What Is Bronchiolitis Obliterans Organizing Pneumonia?

Bronchiolitis Obliterans Organizing Pneumonia (BOOP) is a type of lung disease that is a result of organizing pneumonia that invades the bronchioles and alveoli of the lungs. Bronchioles are small airways through the lungs and alveoli are tiny air sacs found there. This disease is non-infections and causes inflammation of the bronchioles and alveoli.

There is also a lung disease called bronchiolitis obliterans. Bronchiolitis obliterans organizing pneumonia and standard bronchiolitis obliterans are different lung diseases but they can be easily confused. Bronchiolitis obliterans causes the bronchioles to narrow and compress as scar tissue blocks the airways. BOOP, on the other hand, involves inflammation of the bronchioles and scar tissue development in the alveoli. To avoid confusion, the medical community also refers to BOOP as cryptogenic organizing pneumonia (COP).

Research into exact causes of BPPO is ongoing. Known causes include chronic inflammatory diseases, such as rheumatoid arthritis, and connective tissue diseases, such as scleroderma. Radiation therapy and some medications can also cause BOOP to develop. Common known causes are long-term exposure to toxic fumes and chronic bacterial lung infections. When doctors know the cause of the disease in a patient, it is called secondary BOOP.

Bronchiolitis obliterans organizing pneumonia symptoms include shortness of breath, difficulty breathing, and a dry cough. Some patients may also exhibit symptoms that mimic the flu, such as body aches and fatigue. Low fever and weight loss are also common symptoms.

To diagnose BOOP, a series of tests are done. Physical exams often provide a starting point for further testing when doctors notice crackling sounds during a patient’s breathing and oxygen saturation levels are low. Doctors need to see inside the lungs so they can look at the bronchioles and alveoli. Chest x-rays and magnetic resonance imaging (MRI) scans can provide the needed views of the lungs. In some cases, a tissue sample may be needed to rule out lung cancer.

Corticosteroids are the common bronchiolitis obliterans organizing pneumonia treatment. These medicines work to reduce inflammation, which also lowers the risk that a patient will develop scar tissue in the alveoli. Treatment with corticosteroids is short term and doses gradually decrease as the disease responds. Doctors prescribe a higher dose so the medicine works quicker and then the dose is slowly reduced over a few weeks to wean the patient off the corticosteroids.