Function of pituitary-thyroid axis after surgical treatment of non-toxic nodular goitre.

Abstract

ABSTRACT Fifty consecutive patients with benign euthyroid nodular goitre underwent goitre resection. In uninodular goitres a remnant of normal thyroid tissue was left, while in multinodular goitres the remnant presented varying degrees of nodularity. The pituitary‐thyroid function was determined before operation and 3, 6, and 12 months after surgical treatment by measuring serum T4, serum T3, FT4 index, serum TSH, and TSH response to TRH. Moreover, determination of thyroid autoantibodies and 99mTc scintigraphy were carried out. In the uninodular goitre group, removal of a single hypofunctioning adenoma caused a slight but significant increase in thyrotrophic function without significant changes in serum levels of thyroid hormones. The thyrotrophic function showed a more pronounced rise in the multinodular than in the uninodular goitre group. Nonetheless, a decrease in serum levels of thyroid hormones took place. Numerically, the fall was modest, albeit significant. Overt hypothyroidism developed in only one patient. According to the present knowledge of development and maintenance of goitre, our results do not indicate that thyroid replacement therapy is required as a routine measure after nodular goitre resection. Overt thyroid failure or abnormally high TSH levels—conditions in which thyroid substitution should be offered—developed only in the group operated upon for multinodular goitre.