Bronchiolitis obliterans is an inflammatory obstruction of the tiny airways in the lungs 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. This disease is sometimes known as constrictive bronchiolitis, a similar disease in which the small airways narrow in diameter due to inflammation and scarring.
The disease can be caused by inhaling irritating vapors, such as chlorine, ammonia, nitrogen oxide, or sulfur dioxide. Diacetyl, a chemical used to provide a buttery flavor in many foods, is suspected of causing bronchiolitis obliterans in workers who manufacture it or mix it into foods such as butter-flavored popcorn. Bronchiolitis obliterans can also result from respiratory infections, a connective tissue disorder such as rheumatoid arthritis, a reaction to a medication, or after a bone marrow, lung, or heart-lung transplant. In addition, the disease can be idiopathic (without a known cause).
Another disease with a similar name, bronchiolitis obliterans organizing pneumonia, is a completely different disease.
Bronchiolitis obliterans usually causes a dry cough and difficulty breathing, especially during exertion, two to eight weeks after exposure to toxic fumes or a respiratory illness. It may take several months or years to develop after a transplant.
Fatigue and wheezing in the absence of a cold or asthma are other symptoms of this lung disease.
Imaging tests (such as high-resolution chest CT scans) and pulmonary function tests can help detect bronchiolitis obliterans. Chest X-rays are usually normal, and lung 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.
This disease is irreversible. Treatment, however, can help stabilize or at least slow its progression. For this reason, it is important to recognize bronchiolitis obliterans early on, because intervention in the later stages of this disease may be ineffective.
Treatment usually involves medication therapy, primarily the use of corticosteroids (drugs used to treat chronic diseases that are very effective in reducing inflammation and mucus production in the airways of the lungs). In some cases, immunosuppressive therapies, which decrease the body's immune response, are used, and lung transplants may be used to treat the disease.
In the case of toxic exposures, immediate removal from the irritating environment is crucial to slow the progression of the disease.
If left untreated, bronchiectasis can be fatal. It is the leading cause of death after lung or heart-lung transplantation.
Although there is no cure for bronchiolitis obliterans scarring, corticosteroids can help clear mucus from the lungs, reduce inflammation, and open the airways.
Oxygen treatments and medications to stimulate the immune system may be necessary. Breathing exercises and stress reduction techniques can help with breathing difficulties. In the most severe cases of lung damage, a lung transplant may be the best option.
Bronchiolitis obliterans requires additional rest and increased fluid intake. Keeping the air in your home free of smoke and chemicals is very important. A humidifier can also help.
