half of these patients. We investigated six patients with seronegative myasthenia and identified two characteristic cases with MuSK antibodies. A 56-year-old woman developed ptosis and double vision followed by bulbar symptoms and respiratory insufficiency. She showed moderate response to treatment with pyridostigmine and no response to prednisolone, azathioprine, or intravenous immunoglobulin but good response to several plasma exchanges. A 46-year-old man with exercise-induced weakness of the upper limbs and mild bulbar and respiratory symptoms had a milder course for 9 years. These cases highlight the clinical spectrum of MuSK-positive myasthenia and the differences to AChR-positive myasthenia with predominant bulbar symptoms and often severe symptoms with respiratory insufficiency. Finally, they illustrate the therapeutic difficulties with less response to pyridostigmine and immunosuppressive drugs.

Antibodies↗

[Indications and value of thymectomy in myasthenia gravis].

The therapeutic impact of thymectomy on the clinical course of myasthenia gravis is still a matter of debate. Issues in this discussion that are clinically relevant are reviewed. While the surgical procedure is accepted for thymomas its performance is controversial in cases with no thymomatous tissue. Outcome studies show a weak correlation between clinical course and thymus histology, but there is some doubt about the maximum age for thymectomy and about the therapeutic regimen following surgery. Retrospective studies show that thymectomy has a beneficial influence on the natural course of myasthenia. This positive effect is enhanced by appropriate immunosuppressive therapy together with anticholinesterase inhibitor substitution. Unfortunately, the different forms of myasthenia do not all respond in the same manner. Studies have shown that thymoma-associated myasthenia is more difficult to control than non-thymoma-associated myasthenic states. In both groups some patients go into remission after thymectomy alone, and the majority of patients with the institution of additional immunosuppression. In clinically mild cases thymectomy should not immediately be followed by immunosuppression. This will help to identify those patients responding with remission to thymectomy alone. Mostly these are young women with a hyperplastic thymus. Overall, thymectomy is beneficial and should be considered in all patients with generalized myasthenia who are still under 60 years of age.

Combined Modality Therapy↗

[Follow-up of myasthenia gravis. Results of a longitudinal study of the significance of psychosocial predictors].

Forty-two patients suffering from myasthenia gravis were examined in a longitudinal study design. The aim of the study was to investigate possible psychosocial predictors for the course of the disease. At the time of the first examination (T1) the diagnosis myasthenia gravis had been established for no longer than 1 year. Two further examinations were done at 6 months (T2) and 18 months (T3) after T1. Methods consisted of a personality questionnaire (FPI), a coping questionnaire (FKV), an assessment of neurotic symptoms by interviewers (PSKB) and an assessment of the doctor-patient relationship by the attending physicians. Two different severity scores (Oosterhuis Index, Myasthenia Score) served as criteria for the course of the disease. There was no connection between the course of myasthenia gravis and neurotic symptoms like anxiety or depression and the quality of the doctor-patient relationship (both assessed at T1). Also demographic data were independent from the development of severity scores. The personality factor extraversion was associated with a positive course of the disease, aggressiveness and worrying about health with a negative one. Among the coping behaviors religiousness and looking for sense were associated with a favorable course but that was shown only regarding the Oosterhuis Index and not the Myasthenia Score. As several T1 personality factors were predictive for the severity scores at T3, these results may suggest a causal influence of personality factors on the severity of the illness. Whether or not this relationship is actually in operation, however, remains ellusive. Further studies using an experimental design are needed to strengthen this hypothesis.

Adaptation, Psychological↗

The heart in myasthenia gravis.

The cardiac changes associated with myasthenia gravis have been reviewed and specific areas explored. There is no doubt concerning the involvement of the myocardium in this disease as indicated by clinical, ECG, vectorcardiographic, and autopsy data. The doubt lies in the precipitating factor for the pathology found. On the one hand the whole picture could be a direct result of the pathologic process of myasthenia gravis. On the other hand the patient with myasthenia gravis, during the natural history of the disease, encounters many iatrogenic and coincidental variables which could influence the nature of the clinical findings and autopsy data. One fact seems reasonably clear: The association of myocardial pathology with thymoma, especially malignant thymoma, is well established for the more severe form of the myocardial disease. Furthermore, the hypothesis that cardiac muscle antibodies give rise to such reactions is attractive, although not fully resolved. If such cases are excluded then there remain others where cardiac pathology could be due to other disease, primarily coronary heart disease, in the older group. In addition, the mode of death of some patients indicates that intercurrent respiratory problems could play a part. Most patients in this group do not seem to have cardiac abnormalities due to the pathologic process of myasthenia. There is in addition a small group where very striking cardiovascular findings suggestive of myocarditis are found. There is not necessarily a thymoma and no other specific etiologic factors can be found. These are rare cases and might still be related to disorders of immune mechanisms. In conclusion it can be stated that, although there is now a considerable body of evidence concerning the heart in myasthenia gravis, the implication of specific pathology for this neuromuscular disorder affecting the heart must be considered, in the traditional Scottish legal sense, as "not proven."

Arrhythmias, Cardiac↗

Penicillamine-associated myasthenia gravis, antiacetylcholine receptor and antistriational antibodies.

Myasthenia gravis with thymic hyperplasia developed in a patient with Wilson's disease after eight years of penicillamine treatment. Four months prior to the onset of myasthenia, penicillin hypersensitivity was observed. Immunofluorescence on the excised thymus revealed immunoglobulin and complement deposition, but the myasthenia persisted after thymectomy and continuation of penicillamine therapy. Increased antiacetylcholine receptor antibody was demonstrable throughout. This patient subsequently became pregnant, enabling studies to be performed on the transplacental transfer of the immunoglobulin G (IgG) class antiacetylcholine receptor antibody. Eleven cases of rheumatoid arthritis with penicillamine-associated antistriational antibodies have also been observed; in three of these cases there was evidence of myasthenia gravis. These observations extend earlier reports of the association of penicillamine with myasthenia gravis and suggest that antistriational antibody, antiacetylcholine receptor antibody and thymic hyperplasia may be independent effects of penicillamine therapy.

Acetylcholine↗