Therapeutic Plasma Exchange in Severe Thyrotoxicosis: Clinical Observations From a Case Series

Severe thyrotoxicosis and thyroid storm have a high morbidity and mortality risk and are commonly managed with antithyroid drugs. In some patients, a combination therapy with medications and thyroidectomy as definite treatment are required. Therapeutic Plasma Exchange (TPE) can be used as a temporizing measure to achieve thyroid hormone normalization and to prevent perioperative complications before surgery.

We describe 6 cases of severe thyrotoxicosis and/or thyroid storm who underwent TPE as a bridge to thyroidectomy and present the clinical characteristics and outcomes. We aim to propose a preoperative thyroid hormone target.

We collected data of 6 patients who were diagnosed with severe thyrotoxicosis or thyroid storm between April 2023 and April 2024 and that were treated with TPE due to high mortality risk or refractoriness to medical treatment. Data collected included the baseline clinical characteristics, laboratory data, clinical progress, and outcomes. Thyroid hormone levels at diagnosis, before initiation of TPE, and before thyroidectomy were compared using statistical analysis.

Four of 6 patients underwent thyroidectomy, and 2 patients died due to multiorgan dysfunction. The mean free T4 (fT4) level at diagnosis was 4.8 ng/dL (reference range, 0.8-1.8 ng/dL), 5.4 ng/dL pre-TPE, and 2.6 ng/dL prethyroidectomy, resulting in a mean difference of 2.8 ng/dL (51.7%) reduction (95% CI, 1.1-4.5; P = .01). The number of TPE treatments to reach a preoperative fT4 level of 2.5 ng/dL was 5.5 treatments (P = .03).

These results reflect efficacy of TPE as a bridge to thyroidectomy and suggest that a preoperative fT4 goal of 2.5 to 3.3 can be considered in patients with severe thyrotoxicosis and thyroid storm that are refractory to medical treatment.