HYPERTHYROIDISM IN CHILDREN - A MALAYSIAN TERTIARY CENTRE EXPERIENCE

Abstract

INTRODUCTION
Graves’ Disease (GD) and Hashimoto thyroiditis (HT) are the most common cause of acquired hyperthyroidism in children. Use of Anti-thyroid drugs (ATD’s) should be monitored and should aim for disease remission within 2 years. Radioactive iodine therapy or thyroidectomy is considered if remission is not achieved. We aim to study progress with ATD, thyrotoxicosis control and remission rate.

METHODOLOGY
This retrospective study is conducted in paediatric endocrine clinic, involving children who are diagnosed with acquired hyperthyroidism from 2006-2019. Subclinical hypothyroidism is considered if TSH is elevated with normal T4 levels. Complete remission is achieved when both clinical and biochemical parameters are euthyroid for 6 months after cessation of ATD.

RESULTS
Total of 20 patients (75% girls) were studied. Average age at diagnosis was 9.75±4.30 years old. All had carbimazole as ATD. Mean dose at diagnosis was 0.50±0.35 mg/kg/day, and propranolol 0.21±0.30 mg/kg/day. It took 2.68±2.29 months for the initial thyrotoxicosis symptoms to resolve. Mean duration on ATD was 34.40±20.96 months. Throughout treatment, 45% (n=9) had subclinical hypothyroidism (11 events), 35% (n=7) biochemical hypothyroidism (9 events) and 10% (n=2) clinical hypothyroidism (2 events). None had complete remission on ATD. One (5%) developed agranulocytosis which resolves with cessation of therapy. No hepatotoxicity reported. On average, every patient would have 1.4 episodes of relapse clinical thyrotoxicosis throughout duration of ATD. There is no significant difference between age of diagnosis and frequency of relapses (p=0.394). Two (10%) patients had thyroidectomy after an average of 41.5 months on ATD.

CONCLUSION
Whilst clinical thyrotoxicosis state can be managed with adequate dosing of carbimazole, we should consider proposing and executing definitive treatment earlier as per latest guidelines to minimise long term complications associated with hyperthyroidism.