Bronchiolitis Obliterans and Organizing Pneumonia – Causes, Symptoms, Diagnosis, Treatment and Ongoing care



  • A primary or secondary process of the lungs characterized by granulation-like tissue involving the distal airways and alveoli
  • A specific reaction of lung tissue to a variety of injuries
  • It may occur as patchy infiltrates, or it may be nodular or secondary to another lung disease.
  • May also appear to be a migrating process.
  • May have a gradual or sudden onset.
  • Lungs show a pattern of multiple patchy pneumonia, which are seen on the chest X-ray (CXR) as patchy alveolar or ground-glass opacifications, with or without interstitial infiltrates; there may be air bronchograms as well.
  • Most cases will respond to corticosteroids, which may have to be given for a year or more.
  • Synonym(s): Intraluminal fibrosis of distal airways; Idiopathic bronchiolitis obliterans and organizing pneumonitis; Cryptogenic organizing pneumonia; Obliterative bronchiolitis BOOP

Geriatric Considerations

  • More common than originally thought and may be sudden and very severe

Pediatric Considerations

  • Rare, but has been reported after viral pneumonia (adenovirus influenza):
    • Characteristics include delayed recovery, persistent cough, crackles, or wheezing after pneumonia.
    • Laboratory findings generally not helpful
    • Imaging shows: Ventilation-perfusion ratio-matched defects; high-resolution computed tomography (CT), bronchiectasis, bronchogram, pruned tree appearance
    • Diagnosis confirmed by biopsy
  • Treatment includes steroids: 1 mg/kg q.24h for 1 month, followed by weaning over several months


  • Incidence/prevalence in US: Unknown
  • Predominant age: Reported cases range age 0–70; mean age: 50s



Risk Factors

  • AIDS
  • Immunocompromised patients, including transplant patients
  • More likely in smokers

General Prevention

Except for prevention of relapse, none known


  • Idiopathic: A complex response to a variety of injuries, such as toxic inhalation; post mycoplasma, viral and bacterial infection; aspiration; immunologic factors; drugs

Pediatric Considerations

  • In the nontransplant pediatric population, adenovirus infection is the most common cause of bronchiolitis obliterans (1).

Commonly Associated Conditions

  • Drug-induced pneumonitis:
    • Paraquat poisoning
    • Amiodarone toxicity
    • Acebutolol toxicity
    • Amphotericin B
    • Bleomycin
    • Carbamazepine
    • Cephalosporins
    • Gold
    • Minocycline
    • Nitrofurantoin
    • Phenytoin
    • Sulfamethoxypyridazine
    • Sulfasalazine
    • Ticlopidine
    • Freebase cocaine pulmonary toxicity
    • Overdose of L-tryptophan
  • Infections:
    • Chronic infectious pneumonia
    • Malaria
    • Chlamydia
    • Legionella
    • Mycoplasma
    • Pneumocystis
    • Cryptococcus
  • Immunocompromise: Bone marrow, lung, renal, transplantation
  • Connective tissue diseases:
    • Rheumatic lung
    • Sjögren syndrome
    • Polymyositis
    • Scleroderma
    • Essential mixed cryoglobulinemia
  • Miscellaneous:
    • Cystic fibrosis
    • Bronchopulmonary dysplasia
    • Renal failure
    • Congestive heart failure (CHF)
    • Adult respiratory distress syndrome
    • Chronic eosinophilic pneumonia
    • Hypersensitivity pneumonitis
    • Histiocytosis X
    • Sarcoidosis
    • Pneumoconioses
  • Radiation pneumonitis

X-ray computed tomography, Acute respiratory distress syndrome, Pneumonia, Heart failure, Chest radiograph, Weight loss, Bronchiolitis Obliterans Organizing Pneumonia, ventilation perfusion ratio, bronchiolitis obliterans, viral pneumonia, air bronchograms, bronchiectasis,


Think of the possibility in patients presenting with (2):

  • Flulike illness that lasts 4–10 weeks or longer. Most have been treated with antibiotics without success.
  • Fever
  • Dry cough
  • Weight loss
  • Dyspnea may be severe.
  • Bilateral crackles
  • Fatigue


  • Fatigue
  • Weight loss
  • Fever
  • Dry cough
  • Dyspnea may be severe.

Physical Exam

  • Hypoxia
  • Respiratory distress
  • Bilateral crackles

Diagnostic Tests & Interpretation

  • Leukocytosis with a normal differential
  • Elevated erythrocyte sedimentation rate
  • Negative cultures
  • Negative serology for mycoplasma, CoxiellaLegionella, psittacosis, and fungus
  • Negative viral studies


  • CXR: Often appears more normal than the physical exam
  • CXR may show patchy alveolar opacities, often in the middle or upper lung area, a ground-glass pattern that may have air bronchograms
  • Computed tomography (CT) scans more accurately define the distribution and extent of the patchy alveolar opacities with areas of hyperlucency (3).
  • Diagnosis is difficult by CT only.

