The screening test for neonatal hypothyroidism

Ans. (c) TSH and T4 assaysRef Harrison 17th edition Chapter 335* Neonatal hypothyroidism is due to thyroid gland dysgenesis in 80-85%, to inborn errors of thyroid hormone synthesis in 10-15%, and is TSH-R antibody-mediated in 5% of affected newborns.* Because of the severe neurologic consequences of untreated congenital hypothyroidism, neonatal screening programs have been established.* These are generally based on measurement of TSH or T4 levels in heel-prick blood specimens* When the diagnosis is confirmed, T4 is instituted at a dose of 10-15g/Kgper day, and the dose is adjusted by close monitoring of TSH levels.* T4 requirements are relatively great during the first year of life, and a high circulating T4 level is usually needed to normalize TSH.* Early treatment with T4 results in normal IQ levels, but subtle neurodevelopmental abnormalities may occur in those with the most severe hypothyroidism at diagnosis or when treatment is suboptimal