ES16P HYPOTHYROIDISM FOLLOWING HEMITHYROIDECTOMY

Abstract

Background The incidence and risk factors for hypothyroidism in patients undergoing partial thyroid surgery remain unclear. Hypothyroidism is an under‐appreciated sequel of hemithyroidectomy. The early recognition of post‐operative hypothyroidism will alleviate symptoms and may prevent recurrent thyroid disease.Aim To investigate the incidence, time to onset and risk factors for the development of hypothyroidism following hemithyroidectomy.Methods Patients undergoing hemithyroidectomy from August 1992 to June 2006 by a single surgeon were identified from an existing, prospectively collected thyroid database. Records were reviewed retrospectively. Patients were analysed for age, sex, family history of thyroid disease, thyroid antibody levels, pre and post‐operative TSH, histological diagnosis, the presence of concurrent thyroiditis, and the lag time to diagnosis of hypothyroidism. Chi‐squared or Fisher’s exact test were performed.Results Hypothyroidism was diagnosed in 36 (12%) of 300 patients. The mean time to diagnosis was 7.54 months. The mean thyroxine dose was 77.38. Patients with post‐operative hypothyroidism had a higher incidence of elevated pre‐operative TSH levels (8.3% versus 0; P < 0.01), thyroiditis on histology (50% versus 12.2%; P < 0.01) and elevated thyroid antibodies levels (48.1% versus 11.3%; P < 0.01). Age, gender, family history of thyroid disease, and thyroid pathology were not significant risk factors for hypothyroidism.Conclusion Given an incidence of 12%, all patients should have post‐operative thyroid function assessment. Elevated preoperative TSH and thyroid antibody levels, and the presence of thyroiditis on histology are indications for close monitoring.