Amiodarone lung: pathologic findings in clinically toxic patients

Area of Science:

• Pulmonary Pathology
• Toxicology
• Cardiology

Background:

• Amiodarone is a widely used antiarrhythmic drug.
• Amiodarone pulmonary toxicity is a serious adverse effect.
• Characterizing the pathology of amiodarone lung is crucial for diagnosis and management.

Purpose of the Study:

• To characterize the histopathological features of amiodarone-induced lung injury.
• To compare findings in patients with and without amiodarone pulmonary toxicity.

Main Methods:

• Histopathological examination of lung biopsy and autopsy specimens from 12 patients with amiodarone pulmonary toxicity.
• Comparison with autopsy specimens from 5 patients taking amiodarone without pulmonary side effects.
• Electron microscopy was used to identify specific cellular inclusions.

Main Results:

• Interstitial pneumonia was the most common finding in amiodarone lung.
• Key features included interstitial inflammation, fibrosis, and type II pneumocyte hyperplasia.
• Foamy alveolar macrophages and cytoplasmic lamellar inclusions were frequently observed but not specific to toxic cases.

Conclusions:

• Amiodarone lung is primarily an interstitial pneumonia.
• Foamy alveolar macrophages and lamellar inclusions are characteristic but not pathognomonic.
• These findings alone cannot definitively distinguish amiodarone pulmonary toxicity from other lung conditions.