Endocrine Abstracts

Background: Graves’ Disease usually responds well to medical treatment with thionamides. However, in some cases, it fails to respond to this treatment, even at maximum doses. A few reported cases have shown that colestyramine helps to restore normal thyroid function when added to the ongoing anti-thyroidal medications in refractory thyrotoxicosis. We reported a case of relapsing refractory Graves’ disease, in which colestyramine has helped to restore normal thyroid function tests and allowed for subsequent total thyroidectomy.

Case Presentation: A 21-year-old female presented with relapsing Graves’ Disease after 5 years of remission. She was planned for surgery and started on carbimazole in order to restore a euthyroid state before the procedure. This was not achieved despite carbimazole doses being increased to 60 mg over a period of 8 weeks. Colestyramine, 4 mg four times a day, was added as an adjunct, which normalized her thyroid function after 2 weeks of treatment. The patient underwent successful total thyroidectomy subsequently.

Discussion: Bile acid sequestrants (e.g. colestyramine) have been found to reduce thyroid hormone levels in thyrotoxic patients by interfering with enterohepatic circulation and recycling of thyroid hormone. Cholestyramine, given in a dose of 4 g four times daily with thionamides, lowers serum T4 and T3 concentrations more rapidly than thionamides alone and may be useful adjunctive therapy in selected patients who require rapid amelioration of hyperthyroid symptoms. A few case reports have noted that colestyramine, when added to antithyroid drugs in patients with refractory thyrotoxicosis, has successfully achieved a euthyroid state within a few weeks of treatment. This case further supports the growing body of evidence that in medically refractory thyrotoxicosis, colestyramine could be used as an adjunct in reducing thyroid hormone levels to acceptable ranges for surgery to be done. Further studies including randomized control trials could be done to examine the effects of colestyramine in this group of patients.

Conclusion: Colestyramine could be an effective additional treatment in refractory thyrotoxicosis when maximum doses of thionamides fail to restore normal thyroid function.