The swinging thyroid in hepatitis C infection and interferon therapy.

Described is a case of triphasic thyroid response in a 53-year-old man while undergoing combination interferon α-2b and ribavirin treatment for chronic hepatitis C infection. He developed the classical biphasic thyroiditis during treatment and was treated expectantly. However, 8 weeks after the completion of therapy, he developed T3-Graves-like thyrotoxicosis, which was confirmed with a diffuse-uptake thyroid scan and positive thyroid stimulating immunoglobulin. He was treated as having Graves' disease arising de novo with thiourea, and he achieved rapid remission. This is thought to be only the second case described, and it offers a unique opportunity to understand the possible pathogenesis of this fascinating condition. This is a relative novel entity and highlights the need for continuing thyroid monitor after treatment. Management also needs to be specific for each particular phase of the condition.