Summary
Definition
Bronchiolitis obliterans organising pneumonia (BOOP) is defined as organised polypoid granulation tissue in the distal airways extending into the alveolar ducts and alveoli.[1][2][3] BOOP is an inflammatory disorder involving both the peripheral bronchioles and alveoli simultaneously and has distinctive radiographic findings, histological features, and response to therapy.
[Figure caption and citation for the preceding image starts]: Medium-powered pathology slide showing circular and branching bronchioles filled with polypoid plugs of granulation tissue and alveoli filled with organising pneumoniaFrom the collection of Gary R. Epler, MD [Citation ends].
The term cryptogenic organising pneumonia (COP) is a general term referring to organised inflammatory process in the alveoli from an unknown cause.[4][5] The British Thoracic Society guideline for interstitial lung disease contains the term COP, which is noted as a preferred term because it captures an 'acinar' rather than an airway disease, and BOOP may be confused with obliterative bronchiolitis.[5]
However, the author uses the term BOOP because it continues to be recognised and used throughout the world. It is a specific pulmonary lesion recognised by pathologists with a characteristic clinical pattern and response to treatment. BOOP is simultaneous inflammation of the distal bronchiolar airways, respiratory bronchioles, alveolar ducts, and alveoli. BOOP is a diffuse interstitial parenchymal disease and acinar disease and not an airway disease, especially because of the presence of crackles, decreased diffusing capacity, no airflow obstruction, and high-resolution chest CT scans showing triangular-shaped, ground glass opacities with air bronchograms.
BOOP is not confused with obliterative bronchiolitis because BOOP is a diffuse parenchymal lung disease and not an airway disease; wheezing is not a common symptom of BOOP; crackles, and not wheezes, are heard by auscultation in BOOP; the FEV1/FVC ratio is normal or slightly increased in BOOP, not decreased as in airway obstructive diseases; and the radiographic findings show bilateral patchy infiltrates, not normal or hyperinflation seen in airflow obstructive diseases.
The term BOOP is also used for non-idiopathic types such as post-infection BOOP; drug-related BOOP; connective tissue and immunological disease-related BOOP; bone marrow, stem cell, and lung transplant-related BOOP; radiation therapy-related BOOP; occupational and environmentally related BOOP; and continually newly described systemic disease-related BOOP.
Finally, the term BOOP is easy for patients to remember and use to advance their understanding of the disease process by obtaining accessible scientific publications.
History and exam
Key diagnostic factors
- presence of risk factors
- flu-like illness with low-grade fever, fatigue, and arthralgia
Risk factors
- infectious pneumonia
- connective tissue diseases
- immunological diseases and inflammatory bowel disease
- organ transplantation
- medication use
- breast radiotherapy
- exposure to toxins
Diagnostic investigations
Treatment algorithm
Contributors
Authors
Clinical Associate Professor
Harvard Medical School
Boston
MA
Disclosures
GRE is an author of several references cited in this monograph.
Peer reviewers
Professor of Medicine and Director
Division of Pulmonary/Critical Care/Allergy/Sleep Medicine
Medical University of South Carolina
Charleston
SC
Disclosures
SS declares that he has no competing interests.
National Jewish Medical and Research Center
Denver
CO
Disclosures
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.
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