Endocrine Abstracts

Introduction: The long term remission rate of Grave’s disease in children after anti-thyroid drug (ATD) therapy is around 30% as opposed to 40-60% in adults. There still exists a controversy regarding the duration of medical treatment and the markers of long term medical remission that support cessation of therapy. Normalization of TSH Receptor Antibody (TRAb) level is considered to be a favourable marker for remission prior to stopping therapy. We report two patients who received prolonged ATD therapy, remained euthyroid during therapy and had normalization of TRAb levels despite which they relapsed after stopping therapy.

Case 1: A nine year old girl presented with palpitations, weight loss and a goitre alongwith mild exophthalmos and eye pain. Investigations revealed raised FT4 and suppressed TSH. She received Propranolol and a ‘block and replace’ regimen with Carbimazole and Levothyroxine for 4 years. She responded well and remained euthyroid during therapy. Treatment was stopped after documenting negative TRAb levels (<0.3 IU/l) which were previously raised (1.6 IU/l, normal range <0.9 IU/l). She relapsed after a year of treatment cessation with raised TRAb (2.6 IU/l).

Case 2: A seven year old girl presented with increased appetite without weight gain, rapid growth, exophthalmos and goitre, with tachycardia noted on examination. Her blood results confirmed hyperthyroidism. She was treated with Propranolol, and then with Carbimazole and Levothyroxine for 3 years with good response but relapsed 4 months after they were stopped. She was restarted on ATD therapy for another 4 years. Her initial TRAb levels were very high (49.5 IU/l) but were negative (<0.3 IU/l) prior to stopping treatment the second time. However, she relapsed again after 6 months with raised TRAb (5.6 IU/l).

Conclusion: We describe 2 patients who relapsed after prolonged ATD therapy despite normalization of TRAb level prior to cessation of treatment. TRAb levels can go from negative to positive during a relapse and so should continue to be monitored after cessation of treatment. More work is required to establish reliable indicators of long-term remission in childhood Graves’ disease.