Acquired Hypothyroidism in Children

Acquired hypothyroidism is generally also referred to as juvenile hypothyroidism. Hypothyroidism is due to the deficient secretion of thyroid hormones causing metabolic and neurological sequelae at the cellular level. It can present as overt hypothyroidism wherein the thyroid hormones (T4 and T3) secretion fall and thyrotropin (TSH) rises. Acquired hypothyroidism frequently presents between 9 and 11 y of age and is rarely seen before 4 y of age. Approximately 80% of the children and adolescents are asymptomatic at the time of diagnosis. Children with moderate to severe hypothyroidism often present for evaluation of poor growth, constipation, lethargy and/or dry skin. A detailed history and examination will provide us with enough clues for diagnosing hypothyroidism. Primary hypothyroidism can be diagnosed with raised TSH with subnormal levels of T3 and T4. Titres of thyroid antibodies - Anti-thyroperoxidase (TPO) and anti-thyroglobulin (ATG) antibodies, will be high in autoimmune hypothyroidism. Subclinical hypothyroidism is diagnosed with mildly elevated or high normal levels of TSH with free T4 being in the normal range. Insufficient secretion of thyrotropin from the pituitary causes central hypothyroidism. Acquired hypothyroidism is treated by replacement with levothyroxine. Regular monitoring of thyroid profile is necessary for adjusting doses of levothyroxine. Close monitoring and individualization of levothyroxine therapy is essential for normal growth and development of the child.