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PubMed2006

Medical and surgical treatment for ocular myasthenia.

BACKGROUND: Approximately 50% of people with myasthenia gravis present initially with purely ocular symptoms, so called ocular myasthenia and between 50 to 60% of these people will progress to develop generalized disease. The vast majority will do so within the first one to two years. There is controversy surrounding the appropriate management of patients with ocular myasthenia. OBJECTIVES: To perform a systematic review of the literature relevant to the treatment of ocular myasthenia and to answer three specific questions. Are there any medical or surgical treatments that have an impact on the risk of progression from ocular to generalized myasthenia gravis? Are there any medical or surgical treatments that improve symptoms of diplopia or ptosis in ocular myasthenia? What is the frequency of side effects associated with treatments used in people with ocular myasthenia? SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group Trials Register (searched December 2004), MEDLINE (1996 to 2004) and EMBASE (1980 to 2004) for randomized controlled trials as well as case-control and cohort studies. The titles and abstracts of all articles were read by both authors and the full text of all articles that were of possible relevance was reviewed in full. The references of all manuscripts included in the review were scanned to identify additional articles of relevance and experts in the field were contacted to identify additional published and unpublished data. Where necessary and possible, we contacted authors for further information. SELECTION CRITERIA: To be included in the review, studies had to meet three criteria: (a) randomized (or quasi-randomized) controlled study design; (b) active treatment compared to placebo, no treatment or some other treatment; and (c) results reported separately for patients with ocular myasthenia (grade 1) as defined by the Myasthenia Gravis Foundation of America. DATA COLLECTION AND ANALYSIS: We collected data regarding the risk of progression to generalized myasthenia gravis, improvement in ocular symptoms, and the frequency of treatment-related side effects. MAIN RESULTS: We identified two randomized controlled trials relevant to the treatment of ocular myasthenia, only one of which reported results in terms of the pre-specified outcome measures used in this review. This study included only three participants and was of limited methodological quality. In the absence of data from randomized controlled trials, we present a review of the available observational data. AUTHORS' CONCLUSIONS: There are no data from randomized controlled trials on the impact of any form of treatment on the risk of progression from ocular to generalized myasthenia gravis. The available randomized controlled literature does not permit any meaningful conclusions about the efficacy of any form of treatment for ocular myasthenia. Data from several reasonably good quality observational studies suggest that corticosteroids and azathioprine may be beneficial in reducing the risk of progression to generalized myasthenia gravis.

Adrenocorticotropic Hormone↗
PubMed2003

Development of generalized disease at 2 years in patients with ocular myasthenia gravis.

BACKGROUND: Generalized myasthenia gravis will develop in more than 50% of patients who present with ocular myasthenia gravis, typically within 2 years. The optimal treatment of ocular myasthenia gravis, including the use of corticosteroids, remains controversial. In addition, the prevalence of thymoma and the optimal performance of the edrophonium chloride test for ocular myasthenia remain unknown. OBJECTIVE: To assess the effect of oral corticosteroid therapy on the frequency of development of generalized myasthenia gravis within 2 years, the incidence of thymoma, and the amount of edrophonium needed for a positive test result in patients with ocular myasthenia gravis. METHODS: We reviewed an ocular myasthenia gravis database of 147 patients. Patients underwent measurement of acetylcholine receptor (AChR) antibody levels and chest computed tomography. Unless contraindicated, patients with diplopia were recommended for therapy with prednisone, up to 40 to 60 mg/d, with the dosage tapered for 5 to 6 weeks. Most continued to receive daily or alternate-day doses of 2.5 to 10 mg to prevent diplopia. Patients not given prednisone (untreated group) received pyridostigmine bromide or no medication. After the diagnosis, we documented the signs and symptoms of ocular and generalized myasthenia gravis and performed 2-year follow-up in 94 patients. RESULTS: The mean dose of edrophonium chloride to give a positive response was 3.3 mg (SD, 1.6 mg) for ptosis and 2.6 mg (SD, 1.1 mg) for ocular motor dysfunction. Thymoma occurred in 1 patient (0.7%). Generalized myasthenia gravis developed within 2 years in 4 of 58 treated and 13 of 36 untreated patients. The odds ratio (OR) for development of generalized disease in the treated group was 0.13 (95% confidence interval [CI], 0.04-0.45) compared with the untreated group. The AChR antibody level was not predictive of development of generalized myasthenia gravis at 2 years, but the risk was greater in patients with abnormal AChR antibody levels (OR, 6.33; 95% CI, 1.71-23.42). Logistic regression that included age, abnormal AChR antibody level, and prednisone therapy yielded significance only for abnormal AChR antibody level (OR, 7.03; 95% CI, 1.35-36.64) and treatment (OR, 0.06; 95% CI, 0.01-0.30). CONCLUSIONS: At 2 years, prednisone treatment appears to reduce the incidence of generalized myasthenia gravis to 7% in contrast to 36% of patients who did not receive prednisone. Thymoma, although uncommon, occurs in ocular myasthenia gravis. Only small amounts of edrophonium are needed to diagnose ocular myasthenia gravis.

