Thyroid function after resection for non-toxic goitre with special reference to thyroid lymphocytic aggregation and circulating thyroid autoantibodies

Abstract

Abstract. A series of 91 patients operated on for nontoxic goitre was followed systematically during 24 months post-operatively with regard to thyroid function. A thyroid remnant of at least 5 to 8 g was left in the majority of cases, and thyroid replacement was not given. Histopathological grading was performed on goitrous specimens with reference to lymphocytic infiltration. Thyroglobulin antibodies and thyroid microsomal antibodies were determined pre-operatively. Goitre resection provoked a high, but transient increase in serum thyroid stimulating hormone (TSH) levels with peak values 3 to 6 months after operation. Twenty-four months after surgery serum TSH values had normalized, but were still slightly elevated in patients with bilateral surgery and high lymphocytic infiltration, 9% of the patients. The concentration of serum free thyroxine index (FT4I) and serum total triiodothyronine (TT3) decreased after operation, but within reference range. Twenty-four months after surgery, serum FT4I was back to baseline values, while serum TT3 was still lowered compared to the pre-operative level. None of the patients developed overt hypothyroidism. Occurrence of circulating thyroid autoantibodies was not related to post-operative changes in thyroid parameters. We conclude that thyroid replacement therapy seems not to be indicated routinely following resection for non-toxic goitre, but precaution should be taken in case of bilateral resection and high lymphocytic infiltration of goitrous specimens.