Myasthenia gravis characteristics

Vincent A, Newsom-Davis J. Acetylcholine receptor antibody characteristic in myasthenia gravis. Patients with penicillamine-induced myasthenia or idiopathic myasthenia of recent onset. Clin Exp Immunol 1982 49 266-272. 

D-penicillamine is so named because it was first isolated as an amine, from the degradation products of penicillin by Abraham et al [87]. Later studies showed the characteristic chemical behavior of D-penicillamine which involve three types of reactions, formation of disulphide links, formation of thiazolidine rings, and formation of metal complexes and chelates [67]. It was first used in 1956 in the treatment of Wilson s disease [88]. D-penicillamine has since been used in the treatment of many diseases, such as cystinuria [89], rheumatoid arthritis [90-92], systemic sclerosis [93], primary bdiary cirrhosis [94], heavy metal poisoning due to lead [95], cadmium [%], and mercury [97], and hyperviscosity syndrome [99]. In rheumatoid arthritis, D-peni-cdlamine has been widely accepted as an effective second line treatment. Despite of its effectiveness, it causes many adverse effects, such as skin rashes [99,100], taste abnormalities [100,101], hepatic dysfunction [102-104], gastrointestinal toxiciiy [99,105], proteinuria [100,106], hematuria [107, 108], thrombocytopenia [92, 109], aplastic anemia [110], lupus-like syndrome [111, 112], Goodpasture s-tike pulmonary renal syndrome [113-115], vasculitis [116,117], myasthenia gravis [118-122], polymyositis [123, 124], and dermatomyositis [125]. 

Table 2 summarize.s the main clinical and EMG characteristics of some well-known disorders of neuromuscular transmission. Myasthenia gravi.s i.s an autoimmune disorder with postsynaptic impairment of neuromu.scuiar transmission due to complement deposition at the ACh receptor... 

The degree of recorded jitter in SFEMG is directly related to the release of ACh and the function of the ACh receptors in the NMJ. SFEMG therefore provides a window into the operation of the NMJ. Jitter is characteristically increased in conditions (both pre- and post-junctional) of the NMJ which reduce the safety margins of neuromuscular transmission. Thus, there is increased jitter in conditions such as myasthenia gravis and Lambert-Eaton syndrome. Jitter is also increased following the administration of small doses... 

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