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At least 19 recordsLinked to original sources

PubMed1997

Clinical trial of plasma exchange and high-dose intravenous immunoglobulin in myasthenia gravis. Myasthenia Gravis Clinical Study Group.

We have conducted a trial to randomly assess the efficacy and tolerance of intravenous immunoglobulin (i.v.Ig) or plasma exchange (PE) in myasthenia gravis (MG) exacerbation and to compare two doses of i.v.Ig. Eighty-seven patients with MG exacerbation were randomized to receive either three PE (n = 41), or i.v.Ig (n = 46) 0.4 gm/kg daily further allocated to 3 (n = 23) or 5 days (n = 23). The main end point was the variation of a myasthenic muscular score (MSS) between randomization and day 15. The MSS variation was similar in both groups (median value, +18 in the PE group and +15.5 in the i.v.Ig group, p = 0.65). Similar efficacy, although slightly reduced in the 5-day group was observed with both i.v.Ig schedules. The tolerance of i.v.Ig was better than that of PE with a total of 14 side effects observed in 9 patients, 8 in the PE group and 1 in the i.v.Ig group (p = 0.01). Although our trial failed to show a pronounced difference in the efficacy of both treatments, it exhibited a very limited risk for i.v.Ig. i.v.Ig is an alternative for the treatment of myasthenic crisis. The small sample sizes in our trial, however, could explain why a difference in efficacy was not observed. Further studies are needed to compare PE with i.v.Ig and to determine the optimal dosage of i.v.Ig.

Adult↗

PubMed1998

A randomized double-blind trial of prednisolone alone or with azathioprine in myasthenia gravis. Myasthenia Gravis Study Group.

We compared prednisolone (PRED) and azathioprine (AZA) versus prednisolone alone in the treatment of MG. Prednisolone alone or combined with azathioprine is widely used in the treatment of MG, but no randomized placebo-controlled comparative trial data are available. The prednisolone dose and clinical outcome were compared in a multicenter randomized double-blind study of 34 MG patients who were followed up for 3 years. One group (PRED + AZA) received prednisolone (on alternate days) plus azathioprine (2.5 mg/kg); the other group received prednisolone on alternate days plus placebo (PRED + PLAC). Initial high-dose prednisolone (1.5 mg/kg on alternate days) was tapered at remission to the minimal dose required to maintain remission. The prednisolone dose did not differ significantly between the two groups at 1 year (median values: PRED + AZA, 37.5 mg on alternate days; PRED + PLAC, 45 mg on alternate days) but was reduced at 2 and 3 years in the PRED + AZA group (median value at 3 years: PRED + AZA, 0 mg on alternate days; PRED + PLAC, 40 mg on alternate days; p=0.02). Relapses and failures to remit over the 3 years were more frequent in the PRED + PLAC group. There was a sharp rise in the anti-acetylcholine receptor (AChR) titers in the PRED + PLAC group at 2 years. Incidence of side effects was slightly less in the PRED + AZA group. Azathioprine as an adjunct to alternate day prednisolone in the treatment of antibody-positive generalized MG reduces the maintenance dose of prednisolone and is associated with fewer treatment failures, longer remissions, and fewer side effects.

Adolescent↗

PubMed1977

Morphologic and immunologic studies in experimental autoimmune myasthenia gravis and myasthenia gravis.

An indirect immunoperoxidase technique was used to study by light microscopy the binding of serum from experimental autoimmune myasthenia gravis (EAMG) rabbits to junctionally and extrajunctionally located acetylcholine receptors (AChRs) in human and rat muscles. Binding was restricted to junctional AChR. Alpha bungarotoxin (a-BGT) partially blocked the binding of EAMG serum, while myasthenia gravis serum, carbamylcholine, decamethonium, and tubocurarine did not. A radioimmunoassay showed significant binding of antibodies in EAMG sera to 125l AChR. This binding was not inhibited by a-BGT, nor by carbamylcholine, decamethonium, or tubocurarine. Sera from 10 myasthenia gravis patients did not contain antibodies binding to the 125l AChR. We suggest that EAMG in rabbits induced by Torpedo AChR differs serologically from myasthenia gravis in patients, probably owing to antigenic differences between Torpedo and human AChR, and that antigenic differences also exist between junctional and extrajunctional receptors.

Acetylcholine↗

PubMed1976

Experimental autoimmune myasthenia gravis and myasthenia gravis: biochemical and immunochemical aspects.

