Thyroid-stimulating Hormone (TSH) rising following hemithyroidectomy: incidence and adjuvant factors

BACKGROUND: To determine the frequency of serum elevations of thyrotropin in patients submitted to lobectomy within a period of up to 12 weeks after surgery, in the search for factors associated with its occurrence. METHODS: Eighty-eight patients submitted to thyroid lobectomy from September 2002 to September 2004 in the Department of Head and Neck Surgery - University of São Paulo Medical School were retrospectively analyzed. Thyroid hormone determinations were performed from 4 weeks on after the surgery. Cases of patients with altered preoperative hormone determination, need for total thyroidectomy, and loss of postoperative follow-up were excluded. Data regarding age and gender of patients, presence of thyroiditis on histopathologic analysis of the thyroid and time of emergence of hypothyroidism were studied. Statistical analysis was performed using Pearson's chi-square test. RESULTS: Of the 88 patients, 71 (80.7%) were women. The mean age was of 41.7 years. Elevation of thyrotropin was observed in 20 (22.73%) of the 88 studied patients. No statistically significant difference was observed regarding its incidence in relation to gender, age or the presence of thyroiditis. CONCLUSION: Elevation of thyrotropin is frequent after thyroid lobectomy and it may occur early after surgery. In this study, no factor that could predict its occurrence in the short term were found.

Thyrotropin; Hypothyroidism; Thyroidectomy; Thyroiditis

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