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Ocular myasthenia gravis (OMG) is a neuromuscular disease characterized by autoantibody production against post-synaptic proteins in the neuromuscular junction. The pathophysiological auto-immune mechanisms of myasthenia are diverse, and this is governed primarily by the type of autoantibody production. The diagnosis of OMG relies mainly on clinical assessment, the use of serological antibody assays for acetylcholine receptors (AchR), muscle-specific tyrosine kinase (MusK), and low-density lipoprotein 4 (LPR4). Other autoantibodies against post-synaptic proteins, such as cortactin and agrin, have been detected; however, their diagnostic value and pathogenic effect are not yet clearly defined. Clinical tests such as the ice test and electrophysiologic tests, particularly single-fiber electromyography, have a valuable role in diagnosis. The treatment of OMG is primarily through cholinesterase inhibitors (pyridostigmine), and steroids are frequently required in cases of ophthalmoplegia. Other immunosuppressive therapies include antimetabolites (azathioprine, mycophenolate mofetil, methotrexate) and biological agents such as B-cell depleting agents (Rituximab) and complement inhibitors (eculizumab). Evidence is scarce on the effect of immunosuppressive therapy on altering the natural course of OMG. Clinicians must be vigilant of a myasthenic syndrome in patients using immune-check inhibitors. Reliable and consistent biomarkers are required to assess disease severity and response to therapy to optimize the management of OMG. The purpose of this review is to summarize the current trends and the latest developments in diagnosing and treating OMG. [ABSTRACT FROM AUTHOR]

Introduction: Since the onset of the novel coronavirus pandemic, several neurological complications secondary to SARS‐CoV‐2 infection have been reported, affecting central nervous system, peripheral nervous system and neuromuscular junction. Case report: We present the case of a 77‐year‐old man who developed bulbar myasthenia gravis (MG) eight weeks after SARS‐CoV‐2 infection. The search for serum antibodies against the acetylcholine receptor and the muscle‐specific tyrosine kinase (MuSK), performed by radioimmunoassay (RIA), and the search of low‐density lipoprotein receptor‐related protein 4 antibodies, performed by immunohistochemistry, resulted negative, while anti‐MuSK antibodies were detected by cell‐based assay (CBA). The patient was treated with pyridostigmine (60 mg four times a day) with unsatisfactory clinical response, followed by immunosuppressive therapy (azathioprine 1.5 mg/kg/day) with improvement of MG symptoms after two months of treatment. Discussion: Several viral diseases have been described as associated with the onset of MG, although the underlying mechanisms are not yet fully understood. Similarly, a growing number of scientific reports suggest a correlation between SARS‐CoV‐2 infection and autoimmune diseases. The interest of our case lies in the timing of the MG onset (after 2 months from infection), together with the unusual late onset of anti‐MuSK MG. These elements suggest that coronavirus infection may act as a trigger of the disease. We confirm the importance of CBA in the serological diagnosis of RIA‐negative MG. [ABSTRACT FROM AUTHOR]

Myasthenia gravis with antibodies to muscle-specific tyrosine kinase (MuSK-MG) is generally considered a severe disease because of the associated weakness distribution with prevalent involvement of bulbar muscles and a rapidly progressive course and early respiratory crises. Its treatment can be unrewarding, owing to poor response to acetylcholinesterase inhibitors in most patients, disease relapses in spite of high-dose immunosuppression, and development of permanent bulbar weakness. High-dose prednisone plus plasma exchange is the recommended approach for treating rapidly progressive bulbar weakness. In the disease management, oral steroids proved effective, plasma exchange produced marked, albeit short-term, improvement, while conventional immunosuppressants were comparatively less effective. Rituximab is a promising treatment for refractory MuSK-MG; in uncontrolled studies, nearly all treated patients achieved significant improvement with substantial decrease of medication. It is yet to be clarified whether the early use of rituximab could prevent the permanent bulbar weakness, which constitutes a relevant disability in these patients. [ABSTRACT FROM AUTHOR]

Myasthenia gravis (MG) is an autoimmune neuromuscular transmission disorder where welldefined autoantibodies against muscle and muscle cell membrane molecules are directly pathogenetic. All MG patients should be defined for subtype, as such a subclassification has treatment consequences. Ocular MG, early-onset MG, late-onset MG, MG with thymoma, MG with anti-muscle-specific tyrosine kinase antibodies and MG with no defined antibodies constitute the six MG categories. The MG diagnostic process includes neurophysiology, neuroimmunology, neuropharmacology and imaging. In addition to symptomatic therapy with acetylcholine esterase inhibitors, most patients need thymectomy and/or immunosuppressive drugs. Today's treatment is not immunospecific and far from antigen-specific, even if the pathogenesis is known in detail. Strategies for acetylcholine receptor tolerance induction, manipulating acetylcholine receptor antigen presentation or suppressing acetylcholine receptorspecific B-cells or plasma cells work in experimental MG, but have not yet been attempted properly for the human disease, or they do not work. Apart from the 10-15% of patients with paraneoplastic MG, the cause of the disease is not known. Until curative or antigen-specific therapy become available, the well-established treatment gives good-to-excellent results in most patients, with acceptable quality of life and no increased mortality. Acute and intensive care treatment during MG exacerbation is a cornerstone in the treatment. [ABSTRACT FROM AUTHOR]

