(15.02) The Thyroid Storm’s Turbulent Landing as Seizure and Cardiac Arrest

A thyroid storm is a severe and potentially life-threatening complication of hyperthyroidism. Its estimated mortality rate ranges from 8% to 25%. Clinical manifestations usually include fever, tachycardia, and alterations in mental status, among other symptoms. Rarely, seizure can also occur with an incident rate of only 0.2% to 4% and it typically subsides upon achieving euthyroid status. Moreover, signs and symptoms of organ decompensation may present, with cardiopulmonary failure the leading cause of death. Based on our literature review, this might be the first case of thyroid storm-induced seizure and cardiac arrest in a patient with undiagnosed Graves disease. His cardiac function improved, and his seizure subsided after his thyroid function returned to normal.

Case(s) Description : A 30-year-old male with no medical history presented to the Emergency Department (ED) with one week of fatigue, abdominal pain, nausea, and diarrhea. Upon arrival, he was afebrile, normotensive, but tachycardia to 130 beats per minute. Initial labs were significant for thyroid stimulating hormone (TSH) of < 0.01 uIU/mL (0.27-4.20 uIU/mL), and free thyroxine (FT4) of 7.77 ng/dL (0.9-1.8 ng/dL). The Burch-Wartofsky score was 35 indicates an impending thyroid storm. While awaiting treatment, he had multiple episodes of generalized tonic-clonic seizures, after which he experienced altered mental status and hypoxia. He was immediately intubated. Shortly after intubation, he became hypotensive and then underwent asystole. CPR was started and ROSC was achieved in 10 minutes, he was subsequently transferred to the cardiac care unit (CCU) for further management of thyroid storm, seizure, cardiogenic shock, acute renal injury, and acute liver failure. Thyroid stimulating immunoglobin was 20 IU/L(0.00-0.55 IU/L), and TSH receptor antibody was 20.4 IU/L(0.00-1.75 IU/L). Transthoracic echocardiogram (TTE) on day 2 demonstrated a severely decreased left ventricular ejection fraction (EF) of 15%-20%. While in CCU, he received multiple pressors for cardiogenic shock, levetiracetam for seizure, hydrocortisone, cholestyramine, and Lugol’s for thyroid storm. CT head demonstrated no acute pathologic changes. Video electroencephalography was performed on day 4 showing no evidence of epilepsy. On day 10, his thyroid and renal function normalized, and his liver function was significantly improved. His mental status returned to his baseline. Levetiracetam was discontinued, and he was extubated. Repeated TTE showed a normal EF of 50-55%. He was discharged with methimazole 10mg twice daily on day 31.

Below is Table 1. Free T4 and TSH trends during hospitalisation 

Although rare, seizure and cardiac arrest can be the initial presentations of thyroid storm. It is crucial for healthcare providers to be mindful of this possibility to promptly identify and manage patients with severe thyroid storm to optimize their outcomes.