A Rare Case of ARDS Caused by Amiodarone

Abstract

Introduction: Amiodarone is one of the most commonly prescribed antiarrhythmic medications in the United States. Adverse effects have been shown to affect multiple organ systems including cardiac, thyroid, hepatic, ocular and pulmonary. Pulmonary toxicity can vary in presentation from interstitial pneumonitis, eosinophilic pneumonia, organizing pneumonia and acute respiratory distress syndrome (ARDS)1. This is a case of ARDS caused by Amiodarone. Case Presentation: This is a case of an 81 yo male with a history of atrial fibrillation (on Amiodarone 200 mg daily), mechanical aortic valve replacement and diabetes who presented to the hospital with a four week history of dry cough and one week of dyspnea on exertion. He was treated for community acquired pneumonia prior to admission with steroids, Azithromycin, Ceftriaxone and Levofloxacin. On arrival he was afebrile, but hypoxic requiring oxygen support with nasal cannula. Physical exam was concerning for an ill appearing, lethargic elderly gentleman with extensive crackles throughout both lung fields more concentrated in the upper lobes. Laboratory was significant for negative SARS Coronavirus RNA PCR and Leukocytosis 14.7. Computed-tomography revealed extensive bilateral consolidations with air bronchograms worse in the upper lobes. As his clinical status worsened requiring use of non-invasive ventilation and transfer to the intensive care unit, it became clear that this was not an infectious process;work up thus far had been negative. Amiodarone was discontinued and the patient was started on Diltiazem and pulse dose steroids. Within four days, his respiratory and mental status improved. Discussion: Amiodarone pulmonary toxicity has been associated with higher doses of 400 mg, but 1.6% of cases are reported with less, making this case unique. The pathology appears to be related to direct cytotoxic effect and indirect immunological reaction. Patients will usually present with a nonproductive cough and shortness of breath. Imaging is key for diagnosis, demonstrating diffuse patchy infiltrates;with a preference to the right lung and upper lobes. Treatment centers on discontinuation of the drug and 40-60 mg of Prednisone per day tapered over the period of a few months2.