ABSTRACT
Objectives To observe the effects of varied doses of L-thyroxin sodium ( L-T4) on congenital hypothyroidism ( CH) and to determine appropriate dose for early therapeutic intervention. Methods Totally, 108 cases of confirmed CH were divided into two groups (54 in each group). All the cases were administered with L-T4 at varied doses( 10. 1? - 15. 0 ?g ? kg-1? d-1 for large-dose group and 6. 0 - 10. 0 ?g ?kg-1? d-1 for small-dose group) after their parents were trained for basic knowledge of CH by specialists. Their serum levels of T3, T4 and TSH, as well as their body height, weight and head circumference, were measured during follow-up. L-T4 was maintained at doses of 1. 0 - 4. 0 ?g ? kg -1 ? d-1 when their serum levels of T3, T4 and TSH returned to normal. Results All the 108 cases had their clinical symptoms quickly improved and development and growth accelerated after L-T4 substitution. Their serum level of T3 returned to normal in all cases, that of T4 did not return to normal in six cases of large-dose group and in 16 cases of small-dose group, and that of TSH did return to normal in 22 cases of large-dose group and in 39 cases of small-dose group, respectively, after one-month treatment, with a significant difference between the two groups. Cases in large-dose group gained more weight in average than those in small-dose group when they were three months old. Conclusions Early therapeutic intervention for babies with CH with L-thyroxin sodium of 10. 1 -15. 0 ?g ? kg-1? d-1 could quickly correct abnormal function of their thyroid and could avoid abnormal development of their intelligence due to CH.