Prediction of post-treatment hypothyroidism using changes in thyroid volume after radioactive iodine therapy in adolescent patients with Graves' disease.

Nobuhiro Nakatake,Junichi Tajiri,Shuji Fukata

doi:10.1186/1687-9856-2011-14

Nobuhiro Nakatake, Junichi Tajiri + Show 1 more

Open Access

https://doi.org/10.1186/1687-9856-2011-14

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Abstract

BackgroundThe goal of iodine-131 therapy for pediatric Graves' disease is to induce hypothyroidism. However, changes in post-treatment thyroid volume have not been investigated in pediatric and/or adolescent patients.ObjectiveThe aim of this retrospective study was to examine whether changes in thyroid volume predict post-treatment hypothyroidism in adolescent Graves' disease patients.Patients and MethodsWe used ultrasonography to examine changes in thyroid volume, and also assessed thyroid functions, at 0, 1, 3, 5, 8 and 12 months after iodine-131 treatment in 49 adolescents ranging in age from 12 to 19 years retrospectively. Based on thyroid function outcome at 12 months, patients were divided into two groups: 29 patients with overt hypothyroidism requiring levothyroxine replacement and 20 without overt hypothyroidism. We compared changes in post-radioiodine thyroid volume between the two groups.ResultsAbout 90% of patients whose thyroid volume at 3 months after iodine-131 administration was less than 50% of the original volume were hypothyroid by one year after treatment (positive predictive value 88%, sensitivity 75.9%, specificity 85.0%).ConclusionsWe believe ultrasonographic measurement of thyroid volume at 3 months after iodine-131 to be clinically useful for predicting post-treatment hypothyroidism in adolescent Graves' disease patients.

Highlights

Graves’ disease (GD) is the most common cause of hyperthyroidism in children, adolescents and adults [1,2,3]
Anti-thyroid medications are commonly used as first-line therapy for pediatric GD, long-term remission occurs in only 20% to 30% of pubertal cases and 15% of pre-pubertal cases treated pharmacologically [3,6,7,8]
Based on thyroid functions at one year after radioactive iodine (RAI), patients were divided into two groups: 29 (59.2%) with overt hypothyroidism requiring levothyroxine replacement therapy and 20 (40.8%) without hypothyroidism taking no medication at one year after RAI

Summary

Introduction

Graves’ disease (GD) is the most common cause of hyperthyroidism in children, adolescents and adults [1,2,3]. Treatments available for GD include anti-thyroid medications (methimazole or propylthiouracil), surgery and radioactive iodine (RAI) [4,5]. Anti-thyroid medications are commonly used as first-line therapy for pediatric GD, long-term remission occurs in only 20% to 30% of pubertal cases and 15% of pre-pubertal cases treated pharmacologically [3,6,7,8]. Either surgery or RAI is needed to achieve a long-term cure in most pediatric GD patients. RAI is becoming the first-line therapy for GD in children and adolescents [14,15]. Changes in post-treatment thyroid volume have not been investigated in pediatric and/or adolescent patients

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