Initial approach

  • Pulmonary function shows a restrictive/obstructive pattern.
  • Flow-volume loop shows terminal airway obstruction.
  • The involved area may seem to migrate.
  • Ventilation-perfusion ratio scan: Matched patchy defects

Diagnostic Procedures/Surgery

  • Open lung biopsy
  • Transbronchial biopsy
  • It may be wise to use a trial of steroids as a diagnostic trial, although not all would agree.
  • If a diagnostic trial is successful, be prepared to treat the patient for at least 1 year.

Pathological Findings

  • Intraluminal fibrosis of distal airspaces is the major pathologic feature.
  • Fibroblasts and plugs of inflammatory cells and loose connective tissue fill these distal airways.
  • Inflammatory cells are mainly lymphocytes and plasma cells.
  • Interstitial fibrosis is present.
  • Plugs of edematous granulation tissue in the terminal and respiratory bronchioles and alveolar ducts do not cause permanent damage.

Differential Diagnosis

  • Usual interstitial pneumonitis
  • Noninfectious diseases
  • Tuberculosis (TB)
  • Sarcoidosis
  • Histoplasmosis
  • Berylliosis
  • Goodpasture syndrome
  • Neoplasm
  • Polyarteritis nodosa
  • Systemic lupus erythematosus
  • Wegener granulomatosis
  • Sjögren syndrome
  • Chronic eosinophilic pneumonia
  • Cryptogenic bronchiolitis


Inpatient care may be required.


First Line


  • For 1–3 months, 60 mg/d
  • Then taper over a few weeks to 20 mg (this dose may later be given as alternate-day therapy). Increase length of taper for patients on long-term therapy to avoid precipitating addisonian crisis.
  • Treatment may be needed for 1 year or more.
  • Contraindications: Refer to the manufacturer’s literature.
  • Precautions: Be aware of the patient’s Mantoux status and history of peptic ulcer disease. Long-term steroid treatment is associated with significant adverse effects, including Cushing syndrome, fluid retention, osteoporosis, hyperkalemia, and poor wound healing.
  • Significant possible interactions: Refer to the manufacturer’s literature.

Second Line

  • Steroids other than prednisone may be used.
  • 1 paper reported the use of erythromycin 600 mg/d for 3–4 months after initial control with prednisone.
  • Prescribe antimicrobials if the original infection is persistent. The proper choice depends on the pathogen.

Additional Treatment

General Measures

Support's development and hosting
  • Monitor blood gases or pulse oximetry.
  • Oxygen as necessary

Ongoing Care

Follow-Up Recommendations

Patient Monitoring

  • Frequent visits, weekly at first
  • Prednisone must be continued because of the chance of relapse.
  • Monitor the lung disease and the side effects of prednisone therapy: Mantoux, monthly complete blood count (CBC), funduscopic exam every 3–6 months, serial dual energy X-ray absorptiometry (DEXA) scans for osteoporosis


No special diet

Patient Education

Emphasize the need to continue prednisone because of the chance of a relapse.


Complete recovery, but individual case management is mandatory.


  • Bronchiectasis
  • Death, but with proper treatment, recovery is usually complete without permanent sequelae.


1. Moonnumakal SP, Fan LL. Bronchiolitis obliterans in children. Curr Opin Pediatr. 2008;20:272–278.

2. Cordier JF, Loire R, Brune J. Idiopathic bronchiolitis obliterans organizing pneumonia. Definition of characteristic clinical profiles in a series of 16 patients. Chest. 1989;96:999–1004.

3. Müller NL, Staples CA, Miller RR. Bronchiolitis obliterans organizing pneumonia: CT features in 14 patients. AJR Am J Roentgenol. 1990;154:983–7.

Additional Reading

Drakopanagiotakis F, Polychronopoulos V, Judson MA. Organizing pneumonia. Am J Med Sci. 2008;335:34–9.

Epler GR, Colby TV, McLoud TC, et al. Bronchiolitis obliterans organizing pneumonia. N Engl J Med. 1985;312:152–8.

Hardy KA, Schidlow DV, Zaeri N. Obliterative bronchiolitis in children. Chest. 1988;93:460–6.

Lynch DA. Imaging of small airways diseases. Clin Chest Med. 1993;14:623–34.

Schlesinger C, Koss MN. The organizing pneumonias: an update and review. Curr Opin Pulm Med. 2005;11:422–30.

St John RC, Dorinsky PM. Cryptogenic bronchiolitis. Clin Chest Med. 1993;14:667–75.

White KA, Ruth-Sahd LA. Bronchiolitis obliterans organizing pneumonia. Crit Care Nurse. 2007;27:53–66.

Ruth-Sahd LA, White KA et al. Bronchiolitis obliterans organizing pneumonia. Dimens Crit Care Nurs. 2009;28:204–8.

See Also (Topic, Algorithm, Electronic Media Element)

Sjögren Syndrome



516.8 Other specified alveolar and parietoalveolar pneumonopathies


129458007 Bronchiolitis obliterans organizing pneumonia (disorder)

Clinical Pearls

  • Bronchiolitis obliterans and organizing pneumonia and bronchiolitis obliterans are very different.
  • Bronchiolitis obliterans and organizing pneumonia are restrictive problems that are completely reversible.
  • Bronchiolitis obliterans is an obstructive problem that causes permanent lung damage.

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