Stucture of acetylcholine receptor protein (AChR) purified from Electrophorus electricus (eel) by affinity chromatography is described. AChR is detected in extracts from human muscle, rat muscle, and rat thymus. Rats immunized with eel AChR develop humoral antibodies, a small fraction of which recognize AChR from rat muscle. Rats immunized with AChR exhibit myasthenia, but those immunized with denatured AChR do not. Immunoglobulin fraction of antisera to eel AChR can block the activity of AChR in electroplaques. Sera from patients with myasthenia gravis contain antibodies to AChR from human muscle detectabe at an average value 300-fold the background level in sera from nonmyasthenics. Relationship of thymoma and disease intensity to antibody titer is examined. The chronic phase of EAMG appears a good model of MG, since in both cases similar concentrations of 7-S immunoglobulin against determinants on muscle AChR other than the toxin binding site are found. Assay of anti-AChR antibody in sera from MG patients using AChR from rat muscle gives titers 10%-15% of those obtained using AChR from human muscle, and using AChR from eel gives negligible titers. The assay method described for assaying antibodies against AChR from human muscle is suggested as a diagnostic test for MG.

Acetylcholine↗

PubMed1997

Isolated corticotroph insufficiency associated to myasthenia gravis.

Myasthenia gravis, a neuromuscular junction autoimmune disease, may be associated to glandular autoimmune diseases such as adrenalitis. We report here the association of myasthenia gravis with a rare cause of adrenocortical deficiency, i.e. isolated corticotroph deficiency. The patient suffered from myasthenia gravis for 5 yr when she reported increased asthenia. Basal cortisol and ACTH levels were low. Metyrapone failed to increase ACTH and 11-desoxycortisol. Corticotropin-releasing hormone or tetracosactide failed to increase normally the cortisol levels. No other endocrine dysfunction or autoimmune disease could be detected. This observation enlarges the spectrum of endocrine diseases associated to myasthenia gravis and strengthens the need for careful endocrine examination.

Adrenocorticotropic Hormone↗

PubMedDate not supplied

Drug-induced neuromuscular blockade and myasthenia gravis.

Myasthenia gravis is an uncommon disorder of the neuromuscular junction resulting in weakness of all striated voluntary muscles. Therapeutic advances have increased patients' age and survival. Older patients with myasthenia gravis may have additional medication needs. Numerous drugs have experimental and clinical evidence of neuromuscular blockade. A MEDLINE search of the English literature from 1966 to the present pertinent to drug-induced myasthenia gravis was performed. Additional literature was obtained from reference citations of relevant articles. Drugs with several reports of neuromuscular blockade were assessed for causality by a recognized probability scale. Prednisone was most commonly implicated as aggravating myasthenia gravis, and D-penicillamine was most commonly associated with myasthenic syndrome. The greatest frequency of drug-induced neuromuscular blockade was seen with aminoglycoside-induced postoperative respiratory depression. However, drugs most likely to impact myasthenic patients negatively are those used in the treatment of the disease. These include overuse of anticholinesterase drugs, high-dose prednisone, and anesthesia and neuromuscular blockers for thymectomy.

Drug-Related Side Effects and Adverse Reactions↗

PubMed1990

Myasthenia gravis.

Myasthenia Gravis is a disorder of neuromuscular function resulting from an immunologically based premature destruction of acetylcholine receptors. The disease is characterized clinically by variable weakness accentuated by repetitive muscular activity and usually responding to the administration of acetylcholinesterase inhibitors. Myasthenia Gravis is a complex disease and requires understanding of the many facets of its natural history and immunological basis to ensure optimal individual patient management. The long-term goal is control of the immunological imbalance; treatment regimens include thymectomy, corticosteroids, azathioprine, and plasmapheresis. The common use of acetylcholinesterase inhibitors provides symptomatic relief during variable daily muscular activity. Disability due to myasthenia gravis is to a large extent reversible and death is preventable. Early recognition of myasthenia gravis and appropriate treatment are often rewarded by remission that may be permanent.

Diagnosis, Differential↗

PubMed2000

Animal models of myasthenia gravis.

