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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↗
PubMed2005

Myasthenia gravis: myasthenia vs. cholinergic crisis.

A serious complication of myasthenia gravis is respiratory failure. This may be secondary to an exacerbation of myasthenia (myasthenia crisis) or to treatment with excess doses of a cholinesterase inhibitor (cholinergic crisis). Managing respiratory failure and differentiating a myasthenia from a cholinergic crisis is reviewed. Due to the unpredictable development of respiratory failure, hospitalization is recommended for most patients with exacerbations or complications of myasthenia gravis.

Acetylcholine↗
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↗
PubMed2006

The limitation of IL-10-exposed dendritic cells in the treatment of experimental autoimmune myasthenia gravis and myasthenia gravis.

Dendritic cells (DC) are highly specialized antigen presenting cells that play critical roles as instigators and regulators of immune responses including B cell function, antibody synthesis and isotype switch. In this study, we compared immunotherapeutic effect of IL-10-treated DC (IL-10-DC) via both intraperitoneal (i.p.) and subcutaneous (s.c.) delivery in rats with incipient experimental autoimmune myasthenia gravis (EAMG). Spleen DC were isolated from onset of EAMG on day 39 post-immunization, exposed in vitro to IL-10, and then injected into incipient EAMG at dose of 1 x 10(6) cells/rat on day 5 after immunization. Intraperitoneal administration of IL-10-DC suppressed clinical scores, anti-acetylcholine receptors (AChR) antibody secreting cells, antigen-specific IL-10/IFN-gamma production and T cell proliferation compared to control EAMG rats. Importantly, IL-10-DC, if given by s.c. route, failed to ameliorate clinical sign of EAMG. Simultaneously, T cell proliferation, anti-AChR antibody secreting cells and IL-10/IFN-gamma production had no alteration, as compared to control EAMG rats. Both in vitro and in vivo experiments showed that treatment of IL-10 inhibited the migration of DC toward MIP-3beta and lymph node, indicating that in vitro manipulation of DC with IL-10 alters the migration of DC that influences the therapeutic effect in the treatment of autoimmune diseases. In MG patients, neither the improvement of clinical symptom nor the alteration of immunological parameter was observed through s.c. delivery of IL-10-DC, suggesting the limitation of IL-10-DC in the treatment of MG patients.

Animals↗
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↗
PubMed2004

Update on myasthenia gravis.

Myasthenia gravis is an autoimmune disorder caused by autoantibodies against the nicotinic acetylcholine receptor on the postsynaptic membrane at the neuromuscular junction and characterised by weakness and fatigability of the voluntary muscles. It has a bimodal peak of incidence with first peak in the third decade and the second peak in the sixth decade. It is probably underdiagnosed in the very old population. Our understanding of the pathogenesis, immunology, and molecular biology of myasthenia gravis has greatly improved in last three decades. It is almost always possible to establish the diagnosis of myasthenia gravis with the current tests. The modern treatment is highly successful and the mortality of treated myasthenia gravis is practically zero. However, there are still important gaps in our knowledge of the origin of myasthenia gravis, the factors that contribute to chronic disease, and the way to cure the disease. In this article the current knowledge of the various aspects of myasthenia gravis are outlined.

Age of Onset↗
PubMed2005

Ocular Myasthenia Gravis.

Myasthenia gravis (MG) is an autoimmune disorder characterized clinically by proximal weakness and bulbar symptoms and pathologically by damage to the post-synaptic membrane at the neuromuscular junction. Ocular myasthenia gravis (ocular MG) is a form of myasthenia gravis whereby the patients' weakness is limited to the muscles of the eyes and eyelids (levator palpebrae superioris). Although not life-threatening, the limitations posed by ocular myasthenia gravis can prove disabling and distressing to patients. Acetylcholinesterase inhibitors such as pyridostigmine or neostigmine are the preferred first-line treatment for ocular myasthenia gravis, with mild cases requiring no additional intervention. However, in moderate or severe cases, treatment must be tailored to the needs and desires of the patient. Intravenous immunoglobulin, although costly, is safe and effective at treating MG. Corticosteroids are effective at reducing or eliminating symptoms and may modify the long-term course of the illness. Steroid-sparing agents such as azathioprine and mycophenolate mofetil are reasonably safe and well-tolerated alternatives to steroids. Surgical interventions such as strabismus surgery and eyelid suspension serve to correct impairments refractory to medical management. Thymectomy, although less frequently recommended, is a reasonable consideration, especially for young adults, given the potential for long-term benefit.

Journal Article↗
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↗
PubMed2006

Delayed synapsing muscles are more severely affected in an experimental model of MuSK-induced myasthenia gravis.

Myasthenia gravis can be induced in mice by injecting the extracellular domain of rat muscle-specific kinase (MuSK), a transmembrane receptor tyrosine kinase involved in agrin signaling at the neuromuscular junction. About 5-10% of human myasthenia gravis patients have autoantibodies against MuSK. Here we have examined mouse neuromuscular junctions following MuSK immunization in two groups of muscles that can be distinguished on the basis of the timing of neuromuscular synaptogenesis and their response to perturbation of agrin signaling. We used confocal microscopy to characterize the distribution and expression of nicotinic acetylcoline receptors and of two presynaptic makers, neurofilament protein and synaptophysin. We observed disruption of neuromuscular junctions in all muscles examined in this model of myasthenia gravis. However delayed-synapsing muscles, including the diaphragm, sternomastoid and tibialis posterior, were significantly more severely affected than fast-synapsing muscles, including the intercostal, adductor longus and tibialis anterior. These results suggest a basis for the differential susceptibility of muscles in different classes of myasthenia gravis patients, including patients with autoantibodies against MuSK.

Agrin↗
PubMed2006

Drug related crisis in myasthenia gravis.

Myasthenia gravis is an autoimmune disorder where antibodies against the nicotinic Ach receptor resulting in impaired transmission at the NM junction. A number of drugs have been reported to cause neuromuscular blockade and/or to increase weakness in myasthenia gravis. We report a case of myasthenia gravis in which the calcium channel blocker-nifedipine caused the worsening of the symptoms.

Adult↗
PubMed2005

The role of the thymus in the pathogenesis of myasthenia gravis.

Myasthenia gravis is an organ-specific autoimmune disease characterized by the production of anti-acetylcholine receptor antibodies. In this review, I describe the pathophysiological importance of the altered chemokine receptor-mediated signaling in the thymus and peripheral blood of myasthenia gravis patients. The epidemiological and clinical features of myasthenia gravis are also discussed.

Animals↗
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↗