Marinó M, Ricciardi R, Pinchera A, Barbesino G, Manetti L, Chiovato L, Braverman L E, Rossi B, Muratorio A, Mariotti S
Institute of Endocrinology, University of Pisa, Italy.
J Clin Endocrinol Metab. 1997 Feb;82(2):438-43. doi: 10.1210/jcem.82.2.3749.
Myasthenia gravis (MG) may occur in association with autoimmune thyroid diseases (AITD). The aim of this study was to evaluate the features of MG associated with AITD compared to those of MG without AITD. A total of 129 MG patients (34 men and 95 women; age range, 11-81 yr) were subdivided into: group A, 56 MG patients with AITD [25 with autoimmune thyroiditis and 31 with Graves' disease (GD)]; group B, 21 MG patients with nonautoimmune thyroid diseases; and group C, 52 MG patients without thyroid disease. The severity of MG was ranked according to the Osserman score. Laboratory evaluation included assays for antithyroid and antiacetylcholine receptor (AchRAb) antibodies. Ocular MG (Osserman's class 1) was more frequent in group A (41.0%) than in group B (14.2%; P < 0.03) or C (21.4%; P < 0.03). Severe generalized MG (classes > or = 2B) was more frequent in groups B (57.1%; P < 0.03) and C (51.9%; P < 0.02) than in group A (28.5%). GD patients with clinical evidence of ophthalmopathy had a higher frequency (P = 0.05) of ocular MG (57.8%) than GD patients without clinical ophthalmopathy (16.6%). Thymic disease was less frequent in group A (26.7%) than in group B (71.4%; P = 0.001) or C (59.7%; P = 0.001). The prevalence of thymic hyperplasia was 17.8%, 38.0%, and 40.3% in groups A, B, and C, respectively; the prevalence of thymoma was 8.9%, 33.4%, and 19.4%. When only patients with generalized MG were considered, thymic disease was less frequent (P < 0.02) in group A (40.6%) than in the remaining groups (69.4%). AchRAb was more frequent in groups B (57.1%) and C (57.6%; P < 0.03) than in group A (35.7%). In conclusion, MG associated with AITD has a mild clinical expression, with preferential ocular involvement and lower frequency of thymic disease and AchRAb. This supports the hypothesis that ocular and generalized MG are separate diseases with different spectra of associated diseases. Nonautoimmune thyroid diseases have no influence on the features of MG. The association of ocular MG and AITD might be due to a common autoimmune mechanism and/or a peculiar genetic background.
重症肌无力（MG）可能与自身免疫性甲状腺疾病（AITD）相关。本研究的目的是评估与无AITD的MG患者相比，与AITD相关的MG的特征。总共129例MG患者（34例男性和95例女性；年龄范围11 - 81岁）被分为：A组，56例伴有AITD的MG患者[25例患有自身免疫性甲状腺炎，31例患有格雷夫斯病（GD）]；B组，21例患有非自身免疫性甲状腺疾病的MG患者；C组，52例无甲状腺疾病的MG患者。MG的严重程度根据奥斯勒曼评分进行分级。实验室评估包括抗甲状腺和抗乙酰胆碱受体（AchRAb）抗体检测。眼肌型MG（奥斯勒曼1级）在A组（41.0%）中比在B组（14.2%；P < 0.03）或C组（21.4%；P < 0.03）中更常见。重度全身型MG（≥2B级）在B组（57.1%；P < 0.03）和C组（51.9%；P < 0.02）中比在A组（28.5%）中更常见。有眼部病变临床证据的GD患者眼肌型MG的发生率（P = 0.05）高于无临床眼部病变的GD患者（16.6%）。胸腺疾病在A组（26.7%）中比在B组（71.4%；P = 0.001）或C组（59.7%；P = 0.001）中更少见。胸腺增生的患病率在A、B、C组中分别为17.8%、38.0%和40.3%；胸腺瘤的患病率分别为8.9%、33.4%和19.4%。当仅考虑全身型MG患者时，A组（40.6%）的胸腺疾病比其余组（69.4%）更少见（P < 0.02）。AchRAb在B组（57.1%）和C组（57.6%；P < 0.03）中比在A组（35.7%）中更常见。总之，与AITD相关的MG具有轻度的临床表型，以眼肌受累为主，胸腺疾病和AchRAb的发生率较低。这支持了眼肌型MG和全身型MG是具有不同相关疾病谱的不同疾病这一假说。非自身免疫性甲状腺疾病对MG的特征没有影响。眼肌型MG与AITD的关联可能是由于共同的自身免疫机制和/或特殊的遗传背景。
