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At least 307 records · Page 17Linked to original sources

PubMed2004

Pediatric myasthenia gravis and velopharyngeal incompetence.

OBJECTIVE: To determine the clinical course of velopharyngeal incompetence in children with myasthenia gravis (MG). METHODS: A 30-year retrospective study was performed using the medical records of 538 children who presented with velopharyngeal inadequacy (VPI) to a tertiary care academic pediatric center. Children with velopharyngeal incompetence due to myasthenia gravis were identified and their clinical courses were reviewed. RESULTS: Four children were identified with velopharyngeal incompetence associated with myasthenia gravis. All four children required intervention for improvement of speech intelligibility. A speech prosthesis was the uniform intervention. CONCLUSION: Neonatal myasthenia gravis patients should be followed long-term as symptoms may recur as speech impairment. In addition, a high index of suspicion for this entity is required for early diagnosis due to the highly variable presentation and clinical course.

Adolescent↗

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↗

PubMed1987

Alfred Blalock and thymectomy for myasthenia gravis.

In 1936, Alfred Blalock performed the successful removal of a thymic tumor in a patient with myasthenia gravis. The patient experienced marked and sustained improvement for several years. Blalock prophesized then that exploration of the thymic region would be indicated in all patients with severe myasthenia gravis. A few years later, in 1941, he applied this theory by introducing thymectomy for nonthymomatous myasthenia and achieved similar improvement. Despite modern sophisticated knowledge about the disease and advances in thoracic surgical techniques, Blalock's original observations remain valid, and thymectomy has become a standard treatment for myasthenia gravis the world over.

History, 20th Century↗

PubMed1977

Contemporary management of myasthenia gravis: the clinical role of thymectomy.

Thirty-six patients with myasthenia gravis have been evaluated and treated over the past five years. Eleven patients had ocular myasthenia gravis and responded well to anticholinesterase medications. Twenty-five patients had generalized myasthenia gravis, and 22 of them were initially treated with anticholinesterase medications; 18(82%) failed to improve or to maintain an initial improvement on medication, and 14 of these 18 patients underwent thymectomy. In addition, 3 patients underwent thymectomy as part of their initial treatment during the later part of this study. All thymectomies were performed through a median sternotomy. All 17 patients manifested sustained improvement as judged by a gain in strength and decrease in medications. Thymectomy is beneficial in the treatment of myasthenia gravis, and it is most efficacious when performed early in the course of the disease.

Adolescent↗

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↗

PubMed1980

Myasthenia gravis with a monoclonal gammopathy--report of a case.

An elderly man with relapsing myasthenia gravis was found to have hypergammaglobulinaemia, a monoclonal peak of gamma mobility and paraproteinaemia IgG, type K. Bence-Jones proteinuria, type K was present. This is the fourth report of myasthenia gravis associated with a monoclonal gammopathy. Myasthenia gravis is considered to be an autoimmune disease. Recent findings implicate a dysfunction of cellular immunity in the pathogenesis of both immunoproliferative and autoimmune disease. We suggest that the association of myasthenia gravis and monoclonal gammopathy in our patient might have stemmed from a disorder of T lymphocyte function.

Aged↗

PubMed1998

Quantitative ocular tests for myasthenia gravis: a comparative review with detection theory analysis.

Many reports in the literature describe a variety of ocular signs in myasthenia gravis. To determine the utility of laboratory recordings of ocular signs in the evaluation for myasthenia, we reviewed all previous studies of quantitative measures of eye movements or intra-ocular pressures. We selected those studies with data presented for both myasthenic and non-myasthenic ocular palsies. Signal detection theory was used to evaluate the discriminative power of each variable. The characteristics of saccades and quick phases of optokinetic nystagmus at the start of recording were poor at distinguishing between myasthenic and non-myasthenic palsies, except when the comparison was solely between myasthenia and chronic progressive external ophthalmoplegia. The effects of fatigue on saccadic parameters were also not discriminative, though there was insufficient data to evaluate this adequately. Changes induced by edrophonium in the amplitude or peak velocity of saccades or optokinetic quick phases were good diagnostic tests, retaining high sensitivities when criteria were set to yield a specificity of 95%. Most of these parameters were less efficient as screening tests, with modest specificities when criteria were set to yield a sensitivity of 95%. The change in optokinetic quick phase amplitude recorded by infrared oculography was the best test, with ideal characteristics of 97% specificity and sensitivity at a criterion of zero change. This analysis suggests that eye movement recordings of saccades or optokinetic nystagmus have potential as useful and inexpensive tests for myasthenia, and warrant further study.

Edrophonium↗

PubMed2003

The immunologic role of thymectomy in the treatment of myasthenia gravis: implication of thymus-associated B-lymphocyte subset in reduction of the anti-acetylcholine receptor antibody titer.