Administration, Oral↗
PubMed2005

Does this patient have myasthenia gravis?

CONTEXT: Clinicians must be able to diagnose myasthenia gravis, since delays in establishing the diagnosis may put patients at risk for complications from this treatable disease. OBJECTIVE: To determine if items in the history and examination or results of simple tests change the likelihood of myasthenia gravis as a diagnosis. DATA SOURCES: MEDLINE search of English-language articles (January 1966-January 2005) using the terms myasthenia gravis, diagnosis, and test, and a search of bibliographies of retrieved articles. STUDY SELECTION: Studies evaluating a particular symptom or sign in patients both with and without myasthenia gravis. Of 640 articles retrieved, 33 were eligible for review. Of these, 15 met inclusion criteria and form the basis of this review. DATA EXTRACTION: Two authors independently reviewed each study to determine eligibility, abstracted data using a standardized instrument, and classified study quality using previously published criteria. DATA SYNTHESIS: A history of "speech becoming unintelligible during prolonged speaking" and the presence of the peek sign increase the likelihood of myasthenia gravis (likelihood ratio [LR], 4.5; 95% confidence interval [CI], 1.2-17.0 and LR, 30.0; 95% CI, 3.2-278.0, respectively). Their absence does not significantly reduce the likelihood of myasthenia gravis. The identified studies only assessed 1 other historical feature and sign each ("food remaining in the mouth after swallowing" and quiver eye movements, respectively), and neither of these significantly changes the likelihood of myasthenia. The ice test is useful when the response is abnormal (summary positive LR, 24.0; 95% CI, 8.5-67.0) and diminishes the likelihood of myasthenia gravis when the response is normal (summary negative LR, 0.16; 95% CI, 0.09-0.27). A positive response to an anticholinesterase medication (mainly edrophonium test) increases the probability of a diagnosis of myasthenia gravis (summary positive LR, 15.0; 95% CI, 7.5-31.0), and a negative response reduces the diagnostic probability of myasthenia (summary negative LR, 0.11; 95% CI, 0.06-0.21). An abnormal sleep test result is useful in confirming the diagnosis (LR, 53.0; 95% CI, 3.4-832.0). The rest and sleep tests make the probability of myasthenia unlikely when results are normal (LR, 0.52; 95% CI, 0.29-0.95 and LR, 0.01; 95% CI, 0.00-0.16, respectively). CONCLUSIONS: Items in the history and physical examination along with results of certain simple tests performed in the office (ice test, sleep test, and edrophonium test) are useful in predicting the likelihood of myasthenia gravis. These results must be interpreted with caution, however, given the high prevalence of disease in the populations reported in clinical studies. This review is limited by the small number of signs and symptoms scientifically studied and reported in the literature. Future studies evaluating the value of common historical features and easy maneuvers commonly known and practiced by experts in the clinical diagnosis of myasthenia are needed.

