Thyroid storm and lymphocytic myocarditis.

Cardiac failure is the leading cause of mortality in patients with thyroid storm. But the underlying cardiac pathology is unclear. Here, we report a 46-year-old woman who presented with hyperpyrexia and sinus tachycardia subsequent to accidental neck contusion. Her hyperthyroidism was verified by abnormal biochemical changes. Despite vigorous antithyroid treatment including a beta-blocker, glucocorticoid and potassium iodide, the patient eventually succumbed to refractory congestive heart failure in 4 days. Autopsy revealed lymphocytic myocarditis. We propose that lymphocytic myocarditis played a prominent role in her demise.