BACKGROUND AND PURPOSE: Thymectomy is generally accepted as the major option of treatment for myasthenia gravis. To elucidate the biological role of thymectomy in the treatment of myasthenia gravis, the immunologic characteristics of the thymus was studied in association with the postoperative kinetics of the anti-acetylcholine receptor antibody titer. MATERIALS AND METHODS: Thirty-four patients with nonthymomatous myasthenia gravis who had positive anti-acetylcholine receptor antibody titer and undergoing extended thymectomy were subjected to the study. Reduction of anti-acetylcholine receptor antibody titer was evaluated in terms of the proportion of anti-acetylcholine receptor antibody titer at 1 year after thymectomy to that before the operation. The numbers of B lymphocytes (CD19(+) cells) and the germinal center B lymphocytes (CD19(+)CD38(high) cells) present in 1 g of the thymic tissue were calculated by flow cytometry. RESULTS: The proportion of anti-acetylcholine receptor antibody titer at 1 year after thymectomy ranged from 27.5% to 150%. The numbers of B lymphocytes and the germinal center B lymphocytes in 1 g of the thymic tissue ranged from 0.19 x 10(6)/g to 162.8 x 10(6)/g and from 0.09 x 10(6)/g to 33.4 x 10(6)/g, respectively. The proportion of anti-acetylcholine receptor antibody titer at 1 year after thymectomy had a significant inverted correlation with the number of B lymphocytes (P =.002) as well as that of the germinal center B lymphocytes (P =.007). CONCLUSION: Effectiveness of thymectomy was dependent on predominance of B lymphocytes and the germinal center B lymphocytes in the thymus, suggesting that one of the biological roles of thymectomy in the treatment of myasthenia gravis is removing the thymus-associated germinal centers.

ADP-ribosyl Cyclase↗

PubMed2005

[Atypical ocular myasthenia gravis].

The diagnosis of ocular myasthenia gravis is rarely in doubt in patients with a proper history and typical clinical findings. However, myasthenia gravis can mimick any pupil-sparing eye movement disorder and several diseases may masquerade myasthenia gravis. We review the atypical presentations and differential diagnoses in ocular myasthenia gravis, describing four patients with some of these conditions (4th nerve palsy, near spasm reflex, one-and-a-half syndrome, orbital meningioma). The correct interpretation of the clinical findings associated with appropriate neuro-imaging studies allowed the appropriate diagnosis in these cases.

Adult↗

PubMed1999

Chiropractic management of a patient with myasthenia gravis and vertebral subluxations.

OBJECTIVE: The chiropractic management of a patient with myasthenia gravis and vertebral subluxation is described. We discuss the pathophysiology, clinical features, and treatment of patients with these diseases. CLINICAL FEATURES: The 63-year-old male patient suffered from complaints associated with the disease myasthenia gravis along with signs of vertebral subluxation. The patient had an initial complaint of dysphagia. In addition, the patient experienced swelling of the tongue, nausea, digestive problems, weakness in the eye muscles, difficulty breathing, myopia, diplopia, and headaches. Balance and coordination problems resulted in walking difficulties. INTERVENTION AND OUTCOME: Contact specific, high-velocity, low-amplitude adjustments were applied to sites of patient subluxation. Myasthenia gravis is no longer debilitating to the patient; he is medication free and has resumed a "normal life." CONCLUSION: The clinical aspects of the disease, including the possible role of chiropractic intervention in the treatment of patients suffering from myasthenia gravis, are also discussed. This case study encourages further investigation into the holistic approach to patient management by chiropractors vis-a-vis specific adjustments of vertebral subluxation.

Cervical Vertebrae↗

PubMed1984

Antibodies against human neuroblastoma cells in the sera of patients with myasthenia gravis.

The autoimmune nature of acquired myasthenia gravis is well documented. Although anti-acetylcholine receptor antibodies are pathognomonic for this disease, their significance in the immunopathogenesis of myasthenia gravis may differ among patients. The presence of antibodies against human neuroblastoma cells in myasthenic sera was studied using the 125I-labelled protein-A radioimmunoassay and indirect immunofluorescence. For comparison sera of patients with other neurological diseases were examined. Significant levels of antibodies against neuroblastoma cells were found in the sera of over 60% of myasthenia gravis patients and in some patients of the other disease groups, but mainly in lower titers. Our findings suggests a more generalized neuroimmunological abnormality in some myasthenia gravis patients.

Adolescent↗

PubMed1998

The impact of HLA on long-term outcome after thymectomy for myasthenia gravis.

