TSH-Suppressive Therapy: A Thorny Issue

摘要

Thyroid stimulating hormone (TSH)-suppressive therapy with levothyroxine is a cornerstone of thyroid carcinoma follow-up therapy, but the achievement of therapeutic goals must be balanced against L-T4 side effects. We describe the case of a 64-year-old cardiopathic patient with papillary thyroid carcinoma and autoimmune thyroiditis, whose cardiac condition worsened during TSH-suppressive therapy. TSH concentrations also fluctuated widely because of changing intestinal absorption due to coeliac disease.LEARNING POINTS class="unordered" style="list-style-type:disc">TSH-suppressive therapy with levothyroxine (L-T4) to prevent thyroid carcinoma relapse can be a tricky problem in the presence of comorbidities.The recent American Thyroid Association guidelines are a useful reference for complex cases of thyroid carcinoma.When strict TSH control is crucial, the L-T4 liquid solution may be a valuable tool. class="kwd-title">Keywords: Thyroid carcinoma, TSH-suppressive therapy, intestinal malabsorption class="head no_bottom_margin" id="__sec2title">CASE PRESENTATIONA 64-year-old woman with coeliac disease and autoimmune thyroiditis was examined 2 years after thyroidectomy with lymphadenectomy for carcinoma (January 2006). The histopathological report described multifocal papillary carcinoma, follicular variant, associated with lymphocytic thyroiditis; the main nodule (6 mm) had infiltrated the thyroid capsule without affecting the fat tissue, vascular or lymphatic vessels (TNM pT1 (G2) pN0 M0). Ten months after surgery, radioiodine remnant ablation had been performed. Subsequent whole body scintigraphy and periodic ultrasound scans were not suggestive of relapse; thyroglobulin concentrations were undetectable but anti-thyroglobulin antibody positivity persisted.The patient also had ischaemic heart disease, diagnosed on the basis of myocardial scintigraphy as she refused coronarography.At first examination at our clinic (March 2008), thyroid stimulating hormone (TSH) was suppressed on levothyroxine (L-T4) 3 μg/kg/day, but the treatment was not tolerated due to frequent angina and premature ventricular beats despite beta-blocking therapy. Consequently, L-T4 was tapered to the dose allowing satisfactory control of the side effects (2.4 μg/kg/day). The results of periodic tests are shown in .>Table 1Biochemical tests and L-T4 doses