Thyroid storm is a life-threatening condition with mortality rates reaching up to 20 to 30%. First-line treatment includes inhibition of thyroid hormone synthesis, prevention of release of preformed hormones, blocking of peripheral FT4 to FT3 conversion, enhancing hormone clearance, and definitive radioactive iodine ablation. However, in the presence of life-threatening adverse effects (e.g., agranulocytosis) and contraindications (e.g., fulminant hepatic failure), therapeutic plasma exchange (TPE) can be used to rapidly remove circulating thyroid hormones, antibodies, and cytokines in plasma; this is recommended by the American Society of Apheresis (ASFA) and the American Thyroid Association (ATA) as second-line treatment for thyroid storm. Here, we report a 49-year-old female with Graves' disease admitted in our emergency room for a 6-week history of fever, weight loss, jaundice, exertional dyspnea, palpitations, and diarrhea. Her initial thyroid hormone levels were: FT4 64.35 (NV 9.01-19.05 pmol/L), FT3 23.91 (NV: 2.89-4.88 pmol/L), and TSH 0.00000 (NV: 0.35-4.94 mIU/L) and we managed her as a case of thyroid storm (Burch-Wartofsky score 70) by initiating high dose propylthiouracil. However, her sensorium deteriorated and serum bilirubin continued to rise from 307.2 on admission to 561.6 umol/L on the 5th hospital day (NV: 3 - 22 umol/L). TPE was performed after consultation with the Division of Hematology. Over the treatment course, her thyroid hormones normalized: FT4 13.18 pmol/L, FT3 2.30 pmol/L. However, despite TPE, her symptoms worsened and she became comatose, had hypotension despite vasopressors and developed new-onset atrial fibrillation. She expired on her 7th hospital day from multiorgan failure. TPE is effective in decreasing circulating thyroid hormone levels. However, it had no effect on clinically important outcomes as our patient still deteriorated and eventually succumbed. We still wrote and submitted this case report since if only successful cases were reported, the true effectiveness rate of TPE could not be determined.Thyroid storm is a life-threatening condition with mortality rates reaching up to 20 to 30%. First-line treatment includes inhibition of thyroid hormone synthesis, prevention of release of preformed hormones, blocking of peripheral FT4 to FT3 conversion, enhancing hormone clearance, and definitive radioactive iodine ablation. However, in the presence of life-threatening adverse effects (e.g., agranulocytosis) and contraindications (e.g., fulminant hepatic failure), therapeutic plasma exchange (TPE) can be used to rapidly remove circulating thyroid hormones, antibodies, and cytokines in plasma; this is recommended by the American Society of Apheresis (ASFA) and the American Thyroid Association (ATA) as second-line treatment for thyroid storm. Here, we report a 49-year-old female with Graves' disease admitted in our emergency room for a 6-week history of fever, weight loss, jaundice, exertional dyspnea, palpitations, and diarrhea. Her initial thyroid hormone levels were: FT4 64.35 (NV 9.01-19.05 pmol/L), FT3 23.91 (NV: 2.89-4.88 pmol/L), and TSH 0.00000 (NV: 0.35-4.94 mIU/L) and we managed her as a case of thyroid storm (Burch-Wartofsky score 70) by initiating high dose propylthiouracil. However, her sensorium deteriorated and serum bilirubin continued to rise from 307.2 on admission to 561.6 umol/L on the 5th hospital day (NV: 3 - 22 umol/L). TPE was performed after consultation with the Division of Hematology. Over the treatment course, her thyroid hormones normalized: FT4 13.18 pmol/L, FT3 2.30 pmol/L. However, despite TPE, her symptoms worsened and she became comatose, had hypotension despite vasopressors and developed new-onset atrial fibrillation. She expired on her 7th hospital day from multiorgan failure. TPE is effective in decreasing circulating thyroid hormone levels. However, it had no effect on clinically important outcomes as our patient still deteriorated and eventually succumbed. We still wrote and submitted this case report since if only successful cases were reported, the true effectiveness rate of TPE could not be determined.