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PubMed2005

Benefits of FK506 (tacrolimus) for residual, cyclosporin- and prednisone-resistant myasthenia gravis: one-year follow-up of an open-label study.

Thirteen patients with myasthenia gravis, unresponsive to prednisone and cyclosporin after thymectomy, received KF506 (tacrolimus) for 12 months, at starting doses of 0.1 mg/kg per day b.i.d. and then adjusted to achieve plasma concentrations between 7 and 8 ng/mL. The doses of prednisone were progressively reduced and finally discontinued. Anti-acetylcholine antibodies and myasthenia gravis score for disease severity decreased significantly and muscular strength increased by 37%. All patients achieved pharmacological remission, 11 were asymptomatic and two had minimal weakness of eyelid closure. Tacrolimus was well tolerated and appears a suitable approach after unsuccessful treatment with conventional immunosuppressants in patients with disabling myasthenia.

Adult↗

PubMed2004

Safety for preoperative use of steroids for transsternal thymectomy in myasthenia gravis.

OBJECTIVE: Effects of preoperative steroids on morbidity and mortality after transsternal thymectomy are analyzed. METHODS: There were 620 transsternal thymectomies for myasthenia gravis performed in the period 1973-2002. There were 547 patients with nonthymomatous myasthenia, including 17 patients submitted to repeated thymectomy (rethymectomy) and 46 patients with thymoma. There were 522 upper median sternotomies performed in the period 1973-1997 and 98 complete median sternotomies performed in the period 1998-2002 (74 patients without thymoma, 7 thymomas and 17 rethymectomies). One hundred and seventeen of these 620 patients were taking steroids preoperatively. The impact of steroids use on postoperative respiratory insufficiency (ventilator), need for tracheostomy, superficial wound dehiscence, superficial wound suppuration, sternal dehiscence and mortality was analyzed. RESULTS: The rate of morbidity and mortality in the steroids and the no-steroids groups included respiratory insufficiency necessitating the use of a ventilator in 46/503 patients from the no-steroids group (9.1%) and 8/117 patients from the steroids group (6.8%; P = 0.4260), need for tracheostomy in 14/503 patients from the no-steroids group (2.8%) and 3/117 patients from the steroids group (2.6%; P = 9054). Complications with wound healing (including sternal dehiscence, superficial wound dehiscence and superficial wound suppuration) occurred in 47/503 (9.3%) patients from the no-steroids group and in 1/117 (0.9%) patient from the steroids group (P = 0.0023) The overall complications rate was 30.6% (154/503) in the no-steroids group and 11.1% (13/117) in the steroids group (P = 0.0001). Mortality rate in the no-steroids group was 0.4% (2/503 patients) and none in the steroids group. Morbidity in patients with complete sternotomy was low, respiratory insufficiency in three patients (3.1%), and superficial wound suppuration in one patient (1.0%), no other morbidity and no mortality. Changing morbidity in periods 1973-1980, 1981-1990 and 1991-2002 is analyzed. CONCLUSIONS: Preoperative use of steroids for transsternal thymectomy in patients with myasthenia gravis had no negative impact on morbidity and mortality, conversely, the results in patients taking steroids were better, with significant difference of results regarding the overall complication rates and the overall complication rates of wound healing.

Adult↗

PubMed2006

Interleukine-6 (IL-6) may be a link between myasthenia gravis and myoepithelioma of the parotid gland.

Myoepithelioma is a rare benign neoplasm of the salivary glands occurring more frequently in the parotids. Myasthenia gravis (MG) is a chronic, T-cell dependent, antibody and complement-mediated autoimmune neuromuscular transmission disorder. Interleukine-6 (IL-6) is an immune protein belonging to the family of the hematopoietins, liberated in response to infection, burns, trauma, and neoplastic diseases. It seems that an overproduction of IL-6 might play an important role in the pathophysiology of MG. Moreover, it has been discussed the possible role of IL-6 as a modulating factor either in proliferation or in differentiation of pleomorphic adenoma cell line into myoepithelioma. The authors present a rare case of parotid myoepithelioma occurred in a patient affected by myasthenia gravis and suppose a possible IL-6 mediated relationship between myasthenia gravis and parotid myoepithelioma.

