[Changes in TSH-receptor antibody (TR-AB) and thyroid stimulating antibody (TS-AB) after thyroidectomy in thyrotoxic...

Changes in TSH-receptor antibody (TR-Ab) and thyroid stimulating antibody (TS-Ab) after thyroidectomy were examined in seventeen thyrotoxic patients (3 males and 14 females, 40.0 +/- 3.4 yr) with positive TR-Ab and TS-Ab. They were subjected to thyroid surgery because of suspected malignancy, methymazol induced agranulocytosis, cardiac failure, recurrent gastric ulcer or emotional instability. Of these patients, 3 were totally thyroidectomized, 11 were subtotally thyroidectomized and 3 were unilaterally lobectomized. Histological findings in these patients showed diffuse hyperplasia in 8 cases, an adenomatous goiter in 3, diffuse hyperplasia plus follicular adenomas in 5, and Hashitoxicosis in one. Their thyroid function before surgery was as follows: T3 level, 3.9 +/- 0.7 ng/ml; T4, 19.5 +/- 3.3 micrograms/dl; free T3, 11.9 +/- 1.2 pg/ml; free T4, 4.9 +/- 1.0 ng/dl; and TSH, 0.9 +/- 0.1 microU/ml. Mean levels of TR-Ab and TS-Ab before surgery were 56.8 +/- 4.6% and 1,218.6 +/- 262.4%, respectively. Positive anti-thyroid antibody (TGHA) was 47.0%, positive anti-microsomal antibody (MCHA) was 88.2% in these thyrotoxic patients, and mean levels of TGHA and MCHA were 1,688 +/- 715 and 89,280 +/- 34,717 times, respectively. After the operation, these parameters were decreased and their thyroid functions became an euthyroid or a hypothyroid state one month later. The incidence of post-operative hypothyroidism was 45.5% in subtotally thyroidectomized patients, 33.3% in unilaterally lobectomized patients and 100% in totally thyroidectomized patients. TR-Ab levels decreased from 56.2 +/- 6.5% before surgery to 24.5 +/- 12.2% 12 months after surgery, but increased again to 35.0 +/- 15.7% 24 months after surgery in subtotally thyroidectomized patients. These levels also decreased from 50.4 +/- 11.0% before surgery to 37.8 +/- 11.4% 12 months after surgery, and remained unchanged to 38.2 +/- 10.4% 24 months after surgery in unilaterally lobectomized patients. On the other hand, in totally thyroidectomized patients, TR-Ab levels decreased and normalized 12 months after surgery. One of subtotally thyroidectomized or unilaterally lobectomized patients developed recurrent thyrotoxicosis with an increased positive TR-Ab. Mean levels of TS-Ab decreased to 28.3 +/- 181.3% and 152.5 +/- 47.9% 12 and 24 months after surgery, respectively, in subtotally thyroidectomized patients. These levels decreased 12 months after surgery and then increased again to 303.6 +/- 130.6% in unilaterally lobectomized patients. On the other hand, TS-Ab levels decreased and normalized to 94.3 +/- 3.9% 6 months after surgery in totally thyroidectomized patients.(ABSTRACT TRUNCATED AT 400 WORDS)