Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Amiodarone-induced pulmonary toxicity
- Radiologic Findings
- Fig 1. Chest radiograph shows reticulation and GGOs in both lower lung zone.
Fig 2-4. Thin-section CT scans show diffuse reticular densities, fibrosis and GGOs in both lungs, lower lobe predominantly.
Fig 5. The patient have history of treatment with amiodarone for atrial fibrillation during past 3 years. 3 months later, after discontinuation of Amiodarone, follow up CT scan shows decreased extent of diffuse reticular densities, fibrosis and GGOs in both lungs.
Figure 6. CT scan with mediastinal window setting shows relatively high attenuation of the liver compared to spleen.
- Brief Review
- Amiodarone is an iodinated benzofuran derivative that is used to suppress ventricular and supraventricular tachyarrhythmias. Pulmonary toxicity is among the most serious adverse effects of amiodarone. Several forms of pulmonary disease occur among patients treated with amiodarone, including interstitial pneumonitis, organizing pneumonia, ARDS, diffuse alveolar hemorrhage, pulmonary nodules and solitary masses, and also pleural effusion. Other adverse effects from amiodarone include photosensitivity, blue-gray discoloration of the skin, thyroid dysfunction, corneal deposits, abnormal liver function tests, and bone marrow suppression.
Radiology plays a central role in diagnosis. Chest x-rays reveal patchy or diffuse infiltrates, which are commonly bilateral. Some infiltrates have a ground glass appearance. Computed tomography scanning often reveals bilateral interstitial, alveolar or mixed interstitial and alveolar infiltrates. Parenchymal infiltrates that have high attenuation are typical and believed to be associated with the iodinated properties of the drug and its prolonged half-life in the lung. Ground glass opacities are appreciated more easily and seen more frequently on CT scanning. They are often distributed in a peripheral manner and may be an early finding in amiodarone induced pulmonary toxicity. Pleural thickening is commonly seen, especially in areas where the infiltrates are densest. Pleural effusions have been described but are less common. High attenuation may be noted incidentally during CT on views of the liver and spleen, related to the accumulation of amiodarone and its metabolites in tissue macrophages.
Once the diagnosis of APT is considered likely, the drug should be discontinued. After stopping, amiodarone resolution is likely to be slow and some degree of worsening may occur before improvement is noted. This has been attributed to the long elimination half-life of the drug and the tendency to concentrate in tissues such as the lung.
Systemic corticosteroids are recommended for the treatment, although controlled trials demonstrating efficacy are lacking. Cases of relapse on early steroid withdrawal have been reported.
The prognosis of amiodarone lung disease is generally favorable when diagnosed early. However, more advanced disease may be fatal or result in pulmonary fibrosis. Mortality is highest among those who develop ARDS.
- Please refer to
Case 704, Case 593, Case 330, Case 176, Case 114, -
KSTR Imaging Conference 2016 Spring Case 15
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KSTR Imaging conference 2010 Summer Case 15
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KSTR Imaging Conference 2003 Summer Case 10
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KSTR Imaging Conference 2006 Spring Case 4, Case 10,
- References
- 1. Norman Wolkove, MD FRCP and Marc Baltzan, MD. Amiodarone pulmonary toxicity. Can Respir J. 2009 Feb; 16(2): 43
- Keywords
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Lung, Treatment, Drug-related lung disease,