Aged, 80 and over↗

PubMed2005

The early history of myasthenia gravis.

Myasthenia gravis was first recognised as a distinct clinical entity by Thomas Willis, a 17th century Oxford physician, whose 1672 account in Latin was largely unnoticed until 1903. The first modern description was made in 1877 by Samuel Wilks, a London physician. Towards the close of the 19th century, primary muscle diseases and diseases due to denervation of muscle were studied by English, French, and German physicians. The first full descriptions of myasthenia gravis were by Wilhelm Erb, of Heidelberg, and Samuel Goldflam of Warsaw. The account by Willis, and the 19th century literature of myasthenia gravis are reviewed, revealing the dominance of German physicians and neuropathologists in the early understanding of the disease. The development in pathology, aetiology, and therapy in the first half of the 20th century are described.

History, 17th Century↗

PubMed2006

A systematic review of diagnostic studies in myasthenia gravis.

We performed a systematic review to identify studies that reported the accuracy of tests for the diagnosis of myasthenia gravis. We identified 20 studies of reasonable, although variable, methodological quality upon which to base estimates of the accuracy of the ice test, rest test, Tensilon test, acetylcholine receptor antibodies, repetitive nerve stimulation and single fiber electromyography for the diagnosis of myasthenia gravis. After examining inter-study heterogeneity for each diagnostic modality, we calculated pooled estimates of sensitivity and specificity as well as positive and negative likelihood ratios. Results are reported separately for ocular and generalized myasthenia. Studies that have examined the performance of anti-acetylcholine receptor antibody testing and single fiber electromyography were generally of better quality than those that examined other diagnostic modalities. We suggest that caution should be exercised in the interpretation of the diagnostic performance of these tests given the methodological limitations of the studies upon which test performance is based.

Cholinesterase Inhibitors↗

PubMed2005

Non-ptotic ocular myasthenia gravis: a common presentation of an uncommon disease.

BACKGROUND: Myasthenia gravis (MG) is an acquired autoimmune disease of the neuromuscular junction which causes rapid muscle fatigue and weakness. Two thirds of all cases of myasthenia gravis (MG) initially manifest ptosis. In the absence of the characteristic variable ptosis, MG can present a challenge to the clinician. This article will review the current diagnostic and management strategies for MG. CASE REPORTS: Five cases will be presented that did not initially present with ptosis. Each of these cases was previously misdiagnosed as a result of presentation of atypical myasthenia gravis signs and symptoms. The first two cases had signs and symptoms of a typical accommodative/vergence anomaly. The others manifested diplopia not normally associated with MG: one had a noncomitant vertical deviation; another had a stable 6(th) nerve palsy; and the third had a basic esotropia. CONCLUSION: Although the hallmark findings of MG are ptosis and eye muscle palsy with variability, MG may present without ptosis, affect nonstriated muscles, and/or manifest either as a nonstrabismic vergence anomaly or as comitant nonvariable strabismic deviation.

Adult↗

PubMed2000

Ocular myasthenia and nitrofurantoin.

PURPOSE: To report a case of ocular myasthenia associated with administration of nitrofurantoin. METHODS: Case report and review of the literature. RESULTS: While taking nitrofurantoin after urinary tract surgery, a 10-year-old female developed diplopia and ptosis. Sleep test confirmed ocular myasthenia. Signs and symptoms resolved after discontinuation of the drug. CONCLUSION: Ocular myasthenia may be associated with nitrofurantoin administration.

Anti-Infective Agents, Urinary↗

PubMed1992

The edrophonium-Hess screen test in the diagnosis of ocular myasthenia gravis.

