Levothyroxine in Children

Abstract

Thyroid hormones are essential for the development of the central nervous system early in life. Congenital hypothyroidism once caused the devastating cognitive and physical deficits of cretinism, but this condition is now detected routinely at birth using population-wide neonatal screening in most countries. Early and continuous treatment of these children with levothyroxine (LT4), according to age-specific reference ranges, ensures near-normal neuropsychological development, with preserved IQ, although the possibility of subtle residual effects on some indices of neuropsychological functioning remain an active area of research. Children who develop overt hypothyroidism also require treatment with LT4. Most children diagnosed with subclinical hypothyroidism are unlikely to require intervention with LT4, as this condition reverses spontaneously over time. These children should be monitored for possible deterioration of thyroid function in future, especially where thyroid autoimmunity is present.