SUN-376 Thyroid Storm Precipitated by Ruptured Appendicitis: A Call for Early Plasmapheresis as a Bridge to Definitive Management

Abstract Disclosure: Y. Abdullah: None. P. Ehrlich: None. B. Matthew: None. A. Mody: None. M.N. Kulkarni-Date: None. BackgroundThyroid storm is a life-threatening hypermetabolic crisis that, if unrecognized, may progress to rapid multiorgan failure. Perioperative mortality is particularly high when emergent surgical conditions coexist, as anesthesia and surgical stress can exacerbate hyperthyroidism and trigger cardiovascular collapse. Standard antithyroid therapy (e.g., propylthiouracil [PTU], beta-blockade, iodine solution, steroids) typically lowers thyroid hormone levels over days to weeks. However, these therapies may prove insufficiently rapid in situations demanding urgent surgery. Plasmapheresis (PLEX) offers a potential bridging option, removing both free and protein-bound thyroid hormones, thereby enabling safer emergent operations.Clinical CaseA previously healthy 42-year-old man was admitted with acute right lower quadrant abdominal pain accompanied by nausea and vomiting. Physical examination revealed new-onset atrial fibrillation with rapid ventricular response (RVR). Laboratory analysis showed a high free T4 of 3.72 ng/dL (reference range ∼0.9–1.7), TSH <0.01 mIU/L, leukocytosis, and lactic acidosis. Abdominal computed tomography (CT) confirmed acute appendicitis without evident perforation. His Burch–Wartofsky score was 80, confirming thyroid storm. Surgery was deferred pending stabilization, and treatment commenced with PTU, intravenous steroids, Lugol’s iodine solution, intravenous beta-blocker therapy, and piperacillin–tazobactam. Repeat imaging revealed a ruptured appendix, placing him at imminent risk of sepsis, however he remained unfit for anesthesia given persistent thyrotoxicosis. On hospital day three, plasmapheresis was initiated to acutely reduce circulating thyroid hormones. Within 24 hours, free T4 declined substantially, enabling emergent laparotomy. The patient’s postoperative course required mechanical ventilation and a second PLEX session to address residual thyrotoxicosis. No additional thyrotoxic crises recurred. Ultimately, he underwent total thyroidectomy to definitively treat Graves' disease.DiscussionThis case highlights that conventional therapies may inadequately mitigate thyroid storm in time-sensitive settings, especially when emergent surgery is vital. Plasmapheresis can provide an expedited reduction in thyroid hormone levels, effectively bridging to safe operative conditions. Although PLEX is not standard in all thyroid storm patients, our experience suggests it is invaluable for those with refractory hyperthyroidism facing urgent surgical pathology. We advocate for earlier consideration of PLEX to avert catastrophic outcomes in similarly precarious scenarios, urging a more proactive, multidisciplinary approach among critical care, endocrinology, and surgical teams when life-threatening thyrotoxicosis intersects with emergent operative needs. Presentation: Sunday, July 13, 2025