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PubMed1995

Identification of an idiotype associated with antibodies responsible for neuromuscular dysfunction in rats with experimental autoimmune myasthenia gravis.

The primary goal of this study was to continue clarifying past observations made by this laboratory indicating that disease severity in experimentally induced myasthenia gravis in Lewis rats is directly determined by the responsiveness and antibody production of a small subset of the total population of acetylcholine receptor (AChR)-responsive B cells. This disease-causing subset of B cells was found to be associated, at least in part, with an idiotypic determinant recognized by a monoclonal anti-Id antibody (11E10) prepared in this laboratory. Since relationships between total AChR antibody titers and neuromuscular disease severity can be inconsistent both in human myasthenia gravis patients and in animal models of myasthenia gravis, the development of a simple serological test for the clonotypic/idiotypic subset(s) of anti-AChR antibody that is most directly responsible for inducing disease symptoms may point to more direct methods of diagnosing and monitoring disease.

Animals↗

PubMed1995

The effect of thymectomy on myasthenia gravis, thrombocytopenia, and granulocytopenia associated with thymoma: report of a case.

We report the case of a 47-year-old woman with thymoma who developed myasthenia gravis, thrombocytopenia, and granulocytopenia, simultaneously, the concurrent association of these four disorders being extremely rare. Thymectomy was performed, and, during the post-thymectomy course, there were surprising findings concerning the recovery of not only the myasthenia gravis but also of the hematologic disorders. Immediately after thymectomy, the myasthenic symptoms completely disappeared, and the granulocyte and platelet counts recovered to within the normal range within a few days. The laboratory data revealed no difference between pre- and post-thymectomy in the release of cytokines (tumor necrosis factor; TNF, interleukin; IL-2, and IL-6), anti-acetylcholine receptor antibody, or platelet-associated IgG. On the other hand, the serum level of anti-neutrophil cytoplasmic antibody (p-ANCA), against the myeloperoxidase of the granulocytes was dramatically decreased, after thymectomy, showing a significant correlation with the granulocyte count. According to our survey of the literature, this is the first report to show that the removal of a thymoma led to the dramatic resolution not only of myasthenia gravis but also of other associated diseases. It is possible that p-ANCA may be regulated by thymoma, thus causing severe granulocytopenia.

Agranulocytosis↗

PubMed1977

The regional curare test in myasthenia gravis.

30 subjects without disturbance of neuromuscular transmission and 18 patients with myasthenia gravis were used in conducting the regional curare test. The adductor pollicis and the hypothenar muscles were studied with the 3/sec stimulation test. With three different dosages of curare one could find no reliable border between "normal" and "pathological". In the patients with myasthenia no definite relation could be found between the findings with the regional curare test and the clinical picture. The curare concentration reaching the muscle is probably quite variable from case to case as regards diffusion and volume in the tissue. The 3/sec stimulation test with registration from the deltoid muscle, and in certain cases the systemic curare test, appear more suitable than the regional curare test for routine diagnosis as well as indication for thymectomy. But for cases of ocular myasthenia showing no further weakness by the systemic curare test, the regional curare test can be put to use. The advantage lies in the higher concentration of curare which can thereby be brought to the muscle. The precautionary measures should be similar to those taken with the systemic curare test.

Adolescent↗

PubMed1992

Myasthenia gravis with thymoma associated with occult thyroid carcinoma.

We report herein a case of myasthenia gravis associated with thymoma and occult thyroid carcinoma with metastasis to a cervical lymph node, which was treated in two stages by a total thymectomy and radical dissection of the bilateral neck after a total thyroidectomy. A 48 year old woman was admitted with right blepharoptosis and hypodynamia of the proximal muscles. After various examinations, a diagnosis of myasthenia gravis was made. The association of thymoma was clarified upon CT scanning and a total thymectomy performed. However, after surgery, swelling of the cervical lymph nodes became apparent and a biopsy revealed metastasis of thyroid carcinoma in the lymph nodes. A diagnosis of occult thyroid carcinoma with metastasis to a cervical lymph node was subsequently made and a total thyroidectomy and radical dissection of the bilateral neck performed 37 days after the total thymectomy. The patient's postoperative course was uneventful and for the time being, no recurrence is expected. It is considered better to perform two-stage operations for easier and safer postoperative management when myasthenia gravis associated with occult thyroid carcinoma is treated, although it depends on the development of thyroid carcinoma being occult.

