Bronchiolitis obliterans

Bronchiolitis obliterans
Specialty	Pulmonology

Bronchiolitis obliterans, or Constrictive bronchiolitis, is a rare disease of the lungs in which the bronchioles are plugged with granulation tissue. Because of similar names, it is often confused with bronchiolitis obliterans organizing pneumonia (BOOP), a completely different pulmonary disorder.

Etiology

Bronchiolitis obliterans has many possible causes, including: collagen vascular disease, transplant rejection in organ transplant patients, viral infection (RSV, adenovirus, PCP, HIV, CMV), drug reaction, toxic fume exposure (including: diacetyl, sulfur dioxide, nitrogen dioxide, ammonia, ozone and chlorine), aspiration and complications of prematurity (bronchopulmonary dysplasia). Additionally, the disorder may be idiopathic (without known cause).

Presentation

Bronchiolitis obliterans is a lung disease characterized by fixed airway obstruction. Inflammation and scarring occur in the airways of the lung, resulting in severe shortness of breath and dry cough. Standard lung capacity is normally around 80% lung usage. Bronchiolitis Obliterans reduces this to 16% to 21%.

Diagnosis

Bronchiolitis obliterans is often misdiagnosed as asthma, bronchitis, emphysema, or pneumonia.

• Chest X-rays
• Diffusing capacity of the lung (DLCO) are usually normal
• Spirometry tests show fixed airway obstructions and sometimes restriction.
• Lung Volume may show hyperinflation (excessive air in lungs caused by air trapping)
• High-resolution computerized tomography scans of the chest at full inspiration and expiration may reveal heterogeneous air trapping on the expiratory view as well as haziness and thickened airway walls.
• Lung biopsies may reveal evidence of constrictive bronchiolitis obliterans (i.e., severe narrowing or complete obstruction of the small airways). An open lung biopsy, such as by thoracoscopy, is more likely to be diagnostic than a transbronchial biopsy. Special processing, staining, and review of multiple tissue sections may be necessary for a diagnosis]. ^[1]

Prognosis/treatment

This disease is irreversible and severe cases often require a lung transplant. Evaluation of interventions to prevent bronchiolitis obliterans rely on early detection of abnormal spirometry results or unusual decreases in repeated measurements. Symptoms include:

• dry cough
• shortness of breath
• wheezing

The symptoms can start gradually, or severe symptoms can occur suddenly. ^[2]

Popcorn Workers Lung

In rare instances, bronchiolitis obliterans may be caused by inhalation of airborne diacetyl — a chemical used to produce the butter-like flavoring in microwave popcorn and in many other foods such candy and potato chips. In September 2007, Dr. Cecile Rose, pulmonary specialist at Denver's National Jewish Medical and Research Center, warned federal agencies that consumers, not just flavoring or food factory workers, may be in danger of contracting bronchiolitis obliterans. At least one heavy consumer of microwave popcorn has been diagnosed with this disease. David Michaels, of the George Washington University School of Public Health, first published Rose's warning letter on his blog.^[6][7][8]

See also

• Diacetyl
• Bronchiolitis obliterans organizing pneumonia

External links

• National Institute for Occupational Safety and Health (NIOSH) Alert: Preventing lung disease in workers who make or use flavorings

• Harber, Philip; Saechao, Kaochoy; & Boomus, Catherine. Diacetyl-induced lung disease. Toxicological Reviews 2006;vol 25(4):261-72.

• A Case of Regulatory Failure: Popcorn Workers' Lung, a case study from www.defendingscience.org

• Popcorn Workers Lung

References

1. ^{^} Preventing lung disease in workers who make or use
2. ^{^} Center for Disease Control (2002). Fixed obstructive lung disease in workers at a microwave popcorn factory (7th Edition ed.). {{cite book}}: |edition= has extra text (help); Cite has empty unknown parameter: |1= (help)
3. ^{^} California Department of Health Services
4. ^{^} E. Neil Schachter. Popcorn Workers' Lung. New England Journal of Medicine 2002;347(5):360-1.
5. ^{^} David Egilman (2007). Popcorn Workers Lung http://www.ijoeh.com/pfds/IJOEH_1301_Egilman.pdf
6. ^{^} Doctor warns consumers of popcorn fumes, news from www.yahoo.com
7. ^{^} Letter from Cecile Rose to U.S. Food and Drug Administration, from www.defendingscience.org
8. ^{^} David Michaels (2007). Popcorn Lung Coming to Your Kitchen? The FDA Doesn’t Want to Know, a blog post at thepumphandle.wordpress.com