Myasthenia gravis (MG) is an antibody-mediated, autoimmune neuromuscular disease. Animal models of experimental autoimmune myasthenia gravis (EAMG) can be induced in vertebrates by immunization with Torpedo californica acetylcholine receptors (AChR) in complete Freund's adjuvant. The MHC class II genes influence the cellular and humoral immune response to AChR and are involved in the development of clinical EAMG in mice. A dominant epitope within the AChR alpha146-162 region activates MHC class II-restricted CD4 cells and is involved in the production of pathogenic anti-AChR antibodies by B cells. Neonatal or adult tolerance to this T-cell epitope could prevent EAMG. During an immune response to AChR in vivo, multiple TCR genes are used. The CD28-B7 and CD40L-CD40 interaction is required during the primary immune response to AChR. However, CTLA-4 blockade augmented T- and B-cell immune response to AChR and disease. Cytokines IFN-gamma and IL-12 upregulate, while IFN-alpha downregulates, EAMG pathogenesis. However, the Th2 cytokine IL-4 fails to play a significant role in the development of antibody-mediated EAMG. Systemic or mucosal tolerance to AChR or its dominant peptide(s) has prevented EAMG in an antigen-specific manner. Antigen-specific tolerance and downregulation of pathogenic cytokines could achieve effective therapy of EAMG and probably MG.

Animals↗

PubMed1984

Drugs that may exacerbate myasthenia gravis.

Myasthenia gravis is an uncommon disease. The emergency physician should be cautious when prescribing medications to myasthenics for problems not related to myasthenia gravis. We have discussed some of those agents (Figure 3) that are recognized to cause exacerbation of MG or that may have the potential to exacerbate MG. We recommend that management of any medical or surgical problem of the myasthenic be done in consultation with a managing neurologist, and that either early follow-up or admission is necessary when these agents are used in the patient with myasthenia gravis.

Anti-Bacterial Agents↗

PubMedDate not supplied

Pericarditis in myasthenia gravis.

Myasthenia gravis is an autoimmune disorder with antibodies to the acetylcholine receptors (Ach R) in skeletal muscles. Myocardial involvement can present as a myocarditis or with arrhythmias. To our knowledge, there is no documentation in the literature of pericardial involvement in myasthenia gravis. We report the presence of pericardial effusion and atrioventricular conduction block in a patient with myasthenia gravis that responded appropriately to immunosuppressive therapy and plasma exchanges.

Heart Block↗

PubMedDate not supplied

[Pathogenesis of myasthenia gravis].

Myasthenia gravis is a neuromuscular, autoimmune, and acquired disturbance characterized by weakness and fatigue of skeletal muscles. During the past two decades, remarkable progress has been made in the understanding of myasthenia gravis, and the new knowledge has been applied directly to the clinical diagnosis and treatment of this formerly severe disease. Myasthenia gravis is undoubtedly the most thoroughly understood of all human autoimmune diseases and has served as a model for the elucidation of mechanisms underlying other autoimmune disorders. In this review we mention the most important physiopathological aspects and its application in the clinic practice.

Humans↗

PubMed2002

The role of antibodies in myasthenia gravis.

Myasthenia gravis is an autoimmune disease associated with antibodies directed to the postsynaptic acetylcholine receptor. These antibodies reduce the number of receptors. Autoantibodies against AChR and other muscle antigens can be used for the diagnosis of myasthenia gravis and related disorders. The origin and the role of these antibodies in the disease are discussed. Experimental autoimmune myasthenia gravis, an experimental model closely mimicking the disease, has provided answers to many questions about the role of antibodies, complement macrophages and AChR anchor proteins. Genetically modified anti-AChR antibodies may also be used in the future to treat myasthenia.

Autoantibodies↗

PubMed1979

The role of acetylcholine receptor antibodies in myasthenia gravis.

Myasthenia gravis is an autoimmune disease of man characterized by remitting and relapsing muscle fatigability. Although the etiology and pathogenesis are incompletely understood, the presence of circulating antibodies directed against the nicotinic acetylcholine (ACh) receptor in 80--90% of patients with myasthenia gravis and the identification of immune complexes at their neuromuscular junction have helped explain the altered neuromuscular transmission. The ACh receptor antibodies do not block access of ACh to the receptor, but do decrease the number of receptors by accelerating their degradation both in rat myotube cultures and in vivo models. In vitro these antibodies play a major role in myasthenia gravis. However, correlations of antibody titers with the clinical state following thymectomy or in neonatal myasthenia suggest that host factors may be equally important in determining whether the ACh receptor antibodies will result in clinical myasthenia.

Acetylcholine↗

PubMed1976

Audiotympanometric findings in myasthenia gravis.

