Definitive diagnosis in children with congenital hypothyroidism

Objectives To investigate the definitive diagnosis and underlying causes of congenital hypothyroidism (CH) in eligible children through the use of a standardized protocol. Study design Children greater than or equal to3 years of age with CH without an identified permanent cause under-went a diagnostic algorithm. Eligible subjects had an anatomically normal thyroid or had not undergone imaging studies. After thyroxine was discontinued for 4 weeks, thyroid function tests and it thyroid ultrasound were obtained. An abnormal ultrasound was followed by a Te-99m thyroid scan. A perchlorate washout test was performed in subjects with a normal ultrasound but abnormal thyroid function tests. Children with normal results were followed for 1 year. Results Of 33 children, 17 were boys. Nine (27%) had an absent or ectopic thyroid, 12 (36%) had dyshormonogenesis, and 12 (36%) had transient CH. Average thyroxine dose before medication discontinuation was 2.9 +/- 0.83 mug/kg in permanent cases versus 2.0 +/- 0.53 mug/kg in transient (P < .002). No complications from discontinuation of thyroxine occurred. Conclusions A significant percentage of children with CH have it transient requirement for thyroid hormone. A standardized protocol with thyroid ultrasonography is it safe and sensitive approach to a trial off of thyroxine in select patients.