Coma in Thyroid Storm: Review of Aggregated English-Language Case Reports

CONTEXT: Coma is a serious manifestation of thyroid storm (TS) about which little is known. OBJECTIVE: To describe the features, duration, treatment response, and prognosis of coma in the setting of TS. DESIGN: Aggregate analysis of individual English-language case reports of coma in the setting of TS from 1935 to January 2019. SETTING: Hospitals. PATIENTS: Sixty-five cases were identified, 29 from case reports and 36 from case series. INTERVENTIONS: Antithyroid drugs, corticosteroids, beta-blockers, iodine, intubation, plasmapheresis, antibiotics, thyroidectomy, radioiodine, dialysis, and l-carnitine. MAIN OUTCOME MEASURES: Awakening and death rates overall and in relation to administered treatments, day of coma presentation, and time from coma onset; symptoms associated with coma; TS and coma scales; thyroid and cerebrospinal laboratory tests; electroencephalogram; brain imaging; and autopsy results. RESULTS: Mortality was 38% in the setting of TS-related coma, 11% during the years 1978 to 2019 compared with 70% for 1935 to 1977. Both awakening and death commonly occurred within the first 2 days of coma onset. Reduction in total and free T4 values, and possibly also total T3 value, correlated with awakening from coma. Lower death rates were associated with use of antithyroid drugs, corticosteroids, beta-blockers, and intubation. Plasmapheresis was associated with awakening in 67% of cases but not with lower death rates. CONCLUSIONS: Prognosis of coma associated with TS remains poor. Current guidelines for the early use of plasmapheresis in unresolving TS are advocated and should be considered urgently at the point of confusion or delirium in an effort to abort coma.