Bronchiolitis obliterans organizing pneumonia

Last reviewed: 25 Aug 2022
Last updated: 24 Mar 2020



History and exam

Key diagnostic factors

  • flu-like illness with low-grade fever, fatigue, and arthralgia
More key diagnostic factors

Other diagnostic factors

  • cough
  • shortness of breath
  • bilateral crackles
Other diagnostic factors

Risk factors

  • infectious pneumonia
  • connective tissue diseases
  • immunologic diseases and inflammatory bowel disease
  • organ transplantation
  • medication use
  • breast radiation therapy
  • exposure to toxins
More risk factors

Diagnostic investigations

1st investigations to order

  • CXR
  • high-resolution chest CT scan (HRCT)
  • CBC
  • erythrocyte sedimentation rate
More 1st investigations to order

Investigations to consider

  • pulmonary function tests
  • video-assisted thoracoscopic biopsy
  • creatine kinase 
  • anticardiolipin antibodies
  • lupus anticoagulant antibodies
More investigations to consider

Treatment algorithm


rapidly progressive BOOP


idiopathic BOOP

nonidiopathic BOOP


recurrent BOOP, rapidly progressive

recurrent BOOP, not rapidly progressive



Gary R. Epler, MD
Gary R. Epler

Clinical Associate Professor

Harvard Medical School




GRE is an author of several references cited in this topic.

Peer reviewers

Steven Sahn, MD

Professor of Medicine and Director

Division of Pulmonary/Critical Care/Allergy/Sleep Medicine

Medical University of South Carolina




SS declares that he has no competing interests.

Teofilo Lee-Chiong, MD

National Jewish Medical and Research Center




TLC has been reimbursed by the American College of Chest Physicians (ACCP), American Academy of Sleep Medicine, American Thoracic Society, and Cephalon, the manufacturer of modafinil, for attending several conferences. He has been paid by the ACCP for running educational programs and by Elsevier for serving as consultant of the Sleep Medicine Clinics. He has also received research funding from the National Institutes of Health, Respironics, Restore, and Schwarz Pharma, and has been a member of the speakers' bureau for GlaxoSmithKline.

  • Bronchiolitis obliterans organizing pneumonia images
  • Differentials

    • Nodular sarcoidosis
    • Chronic eosinophilic pneumonia (CEP)
    • Bronchiolitis interstitial pneumonia (BIP)
    More Differentials
  • Guidelines

    • An official American Thoracic Society/European Respiratory Society statement: update of the international multidisciplinary classification of the idiopathic interstitial pneumonias
    More Guidelines
  • Patient leaflets


    More Patient leaflets
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