Bronchiolitis obliterans organizing pneumonia
Bronchiolitis obliterans organizing pneumonia is a very rare lung disorder that causes severe inflammation in the lungs and blocks the small air sacs in the lungs known as alveoli. It is difficult to treat and some patients may even require a lung transplant. Bronchiolitis obliterans organizing pneumonia is also known as Epler's pneumonia and cryptogenic organizing pneumonia. The cause is often unknown or idiopathic.
Definition & Facts
Bronchiolitis obliterans organizing pneumonia has only been a recognized condition since the 1980s, when it was first described in the medical literature by Dr. Gary Epler. Unlike other kinds of pneumonia, in which the lungs may become congested with fluid or lung secretions, bronchiolitis obliterans organizing pneumonia causes swirls or plugs of inflamed lung tissue. These plugs fill the small airways and alveoli.
Bronchiolitis obliterans organizing pneumonia is not an infection, but an inflammatory process similar to conditions like asthma. In some cases, this condition appears and progresses very fast, leading to acute respiratory failure within a few days. Although bronchiolitis obliterans organizing pneumonia may occur in people of any age, it is most likely to appear in individuals between the ages of 40 and 60. It affects men and women equally.
Symptoms & Complaints
In most cases, the symptoms develop slowly over a few weeks or months. A persistent, non-productive cough is the most common symptom. Patients who develop flu-like symptoms often complain of fatigue, unexplained weight loss and report they simply don't feel well. If shortness of breath is present, it usually gets worse, as does the cough.
On physical examination, patients may have small crackling or rattling lung sounds that can be heard with a stethoscope. Rarely, affected individuals may experience chest pain, joint pain or night sweats, or cough up blood.
The symptoms of bronchiolitis obliterans organizing pneumonia can vary from case to case, which may make it harder to diagnose. In a few cases, the symptoms are mild or not apparent, and the disease is picked up through something like a chest X-ray.
Doctors may also suspect bronchiolitis obliterans organizing pneumonia when the patient has symptoms similar to pneumonia but remains symptomatic and does not respond to antibiotic treatment.
In most cases, the cause of bronchiolitis obliterans organizing pneumonia is idiopathic (unknown). Among the causes that have been identified are radiation therapy – particularly radiotherapy for breast cancer – and exposure to certain fumes or chemicals.
More than 35 medications have been linked to bronchiolitis obliterans organizing pneumonia. These include antibiotics like bleomycin, minocycline, nitrofurantoin, and penicillamine. Antiseizure medications like carbamazepine and phenytoin have also been linked to bronchiolitis obliterans organizing pneumonia.
Bronchiolitis obliterans organizing pneumonia may also occur after a respiratory infection like pneumonia and sometimes occurs after an organ transplant. It seems more likely to occur in people who have had a bone marrow transplant than in other types of transplantation surgery.
Connective tissue disorders, immunological disorders and inflammatory bowel disease are often associated with bronchiolitis obliterans organizing pneumonia and it has also been seen in connection with lung abscesses, lung cancer, and lymphoma.
The typical bronchiolitis obliterans organizing pneumonia lesions are more commonly seen in people who have pulmonary fibrosis. In those cases, the pulmonary fibrosis is the primary problem and bronchiolitis obliterans organizing pneumonia is a secondary process rather than a distinct disease.
Diagnosis & Tests
A clinical evaluation and detailed medical history are the first steps in diagnosing bronchiolitis obliterans organizing pneumonia. Sometimes the diagnostic process may be primarily a matter of eliminating other lung conditions that are similar, such as cancer of the lung, idiopathic pulmonary fibrosis, acute respiratory distress syndrome, or acute interstitial pneumonia.
Specialized tests include X-ray studies like a high-resolution chest computed tomography (CT) scan or HRCT (High-resolution computed tomography), which can show the plugs in the lung tissue. The HRCT scan often shows opaque areas of “ground glass” that are typically triangular in shape.
A lung biopsy and microscopic tissue analysis may also help in diagnosis. A lung tissue biopsy is usually considered the gold standard in making a diagnosis. The tissue is obtained through means of a video-assisted thoracoscopic surgery in which a tiny camera is inserted into the lung through a small incision. A chest tube is left in place for several days after the procedure.
Treatment & Therapy
Some cases of bronchiolitis obliterans organizing pneumonia may resolve without treatment. This is more likely when bronchiolitis obliterans organizing pneumonia is the result of radiation therapy for breast cancer. Watchful waiting may be the best choice in those who have no symptoms or whose symptoms don't become worse. Treatment can always be undertaken at a later date if the patient becomes sicker.
Steroids are the usual treatment of choice and may cause dramatic improvement in a relatively short period of time. However, symptoms may reoccur in some cases, when the steroids are discontinued. Approximately 30 percent of patients relapse when treatment is withdrawn. Recurrence is more likely if patients are treated for less than a year. Treatment can be repeated, however, and most patients respond to the additional treatment.
Some cases of bronchiolitis obliterans organizing pneumonia respond to treatment with cytoxan, a chemotherapy medication. Supportive treatment such as oxygen therapy or antibiotics may be helpful. In rare cases when patients don't respond to any form of treatment, lung transplantation may be necessary.
Prevention & Prophylaxis
Patients with these conditions should be alert to changes in lung function and need regular pulmonary function tests. It is also important to take medications as prescribed and report any changes in symptoms to the treating physician.