Walsh & Hoyt: Graves' Disease

Perhaps the most common systemic disorder associated with diplopia, ophthalmoparesis, and infiltration of extraocular muscles is Graves disease. Graves orbitopathy often occurs in the context of mild hyperthyroid myopathy, producing mild proximal limb muscle weakness. Serum CK activity is normal in hyperthyroid myopathy. The incidence of myasthenia gravis is also increased in frequency in patients with Graves disease, potentially producing diagnostic confusion about the pathophysiology of the ophthalmoparesis. Jacobson measured the titer of acetylcholine (ACh) receptor antibodies in 50 consecutive patients with Graves ophthalmopathy and compared the clinical and biochemical features of those who had positive titers to those who did not. Four of the patients (8%) had positive titers. No clinical or serologic distinguishing features were identified, and none of these patients developed clinical features of myasthenia during a median follow-up period of 4.5 years. Graves orbitopathy may occur months or years before there is any clinical or laboratory evidence of thyroid dysfunction. Such persons are said to have ""euthyroid Graves disease."