Cholinesterase Inhibitors↗
PubMed2006

Intravenous immunoglobulin for myasthenia gravis.

BACKGROUND: Myasthenia gravis is an autoimmune disease in which autoantibodies interfere with neuromuscular transmission. As with other autoimmune diseases, people with myasthenia gravis would be expected to benefit from intravenous immunoglobulin. OBJECTIVES: The objective of this review was to examine the efficacy of intravenous immunoglobulin for treating exacerbations of myasthenia gravis or for chronic myasthenia gravis. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group trials register (March 2005) and MEDLINE (January 1966 to March 2005) using 'myasthenia gravis' and 'intravenous immunoglobulin' as the search terms. SELECTION CRITERIA: We included all randomised or quasi-randomised trials in which intravenous immunoglobulin was compared with no treatment, placebo or plasma exchange, in people with myasthenia gravis. DATA COLLECTION AND ANALYSIS: One author extracted the data and the two others checked these data and the source from which they were derived. For methodological reasons, no formal meta-analysis was performed. MAIN RESULTS: We identified five randomised controlled trials, all of which investigated short-term benefit. The first study of 87 participants with exacerbation found no statistically significant difference between immunoglobulin and plasma exchange after two weeks. The second study of 12 participants with moderate or severe myasthenia gravis treated in a crossover design trial found no statistically significant difference in the efficacy of immunoglobulin and plasma exchange after four weeks. The third study with 15 participants with mild or moderate myasthenia gravis found no statistically significant difference in efficacy of intravenous immunoglobulin and placebo after six weeks. The fourth study terminated early. It included 33 participants with moderate exacerbations of myasthenia gravis and showed no statistically significant difference in the efficacy of intravenous immunoglobulin and methylprednisolone. The fifth trial including 173 people with myasthenia gravis exacerbations, showed no superiority of intravenous immunoglobulin 1 g/kg on two consecutive days over intravenous immunoglobulin 1 g/kg on a single day. AUTHORS' CONCLUSIONS: In severe exacerbations of myasthenia gravis, one randomised controlled trial did not show a significant difference between intravenous immunoglobulin and plasma exchange. Another showed no significant difference in efficacy between 1 g/kg and 2 g/kg of intravenous immunoglobulin. A further trial showed no significant difference between intravenous immunoglobulin and oral methylprednisolone. In chronic myasthenia gravis, there is insufficient evidence from randomised trials to determine whether intravenous immunoglobulin is efficacious. More research is needed to determine whether intravenous immunoglobulin reduces the need for steroids as suggested by two case series.

Humans↗
PubMedDate not supplied

Clinical forms of acquired myasthenia gravis in dogs: 25 cases (1988-1995).

