The differential diagnostic problems in unilateral euthyroid Graves' ophthalmopathy

Nine consecutive patients with unilateral ophthalmopathy with suspected endocrine pathogenesis were investigated with a TRH test, a T3 suppression-test, thyroid autoantibodies and a subsequent computerized tomography (CT)-scan. All patients were clinically and biochemically euthyroid. Seven of 9 patients had a normal TRH test and 6 of 7 had a normal T3 suppression test. Slightly to moderately elevated microsomal and thyroglobulin (determined with radioimmunoassay) autoantibodies were found in 5 of 8 patients and in 1 patient thyroid stimulating immunoglobulins (TSI) were found. Three of the patients had normal thyroid function tests and no detectable thyroid autoantibodies. The subsequent CT-scan revealed that one of these had a maxillary tumour protruding into the orbita. The remaining 8 patients had enlargement of one (3 patients) or more (5 patients) eye muscles. Two of the 8 patients had bilaterally enlarged eye muscles, one of which was the patient with positive TSI. The remaining 6 patients had unilateral extraocular muscle enlargement. Thus, 2 of 9 patients had ophthalmopathy without thyroid dysfunction so-called isolated autoimmune ophthalmopathy or Graves' ophthalmopathy. Thyroid function tests seem to be of limited value in the diagnosis between endocrine and non-endocrine eye disease, and we recommend the use of diagnostic imaging (e.g. CT-scan) in patients with unilateral exophthalmus in order to diagnose malignant processes.