Hyperthyroidism in children.

This study was done to characterize the clinical features, laboratory parameters and response to therapy and outcome of childhood hyperthyroidism. The evaluation included history, examination, laboratory investigations: serum T3, T4, TSH, free T3, free T4 by RIA or immunochemiluminescence (IC), antithyroid antibodies by standard techniques, bone age (BA) by Greulich and Pyle's method, clinical and laboratory response to treatment, and follow-up of 15 children with hyperthyroidism seen in past eight years. Age of onset, presentation, nature and duration of symptoms, family history, anthropometry and signs of hyperthyroidism were recorded. There were 10 girls and 5 boys (2:1). Three families had a history of thyroid disorders. Mean ages of onset and presentation were 8.25 +/- 3.4 and 9.27 +/- 3.2 years respectively. Clinical features included weight loss, heat intolerance and sweating, diarrhoea, behavioral problems, ophthalmopathy and tachycardia. BA was advanced. Serum T3 (mean = 4.29 +/- 1.77 ng/mL), T4 (18.75 +/- 5.64 micrograms/dL), FT3 (7.11 +/- 4.58 pg/mL) and FT4 (2.93 +/- 0.29 ng/mL) were markedly elevated. TSH was suppressed. Anti-microsomal antibodies (AMA) and anti-thyroglobulin antibodies (ATG) were positive in five. They were started on standard treatment with carbimazole 0.5-0.7 mg kg-1. Clinical and biochemical euthyroidism was achieved within 2.5 to 6 months in all, after which the drug was tapered, however, they required treatment for 2 years to 7.5 years. Four children were retreated for relapse and are now euthyroid and off treatment. Childhood hyperthyroidism requires long term treatment and careful monitoring. This study shows a remission rate of 67%.