B-ENT

Levothyroxine replacement therapy after thyroid surgery

1.

Department of Otorhinolaryngology, Head and Neck Surgery, University Hospitals Leuven, Leuven, Belgium

2.

Leuven Cleft Lip Palate Team coordinated by V. Vander Poorten

3.

Department of Maxillofacial Surgery, University Hospitals Leuven, Catholic University of Leuven, Belgium

4.

Leuven Cancer Institute, Leuven, Belgium

5.

Department of Endocrinology, University Hospitals Leuven, Leuven, Belgium

6.

Department of Otorhinolaryngology, Head and Neck Surgery, University Hospitals Leuven, Belgium

B-ENT 2006; 2: 129-133
Read: 749 Downloads: 590 Published: 22 February 2020

Levothyroxine replacement therapy after thyroid surgery. Introduction and aim: New entities, such as ‘subclinical’ over- and undersubstitution, are easily diagnosed after thyroid surgery due to improved testing methods, and the incidence of thyroidectomy with lifelong hormone substitution is increasing. Thus, there is a need to review conventional replacement therapy after thyroid surgery. We investigated the adequacy of our thyroid hormone replacement therapy for three months after total-, subtotal-, and hemithyroidectomy using an upper reference limit of thyrotropin (TSH) of 4.6 mU/L.

Materials and methods: Eighty-seven patients undergoing thyroidectomy for benign thyroid pathology participated. Levothyroxine (L-T4) treatment began five days after surgery. Preoperatively euthyroid patients received 150 µg L-T4 daily following total thyroidectomy, 100 µg L-T4 after subtotal thyroidectomy, and 50 µg L-T4 after hemithyroidectomy. Preoperatively hyperthyroid patients received 100 µg L-T4 following total thyroidectomy and 50 µg L-T4 following subtotal thyroidectomy. An average of six weeks after surgery, thyrotropin (TSH) was measured (reference limits 0.15- 4.60 mU/L), and necessary dose adjustments were made.

Results: Of the patients who were preoperatively euthyroid, 45% with total thyroidectomy, 42% with subtotal thyroidectomy, and 17% with hemithyroidectomy required L-T4 dose adjustments. Of the patients who were preoperatively hyperthyroid, 60% of those with total thyroidectomy and all of those with subtotal thyroidectomy required L-T4 dose adjustments.

Conclusions: To avoid over- and undersubstitution after thyroidectomy, an optimal replacement therapy dose is necessary. A small majority of our preoperatively euthyroid patients received adequate therapy. Endocrinological follow-up six weeks after surgery revealed the need for L-T4 dose adjustments, especially in preoperatively hyperthyroid patients. When the extent of resection was similar for hyperthyroid and euthyroid patients, the same initial dose of L-T4 was justified.

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EISSN 2684-4907