Myasthenia gravis can be a difficult diagnostic and therapeutic problem. Our study on six patients consisted of pure-tone audiograms, tympanometry, and acoustic reflex tests. Positive findings in the myasthenia gravis patients prior to medication included hyperacusis and increase in the intensity of sound required to elicit an acoustic reflex. Following medication, the hyperacusis lessened and the intensity of sound required to elicit the acoustic reflex decreased. During follow-up of two of the patients we encountered cholinergic (overdosage) crisis in one patient and myasthenic (underdosage) crisis in the other patient. Muscle weakness can be a common factor in both conditions. The acoustic reflex test can differentiate between the two types of crises. We believe audiotympanometric tests can aid in diagnosis and treatment of myasthenia gravis patients.

Acoustic Stimulation↗

PubMed1980

Myasthenia gravis.

Myasthenia gravis is characterized by muscle weakness, which is alleviated by rest and by anticholinesterase drugs. There are two forms of the disease in the dog, acquired and congenital. The acquired form occurs either in young adults, or in older animals that have developed mediastinal tumors. Clinically, there is weakness of the muscles of the limbs, neck, and head, together with dilatation of the esophagus. In some cases, circulating antibody to acetylcholine receptor is present and the amount of receptor in the end-plates is decreased. It is thought to be an autoimmune disease. The congenital form of canine myasthenia gravis occurs most frequently in Jack Russell terriers from six to eight weeks of age. The clinical manifestations are similar to those accompanying acquired myasthenia, although dilatation of the esophagus is not a feature. Raised antibody levels to acetylcholine receptor have not been noted, although the amount of receptor in the end-plates is decreased. Thus, the congenital form does not appear to be an autoimmune disease and the pathophysiology has yet to be established. Both forms of canine myasthenia gravis provide useful models analogous to the disease in man.

Animals↗

PubMed1991

Extraocular muscle surgery in myasthenia gravis.

Myasthenia gravis is typically a disease of young people in active employment who need a field of binocular single vision. Although it is systemically controllable with a good chance of spontaneous remission, persistent loss of binocularity may cause chronic disability. We report our experience of extraocular muscle surgery in five patients with stable myasthenia gravis and persistent double vision. Extraocular muscle involvement was selective, giving rise to incomitant and concomitant squints, with individual muscle overactions as well as underactions. Treatment was by conventional recession and resection procedures with the additional use of Faden and adjustable sutures where appropriate. In all five cases a larger, stable field of binocular single vision was established. It is concluded that extraocular muscle surgery may be beneficial in selected cases of myasthenia gravis.

Adolescent↗

PubMedDate not supplied

[ORL manifestations of myasthenia gravis].

Myasthenia gravis is an illness of insidious onset whose first manifestation often is dysphagia. We report the case of a 25 year-old woman who consulted for nosebleed. On her first visit she referred progressive dysphagia, but the results of endoscopic digestive examination and indirect laryngoscopy were normal. The condition evolved until the appearance of weakness of the extremities suggested myasthenia. Myasthenia gravis was diagnosed by means of electromyography and determinations of antibodies against acetylcholine receptors. We reviewed the literature on the clinical manifestations, diagnostic procedures, and treatment of this condition. This case highlights the importance of suspecting myasthenia gravis in young women with dysphagia and a family or personal history of autoimmune disease in order to reach an early diagnosis and treatment.

Adult↗

PubMed1997

[Thymectomy in myasthenia gravis].

Myasthenia gravis is a relatively uncommon autoimmune disorder of neuromuscular transmission. Surgical therapy plays an important role in addition to medical treatment. Follow-up results of 52 patients with thymectomy are presented. Between 1984-1996 thymectomy via median sternotomy was performed in 52 patients with myasthenia gravis (female = 28, male = 24). The score described by Ossermann and Genkins was used for classification. According to this classification, we found 12 patients in class II(I), 21 in class IIA, 17 in class IIB and 2 in class III, respectively. A thymoma was found in 19, follicular lymphoid hyperplasia in 24 and an atrophic thymus in 9 cases, respectively. There was no mortality. Severe postoperative complications consisted of bleeding and reoperation in one patient and another patient developed a sternal instability with consecutive operative refixation. Follow-up evaluation after a mean period of 36 months (min. 6 months, max. 130 months) revealed a relief of myasthenic symptoms in 37 patients. Thymectomy is effective in the treatment of myasthenia gravis with a low complication rate.

Adult↗