ESPE Abstracts

Background: Antithyroid drugs such as carbimazole form the mainstay of medical management of hyperthyroidism in children. Parents are always warned about agranulocytosis, which is a rare side effect of these drugs. Development of arthralgia after starting antithyroid medication can be a disabling side effect and needs to be distinguished from the more serious antineutrophil cytoplasmic antibody (ANCA) positive vasculitis.

Objective and hypotheses: Here we report a 10 years old patient who developed significant joint pains after commencing carbimazole.

Method: Case presentation: A 10 years old girl with background of asthma presented with complaints of weight loss and tremors. Her thyroid function tests showed hyperthyroid picture with suppressed TSH and elevated fT₄ measurements. She was started on carbimazole at a starting dose of 10 mg BD. Within 10 days of treatment she started experiencing significant multiple joint pains making her wheelchair-bound. This did not settle with use of non steroidal anti-inflammatory drugs. Her auto-antibody screen, including ANCA was negative. Her symptoms settled down within 4 weeks of stopping Carbimazole. Her hyperthyroidism is currently being managed using propylthiouracil and she is waiting to undergo definitive treatment.

Conclusion: Development of arthralgia on antithyroid medication should warrant immediate investigation to rule out ANCA positive vasculitis. Symptoms of transient migratory polyarthritis or antithyroid arthritis syndrome usually subside on discontinuation of treatment. More definitive treatment options should be discussed with family while maintaining the patient on alternative antithyroid medication as a temporary measure.