Therapeutic Plasma Exchange for the Treatment of Hyperthyroidism: Approach to the Patient with Thyrotoxicosis or Antithyroid-Drugs Induced Agranulocytosis

: Primary hyperthyroidism is an endocrine disorder characterized by excessive thyroid hormone synthesis and secretion by the thyroid gland. Clinical manifestations of hyperthyroidism can vary from subclinical to overt forms. In rare cases, hyperthyroidism may represent a clinical emergency, requiring admission to an intensive care unit due to an acute and severe exacerbation of thyrotoxicosis, known as a thyroid storm. First-line treatment of hyperthyroidism is almost always based on medical therapy (with thioamides, beta-adrenergic blocking agents, glucocorticoids), radioactive iodine or total thyroidectomy, tailored to the patient's diagnosis. In cases of failure/intolerance/adverse events or contraindication to these therapies, as well as in life-threatening situations, including a thyroid storm, it is necessary to consider an alternative treatment with extracorporeal systems, such as therapeutic plasma exchange (TPE). This approach can promptly resolve severe conditions by removing circulating thyroid hormones. Here we described two different applications of TPE in clinical practice: the first case is an example of thyrotoxicosis due to amiodarone treatment, while the second one is an example of a severe adverse event to antithyroid drugs (agranulocytosis induced by methimazole).