MEDizzy - You are evaluating a 42-year-old woman with a history of

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Disorders of the cardiovascular system 2

You are evaluating a 42-year-old woman with a history of Hashimoto thyroiditis many years ago who was treated successfully with radioactive iodine. She presents to the emergency department after passing out at home and reports several days of worsening lethargy and chest discomfort. She is short of breath, with a resting heart rate of 110 bpm and blood pressure of 77/62 mmHg. Her extremities are cool, and she seems sleepy. Her whole blood lactate is elevated, and urine output for the first 2 hours of her stay is minimal. On the cardiac monitor, she repeatedly has salvos of nonsustained ventricular tachycardia. Echocardiogram reveals a left ventricular ejection fraction of 15%, and an emergent endomyocardial biopsy shows difuse granulomatous lesions surrounded by extensive inflammatory infiltrate. Which of the following statements is true regarding her diagnosis?

ExplanationGiant cell myocarditis accounts for 10%–20% of biopsy-positive cases of myocarditis. Giant cell myocarditis typically presents with rapidly progressive heart failure and tachyarrhythmias. Difuse granulomatous lesions are surrounded by extensive infammatory infltrate unlikely to be missed on endomyocardial biopsy, often with extensive eosinophilic infltration. Associated conditions are thymomas, thyroiditis, pernicious anemia, other autoimmune diseases, and occasionally recent infections. Glucocorticoid therapy is less efective than for sarcoidosis and is sometimes combined with other immunosuppressive agents. The course is generally of rapid deterioration requiring urgent transplantation. Although the severity of presentation and myocardial histology are more fulminant than with sarcoidosis, the occasional fnding of giant cell myocarditis after sarcoidosis suggests that they may, in some cases, represent diferent stages of the same disease spectrum.