Background: It is suggested that obese children may show similar ultrasound (US) image of thyroid gland to those with Hashimoto’s thyroiditis due to the morphological changes caused by obesity. The aim of the study was to evaluate US features of thyroid in obese children and differences between those two states.
Methods: Two groups underwent US examination: 109 obese children (53 girls), aged 6-17 years old, and 62 non-obese children (54 girls) of the same age group with Hashimoto’s thyroiditis as a control group. TSH, fT4, fT3 and anti-thyroid antibodies were performed in all children.
Results: US examination of the obese group (OG) revealed: reduction of echogenicity- mainly in peripheral part of the gland- in 67 children (46,6%), isthmus enlargement in 50 children (45,9%), mildly increased intraparenchymal blood flow in in 3 cases (2,8%) and presence of the thyroid adjacent lymph nodes in 10 (9,2%). Simultaneous occurrence of all above elements was noted in 3 patients (2,8%) of the OG and in 59 children (95,2%) of the Hashimoto's thyroiditis group (HG). In the OG mean thyroid volume was 9,87 ml. Thyroid volume in HG was significantly higher (20,35ml) than in the OG (p<0,05). The isthmus width (3,42mm) was above norm but lower than in HG (6,92mm, p<0,05). Positive antibodies were found in all HG and in 4 children (3,7%) of OG patients. Three of those four patients in OG were suspected to have Hashimoto's disease after the US examination, with high thyroid volumes and with TSH above norm.
Conclusion: Reduction of echogenicity, especially in peripheral parts of the gland and moderate isthmus enlargement in ultrasound examination are typical changes in obese children and should not be considered as signs of Hashimoto's thyroiditis, especially when thyroid itself is not enlarged.
