Amiodarone pulmonary toxicity

Abstract

Amiodarone is an antiarrhythmic agent commonly used to treat supraventricular and ventricular arrhythmias. This drug is an iodinecontaining compound that tends to accumulate in several organs, including the lungs. It has been associated with a variety of adverse events. Of these events, the most serious is amiodarone pulmonary toxicity. Although the incidence of this complication has decreased with the use of lower doses of amiodarone, it can occur with any dose. Because amiodarone is widely used, all clinicians should be vigilant of this possibility. Pulmonary toxicity usually manifests as an acute or subacute pneumonitis, typically with diffuse infiltrates on chest x-ray and high-resolution computed tomography. Other, more localized, forms of pulmonary toxicity may occur, including pleural disease, migratory infiltrates, and single or multiple nodules. With early detection, the prognosis is good. Most patients diagnosed promptly respond well to the withdrawal of amiodarone and the administration of corticosteroids, which are usually given for four to 12 months. It is important that physicians be familiar with amiodarone treatment guidelines and follow published recommendations for the monitoring of pulmonary as well as extrapulmonary adverse effects.

Figures

Figure 1)

Lung parenchyma showing interstitial inflammation and thickening with fibroblastic tissue in airway lumens consistent with organizing pneumonia (arrow) (hematoxylin and eosin stain, original magnification ×100)

Figure 2)

Microscopic image of an alveolus showing interstitial inflammation and type II pneumocyte hyperplasia. The pneumocytes show many coarse cytoplasmic vacuoles (arrow) (hematoxylin and eosin stain, original magnification ×400)

Figure 3)

Posterior-anterior chest radiograph of a 79-year-old woman with amiodarone pulmonary toxicity. Bilateral patchy airspace and interstial infiltrates are seen

Figure 4)

Computed tomography scan of the same patient as seen in Figure 3. A Upper lobe cut shows bilateral patchy infiltrates with some areas of ground glass opacification (G). B A lower lobe computed tomography cut shows bilateral basilar infiltrates and small pleural effusions. Complete resolution occurred after withdrawal of amiodarone and institution of corticosteroids