Plasma exchange in the treatment of thyroid storm secondary to type II amiodarone-induced thyrotoxicosis

Type II amiodarone-induced thyrotoxicosis (AIT) is an uncommon cause of thyroid storm. Due to the rarity of the condition, little is known about the role of plasma exchange in the treatment of severe AIT. A 56-year-old male presented with thyroid storm 2months following cessation of amiodarone. Despite conventional treatment, his condition deteriorated. He underwent two cycles of plasma exchange, which successfully controlled the severe hyperthyroidism. The thyroid hormone levels continued to fall up to 10h following plasma exchange. He subsequently underwent emergency total thyroidectomy and the histology of thyroid gland confirmed type II AIT. Management of thyroid storm secondary to type II AIT can be challenging as patients may not respond to conventional treatments, and thyroid storm may be more harmful in AIT patients owing to the underlying cardiac disease. If used appropriately, plasma exchange can effectively reduce circulating hormones, to allow stabilisation of patients in preparation for emergency thyroidectomy. LEARNING POINTS: Type II AIT is an uncommon cause of thyroid storm and may not respond well to conventional thyroid storm treatment. Prompt diagnosis and therapy are important, as patients may deteriorate rapidly. Plasma exchange can be used as an effective bridging therapy to emergency thyroidectomy. This case shows that in type II AIT, each cycle of plasma exchange can potentially lower free triiodothyronine levels for 10h. Important factors to consider when planning plasma exchange as a treatment for thyroid storm include timing of each session, type of exchange fluid to be used and timing of surgery.