Rationale: Various neurological manifestations are observed in thyroid storm patients but protracted disturbance of consciousness is rare.
Patient concerns: A 58-year-old male was admitted to our hospital after a traffic accident.
Diagnoses: Although awake on arrival, he fell into coma after admission. Based on the clinical symptoms and hyperthyroidism, the patient was diagnosed with thyroid storm (TS).
Interventions: Even after improvement of hyperthyroidism, disturbance of consciousness was protracted. Considering the possibility of immune-related etiology, methylprednisolone pulse was started.
Outcomes: His consciousness level improved over a 3-month period, and he became able to walk with some assistance after 6 months.
Lessons: His condition was atypical of TS-associated encephalopathy because of the long clinical course. Reversible splenial lesion was visible using brain imaging. In some cases of TS, disturbance of consciousness can be protracted for several months, but it is reversible. Therefore, it is necessary to judge the long-term neurological outcome carefully.