Endocrine Abstracts

Introduction: Drug-based therapy is usually the initial treatment for thyrotoxicosis in children, but there is some debate about treatment duration. Our objective was to assess the effect of long-term Carbimazole therapy by block and replacement regime on thyrotoxicosis remission in children.

Methods: 15 children with thyrotoxicosis seen in endocrine clinic between January 2006 and January 2010 were included in the audit. Data was collected retrospectively from the notes. Minimum of 24 months of treatment by block and replacement regime was considered as one complete course (cycle).

Results: Treatment duration of the first cycle ranged from 2 to 5 year 3 months (average 39 months). 10/15 patients relapsed (66.6%). 7/10 relapsed after treatment was stopped, 5 of these relapsed within a year. 3/10 relapsed while still on treatment. Longer treatment duration did not seem to have any effect on long term remission. 3/15 (20%) did not relapse. 1/15 is still on treatment despite remission as stopping treatment is not appropriate for other medical reasons. 1/15 moved out of area soon after stopping treatment. 4/10 patients who relapsed needed high dose of Carbimazole (60 mg/day). None of these had any noted side effects of Carbimazole. All 10 patients who relapsed were treated with 2nd cycle. 5/10 had total Thyroidectomy and 1/10 had radioactive iodine treatment during this second cycle. 1/10 relapsed after completing the 2nd cycle and then had total thyroidectomy. 3/10 are still under treatment with 2nd cycle.

Conclusion: Relapse rate was high (66.6%) after completion of the first cycle of medical treatment. Longer duration of treatment did not seem to offer any benefit for long term remission. The second course of treatment required higher doses of Carbimazole to induce remission. This was well tolerated and was not associated with side effects.