Bronchiolitis obliterans (patient information)
(Condition) On the Web
Bronchiolitis obliterans is an inflammatory obstruction of the lung's tiniest airways, called bronchioles. The bronchioles become damaged and inflamed by chemical particles or respiratory infections, particularly after organ transplants, leading to extensive scarring that blocks the airways. The disease is sometimes referred to as constrictive bronchiolitis, a similar condition in which the small airways become constricted in diameter because of inflammation and scarring.
What are the symptoms of Bronchiolitis obliterans?
Bronchiolitis obliterans usually causes a dry cough and shortness of breath, especially on exertion, two to eight weeks after toxic fume exposure or a respiratory illness. It may be several months or years until it presents itself after a transplant.
What causes Bronchiolitis obliterans?
The disease can be caused by breathing in irritant fumes, such as chlorine, ammonia, oxides of nitrogen or sulfur dioxide. Diacetyl, a chemical used to provide butter flavor in many foods, has also been suspected of causing bronchiolitis obliterans in workers who manufacture it or mix it into foods, such as butter-flavored popcorn. Bronchiolitis obliterans also can result from respiratory infections, a connective tissue disorder such as rheumatoid arthritis, a medication reaction, and after a bone marrow, lung or heart-lung transplant. Also, the disease may be idiopathic (without a known cause).
Another similarly named disease, bronchiolitis obliterans organizing pneumonia, is a completely different disease.
Who is at highest risk?
Imaging tests (such as high resolution chest CT scan) and pulmonary function tests can help detect bronchiolitis obliterans. Chest x-rays are usually normal, and pulmonary function tests may decline slowly in some types of bronchiolitis obliterans, requiring repeat medical testing and follow up. A surgical lung biopsy, however, is the most definitive way to diagnose the disease.
When to seek urgent medical care?
The disease is irreversible. Treatment, however, can help to stabilize or at least slow its progression. For that reason, it is important to recognize bronchiolitis obliterans early because intervention in the late stages of the disease may prove ineffective.
Treatment usually involves medication therapy, primarily the use of corticosteroids. In some cases, immunosuppressive therapies, which decrease the body's immune response, and lung transplants are used to treat the disease.
In the case of toxic exposures, immediate removal from the irritating environment is crucial to slowing progression of the disease.
If left untreated, bronchiolitis obliterans can be fatal. It is the primary cause of death following a lung or heart-lung transplant.