Treatment and follow-up of children with transient congenital hypothyroidism.

Objective: To study the clinical therapy and prognosis in children with transient congenital hypothyroidism (CH).

Methods: Fifty-seven children with CH diagnosed after neonatal screening were treated with low-dosage levothyroxine (L-T4). Follow-up evaluation included the determination of TT3, TT4 and TSH serum levels and the assessment of thyroid gland morphology, bone age, growth development and development quotients (DQ). A full check-up was performed at age 2, when the affected children first discontinued the L-T4 treatment for 1 month, and one year later. Development quotients were compared with a control group of 29 healthy peers.

Results: The initial L-T4 dosage administered was 3.21-5.81 microg/(kg.d) with an average of (16.25+/-3.87) microg/d. Mean duration of therapy was (28.09+/-9.56) months. No significant difference was found between study group and control group in the DQ test (average score (106.58+/-14.40) vs (102.4+/-8.6), P>0.05) and 96.49% of the CH children achieved a test score above 85. Bone age, 99mTc scans and ultrasonographic findings were all normal, and evaluation of physical development was normal too, as were the serum levels of TT3, TT4 and TSH after one year of follow-up.

Conclusion: A L-T4 dosage of 3.21-5.81 microg/(kg.d) was found sufficient for the treatment of transient CH. The treated children showed satisfactory overall mental and physical development at age 2. So it is possible for CH children to stop taking medicine if their laboratory findings and physical development are all normal after regular treatment and 2-3 years of follow-up.