Cryptogenic Organizing Pneumonia

Cryptogenic Organizing Pneumonia is a topic covered in the 5-Minute Clinical Consult.

To view the entire topic, please or purchase a subscription.

Medicine Central™ is a quick-consult mobile and web resource that includes diagnosis, treatment, medications, and follow-up information on over 700 diseases and disorders, providing fast answers—anytime, anywhere. Explore these free sample topics:

Medicine Central

-- The first section of this topic is shown below --



  • Cryptogenic organizing pneumonia or COP is the idiopathic inflammatory process of diffuse interstitial granulation extending to the distal airways and alveoli.
  • As opposed to secondary organizing pneumonia that has multiple causative etiologies such as medication, infection, connective tissue disease, malignancy, COP has no known precipitant.
  • May have a gradual or sudden onset
  • Unknown pathogenesis
  • Chest x-ray (CXR) shows a pattern of bilateral, diffuse, or patchy infiltrates and consolidative or ground glass opacifications. There may be air bronchograms as well.
  • Completely reversible restrictive problem. Most cases will respond to corticosteroids, which may have to be given for a year or more.
  • Synonym(s): previously known as bronchiolitis obliterans organizing pneumonia or BOOP; intraluminal fibrosis of distal airways; idiopathic BOOP; obliterative bronchiolitis

Geriatric Considerations
More common than originally thought and may be sudden and very severe

Pediatric Considerations
Rare but has been reported after viral pneumonia


  • Incidence/prevalence in the United States: estimated at 0.01% but may be underdiagnosed
  • Predominant age: most commonly seen in age 50s to 60s


Etiology and Pathophysiology

Idiopathic: a specific complex reaction of lung tissue to alveolar cell injury

No known genetic component

Risk Factors

  • Immunocompromised patients, including transplant recipients and AIDS patients
  • Other autoimmune conditions
  • Gastroesophageal reflux disease causing microaspiration
  • Reported frequency of tobacco use in diagnosed cases 25–50%, making smoking unlikely to be a precipitating factor

General Prevention

Except for prevention of relapse, none known

-- To view the remaining sections of this topic, please or purchase a subscription --


* When formatting your citation, note that all book, journal, and database titles should be italicized* Article titles in AMA citation format should be in sentence-case
TY - ELEC T1 - Cryptogenic Organizing Pneumonia ID - 1688229 ED - Baldor,Robert A, ED - Domino,Frank J, ED - Golding,Jeremy, ED - Stephens,Mark B, BT - 5-Minute Clinical Consult, Updating UR - PB - Wolters Kluwer ET - 27 DB - Medicine Central DP - Unbound Medicine ER -