Antithyroid Drug-Resistant Graves’ Disease Stabilised with Supersaturated Potassium Iodide before Thyroidectomy and Complicated by Post-operative Levothyroxine Malabsorption

Graves’ disease is typically responsive to antithyroid drugs (ATDs), with true pharmacologic resistance being rare. We report a young female with refractory Graves’ disease who demonstrated minimal biochemical improvement despite prolonged high-dose ATD therapy, raising concern for impaired drug absorption. A short pre-operative course of supersaturated potassium iodide (SSKI) resulted in rapid biochemical stabilisation and enabled safe total thyroidectomy. Postoperatively, she developed progressive hypothyroidism despite escalating levothyroxine doses, again suggesting malabsorption. Although prior endoscopy and celiac serology were negative, the patient had a strong family history of celiac disease and micronutrient deficiencies, keeping seronegative or early enteropathy a consideration. This case highlights the importance of recognising malabsorption in both hyperthyroid and hypothyroid phases and the value of SSKI when ATD resistance limits pre-operative optimisation.