Diagnostic possibilities for autoimmune thyroiditis using non-invasive determination of intrathyroid iodine concentration in children

Sixty-seven children (55 girls and 12 boys) aged 5-16 years were examined. Autoimmune thyroiditis (AT) was diagnosed in 28 and diffuse nontoxic goiter (DNG) in 39. The diseases were diagnosed on the basis of case history, results of examination and palpation of the thyroid, ultrasonic findings, presence of antibodies to thyroglobulin (in AT) or their absence (in DNG), and the microsomal fraction detected by enzyme immunoassay using Boehringer Mannheim kits. AT diagnosis was confirmed cytomorphologically in all patients. Intrathyroid stable iodine (ISI) was measured by a Russian noninvasive x-ray fluorescent analyzer. ISI concentration was notably decreased in children with autoimmune thyroiditis confirmed by cytomorphological methods: below the threshold level of the method in 46%) cases and 120±10 mcg/g in 54%). This confirms a high informative value of the proposed method in this disease. Measurements of ISI in children with enlarged thyroid helps differentiate the hypertrophic form of AT from DNG: ISI concentration under 200 mcg/g is characteristic of AT, while in DNG the concentration of ISI in Moscow children is 500±40 mcg/g (M±m).