Plasmapheresis as First Line Therapy for Thyrotoxicosis in a Critically Ill Patient

Introduction: The role of plasmapheresis (TPE) in thyrotoxicosis management is not well established. Its use may be determined on an individualized basis (1). We report a case of a critically ill patient where TPE was utilized as first-line therapy for refractory thyrotoxicosis. Clinical Case: A 33-year-old woman with Graves’ disease complicated by medication non-adherence presented with rapidly ascending paralysis and bulbar weakness. Primary work up was consistent with acute inflammatory demyelinating polyneuropathy (AIDP) based on EMG findings of motor fiber polyneuropathy with demyelinating features. Laboratory evaluation revealed uncontrolled hyperthyroidism (TSH <0.05 uU/mL, N 0.3-4.2 uU/mL; fT4 3.9 ng/dL, N 0.6-1.5 ng/dL; tT3 318, N 60-160 ng/dL). Initially, there was low concern for thyrotoxicosis based on a Burch-Wartofsky score of 15 (2). Standard dose methimazole and aggressive beta-blockade were initiated. Hospital course was complicated by hypoxic respiratory failure due to progressive paralysis requiring intubation and septic shock from Klebsiella pneumonia requiring initiation of pressors and broad-spectrum antibiotics. Biochemical evaluation showed increasing fT4 (3.8 ng/dL) and tT3 (419 ng/dL) levels. Burch-Wartofsky score increased to 55, consistent with a thyrotoxic crisis. Due to the patient’s critical condition, TPE was rapidly initiated along with standard therapy for thyrotoxic crisis (high dose methimazole, esmolol drip, stress dose corticosteroids, cholestyramine, and potassium iodide) as a bridge to definitive management with thyroidectomy. Rapid clinical improvement with a decline in fT4 levels (3.8 to 2.1 ng/dL) was noted after initiation of TPE with normalization in fT4 (1.5 ng/dL) and tT3 (54 ng/dL) after three sessions. Thyroidectomy was pursued after clinical stabilization. Surgical pathology showed diffuse papillary hyperplasia consistent with Graves’ disease. Due to persistent respiratory failure, the patient underwent tracheostomy placement. Repeat EMG revealed severe myopathic dysfunction without demyelinating features favoring a diagnosis of acute thyrotoxic myopathy over AIDP. Patient was ultimately discharged to a long term acute care facility due to slow neurological recovery. Conclusion: TPE should be considered as first line management in conjunction with conventional medical therapy in critically ill patients with thyrotoxicosis as a bridge to thyroidectomy due to rapid time to effect and patient stabilization. References: (1) Padmanabhan A, et al. J Clin Apher. 2019 Jun;34(3):171-354. (2) Bahn Chair RS, et al. Thyroid. 2011 Jun;21(6):593-646.