The interpretation of the edrophonium (Tensilon) test in the diagnosis of acquired strabismus caused by myasthenia gravis has been problematic because of poorly defined endpoints and unknown sensitivity and specificity. We evaluated the endpoint criteria, dynamics, sensitivity, and specificity of binocular alignment in response to edrophonium by using the Hess screen test in ten normal control subjects, 12 nonmyasthenic patients with acquired strabismus, and in ten patients with acquired strabismus caused by ocular myasthenia gravis. A positive response to the edrophonium-Hess screen test was defined as a 50% or greater reduction in the strabismic deviation at the fixation point associated with maximum deviation within one minute of edrophonium infusion. All myasthenic patients had a 50% or greater reduction in the initial deviation within one minute of edrophonium infusion. Myasthenic patients had a statistically significant reduction in the average deviation up to 150 seconds after edrophonium infusion (P < .05 for all time periods). In contrast, with or without edrophonium infusion, control subjects had a purely horizontal fluctuation in binocular alignment of less than or equal to 2 degrees for the entire four-minute period after edrophonium infusion. None of the 12 nonmyasthenic patients tested positive to the edrophonium-Hess screen test. According to the criterion of positive response as was defined in this study, the test had a high sensitivity and specificity in this sample. These results suggest that clearly defined endpoint criteria make the edrophonium-Hess screen test a sensitive and specific quantitative study for the diagnosis of acquired strabismus caused by myasthenia gravis.

Adult↗

PubMed1985

Penicillamine-induced ocular myasthenia gravis.

Two patients with rheumatoid arthritis (two women, 58 and 62 years old) developed reversible penicillamine-induced ocular myasthenia gravis. Both had the HLA-DR1 antigen, unlike most patients with idiopathic myasthenia gravis who show HLA-DR3, suggesting that penicillamine-induced myasthenia gravis and its idiopathic counterpart occur in patients with different genetic backgrounds. In both cases, cessation of drug treatment led to resolution of the symptoms.

Eye Diseases↗

PubMed2001

Infrasternal mediastinoscopic thymectomy in myasthenia gravis: surgical results in 23 patients.

BACKGROUND: Infrasternal mediastinoscopic surgery is a new approach to resection of the anterior mediastinal mass. METHODS: We evaluated this new approach in 23 patients with myasthenia gravis who underwent total thymectomy assisted by infrasternal mediastinoscopy between 1998 and 2000. The results were analyzed with special reference to morbidity and short-term improvement of the disease severity determined according to quantitative myasthenia gravis (QMG) scores. RESULTS: Complete removal of the thymic gland with the pericardial adipose tissue was accomplished through an infrasternal mediastinoscopic approach in 21 of the 23 (91.3%) patients. The remaining 2 patients required conversion to sternotomy, the one for insufficient sternal lifting with vascular tape and the other for invasion of a thymoma to the innominate vein. There was no related mortality and only one complication, a phrenic nerve injury in 1 patient (4.3%). Significant clinical improvement of disease was achieved in the short term and several advantages were apparent. CONCLUSIONS: Infrasternal mediastinoscopic thymectomy is safe and feasible for patients with myasthenia gravis.

Adult↗

PubMed2002

Thymectomy by partial sternotomy for the treatment of myasthenia gravis.

BACKGROUND: Myasthenia gravis is an autoimmune disease characterized by weakness and fatigue of voluntary muscles. Surgical treatment of choice for myasthenia gravis has been thymectomy. However, thymectomy indications and surgical approach are still controversial. The purpose of this study is to evaluate the efficacy of partial median sternotomy approach to the thymus. METHODS: From 1973 to 1999, 478 patients with myasthenia gravis underwent thymectomy through a partial median sternotomy. RESULTS: Sixty-one patients (12.7%) had complete remission of symptoms, 299 (62.5%) had a significant improvement, and 83 (17.4%), a mild improvement; whereas 35 patients (7.4%) had no improvement of clinical symptoms. CONCLUSIONS: Partial median sternotomy has shown to be a useful surgical approach to the thymus, as demonstrated by the good functional and aesthetic results, associated with low morbidity and no mortality.

