Ultrasonographic estimation of the normal volume of the thyroid gland in pediatric populations.

Abstract

Introduction. The World Health Organization bases its reference standards for normal thyroid volume on values derived from measurements of European children. However, WHO recommends that normal values for each region be estimated separately, given the variability as a consequence of geographic, racial, and nutritional differences.
Objective. A normal standard of thyroid volume was estimated for the pediatric population of Bogotá, Colombia.
Materials And Methods. A cross-sectional study was carried-out in 591 children assessed at the Clínica Jorge Bejarano, Bogotá, Colombia, between January and August 2003. Children with maternal or personal history of thyroid disease and those with abnormal weight or height characteristics were excluded. Age, weight, and body surface index were recorded for each child. Thyroid volume was estimated by ultrasonography using the ellipse formula.
Results. The mean estimated volume for each age group was as follows: 0.6 +/- 0.2 cm3 for neonates, 1.1 +/- 0.6 cubic centimeters for milk-fed babies, 2.2 +/- 1.3 cc for pre-school age children, 3.0 +/- 1.7 cc for school age children and 5.7 +/- 3.1 cc for adolescents. Thyroid volume increases with increasing body surface. A linear relationship between the natural logarithm of the thyroid volume and the square root of the body surface was found.
Conclusions. The normal thyroid volume for Bogotá children was smaller than the World Health Organization reference value. Values described in the current study are recommended for local use as the normal parameter.