Ultrasound scanning assessment of L-Thyroxine treatment effectiveness in a group of children with diffuse goiter

Abstract

Ultrasound scanning is an accurate and objective method to assess thyroid volume; therefore it is useful to evaluate the effectiveness of L-thyroxine treatment in reducing goiter size, especially in children where clinical evaluation is inaccurate. In this prospectic study we evaluated the effectiveness of one-year L-thyroxine treatment in a group of children with nontoxic diffuse goiter coming from an area with low iodine intake. We examined 11 children (7 females, 4 males), age range 9–14 years. At clinical examination, 6 patients had a goiter classified la (according to WHO criteria), 4 had a class lb and only 1 had a class II goiter. In order to achieve an accurate goiter evaluation, the thyroid volume was determined by ultrasonic scanning with a 5 MHz linear probe before and after treatment. Patients were given a dose of L-thyroxine (1.5–2.0 µg/kg/die) in order to significantly reduce serum TSH levels (from 1.8 ± 0.6 to 0.8 ± 0.5 mU/l, mean ± SD). Patients were reexamined at 12 months of therapy and again at 10 months after therapy withdrawal. A significant reduction of the goiter volume (> 20%) was obtained in 6/11 (54%) patients, although serum TSH levels were fully suppressed only in one. The mean goiter size reduction in “responders” was −31.2 ± 9.3 % (m ± SE). After therapy withdrawal goiter size increased in the majority of cases (in 4/11, > 20%). Our study demonstrates that L-thyroxine treatment is effective in reducing goiter size in the majority of children with a diffuse goiter. Full TSH suppression is not necessary to obtain goiter volume reduction because a decrease of TSH levels to low values can already mediate a good therapeutical response. Since the majority of patients shows an increase of thyroid volume after therapy withdrawal, L-thyroxine administration should be a long term therapy.