Female↗

PubMed1996

Galectin-1 is expressed by thymic epithelial cells in myasthenia gravis.

Galectin-1, a member of a family of carbohydrate binding proteins, is synthesized by thymic epithelial cells in normal juvenile thymus, and mediates adhesion of immature T cells to thymic epithelium. Because cell adhesion molecules are proposed to play a role in the thymic hyperplasia and neoplasia seen in the autoimmune disease myasthenia gravis, we examined the expression of galectin-1 in myasthenic thymi. We detected abundant galectin-1 expression in thymic epithelial cells in 27 hyperplastic and neoplastic thymi from patients with myasthenia gravis. Primary cultures of neoplastic epithelial cells from a thymoma continued to express galectin-1, and bound immature T cells; T cell binding was inhibited by the addition of the beta-galactosides lactose and thiodigalactoside, suggesting that galectin-1 on the thymoma cells and a saccharide ligand on the T cells participated in cell-cell adhesion. Expression of galectin-1 by thymic epithelial cells may play a role in the thymic pathology seen in myasthenia gravis.

Cell Adhesion↗

PubMed1978

Radiologic evaluation of the thymus in juvenile myasthenia gravis.

Clinical records and chest radiographs of nineteen patients with juvenile myasthenia gravis treated by thymectomy were reviewed retrospectively. Correlation of radiographic findings, clinical data, and pathologic observations were sought to determine the value of radiography in the pre-operative assessment of juvenile myasthenia gravis patients. Although the vast majority of patients had normal plain films and tomographic chest radiographs the thymuses in seventeen of the nineteen patients were pathologically abnormal. The pathologic abnormalities consisted of hyperplasia and/or the presence of germinal centers within the glands. Despite these histologic abnormalities, the weights of the surgically removed thymuses were generally in the range of normal for patients of this age. None of the nineteen patients had a thymoma. In our series, there was no apparent benefit from radiographic examination of the thymus gland in consideration of thymectomy for patients with juvenile myasthenia gravis.

Adolescent↗

PubMed1984

[Heterogeneity of acetylcholine receptor antibodies in patients with myasthenia gravis].

Antibodies against the nicotinic acetylcholine receptor in sera of 21 myasthenia gravis patients were checked for their ability to block or split binding of alpha-bungarotoxin to the human acetylcholine receptor. Affinity-purified acetylcholine receptors from human skeletal muscle were used in parallel in the common precipitation assay and an inhibition assay. Cross-reactivity of acetylcholine receptor antibodies was analyzed with receptor preparation from different species (calf, rat, Torpedo c. and Electrophorus e.), purified identically to high specific activity. An antibody pattern was set up for each patient and related to the clinical state of the disease. alpha-Bungarotoxin-inhibiting antibodies were demonstrable in 74% of myasthenia gravis patients, alpha-bgt displacing antibodies were found in 39% of the investigated sera. Broad cross-reactivity with acetylcholine receptors from other mammalian muscle was evident (calf 75%, rat 90%) only very few sera reacted with acetylcholine receptors from electric fish (Torpedo c. 14%, Electrophorus e. 38%). Antibody concentrations determined by using xenoantigens were much lower than those obtained by human acetylcholine receptor. The lack of a clear-cut correlation between the amount of serum antibodies and the clinical state of myasthenia gravis can be explained by the established antibody-heterogeneity, shown by a constant antibody pattern characteristic for each patient. However, between this specific antibody pattern and the state of the disease no correlation could be established either.

Adolescent↗

PubMed1991

Sarcoidosis in a patient with myasthenia gravis. Case report and review of the literature.

