ESPE Abstracts

A 12 year old Caucasian girl presented with a 2-month history of weight loss, anxiety, labile mood and eye discomfort. Initial fT4 was 55.5 pmol/L (NR 6.3 – 14), fT3 > 30 pmol/L (2.5 – 5.7) TSH < 0.005 mU/L (0.3 – 5.6), TSH-receptor and TPO antibodies positive (Table). She was tachycardic (147/min), had a soft non tender goitre and mild lid retraction. She was started on Carbimazole 10 mg TDS (0.7 mg/kg/day) and Propranolol (20 mg TDS) and once the fT4 was within range the propranolol was stopped. Menarche occurred 2 months after diagnosis. Complaints of palpitations was evidenced with a fitness watch and home ECG monitoring. TSH remained suppressed for 2 months, then Carbimazole was reduced and Levothyroxine started with TSH escape. Complaints of tachycardia remained with resting tachycardia of 150/min reported when fT4 was in the normal range as well as when hypothyroid. Episodes of daytime tachycardia was captured in a 24 hour Holter. Repeated cardiology review was normal without concerns regarding the tachycardia. Carbimazole was reduced to 5 mg BD for 3 months following TSH increase and increased to 10 mg BD when TSH became suppressed, reaching 40 mg a day 10 months on. Three years on she is on Levothyroxine 100 mg OD and Carbimazole 15 mg BD. Propranolol has been beneficial for symptomatic management of daytime tachycardia.. TPO antibodies rose significantly to 1372.5 IU/ml 2 years later, currently > 1542 IU/ml with TSHRAb still raised but much reduced.

Discussion: A teenager 3 years post diagnosis on block and replace management has persistent goitre and tachycardia with significantly raised TPO and TSHR-antibodies. Tachycardia is a well-known symptom of hyperthyroidism but also anxiety. Serial TPO and TSHR antibody monitoring may have alerted the clinician to the ever-changing thyroid profile and treatment options.