Função tireóidea após lobectomia total por bócio não tóxico / Thyroid function after total lobectomy for non-toxic goiter.

AUTOR(ES)

Dorival de Carlucci Junior

DATA DE PUBLICAÇÃO

2007

RESUMO

INTRODUCTION: Thyroid nodules, recently, have their diagnosis increased because of the improvement of imaging methods, especially ultrasound. Around 17% of these nodules may be identified in adult women by ultrasound. Total lobectomy is considered an appropriate procedure for benign thyroid nodules. Hypothyroidism may occur in 5% to 35% patients after total lobectomy and it is related to the volume of the remnant thyroid tissue and its functional quality. This study was designed to evaluate the incidence of postoperative hypothyroidism and to determine patients with high risk for this disease. METHODS: From March 1996 to July 2005, 228 euthyroid patients, from the Department of Head and Neck Surgery of the Brazilian Institute for Cancer Control (IBCC) and from the author?s private office, had a total lobectomy due to non-toxic goiter. Out of these patients, 186 were selected for this retrospectively study. Thyrotrophin (TSH) levels, antithyroid antibodies, volume of the remnant thyroid by ultrasound and a semiquantitatively review of the histological specimens considering lymphocytic infiltration were studied. Hypothyroidism was defined for TSH = 5,5 mU/L up to eight weeks postoperative. RESULTS: Women were predominant (88%) with ages varying from 16 to 72 years old and the median age of 45 years old. The average time of follow-up was 29 months, ranging from six months to nine years. TSH ³ 5,5 mU/L occurred in 61 patients (32,8%). Adenomatous goiter was the principal diagnosis in 82% of the hypothyroids patients and 80,7% of the euthyroids. Age, sex and lymphocytic infiltrate did not show any difference between the two groups. Postoperative hypothyroidism was related to: higher preoperative TSH level than the euthyroids postoperative patients (2,1 mU/L versus 1,2 mU/L, respectively) (p<0,001), smaller thyroid remnant volume, 3,9 cm3 in hypothyroid group against 6,0 cm3 in the euthyroid group (p=0,003), right lobectomy while the euthyroid patients had more left lobectomy (p=0,006) and, finally, higher positive titles of the antiperoxidase antibodies (AcTPO) (p=0,009). The risk for postoperative hypothyroidism was 7.1 times higher for those with preoperative TSH >2,0 mU/L. When right lobectomy was analyzed with the remnant volume = 4,0 cm3, the risk for postoperative hypothyroidism was 7,4. CONCLUSIONS: Postoperative hypothyroidism occurs in 32,8% of patients who have undergone a total lobectomy for non-toxic goiter. Possible indicators for development of postoperative hypothyroidism are: preoperative TSH >2,0 mU/L and postoperative positive AcTPO, small thyroid volume at ultrasound, and right lobectomy.

ASSUNTO(S)

bócio nodular/cirurgia autoimmune thyroiditis/pathology hipotireoidismo/diagnóstico thyroidectomy/methods autoimmune thyroiditis/immunology tireoidectomia/métodos autoimmune thyroiditis/diagnostic hypothyroidism/diagnostic tireoidite auto-imune/imunologia nodular goiter/surgery tireoidite auto-imune/diagnóstico tireoidite auto-imune/patologia

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