Myasthenia gravis, pernicious anemia, and Hashimoto's thyroiditis.

A 68-year-old woman with clinical, electromyographic, and pharmacologic evidence of myasthenia gravis experienced increasing proximal and bulbar muscular weakness. The diagnosis of pernicious anemia was established by typical abnormalities in the peripheral blood and bone marrow aspirate, the serum B12 level, by results of the Schilling test, and by the presence of serum parietal cell antibody. The diagnosis of Hashimoto's thyroiditis was established by the presence of diffuse thyroid enlargement, microsomal thyroid antibodies, an increased thyroid stimulating hormone level, and depressed T2 and T4 levels.