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Amiodarone Pulmonary Toxicity

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Amiodarone Pulmonary Toxicity

  • See Also
  • Epidemiology
  1. Occurs in 1-2% of patients on Amiodarone per year
  • Pathophysiology
  1. Acute or subacute pneumonitis related to pulmonary drug deposition
  • Symptoms
  1. Dyspnea
  2. Fever and cough may occur
  • Differential Diagnosis
  • Imaging
  1. Chest XRay
    1. Diffuse Pulmonary Infiltrates
    2. In some cases may appear similar to lobar Pneumonia
  2. CT Chest
    1. Extensive bilateral alveolar and Interstitial Infiltrates
    2. Ground-glass opacities
  • Diagnosis
  1. Clinical diagnosis only (no lab or imaging study is diagnostic)
  2. Pulmonary Function Tests
    1. Restrictive Lung Disease pattern with decreased DLCO
  3. Bronchoscopy with bronchoalveolar lavage (BAL)
    1. Evaluates for other causes of diffuse lung disease
    2. Absence of foamy Macrophages makes Amiodarone toxicity unlikely
      1. However foamy Macrophages are also seen in up to 50% of patients on Amiodarone
  • Precautions
  1. Often mis-diagnosed as Pneumonia or Congestive Heart Failure
  2. Consider Amiodarone toxicity in refractory Pneumonia or CHF
  • Management
  1. Discontinue Amiodarone (best prognosis with early discontinuation)
  2. Prednisone 40-60 mg orally daily and slowly tapered over 4-12 months
  • Prognosis
  1. Most cases, if discontinued early, improve after discontinuation of Amiodarone
    1. Improvement may take months due to the Amiodarone long half-life
  2. Amiodarone Pulmonary Toxicity is fatal in some cases
  • Prevention
  1. Obtain baseline tests before starting Amiodarone
    1. Pulmonary Function Tests
    2. Chest XRay
  • References
  1. Weinstock, Orman, Frank and Greenwald in Herbert (2016) EM:Rap 16(1):9-11
  2. Wolkove (2009) Can Respir J 16(2): 43–8 +PMID:19399307 [PubMed]