The case of a 38-year-old white female, with a long history of myasthenia gravis, who developed sarcoidosis is presented. The diagnosis of myasthenia gravis had been established on the basis of typical clinical symptoms with severe myastenic crises necessitating respiratory support, characteristic electromyographic findings, positive anti-acetylcholine receptor antibodies and response to appropriate medications. After 9 years of disease and while in apparent remission, she presented with ankle arthritis and bilateral hilar adenopathy. A transbronchial lung biopsy showed noncaseating granuloma, typical of sarcoidosis. To our knowledge, the combination of myasthenia gravis and sarcoidosis is extremely rare and emphasizes the intriguing tendency of some immunologic disorders to appear together in certain individuals.

Adult↗

PubMed1992

Anaesthesia and myasthenia gravis.

Myasthenia gravis is an autoimmune disease, resulting from the production of antibodies against the acetylcholine receptors of the endplate. These antibodies reduce the number of active receptors, brought about either by functional block of the receptors, by increased rate of receptor degradation, or by complement-mediated lysis. In myasthenic muscles, the miniature endplate potential amplitude is decreased, and a large proportion of the endplate potentials are subthreshold. Repetitive nerve stimulation results in a decremental response. The disease is frequently associated with morphological abnormalities of the thymus. In young patients, thymic hyperplasia is common while thymoma is more frequent in elderly patients. Medical treatment of myasthenia gravis aims at improving of neuromuscular transmission by anticholinesterases, suppressing the immune system by corticosteroids and immunosuppressants, or by decreasing the circulating antibodies by plasmapheresis. Adults with generalized myasthenia should have a trans-sternal thymectomy. A balanced technique of general anaesthesia which includes the use of muscle relaxants can be safely used, provided neuromuscular transmission is monitored. Myasthenic patients are sensitive to nondepolarizing relaxants but intermediate-acting nondepolarizing relaxants such as atracurium and vecuronium are eliminated rapidly, and can be titrated to achieve the required neuromuscular block that can be completely reversed at the end of surgery. Postoperatively, ventilatory support may be required in high-risk patients. Also, medical treatment may be maintained, tapered or discontinued depending on the outcome of surgery. Thymectomy benefits nearly 96% of patients, 46% develop complete remission and 50% are asymptomatic or improve on therapy.

Adolescent↗

PubMed1998

[Thymectomy in myasthenia gravis--an analysis of current status].

Between May 1992 and June 1997, 11 patients with myasthenia gravis and 1 asymptomatic patient with thymoma underwent extensive thymectomy through a median sternotomy. Seven patients were male and 5 female. The mean age at onset of myasthenia gravis was 46.5 (13-73) years. The interval between the first symptom and diagnosis was 3.6 months (1 week-7 months), between the first symptom and thymectomy 8.3 months (2 weeks-36 months) and the mean follow-up period was 28.4 months (3-57 months). Clinical improvement after extensive thymectomy was noted in 80% of patients. Four patients became asymptomatic under decreased medication. Thymectomy was found to be beneficial even in older patients or patients with the purely ocular type of myasthenia gravis. There was no perioperative mortality or long-term morbidity.

Adolescent↗

PubMed2000

[Immunohistochemical detection of complement factors: a reliable method for the diagnosis of myasthenia gravis].

A 57-year-old woman suffered from generalized muscular weakness without diplopia or dysphagia for about 2 years. An abnormal decremental response on low frequency nerve stimulation and improvement upon administration of edrophonium chloride suggested a diagnosis of myasthenia gravis. However, this diagnosis remained uncertain, since repeated tests for antiacetylcholine receptor antibodies were negative. In addition, the patient reported that she was never able to keep up with peers in prolonged physical activities since childhood. For this reason, a congenital myasthenic syndrome was suspected and an intercostal muscle biopsy performed for special end-plate studies. Immunohistochemistry of the muscle biopsy revealed membrane attack complex deposits at the end-plates. This finding definitely confirmed the diagnosis of autoimmune myasthenia gravis. In conclusion, immunohistochemistry for complement deposits at the end-plates is a simple and reliable method of confirming the diagnosis of myasthenia gravis in uncertain cases.

Biopsy↗

PubMed1996

Oculo-bulbar myasthenia gravis induced by cytokine treatment of a patient with metastasized renal cell carcinoma.

