Clinical differences between early- and late-onset myasthenia

Objective\r\nTo explore the clinical differences between patients with early-onset myasthenia gravis(EOMG)and those with late-onset myasthenia gravis(LOMG). \r\n\r\n\r\nMethods\r\nThis was a retrospective study enrolling 157 MG patients.Based on the age of onset, patients were divided into the EOMG group(n=85)and the LOMG group(n=72). The groups were compared on clinical characteristics, including clinical manifestations, MG classification, electrophysiological findings on repetitive nerve stimulation(RNS), single fiber electromyography(SFEMG), levels of antibody against acetylcholine receptors(Ach-R Ab), antibody to muscle-specific kinase(MuSK Ab), titin antibody(Titin Ab), ryanodine receptor antibody(RyR Ab), thyroid function, thymectomy, thymus pathology and responses to treatment. \r\n\r\n\r\nResults\r\nThe mean ages of onset were markedly different〔(40.9±9.7)years vs.(62.0±12.2)years, P 0.05). Moreover, patients in the EOMG group were more likely to have abnormal thyroid function and higher percentages of receiving steroids, tacrolimus, plasma exchange therapy, and thymectomy(P\u003c0.05). \r\n\r\n\r\nConclusions\r\nThe clinical profiles of LOMG are different from those of EOMG in clinical manifestations, thyroid function, thymectomy frequency, striational antibody levels and disease-modifying drug options.\r\n\r\n\r\nKey words: \r\nMyasthenia gravis; Recepors, cholinergic