The purpose of this project was to investigate the clinical forms of acquired myasthenia gravis in dogs. The medical records from 25 dogs with seropositive acquired myasthenia gravis were reviewed, and the following data were recorded for each patient: signalment, history, clinical findings; results of IV edrophonium chloride administration, repetitive nerve stimulation, and presence or absence of muscle membrane staining by immunocytochemical methods; serum acetylcholine receptor antibody concentration; treatment; and outcome. Several clinical forms of acquired myasthenia gravis were identified. Nine of the 25 patients (36%) had no historical or clinical evidence of appendicular muscle weakness, and were designated as focal myasthenics. These dogs exhibited focal weakness in one or more of the following muscle groups: facial (3 of 9), pharyngeal (3 of 9), and laryngeal (3 of 9). The remaining 16 dogs (64%) exhibited appendicular muscle weakness. Four of these 16 dogs had acute onset and rapid development of clinical signs, and were designated as acute fulminating myasthenics. The remaining 12 dogs were classified as generalized myasthenics. All 4 dogs with acute fulminating myasthenia gravis had megaesophagus, 2 had facial muscle weakness, and 1 had pharyngeal muscle weakness. Ten of the 12 dogs with generalized myasthenia gravis had megaesophagus, 4 had facial muscle weakness, 4 had pharyngeal muscle weakness, and 3 had laryngeal muscle weakness. Historical or clinical evidence of exercise-associated appendicular weakness was found in only 6 of the 12 (50%) dogs with generalized myasthenia gravis, and in none of the dogs with acute fulminating myasthenia gravis. Seven of the 12 dogs with generalized myasthenia gravis had weakness primarily (n = 1) or exclusively (n = 6) of the pelvic limbs. Two of the 4 dogs with acute fulminating myasthenia gravis had primarily pelvic limb weakness. Twelve of the 25 dogs (48%) died or were euthanized shortly after admission to the hospital due to aspiration pneumonia. The dogs with acute fulminating myasthenia gravis had a markedly higher 1-year mortality rate in comparison with the other 2 groups. The use of immunosuppressive therapy had a significant positive effect on patient survival, regardless of the type of myasthenia gravis. This investigation demonstrates that acquired myasthenia gravis in dogs is a disorder with a wide spectrum of clinical forms, similar to the analogous disorder in people.

Animals↗
PubMed2003

Intravenous immunoglobulin for myasthenia gravis.

BACKGROUND: Myasthenia gravis is an autoimmune disease. In up to 90 per cent of cases IgG autoantibodies to the nicotinic acetylcholine receptor are detectable which mediate the neuromuscular transmission disorder. As with other autoimmune diseases, patients would be expected to benefit from intravenous immunoglobulin. Case series and two randomised controlled trials suggest that intravenous immunoglobulin may be beneficial. OBJECTIVES: The objective of this review is to examine the efficacy of intravenous immunoglobulin for treating exacerbations of myasthenia gravis or for chronic myasthenia gravis. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group trials register (21 July 2002) and MEDLINE (January 1966 to July 2002) using 'myasthenia gravis' and 'intravenous immunoglobulin' as the search terms. SELECTION CRITERIA: All randomised or quasi-randomised trials in which intravenous immunoglobulin was compared with no treatment, placebo or plasma exchange, in people with myasthenia gravis who were diagnosed by an internationally accepted definition. DATA COLLECTION AND ANALYSIS: One author extracted the data and the two others checked these data and the source from which they were derived. For methodological reasons, no formal meta-analysis was performed. MAIN RESULTS: We identified four randomised controlled trials (147 participants in total), all investigating short-term benefit. In the first study of 87 people with myasthenia gravis exacerbation, comparing intravenous immunoglobulin and plasma exchange, there was no statistically significant difference between the efficacy of the two treatments after two weeks. In the second study 12 people with moderate or severe myasthenia gravis were treated in a cross-over design trial with intravenous immunoglobulin or plasma exchange: no statistically significant difference in the efficacy of the two treatments was found after four weeks. In the third study 15 people with mild or moderate myasthenia gravis received intravenous immunoglobulin or a placebo: no significant difference in efficacy of intravenous immunoglobulin or placebo was found six weeks after treatment. The last study, which included 33 people with moderate exacerbations of myasthenia gravis, compared intravenous immunoglobulin and methylprednisolone and showed no statistically significant difference in the efficacy of the two treatments. REVIEWER'S CONCLUSIONS: One randomised controlled trial did not show a significant difference between intravenous immunoglobulin and plasma exchange for treatment of severe exacerbations of myasthenia gravis. There is no evidence from randomised controlled trials to determine whether intravenous immunoglobulin for moderate or severe myasthenia gravis improves functional outcome or has a sparing effect on steroid dosage, nor is there sufficient evidence to favour intravenous immunoglobulin over steroids in moderate exacerbations. Further randomised controlled trials are needed.

Humans↗
PubMed2006

[Myasthenia gravis and hyperthyroidism: two cases].