In a retrospective series of 86 patients with myasthenia gravis, the only factors predictive of improvement in muscular strength after transsternal thymectomy were preoperative severity of myasthenia (90% versus 54%, p = 0.0014) and HLA-B8 (79% versus 50%, p = 0.0060) in bivariable and multivariable analyses. Both factors were not interrelated (p = 0.824). The statistical effect of HLA-B8 was independent from preoperative severity of disease. Typing for HLA-B8 may thus be a valuable adjunct in predicting the benefit of thymectomy in myasthenia. The observation that an MHC class I allele is associated with clinical improvement after thymectomy suggests that the clinical course of myasthenia may be influenced by class I restricted T-cells.

Alleles↗

PubMed1998

Antibodies against beta1 and beta2 adrenergic receptors in myasthenia gravis.

Patients with myasthenia gravis have antibodies and T cells that react with the beta1- and beta2-adrenergic receptors. These receptors, as well as other auto-antigens, are present on cardiomyocytes, skeletal muscle cells and lymphocytes and are of importance for the regulation of the functions of these organs. Antibodies against the beta1-adrenergic receptor have been implicated in dilated cardiomyopathies. Myasthenia gravis (MG) patients have been suggested to have a higher than normal prevalence of heart disease. We have analysed the isotypes, subclasses, and binding sites of the beta-adrenergic receptors antibodies in both MG patients and healthy individuals and the correlation between beta-adrenergic receptors antibodies and heart disease in MG patients. The patients have IgG antibodies that react with both beta1- and beta2-adrenergic receptors. The subclasses were predominantly IgG2 and IgG4. By using synthesised overlapping peptides representing the immunodominant regions on the receptors, it was shown that the antibodies bound to partially overlapping sites on both beta1- and beta2-adrenergic receptors, but not to peptides from the acetylcholine receptor. beta-adrenergic receptor antibodies were found in 34/125 MG patients. Seven out of these 34 patients had symptomatic heart disease, all seven were over 70 years of age and had arteriosclerotic heart disease. There was no difference in the prevalence of clinical heart disease in patients with and without beta-adrenergic receptor antibodies. However, patients with heart disease had significantly higher levels of antibodies than healthy individuals and other patients. Antibodies against beta-adrenergic receptors in patients with myasthenia gravis binds to both beta1- and beta2-adrenergic receptors and might be implicated in the few patients with myasthenia gravis who have heart disease.

Aged↗

PubMed1988

Pemphigus, myasthenia gravis, and pregnancy.

A 27-year-old woman with active but stable myasthenia gravis developed pemphigus while she was pregnant. Therapeutic abortion performed for personal reasons was followed by clinical and serologic improvement in her immunobullous disease. Both autoimmune conditions, pemphigus and myasthenia gravis, may be adversely affected by pregnancy. As with another immunobullous disease, herpes gestationis (bullous pemphigoid of pregnancy), hormonal factors appear to induce pemphigus. Although myasthenia gravis and pemphigus have been reported during pregnancy, this is the first instance of coexisting myasthenia gravis and pemphigus in a pregnant woman.

Abortion, Therapeutic↗

PubMed2002

Myasthenia gravis and disorders of neuromuscular transmission.

Myasthenia gravis is a disorder of neuromuscular transmission that occurs in congenital and acquired autoimmune forms. Acquired myasthenia gravis is probably the most common neuromuscular disorder in dogs that can be diagnosed and treated. An early, accurate diagnosis and appropriate therapy is of utmost importance to a good clinical outcome in this disorder. This article focuses on the diagnosis and treatment of acquired myasthenia gravis in dogs and cats with brief discussions of other disorders of neuromuscular transmission, including congenital myasthenia gravis, tick paralysis, botulism, and organophosphate intoxication.

Animals↗

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↗

PubMed2001

[Myasthenia gravis and elderly persons. A case study].

INTRODUCTION: Myasthenia gravis is an uncommon autoimmune disease which affects all ages. There are late-onset occurrences whose diagnosis is not considered often enough in geriatrics. EXEGESIS: We report a case of late-onset myasthenia gravis with a 78-year-old woman who was multi-pathologic and hospitalized for a diplopia check-up and recurrent falls. These stress the difficulty of suggesting myasthenia gravis in geriatrics due to the number of differential diagnoses that can mislead the physician. For the elderly subject, the diagnostic methodology is close to that of the younger subject. The search for related diseases must be systematic. CONCLUSION: Late-onset myasthenia gravis must remain a diagnosis present in the mind of the physician because of the significant improvement of the functional prognosis after the start of the treatment. The majority of subjects will recover a normal life.

Accidental Falls↗

PubMed1998

Juvenile myasthenia gravis: treatment with immune globulin and thymectomy.

Juvenile myasthenia gravis is rare, representing just 10% of all myasthenia gravis. Treatment of the juvenile form is similar to the adult form, although concerns of long-term side effects limit use of immunomodulators and thymectomy in children, especially the very young. We review the clinical course of three children with juvenile myasthenia gravis, as well as the current status of intravenous immunoglobulin and thymectomy as treatments for juvenile myasthenia gravis.

Adolescent↗