OBJECTIVE: The occurrence of autoimmune diseases or deterioration of pre-existing disorders has recently been described after cytokine treatment. The present report gives evidence for acquired myasthenia gravis induced by externally administered interferon-alpha and interleukin-2 in a patient with metastasized renal cell carcinoma. Electromyographic investigations did not reveal generalised myasthenia gravis. However, a highly elevated titre of antibodies against the human acetylcholine receptor and a significant improvement in clinical symptoms during therapy with anticholinesterase drugs, combined with a decremental response in electronystagmography, indicated an intermittent mainly oculo-bulbar form of myasthenia gravis.

Carcinoma, Renal Cell↗

PubMed2002

Myasthenia mimicking vertebrobasilar stroke.

The advent of thrombolysis has offered a remarkable opportunity for treatment of acute ischemic stroke. Other therapies involving neuro-protection may be forthcoming. These treatments, however, are not without risk, making accurate diagnosis of stroke all the more important. Several conditions may mimic stroke in the emergency department, with myasthenia being an uncommon stroke mimic. We present two cases of myasthenia presenting as posterior circulation stroke. In one case, the tempo suggested basilar thrombosis. Treatment decisions regarding thrombolysis for stroke must be made rapidly. Stroke mimics continue to present a diagnostic challenge, myasthenia included. Accurate diagnosis is essential to avoid unnecessary hazard, as well as to implement effective treatment for the appropriate diagnosis.

Aged↗

PubMed1997

Outcome in juvenile-onset myasthenia gravis: a retrospective study with long-term follow-up of 79 patients.

Randomised and controlled treatment studies of juvenile-onset myasthenia gravis have not been published. We therefore report our retrospective analysis of 79 patients with juvenile-onset myasthenia gravis observed for as long as 30 years. The mean age at onset was 13.7 years and median follow-up 7.7 years. The initial presentation was generalised disease in 90% and ocular disease in the remaining patients. Sixty-five patients (82%) were thymectomised. In 14 of these, treatment consisted of a combination of azathioprine (2-3 mg/kg), corticosteroids (prednisolone up to 60 mg for a maximum duration of 12 months with subsequent tapering) and acetylcholinesterase (AChE) inhibitors, and of azathioprine and AChE inhibitors in 27 patients. One patient received azathioprine and 22 AChE inhibitors only; in another no further medication was necessary. In the severely affected group (n = 16), plasmapheresis was performed additionally before thymectomy and continued for some time after the operation. Treatment was started between 1 and 14 months (mean 2.4 months) after the onset of myasthenic symptoms. No thymectomy was done in 14 patients, and immunosuppressive treatment and AChE inhibitors were given in 9 of these cases. One patient received azathioprine only; 4 patients received AChE inhibitors only. The histology of the thymus gland showed follicular hyperplasia in 89% of the 65 thymectomised patients and normal findings in the remainder. Remission occurred in 60% of patients who underwent thymectomy and in 29% of those who were not thymectomised. Hyperthyroidism (6 patients, 8%), diabetes mellitus (2 patients, 3%) and rheumatoid arthritis (2 patients, 3%) were the most frequent associated immune-mediated diseases. Epileptic seizures and neoplasia were coincident diseases in 2 (3%) and 3 (4%) patients, respectively. There were no deaths from thymectomy or from immunosupression. This open, retrospective analysis suggests that juvenile-onset myasthenia gravis can be treated satisfactorily in most patients by the use of thymectomy and/or immunosupressive medication.

Adolescent↗

PubMed2006

Inclusion of the transcervical approach in video-assisted thoracoscopic extended thymectomy (VATET) for myasthenia gravis: a prospective trial.