Objective: Myasthenia gravis (MG) is an autoimmune neuromuscular disorder for which current therapies carry a high risk of side-effects and may be insufficient in stabilizing the clinical status. Many therapeutic options can be ruled, such as thymectomy, corticosteroids, azathioprine, cyclophosphamide, mycophenolate mofetil, methotrexate, intravenous immunoglobulin (IVIg) or less frequently plasmapheresis must be ruled. Methods: We followed prospectively six patients with MG who presented with a poor response to two or three lines of immunosuppressive conventional drugs associated with oral corticosteroids. All but one were acetylcholine receptor negative and three were anti-MuSK positive. IVIg did not improved the neurological status and all patient required high doses of cholinesterase inhibitors. Results: Rituximab was introduced with a mean follow-up of 1.5 years (375 mg/m2, days 1, 8, 15, 28 during the first month and then one dose every 2 months). After 2 years of follow-up, all patients stopped corticosteroids and tapered off cholinesterase inhibitors from 60 to 180 mg/day without severe infectious events. Conclusion: Rituximab, a chimeric IgG k monoclonal antibody that target CD20 is used for the treatment of relapsing/refractory CD20 positive low-grade non-Hodgkin’s lymphoma and other autoimmune neuromuscular diseases. Four previous short reports have described a good response of MG associated with lymphoma with rituximab. It appears to be a promising and effective drug for the treatment of MG without lymphoma, with a substantial benefit to the clinical status and good tolerability. [ABSTRACT FROM AUTHOR]

Myasthenia gravis (MG) with antibodies against the muscle-specific tyrosine kinase (MuSK abs) is often a severe disease requiring aggressive treatment. Various immunosuppressive (IS) regimens have been employed; the efficacy of plasma exchange is unanimously recognized, while the indication for thymectomy is controversial. We evaluated the response to therapy in 57 MuSK-positive patients (12 M/45 F) comparing our experience with other authors' results. Disease severity and response to treatment were graded according to MG Foundation of America; follow-up ranged from 0.5–29 years. Owing to both MG severity and the unsatisfactory response to cholinesterase inhibitors, most patients (54/57) needed IS treatment, and 35 received one or more courses of plasma exchange and intravenous immunoglobulin. At the end of follow-up, the rate of complete remission was 8.8%, and IS treatment had been withdrawn in only 10/54 patients. The extent of therapeutic response varied considerably. With conventional IS therapy (prednisone alone or in combination with azathioprine or cyclosporine), most patients achieved good control of their disease, but 30% of them were left with permanent facial and bulbar weakness. In patients with refractory disease, the use of mycophenolate mofetil and rituximab proved very effective, as also reported by other authors. In our and others' experience, MuSK-positive MG markedly improves with IS therapy, although, in comparison with the AChR-positive disease, it is characterized by a lower remission rate, as a higher proportion of patients remain dependent on treatment. Thymectomy is mostly considered scarcely effective; however, at present, no firm conclusions can be drawn on its role in the treatment of this form of MG. [ABSTRACT FROM AUTHOR]

Abstract: Anti-MuSK antibodies have been reported in about 40–50% of patients with seronegative myasthenia gravis. Curiously, this condition has never been reported in association with fetal or transient neonatal myasthenia gravis, despite a known female predominance. We report the case of a 22-year-old woman who developed seronegative, mild steroid-responsive myasthenia gravis. When aged 26, she gave birth to a baby boy with neonatal myasthenia gravis characterized by hypotonia, stridor and sucking difficulties. Intubation was required for a few weeks. Anti-MuSK antibodies were assessed and found positive in both patients. Progressive hydramnios during the last trimester, with a decrease in spontaneous fetal mobility in the last weeks, long-lasting stridor, ptosis and occasional difficulties in swallowing liquids till two years of age, despite anti-MuSK antibodies becoming negative, suggest a fetal onset. The possible pathophysiology of this disorder, based on recent findings on the expression and function of MuSK protein, is reviewed. [Copyright &y& Elsevier]

A 37-year-old man with anti-muscle-specific tyrosine kinase (MuSK) antibody-positive myasthenia gravis (MG) presented with subacute progressive dysphagia and muscle weakness of the neck and bilateral upper extremities. Conventional immune-suppressive treatments and high-dose intravenous immunoglobulin were ineffective. He then displayed repeated exacerbations and remissions over the course of two years, despite two to four sessions of plasma exchange (PE) every two months. The patient was successfully treated with outpatient periodic weekly blood purification therapy with alternative PE and double-filtration plasmapheresis using an internal shunt. This case report suggests the benefits of blood purification therapy with an internal shunt against anti-MuSK antibody-positive MG.