Cryptogenic Organizing Pneumonia (COP)

Bronchiolitis obliterans with organizing pneumonia (BOOP) is a rare lung condition in which the small airways (bronchioles) and air exchange sac (alveoli) become inflamed with connective tissue. This is an uncommon illness occurring in one study in 6 out of 100, 000 hospitalizations. It usually starts with a flu-like illness associated with fever, malaise, fatigue and cough. The cough may be persistent and troubling. There is shortness of breath with exertion and weight loss occurs in about half of patients.

This condition is a form of interstitial [within the fine supporting tissue of the lung] pneumonia of unknown origin. Very similar interstitial pneumonias can be seen in association with connective tissue diseases such as lupus erythematosis, several drug exposures and malignancies.

The physician examination is typical of other interstitial pneumonias but the chest x-ray and chest CT scan are distinctive and should lead an experienced lung specialist to suspect the diagnosis. However these findings are not definitive and a lung biopsy is recommended for confirmation. Pulmonary function tests are nonspecific.

The course of the disease is variable however it tends to be persistent and not self limited.

Current therapy involves relatively high doses of corticosteroids [e.g. prednisone] for several months depending upon the response. Other immunosuppressive drugs [e.g. cyclophosphamide] may also be used. Treatment usually but not always results in significant improvement. However recurrences are common and patients should be periodically monitored with chest radiography, especially in the first year after treatment.