Thyroid Storm and Reversible Thyrotoxic Cardiomyopathy After Ingestion of Seafood Stew Thought to Contain Marine Neurotoxin

Abstract

Thyroid storm and severe decompensated thyrotoxicosis are life-threatening diseases, requiring immediate treatment in an intensive care unit. Thyrotoxic heart disease is common in patients with hyperthyroidism; thyrotoxic cardiomyopathy with poor left ventricular systolic function is rare. Here, we report a patient who presented with severe decompensated thyrotoxicosis and reversible thyrotoxic cardiomyopathy after ingestion of a mixed seafood stew thought to contain tetrodotoxin or a related marine neurotoxin. The patient was a 50-year-old woman who was seen at the emergency room of another hospital with altered mentality and flaccid quadriplegia after eating a mixed seafood stew. At the other hospital, she was diagnosed as having tetrodotoxin intoxication on the basis of her clinical presentation. The patient was placed on assisted ventilation and transferred to our hospital the following day because of persisting fever, tachycardia, and respiratory depression. Upon admission, thyroid storm was diagnosed on the basis of thyroid function tests (total triiodothyronine was 354 ng/dL, free thyroxine was 3.45 ng/dL, and thyroid-stimulating hormone was <0.01 mU/L) and clinical manifestations. On the third hospital day, she complained of chest discomfort and progressively worsening dyspnea. Echocardiography showed reduced left ventricular systolic function (left ventricular ejection fraction, 47%; left ventricular fractional shortening, 24.4%) with regional wall motion abnormality of anteroseptal wall and apex and diastolic dysfunction (grade 1, relaxation abnormality), suggesting thyrotoxic cardiomyopathy. She was treated with 10 mCi of radioactive iodine and methimazole, and her thyroid and cardiac function normalized. The patient reported here developed thyroid storm and cardiac decompensation shortly after a clinical event consistent with ingestion of marine neurotoxin. This adds to the list of stresses that have been associated with thyroid storm and emphasizes the need to fully evaluate patients who, on initial evaluation, appear to have only a single disorder.