Resistance to Anti-Thyroid Drugs in Graves’ Disease: Clinical-Biological Characteristics and Alternative Therapy in Tropical Area

Background: Resistance to anti-thyroid drugs (ATDs) is a rare entity recently described. We report two African observations in the treatment of Graves’ disease. Case 1: A 19-year-old Senegalese woman presented on admission with thyrotoxicosis syndrome associated with diffuse goitre and Grave’s orbitopathy. TSH levels were low (0.005 mIU/ml; N = 0.27 - 4.20) and fT4 elevated (60 pmol/L; N = 12 - 22]. Combination therapy with propranolol (40 mg/day) and carbimazole (starting dose of 45 mg/day and increased to 60 mg/day) was initiated. In view of the persistence of symptoms despite good therapeutic compliance, carbimazole was replaced by methimazole with an initial starting dose of 40 mg/day, followed by 60 mg/day. Despite the change in therapy, clinical symptoms of thyrotoxicosis persisted, and fT4 levels remained elevated. The patient was diagnosed with resistance to ATDs in Graves’ disease. Total thyroidectomy following 10 days of preoperative preparation with 1% Lugol’s solution was performed successfully. Case 2: A 22-year-old woman was referred for continued management of Graves’ disease with elevated thyroid-stimulating hormone receptor antibody (TRAb) levels (34 UI/mL; N