Adult↗

PubMed2002

Transcervical thymectomy for myasthenia gravis achieves results comparable to thymectomy by sternotomy.

BACKGROUND: It remains controversial whether transcervical thymectomy offers results equivalent to thymectomy by way of a median sternotomy in the treatment of myasthenia gravis. Furthermore, preoperative prognostic factors have not been clearly defined. METHODS: This study is a retrospective chart review and interview of 78 patients completing transcervical thymectomy for myasthenia gravis between 1992 and 1999. RESULTS: There were 24 men and 54 women. Mean age was 40 years (range, 13 to 78 years). Twelve patients were in Osserman class 1, 25 in class 2, 30 in class 3, and 11 in class 4 (mean, 2.5). There was no perioperative mortality and 6 (7.7%) morbidities. Mean length of stay was 1.5 days and mean follow-up, 54.6 months. The crude cumulative complete remission (asymptomatic off medications for 6 months) rate was 39.7% (n = 31). Only 8 patients (10.3%) failed to improve after transcervical thymectomy. Kaplan-Meier estimates of complete remission were 31% and 43% at 2 and 5 years, respectively. Eight patients with thymoma had a 5-year estimated complete remission rate of 75% in contrast to 43% in 38 patients with thymic hyperplasia and 36% in 32 patients with neither thymoma nor hyperplasia (p = 0.01). Twelve patients with ocular myasthenia had a 5-year estimated complete remission rate of 57%, whereas patients with mild-to-moderate (n = 55) or severe (n = 11) generalized symptoms had 5-year complete remission rates of 43% and 30%, respectively (p = 0.21). CONCLUSIONS: Overall, extended transcervical thymectomy offers results that are comparable to those published for the transsternal procedure. Patients with milder disease (including isolated ocular disease) and taking no preoperative immunosuppressive agents appear to experience higher remission rates. In contrast to previous studies, we also find that small thymomas predict better responses to thymectomy.

Adolescent↗

PubMed1997

Dramatic response of postthymomectomy myasthenia gravis with multiple lung nodules to corticosteroids.

A 36-year-old woman underwent thymomectomy and left pneumonectomy with total pleurectomy for stage IVa invasive thymoma without myasthenia gravis. Six years later, a crisis of myasthenia gravis developed associated with multiple lung nodules. Steroid therapy induced remarkable regression of the lung nodules that has persisted for more than 11 months. Concurrently, the clinical severity of her myasthenia gravis markedly decreased and recovered to the extent of permitting her to return to normal life.

Adult↗

PubMed1997

Altered tumor growth factor beta mRNA expression is associated with thymectomy-related clinical remission in myasthenia gravis.

Clinical remission in myasthenia gravis after thymectomy and immune suppressive treatment may be reflected by changes of immunoregulatory cytokines. Mononuclear cells from paired blood samples from fifteen patients with myasthenia gravis before and after thymectomy and immunosuppressive therapy were examined by in situ hybridization for acetylcholine receptor-induced mRNA expression of the T helper type 1 proinflammatory cytokines interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha) and TNF-beta, the T helper type 2 cytokines interleukin 4 (IL-4) and IL-10 and the immune response downregulating cytokine tumor growth factor beta (TGF-beta). A significant change was observed for TGF-beta, with increased expression after treatment and induction of clinical remission. Augmentation of TGF-beta may play a role in the induction of remission in myasthenia gravis.

Adolescent↗

PubMed1996

Results of video-assisted thymectomy in patients with myasthenia gravis.

