Thyroid function after subtotal resection for hyper‐thyroidism: a prospective study

Abstract

Eight-seven patients treated for thyrotoxicosis by subtotal thyroidectomy were examined 6 weeks, 6 months and 12 months after surgery. Thirty-six of the patients were also examined 24 months after surgery.The patients were divided into two groups according to serum concentration of thyrotrophin (TSH) 6 weeks after surgery. Group I contained fifty-five patients with a normal serum TSH, of whom three developed recurrent hyperthyroidism during the observation period. The remaining fifty-two patients were clinically euthyroid during the entire observation period but had rather low serum thyroxine (T4) levels and normal serum triiodothyronine (T3) levels 6 weeks after surgery. Most patients had a normal TSH response to thyrotrophin-releasing hormone (TRH). T4 levels rose significantly within 6 months after surgery and then remained almost unchanged.Group I1 contained thirty-two patients with a serum TSH above 5 mU/1 6 weeks after surgery. Seven of these patients developed hypothyroidism within 1 year of surgery. The twenty-five remaining patients had low serum T4 with normal serum T3 levels at 6 weeks. TSH response to TRH was pathologically raised. Basal TSH level remained raised during the observation period but serum T4 levels approached those in group I within 12 months.These investigations show that patients with a raised basal serum TSH are at risk of developing hypothyroidism. Normal serum concentrations of thyroid hormones are reached sooner by patients with normal TSH levels than by patients with raised TSH levels. The basal serum TSH level seems to be a better indicator of risk of hypothyroidism than the serum T4 level, which is low in most patients 6 weeks after surgery.

Alternating from subtotal thyroid resection to total thyroidectomy in the treatment of Graves’ disease prevents recurrences but increases the frequency of permanent hypoparathyroidism

“…These complications occurred in the beginning of the study period, and the rate is comparable to those reported in other studies from that time [26]. The findings speak in favour of Dunhill's operation as the method of choice for the surgical treatment of Basedow's disease (see further below).…”

“…Previously, many surgeons have considered long-term euthyroidism without medication as the ideal therapeutic goal of the surgical treatment of Graves' disease [26,27]. The traditional bilateral subtotal thyroidectomy with a remnant of 3-7 g of thyroid tissue does leave a majority of the patients with euthyroidism but the risk of recurrent disease is high, ranging between 3% and 14% [26,27]. Our finding of a 9.9% recurrence rate with a 3.5 g thyroid remnant is in accordance with Sugino et al who reported a relapse rate of 10.9% with remnants of <5 g [27].…”

A study of thyroid function after subtotal thyroidectomy for Graves' disease: particularly on TRH tests, T3 suppression tests and antithyroid antibodies in euthyroid patients

“…In recent years the rapid development of labora¬ tory techniques for measuring thyroid and pitu¬ itary hormones and their relation to thyroid disease has permitted a more detailed analysis of thyroid function (Lundström et al 1978). Thus, Hedley et al (1971) found that serum TSH was elevated in many patients after subtotal thyroidectomy and proposed this as a sensitive indicator of thyroid failure even before clinically detectable signs had appeared.…”