It is well known that hyperthyroidism occurs in approximately 2 to 17.5% of patients with myasthenia gravis. Hyperthyroidism may influence the clinical course of myasthenia gravis. We report the cases of two patients, a 53-year-old man and an 18-year-old woman, who had both severe myasthenia gravis and hyperthyroidism due to Graves' disease. Myasthenia gravis affected in particular facio-ocular areas with diffuse myopathy and signs of neuromuscular block on the electromyogram. In one patient, the diagnosis of thyroid disease was made three months before the diagnosis of myasthenia gravis while in the other, thyroid disease was recognized four months after myasthenia gravis. Myasthenia gravis worsened after the development of hyperthyroidism in the second patient. Both patients were given anti-cholinesterase drugs. One underwent thymectomy. Radioiodine used for the treatment of hyperthyroidism improved the symptoms of myasthenia gravis in the first patient. The association of myasthenia gravis and hyperthyroidism is more than a coincidence; our cases illustrate the difficult diagnosis and management of these diseases. Clinicians should look for myasthenia gravis in hyperthyroid patients and vice versa, especially when symptoms of myasthenia gravis or hyperthyroidism worsen.

Adolescent↗
PubMed2004

[Clinical characteristics and outcome of myasthenia gravis with and without thymoma after operation].

OBJECTIVE: To explore the clinical characteristics and outcome of myasthenia gravis with and without thymoma after operation. METHODS: Two hundred and forty-three patients with myasthenia gravis surgically treated in our department from 1978 to 2003 were studied retrospectively. The clinical characteristics, complication, remission and survival were compared between myasthenia gravis with and without thymoma. RESULTS: The patients of myasthenia gravis with thymoma were significantly older (t = 6.138, P = 0.000), had shorter duration of symptom (t = 3.783, P = 0.000), and also had higher myasthenia crisis rates after operation (chi(2) = 64.77, P = 0.000) than those of myasthenia gravis without thymoma. No differences of Osserman classification was found between the two groups (chi(2) = 7.678, P = 0.104). The complete remission rates and partial remission rates of myasthenia gravis with thymoma were significantly lower than those of myasthenia gravis without thymoma at 1 and 3 years (P = 0.049, P = 0.000; P = 0.015, P = 0.010), but no differences at 5 year (P = 0.457; P = 0.699). The survival rates of MG with thymoma were lower than that of MG without thymoma (Log-rank = 18.58, P = 0.000). CONCLUSIONS: The clinical characteristics are different between myasthenia gravis with and without thymoma. The remission of symptom of myasthenia gravis with thymoma is worse than that of myasthenia gravis without thymoma in the near future, but is similar in the long future. The death rates of MG with thymoma is significantly higher than that of MG without thymoma.

Adolescent↗
PubMedDate not supplied

Myasthenia gravis in childhood and adolescence. Report on 209 patients and review of the literature.

Authors review the different theoretical and practical problems of childhood and adolescent myastenia gravis, including the heterogeneous group of congenital myasthenia and the big casuistics of the literature. There are reports on 113 cases with childhood myasthenia gravis and 96 cases of adolescent myasthenia. Ratio of these forms ranged 10.76% in childhood myasthenia and 9.14% in adolescent age, resp., 19.9% of the whole patient material. A classification is given concerning juvenile myasthenia: 1. Neonatal (transitory) myasthenia. 2. Congenital (local, non-progressive) form. 3. Congenital form with late generalized symptoms. 4. Myasthenia simulating brain-stem process. 5. Generalized childhood myasthenia. 6. Adolescent type myasthenia (juvenile form). 7. Associated myasthenia, myasthenic syndrome or reaction. A new form of the disease is described in which the congenital myasthenia changes into generalized form in the later course of the disease. Report is given on thymectomies in childhood and adolescence which produce in general excellent results. Thymic pathology and activity are dealt with.

Adolescent↗