The differing outcomes of hyperthyrotropinaemia.

Hyperthyrotropinaemia, in which normal levels of T4 occur in association with raised TSH, is picked up on neonatal screening. The outcome of children with persistent hyperthyrotropinaemia is uncertain. The study objective was to evaluate the outcome of children with the persistent form of hyperthyrotropinaemia. We carried out a retrospective analysis on children who attended one institution over the last 20 years with this diagnosis. Eight children were diagnosed with hyperthyrotropinaemia lasting more than 3 months in total. Four had a transient form lasting between 3 and 18 months in total. Three continue to have persistently raised TSH at 5, 9 and 17 years, respectively. One patient became biochemically hypothyroid at 1 year of age requiring treatment with replacement thyroxine. All of our group had normal growth and development. We recommend that thyroid function monitoring should continue in all children with hyperthyrotropinaemia until the thyroid function tests have normalised.