Neurology Service, Department of Veterans Affairs, Pittsburgh, PA 15240, USA.
J Neurol. 2012 Oct;259(10):2167-71. doi: 10.1007/s00415-012-6478-6. Epub 2012 Apr 5.
An increasing incidence of myasthenia gravis (MG) has been reported in the elderly, but the full clinical ramifications of late-onset myasthenia gravis (LOMG) remain unclear. We describe the clinical features of our cohort of patients with MG with an emphasis on an onset after the age of 50. This was a retrospective analysis of medical records of a cohort of patients followed in two tertiary neuromuscular clinics and comparison of early onset MG (EOMG) versus LOMG. There were 174 patients with a mean age of onset of 55.2 ± 19.1 years, and 44 % were women. Late onset of myasthenia gravis after age 50 was reported in 114 patients (66 %). Anti-AChR antibody titers were elevated in 78 % of patients (65 % with EOMG vs. 85 % with LOMG; p = 0.003), and frequency of elevated titers of anti-MuSK antibodies was similar in both groups (present in 38 % of all tested seronegative patients). Myasthenic crisis was equally common in generalized EOMG and LOMG (13 %). Ocular MG was more common in LOMG compared to EOMG (40 vs. 18 %, p = 0.021). Diabetes was more prevalent with LOMG (27 vs. 5 %; p = 0.0002). Overlapping clinical features of EOMG and LOMG are consistent with a continuous clinical spectrum of a single condition, with more frequent occurrence of seropositive and ocular MG with a late onset. A higher burden of comorbidities, such as diabetes mellitus, may warrant a modified approach to treatment of myasthenia in LOMG. However, overall disease severity may not be higher with aging. These observations have implications for design of MG clinical trials and outcomes studies.
重症肌无力（MG）在老年人中的发病率不断增加，但迟发性重症肌无力（LOMG）的全部临床后果仍不清楚。我们描述了我们的 MG 患者队列的临床特征，重点是 50 岁后发病。这是对在两个三级神经肌肉诊所就诊的患者队列的病历进行的回顾性分析，并比较了早发性 MG（EOMG）与 LOMG。患者的平均发病年龄为 55.2 ± 19.1 岁，其中 44%为女性。114 例患者（66%）报告在 50 岁后出现迟发性 MG。78%的患者乙酰胆碱受体抗体滴度升高（65%的 EOMG 与 85%的 LOMG 相比，p = 0.003），两组抗 MuSK 抗体滴度升高的频率相似（所有测试阴性患者中有 38%存在）。全身性 EOMG 和 LOMG 中肌无力危象同样常见（13%）。与 EOMG 相比，LOMG 中更常见眼肌型 MG（40%比 18%，p = 0.021）。LOMG 更常见糖尿病（27%比 5%；p = 0.0002）。EOMG 和 LOMG 的重叠临床特征与单一疾病的连续临床谱一致，血清阳性和眼肌型 MG 的发生更为频繁，发病较晚。合并症（如糖尿病）的负担较高，可能需要对 LOMG 中的肌无力治疗方法进行修改。然而，随着年龄的增长，疾病的严重程度可能不会更高。这些观察结果对 MG 临床试验和结果研究的设计具有重要意义。
