High fT3 (free triiodothyronine), new syndrome or innocent bystandar
Saranac Ljiljana, Zivanovic Snezana & Novak Martin
Aim: To evaluate clinical presentation and thyroid dysfunction types in children with thyromegaly.
Patients and methods: Thirty-nine children were referred to endocrinologist examination because of thyromegaly. Assessment of clinical history, physical examination, auxological data pubertal staging and complete evaluation of basal thyroid function were carried out in all children. Thyroid autoantibodies, urinary iodine excretion (UIE) and ultrasound examination of thyroid gland volume and structure were also performed. Twelve healthy children were control.
Results: Majority of children were euthyroid (64.10%), Subclinical hypothyroidism was present in 7 children (17.95%), subclinical hyperthyroidism in one child (2.56%) and 6 children (15.38) showed high fT3 levels. Mean UIE in the study group was suboptimal (94.88 μg/l) versus 135.00 in control group, but without significance. UIE was under lower limit of normal value in 48.72%, normal in 46.15 and high in 5.13%. The mean thyroid volume/body mass ratio was significantly higher in the study group (P<0.001). Diagnosis of CAT (chronic autoimmune thyroiditis) was made in 6 patients among children with goiter. The characteristics of children with high fT3 values were an increased linear growth and signs of mild hyperthyroidism (heat intolerance, tachycardia, nervousness, fine tremor).
Goitrious children started puberty earlier and presented excellent growth (the mean percentile was 71.24 (+0.99 S.D).
Conclusion: Among children with thyromegaly small group presented high fT3 values, tall stature and clinical signs that could be attributed to hyperthyroidism. It might be homeostasis modulation due to hyper caloric intake. Further studies are necessary.