ADVANCES IN THE MANAGEMENT OF PATIENTS WITH THYROID-DISEASE

Discoveries related to thyroid immunology, especially concerning the t hyroid-stimulating hormone (TSH) receptor, may facilitate new immunolo gic approaches to the therapy of Graves' disease and the thyroiditis s yndromes. Advances in genetics are being applied to the thyroid hormon e resistance syndromes and papillary and medullary carcinomas. The dev elopment of ever more sensitive TSH assays has led to the detection of subclinical thyroid disease, which has special implications for the s ick and elderly patients, Sensitive TSH assays also allow more precise titration of levothyroxine (T4) dosages, especially for patients with a past history of thyroid cancer. Evidence continues to accumulate su ggesting that postmenopausal women on T4 doses that suppress the TSH l evel below 0.1 ulU/mL have lower bone mineral density than matched pat ients with healthy TSH levels. Also, pregnant hypothyroid women need h igher T4 doses to normalize the TSH levels, In the evaluation of thyro id nodules, fine-needle aspiration biopsy is the single most definitiv e modality in selecting the patients for surgery. Scintigraphy provide s a complimentary role, especially in defining autonomously functionin g thyroid adenomas (AFTA), because these should not be treated with T4 suppression. Ultrasound-guided needle biopsy is occasionally helpful with nodules that are difficult to palpate. Concern for possible trach eal compression after treatment of toxic multinodular goiter with larg e doses of radioactive iodine (1-131) in the range of 50 to 150 mCi (1 .85 to 5.5 GBq) does not seem warranted, Work, primarily out of Italy, suggests AFTA can be ablated with repeated ethanol injections. Residu al tissue after thyroidectomy for differentiated carcinoma can be ''st unned'' by tracer doses of I-131 greater than 3.0 mCi (111 MBq), which diminishes the uptake and effectiveness of a subsequent therapy dose. Positron emission tomography, imaging with thallium-201, and Techneti um 99m Sestamibi can identify a small number of patients shown to have metastases from differentiated thyroid carcinoma by increasing thyrog lobulin levels in the absence of I-131 uptake. Several groups have rec ently advocated treating such patients empirically with I-131. Copyrig ht (C) 1995 W.B. Saunders Company