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OBJECTIVE The relationship between the method of treatment of hyperthyroidism due to Graves' disease and the course of Graves' ophthalmopathy is debated. Antithyroid drug therapy is associated with no change, or even amelioration, of ophthalmopathy. Although controversial, radioiodine may be followed by progression of eye disease, preventable by glucocorticoid administration. Whether thyroidectomy affects the course of ophthalmopathy is uncertain. DESIGN In a case control study, the course of non-severe Graves' ophthalmopathy after thyroidectomy was investigated and the results compared with those observed in patients treated with methimazole. PATIENTS Thirty patients with Graves' hyperthyroidism and non-severe/absent ophthalmopathy were treated with near-total thyroidectomy (Group 1, Tx), after achievement of euthyroidism with methimazole. After surgery, all patients started levothyroxine replacement therapy. Sixty patients treated with methimazole, matched for age, sex, duration of hyperthyroidism, degree of ocular involvement and smoking habits, were used as controls (Group 2, MMI). MEASUREMENTS Patients were seen every 1-2 months for 12 months for thyroid tests and ocular evaluation. RESULTS In Group 1, ocular parameters did not change in 17 of 18 patients with pre-existing ophthalmopathy, and in 12 patients without ophthalmopathy. Eye manifestations worsened only in one (3.3%) patient with pre-existing ophthalmopathy. In Group 2, ocular parameters did not change in 58 patients (33 with, and 25 without ophthalmopathy), while new ophthalmopathy occurred in two without pre-existing eye disease. One of the 30 patients treated by surgery (3.3%) had permanent hypoparathyroidism. CONCLUSIONS Treatment of Graves' hyperthyroidism with near-total thyroidectomy in patients with non-severe or absent pre-existing ophthalmopathy is not associated in the short term with significant effects on the course of ophthalmopathy.

An ultrasensitive immunoradiometric assay (IRMA) using two monoclonal anti-TSH antibodies has been used for TSH measurements in basal conditions and after TRH stimulation. The results have been compared with those obtained by conventional radioimmunoassay (RIA). The IRMA method had very high sensitivity (0.07 microU/ml). Detectable serum TSH concentrations were found in all normal subjects by IRMA, but in only 76% by RIA. No overlap was observed with the results obtained by IRMA in untreated overtly hyperthyroid patients, in whom serum TSH was below the limit of detection. The relationship between basal and TRH-stimulated serum TSH concentrations by IRMA and RIA was evaluated in 176 subjects including normals and patients with untreated and treated hyperthyroidism, functioning thyroid adenoma, nontoxic goitre and patients on L-thyroxine therapy. A normal TSH response to TRH was observed in virtually all patients with detectable basal serum TSH by both methods. When patients with undetectable basal serum TSH levels were considered, all but one (98%) had no TSH response to TRH by IRMA. On the contrary using RIA, an absent response was found only in 47% of subjects, a blunted responses in 10% and a normal response in 42%. These data indicate that basal serum TSH measurements by IRMA allows a complete discrimination of normal from hyperthyroid patients and can avoid the need for TRH stimulation tests.