BACKGROUND: Because evidence-based data regarding the quality of video-assisted thoracoscopic thymectomy for the treatment of myasthenia gravis are lacking, a prospective trial comparing three different operative approaches was conducted to evaluate their efficacy. METHODS: This prospective study enrolled 20 consecutive patients with nonthymomatous myasthenia gravis. A series of three approaches for bilateral video-assisted thoracoscopic extended thymectomy (VATET) using the anterior chest wall-lifting method (original), the original method with a flexed-neck position (modified), and the original method with a transcervical approach (final) were prospectively performed in each patient for quantitative and pathologic evaluation of the residual thymus after each approach. RESULTS: Complete VATET required 242 +/- 48 min, with the transcervical procedure requiring 23 +/- 12 min. After the modified method, the residual thymus in the cervical region was 1.5 cm in size and weighed 0.8 g (0.8% of the entire thymus), as compared with a size of 2.2 cm and a weight of 1.3 g (3.2%) after the original method. Each value is the result of comparison with the final method. Histopathologic studies showed residual tissue in the germinal center as well as Hassall's corpuscles in more than 70% of cases. CONCLUSION: The findings show that VATET without the transcervical approach could be an immunologically incomplete treatment for myasthenia gravis. Therefore, the transcervical approach should be included in VATET procedures to ensure radicality.

Adult↗

PubMed2002

High-dose intravenous immunoglobulin G treatment of myasthenia gravis.

IVIg is a safe and effective adjunctive treatment for myasthenia gravis, but there are no well established guidelines for the use of IVIg in this disease, lacking controlled randomized trials to assess its efficacy in homogeneous group of patients. The main advantages of IVIg are the rapid onset of the effect, the lack of long-term toxicity, and the possibility to reduce the required doses of immunosuppressive drugs. IVIg appears to have a role as an acute treatment in rapidly progressive myasthenia gravis weakness, particularly in situations when therapeutic apheresis is not feasible. In addition, IVIg is safer than plasma exchange (PE) in patients with hypotension or autonomic instability, in children, in patients of older age (>65 years), and in those suffering from sepsis. For these reasons, at present, IVIg are recommended during crises of myasthenia gravis in older patients when PE is contraindicated or not feasible IVIg can be also used as a chronic maintenance therapy when other immunosuppressive treatments have failed or cannot be used. Periodic administration of IVIg on a bimonthly or monthly basis may be able to stabilize chronic, nonresponding patients.

Autoantibodies↗

PubMed1975

Studies in myasthenia gravis: early thymectomy. Electrophysiologic and pathologic correlations.

Indications for thymectomy in myasthenia gravis have been recently expanded to include all cases with extraocular symptoms as a result of the minimal morbidity and negligible mortality of the transcervical approach. As increasing numbers of patients with myasthenia gravis, covering the entire spectrum of generalized disease, have been added to the thymectomy population, a more accurate evaluation of the effects of the operation is possible. Our experience with 353 patients who have undergone thymectomy indicates that early thymectomy, particularly in patients who do not have germinal centers, is followed by early remission of the disease. Delayed remission after thymectomy is related to the duration and severity of the disease, and to presence of thymic germinal centers. Germinal centers were found more frequently in patients with long duration of the disease and in patients in whom the disease had progressed to respiratory involvement. Marked improvement in electromyographic findings immediately after thymectomy was observed in the majority of patients who had had the disease for 1 year of less and where germinal centers were absent. The percentage of malignant thymomas was higher in patients who underwent thymectomy 1 year or more after the onset of symptoms of myasthenia gravis. These data indicate the importance of early thymectomy while the disease is still in the mild stages. Transcervical thymectomy is the treatment of choice as it is followed by a higher percentage of remissions and by less morbidity than other forms of treatment.

Adolescent↗

PubMed1980

The current role of thymectomy for myasthenia gravis.

Myasthenia gravis is an autoimmune disease characterized by muscle weakness and fatigability due to a reduction in available acetylcholine receptors at the neuromuscular junction. Treatment with anticholinesterase drugs and corticosteroids has improved the prognosis for patients with this disease. However, controversy continues concerning the indications for thymectomy. During a 9 year period, 27 patients who underwent thymectomy by median sternotomy were reviewed. Eighty-one percent of these patients benefited from the procedure. Clinical improvement did not correlate with age, sex, duration of symptoms, severity of disease or thymic histology, This suggests that the indications for thymectomy should be liberalized to include most patients with generalized myasthenia who fail to respond readily to conventional medical therapy. The importance of immunosuppression nd plasmapheresis in the therapy of myasthenia gravis awaits further delineation of the immune defect associated with the disease.

Adolescent↗