Hypothyreosis after Hemithyroidectomy - surprisingly frequent complication in aftercare

Background Hemithyroidectomy is a frequent treatment for thyroid nodules. Postoperative hypothyroidism is an often underestimated complication. We studied the incidence, time, symptoms and risk factors of postoperative hypothyroidism. Material and methods 127 Patients were analyzed in a retrospective chart review and with a structured assessment of the general practitioners and endocrinologists. Patients were classified according to the postoperative TSH as hypothyroid (>4.0 mU/L) or euthyroid (0.4-4.0 mU/L). Thyroid hormone was assessed at 4-6 Weeks, 6 months and 1 year. Results 55 patients (43 %) had postoperative hypothyroidism and 72 (57%) stayed euthyroid during follow up. The hypothyroidism occured during the first 2 months in 39 patients (71 %), between 2-6 months in 13 patients (24 %) and between 6-12 months in 3 patients (5 %). 33 patients (60 %) with hypothyroidism were asymptomatic and 16 patients (29 %) had symptoms. Preoperative TSH level was significantly higher in the hypothyroid group (1.64) compared to the euthyroid group (1.13, P = 0.0017). The other variables as age, gender, preoperative levels of T3, T4, Calcium and PTH showed no significant difference. Conclusion Postoperative hypothyroidism is an important complication after hemithyroidectomy which should not be missed. Preoperative elevated TSH level is a riskfactor for postoperative hypothyroidism. All Patients after hemithyroidectomy should have postoperative TSH assessment after 4-6 weeks, 6 months and 12 months