CLINICAL EXAMINATION IS NOT AN ACCURATE METHOD OF DEFINING THE PRESENCE OF GOITER IN SCHOOLCHILDREN

OBJECTIVE There are few published data on thyroid size and body size v ariables in children. We aimed to develop an index for normal thyroid size in schoolchildren using ultrasonography and to evaluate the accur acy of clinical examination in the diagnosis of goitre. DESIGN A study to screen and diagnose goitre SUBJECTS A population based sample of 1 094 schoolchildren aged 6-14 years (556 boys and 538 girls) were submi tted to clinical examination of the thyroid. One hundred and nineteen were considered to have goitre. Ultrasonography was performed in 85 wh o agreed to participate in the study and in 62 schoolchildren selected randomly from those thought to have no goitre. MEASUREMENTS Clinical examination and definition of goitre were performed according to WHO c riteria. Thyroid volume was measured by ultrasonography (7.5 MHz trans ducer). RESULTS The gland volume of 62 schoolchildren without goitre o n clinical examination showed a positive correlation with body surface area, age and skinfold thickness. When these factors were entered in multiple regression analysis, only body surface area remained associat ed with thyroid volume. The upper limit (95th percentile) of the ratio of thyroid volume to body surface area (Ecobody index) was 6.2 ml/m(2 ). Taking this index as the standard criterion, the performance parame ters of clinical examination for the detection of goitre in the 1094 s choolchildren were: sensitivity 41%, specificity 91%, positive predict ive value 27% and negative predictive value 95%. CONCLUSIONS Clinical examination of the thyroid is unreliable in establishing the presence of goitre in schoolchildren because it tends to overestimate thyroid s ize. Nevertheless, it can be used as a screening test, Ultrasonography should be performed when the thyroid gland is thought to be enlarged.