What is the significance of raised plasma TSH levels after thyroid surgery?

The management of hyperthyroidism

Although effective treatments for hyperthyroidism are available, none is perfect. Particularly with respect to Graves' disease, what is needed is a therapy directed at modulating the disease process itself rather than merely reducing the synthesis and secretion of thyroid hormones in the hope that the underlying Graves' disease will remit. Greater understanding of the pathogenesis of Graves' disease, resulting from cloning of the thyrotropin receptor and better knowledge of the interactions between these receptors or other thyroid antigens and the immune system, may lead to such treatment. Broad-spectrum immunosuppression, with all its side effects, is not the answer; more focused therapies to inhibit the immune response to specific thyroid antigens may represent the treatment of the future. Meanwhile, radioiodine therapy is the most effective and convenient method of achieving long-term control of hyperthyroidism, although at the cost of hypothyroidism in many patients.

Late onset hypothyroidism after subtotal thyroidectomy for hyperthyroidism: implications for long term follow-up

A follow-up register has been used in Aberdeen and Dundee to record early and late onset hypothyroidism occurring in a large population of post-thyroidectomy patients treated for hyperthyroidism. In one centre, in a total of 1170 patients, the prevalence of postoperative hypothyroidism, at the time of entry to the register, was 41 per cent. Of these early cases of hypothyroidism 93 per cent occurred within 18 months of operation. Results are presented from a 12-year prospective study of patients treated in two centres, who were euthyroid when entered on the follow-up register. In one centre, based on 683 patients, the 10-year incidence of late onset hypothyroidism estimated by actuarial methods was 7.4 per cent (95 per cent confidence limits, 3.8-11.1); in the other centre with 156 patients the 5-year incidence was 10.8 per cent (95 per cent confidence limits, 3-18.6). The minimum predicted annual incidence is 1 per cent. Large thyroid remnants do not protect some patients against early or late postoperative hypothyroidism but do lead to an increased risk of recurrent hyperthyroidism. Hypothyroidism after subtotal thyroidectomy for hyperthyroidism shows a bimodal pattern and this study emphasizes the need to maintain life-long follow-up.