Thyroid auto-antibodies, lymphocytic infiltration and the development of post-operative hypothyroidism following hemithyroidectomy for non-toxic nodular goitre.

Abstract

BACKGROUND: Auto-immune thyroiditis, associated with detectable thyroid auto-antibodies (TAAs) and lymphocytic infiltration into the gland, is known to be associated with progressive development of hypothyroidism. This study examines those patients who required surgical treatment of non-toxic nodular goitre by hemithyroidectomy to determine whether the presence of TAAs in the circulation and/or lymphocytic infiltration of the gland resulted in a significant degree of post-operative hypothyroidism. METHOD: This was a prospective study, with data collected retrospectively. All patients operated on for thyroid disease in the unit over a 5-year period were documented, and those patients treated by hemithyroidectomy for non-toxic nodular goitre formed the study group. TAAs were measured, histology re-examined and patients followed up for at least 2 years to detect clinical or sub-clinical hypothyroidism. RESULTS: Of the 158 patients who comprised the study group, 38 (24.1%) developed hypothyroidism. Forty-one (25.9%) had circulating levels of TAAs, 31 of these (75.6%) having high levels. Of these 41 patients, 22 (53.7%) became hypothyroid. Twenty (64.5%) of the 31 patients with high levels of TAAs required post-operative thyroxine. Of the remaining 117 patients with no detectable TAAs, only 16 (13.7%) became hypothyroid. CONCLUSION: All patients requiring treatment by hemithyroidectomy should have circulating TAA measurements carried out pre-operatively. If positive, they should be followed up indefinitely because of the strong possibility (P < 0.001) of the development of hypothyroidism.