Endocrine Abstracts

Agranulocytosis is a rare but potentially life-threatening complication of anti-thyroid medications. While the actual risk is unknown, agranulocytosis induced by one thionamide is generally regarded as a contraindication to the use of another thionamide due to the risk of cross-reactivity. Consequently, clinical experience of prescribing carbimazole in patients with a history of PTU-induced agranulocytosis is exceptionally limited. We present the case of a 64-year-old female who presented with pyrexia, weight loss and uncontrolled fast atrial fibrillation with a takotsubo cardiomyopathy. Thyroid function test revealed a TSH<0.01mIU/l, fT4 >100.0 pmol/l (11.9- 21.6) with positive TSH-receptor antibodies. She was diagnosed with a thyroid storm secondary to Graves’ disease. She was commenced on high-dose PTU 200 mgs qds and other supportive therapy. However, after 14 days she developed agranulocytosis and neutropenic sepsis. She developed thyrotoxicosis-induced severe myopathy and respiratory compromise necessitating a prolonged ITU ventilatory support. She had persistent thyrotoxicosis, so Lugol’s iodine and lithium were used in preparation for a salvage thyroidectomy. However, she remained unfit for a thyroidectomy after two weeks, so the Lugol’s iodine was stopped. After careful consideration, a decision was made to commence carbimazole; 10 mg with daily close monitoring of her blood counts. Her TFTs normalised and blood counts remained stable (without GCSF support) on carbimazole. She ultimately underwent a total thyroidectomy after 6 weeks of intensive inpatient rehabilitation. In conclusion, we report a case of successful carbimazole use in a critically ill patient unfit of early surgery with preceding PTH-induced agranulocytosis and limited alternative therapeutic options.