From the Guidelines
Lung imaging findings in Amiodarone toxicity typically include patchy interstitial infiltrates on chest radiographs, with high-resolution computed tomography (HRCT) being more sensitive and able to detect characteristic findings such as ground-glass opacities and high-attenuation lung parenchymal changes due to iodine accumulation in the lungs. The clinical presentation of amiodarone pulmonary toxicity often involves subacute cough and progressive dyspnea, with associated radiographic abnormalities 1. Key findings on imaging include:
- Patchy interstitial infiltrates on chest radiographs
- Ground-glass opacities on HRCT
- Interstitial thickening on HRCT
- High-attenuation lung parenchymal changes due to iodine accumulation in the lungs on HRCT Pulmonary function tests can also aid in diagnosis, typically revealing a restrictive pattern with decreased diffusion capacity 1. It is essential to perform imaging promptly when amiodarone toxicity is suspected, as early detection can prevent progression to irreversible fibrosis. Management involves discontinuation of amiodarone and, in severe cases, corticosteroid therapy 1. Follow-up imaging is recommended to monitor resolution, though some radiographic abnormalities may persist despite clinical improvement due to amiodarone's long half-life 1.
From the FDA Drug Label
Pulmonary Disorders Early-onset Pulmonary Toxicity There have been postmarketing reports of acute-onset (days to weeks) pulmonary injury in patients treated with intravenous amiodarone. Findings have included pulmonary infiltrates and/or mass on X-ray, bronchospasm, wheezing, fever, dyspnea, cough, hemoptysis, and hypoxia. Some cases have progressed to respiratory failure and/or death ARDS Two percent (2%) of patients were reported to have adult respiratory distress syndrome (ARDS) during clinical studies involving 48 hours of therapy. ARDS is a disorder characterized by bilateral, diffuse pulmonary infiltrates with pulmonary edema and varying degrees of respiratory insufficiency The clinical and radiographic picture can arise after a variety of lung injuries, such as those resulting from trauma, shock, prolonged cardiopulmonary resuscitation, and aspiration pneumonia, conditions present in many of the patients enrolled in the clinical studies. There have been postmarketing reports of ARDS in intravenous amiodarone patients Intravenous amiodarone may play a role in causing or exacerbating pulmonary disorders in those patients. Postoperatively, occurrences of ARDS have been reported in patients receiving oral amiodarone therapy who have undergone either cardiac or noncardiac surgery. Although patients usually respond well to vigorous respiratory therapy, in rare instances the outcome has been fatal Until further studies have been performed, it is recommended that FiO 2 and the determinants of oxygen delivery to the tissues (e.g., SaO 2, PaO 2) be closely monitored in patients on amiodarone. Pulmonary Fibrosis Only 1 of more than 1000 patients treated with amiodarone HCl injection in clinical studies developed pulmonary fibrosis. In that patient, the condition was diagnosed 3 months after treatment with amiodarone HCl injection, during which time she received oral amiodarone Pulmonary toxicity is a well-recognized complication of long-term amiodarone use (see labeling for oral amiodarone).
The lung imaging findings in Amiodarone toxicity include:
- Pulmonary infiltrates and/or mass on X-ray
- Bilateral, diffuse pulmonary infiltrates with pulmonary edema, characteristic of ARDS
- Pulmonary fibrosis in rare cases 2
From the Research
Lung Imaging Findings in Amiodarone Toxicity
The lung imaging findings in amiodarone toxicity include:
- Bilateral air-space disease 3
- Parenchymal bands 3
- Thickened septal and bronchiolitis obliterans 3
- Ground-glass opacities associated with consolidations, thin intralobular reticulations, or both 4
- Subpleural or central location of ground-glass opacities 4
- High-density areas 4
- Pleural thickening 4, 5
- Bronchial abnormalities, including dilation and wall thickening 4
- Interstitial nodules 5
- Alveolar nodules 5
- Consolidations 5
- Parenchymal masses 5
- Fibrosis 5
- Reduced lung volume 5
- Pleural effusion 5
High-Resolution Computed Tomography (HRCT) Findings
HRCT findings in amiodarone toxicity include:
- Increased attenuation of either pleural or pulmonary densities representing high iodine amiodarone deposits 3
- Ground-glass opacities associated with thin intralobular reticulations and/or subpleural consolidations 4
- High-density areas 4
- Pleural thickening 4, 5
- Fibrosis associated with alveolar opacities 5
- HRCT scans obtained with the patient in a prone position can be helpful in differentiating dependent opacity from lung disease 6
Diagnostic Value of HRCT
HRCT may be a valuable noninvasive test to aid in the diagnosis of amiodarone pulmonary toxicity in symptomatic patients 3, 6 Combination of HRCT in supine and prone positions can provide a more reproducible method for evaluating the global extent of amiodarone-induced pulmonary toxicity 6