Clinical Studies on Associated Autoimmune Disease with Myasthenia Gravis

ABSTRACT

It is well known that myasthenia gravis is one of the most important autoimmune disease in neurology. Authors analyzed clinical and laboratory data of 118 patients with myasthenia gravis who were diagnosed at our hospital from January 1985 to August 1990. They consisted of 37 cases with ocular type, 38 cases with mild generalized type, 25 cases with moderate generalized type, 13 cases with myasthenic crisis, and 5 cases with late severe type. Of 118 patients, 11 cases were associated with thyroid diseases (9.3%), 1 with rheumatoid arthritis (0.8%), 2 with polymyositis (1.7%), 1 with insulin dependent diabetes mellitus (0.8%), and 1 with probable pemicious anernia (0.8%). Eleven cases with thyroid diseases consisted of hyperthyroidism in seven, hypothyroidism in two, and euthyroid status in three such as nontoxic goiter. Interestingly one patient was diagnosed as polyglandular autoimmune syndrome who had myasthenia gravis, thyrotoxicosis and diabetes mellitus. Symptoms of the thyroid disease preceded myasthenic symptoms in five of them. However the myasthenic symptoms appeared concomitantly in three, and followed by the clinical manifestations of thyroid disorder in three. Most of the myasthenic patients with thyroid disease showed favorable responses to medical treatment. Of the other 67 cases who were not associated with definite clinical autoimmune diseases, ten (14.9%) also revealed positive results for one of those antinuclear antibody, rheumatoid factor, antithyroglobulin antibody and antimicrosomal antibody tests.