OBJECTIVE: The efficacy of video-assisted thoracic surgery for thymectomy with myasthenia gravis has not been examined. METHODS: Thirty-three consecutive patients underwent total thymectomy by video-assisted techniques between 1992 and 1995. There were 13 male and 20 female patients with a mean age of 38.42 +/- 16.88 years (range 9 to 84 years). The procedures were performed by either a right (n = 11) or left (n = 22) thoracoscopic approach and all anterior mediastinal tissue was removed. RESULTS: There was no perioperative mortality or long-term morbidity. One patient required conversion of the video-assisted technique to a lateral thoracotomy. All patients except one were extubated immediately. The mean hospital stay was 4.12 +/- 6.07 days (range 1 to 37 days) with a median of 3 days. Mean follow-up is 23.39 +/- 11.72 months (range 4 to 47 months). Clinical improvement was seen in 87.9% (29/33): one of two patients (50%) in stage I, 17 of 19 (89.4%) in stage IIA, eight of nine (88.8%) in stage IIB, and three of three (100%) in stage III. Metaanalysis of these results compared with results in nine published series in which other techniques were used showed no difference in clinical improvement after thymectomy between series. CONCLUSION: We conclude that video-assisted thymectomy is as effective as the traditional open surgical approaches for performance of thymectomy in the management of patients with myasthenia gravis. In addition, the improved cosmesis of the video-assisted approach ideally will lead to earlier thymectomy in patients with myasthenia gravis.

Adolescent↗

PubMed1975

Thymopoietin and myasthenia gravis: neostigmine-responsive neuromuscular block produced in mice by a synthetic peptide fragment of thymopoietin.

Thymopoietin is the thymic hormone responsible for inducing the differentiation of thymocytes. A synthetic peptide corresponding to positions 29-41 of bovine thymopoietin II, which can reproduce this function of the parent molecule in vitro, also caused neostigmine-responsive neuromuscular block in mice similar to that which thymopoietin itself produces, and which resembles the neuromuscular block of myasthenia gravis. This 13 aminoacid sequence must therefore contain the key residues in the thymopoietin molecule responsible for both T-cell differentiation and neuromuscular effects. These data provide further support for the view that myasthenia gravis is a consequence of thymic disease associated with systemic release of thymopoietin, with ensuing neuromuscular block. This evidence supports the empirically proven treatment of myasthenia gravis by early total thymectomy.

Action Potentials↗

PubMed1975

Humoral antibodies to acetylcholine receptor in patients with myasthenia gravis.

Sera from patients with myasthenia gravis (M.G.) were studied by the quantitative micro-scale complement-fixation assay for the presence of humoral antibodies against acetylcholine receptor (AChR). The purified receptor was extracted from the electrogenic tissue of the electric ray, Torpedo californica. A significant difference in the antibody titres was observed between myasthenic and non-myasthenic patients. Out of fifteen patients with myasthenia gravis, at least 12 (80%) had antibodies against AChR. Only one case out of twenty-four controls had an indication of anti-receptor antibodies. In view of observations on the role of AChR as the autoantigen in myasthenia gravis, such antibodies may have significance in producing the neuro-muscular block characteristic of the disease.

Acetylcholine↗

PubMed2003

Breakage of tolerance to hidden cytoplasmic epitopes of the acetylcholine receptor in experimental autoimmune myasthenia gravis.

The acetylcholine receptor (AChR) is the major autoantigen in the antibody-mediated disease myasthenia gravis (MG) and its animal model experimental autoimmune myasthenia gravis (EAMG). This study demonstrates that rats immunized with a recombinant fragment corresponding to the normally exposed extracellular region of the rat AChR alpha-subunit first develop antibodies to the injected extracellular portion only, but later develop antibodies to intracellular cytoplasmic epitopes of AChR. The presence of autoantibodies to intracellular epitopes seems to be correlated with development of clinical signs of disease. We propose that a similar process of epitope spreading may take place in the natural course of myasthenia.

Animals↗