Endocrine Abstracts

Introduction: The incidence of agranulocytosis with thionamide therapy is uncommon, ranging between 0.2 and 0.5 percent. Most reports document agranulocytosis after short duration of high dose Carbimazole in older patients. We report a 32-year-old lady with Graves’ disease who developed neutropaenic sepsis secondary to Carbimazole therapy on 5 mg daily and on treatment for the last 13 months.

Case report: Our patient was diagnosed with Graves’s thyrotoxicosis when she was 14 weeks pregnant. She was commenced on high dose Carbimazole then reduced to 5 mg on alternate days. She had an uneventful delivery of a healthy baby boy. Post-partum, her dose of Carbimazole was increased to 5 mg daily.

Four days before she was admitted, she had developed fever, sore throat and an itchy rash. A blood test done by her GP at day 4 showed a neutrophil count of 0.75 and she was urgently admitted. She was treated as neutropaenic sepsis and her Carbimazole was stopped. She was clinically euthyroid on admission (TSH <0.01, T₄ 13.7, and T₃ 5.8). A joint decision was made by the ENT and Endocrinology team for her to have an urgent total thyroidectomy. A dermatology opinion was sought and confirmed the widespread confluent rash to be related to carbimazole therapy. Her neutrophil count recovered to 2.04 at day 5 and she had her total thyroidectomy 5 days later.

Discussion: All patients should receive written and verbal warnings to look out for the typical warnings signs of possible agranulocytosis, not only prior to starting anti thyroid drugs but also at each clinic visits if possible. Our case serves as a reminder that agranulocytosis with Carbimazole can happen even at low dose with duration of treatment of more than 12 months in a young age group.