Bronchiolitis Obliterans Organizing Pneumonia
Bronchiolitis Obliterans Organizing Pneumonia Definition
Bronchiolitis obliterans organizing pneumonia (or BOOP) is the inflammation of the bronchioles and surrounding tissue in the lungs. BOOP is often the result of a pre-existing chronic inflammatory disease like rheumatoid arthritis. BOOP can also be a side effect of certain medicinal drugs, such as amiodarone. In cases where no cause is detected, the disease is called cryptogenic organizing pneumonia. The clinical characteristics and radiological imaging resemble infectious pneumonia. However, diagnosis is suspected after there is no response to multiple antibiotics, and blood and sputum cultures are found to be negative for organisms.
Bronchiolitis Obliterans Organizing Pneumonia Diagnosis
Lung biopsy continues to be method preferred for establishing a diagnosis. The video-assisted thoracoscopic procedure has become the established technique of diagnosis. In a study of 49 patients who underwent the video-assisted thoracoscopic procedure for interstitial lung disease, the average length of the operation was 45 minutes, the chest tube was inserted for 1.3 days, there were no deaths, there were no reexplorations, and none were converted to an open thoracotomy.
Bronchiolitis Obliterans Organizing Pneumonia Symptoms and Signs
Individuals affected with BOOP display symptoms such as cough, dyspnea, influenza-like symptoms, febrile illness, widespread crackles, and mild resting hypoxemia. On examination, crackles commonly found, but clubbing is not. Plain chest radiography shows normal lung volumes, with distinct patchy unilateral or bilateral consolidation. Small nodular opacities appear in up to 50% of patients and large nodules in 15%. On HRCT, airspace consolidation with air bronchograms is evident in more than 90% of patients, often with a lower zone predominance A subpleural or peribronchiolar distribution is seen in up to 50% of patients. Ground glass or hazy opacities associated with the consolidation are detected in almost all patients. Pulmonary physiology is restrictive with decreased DLCO. Airflow limitation is rare; gas exchange is usually abnormal and mild hypoxemia is common. Bronchoscopy with BAL shows up to 40% lymphocytes, along with more subtle increases in neutrophils and eosinophils. In patients with typical clinical and radiographic features, a transbronchial biopsy that shows the pathologic pattern of organizing pneumonia and is missing features of an alternative diagnosis is enough to make a tentative diagnosis and start therapy.
Bronchiolitis Obliterans Organizing Pneumonia Treatment
Prednisone, with its potent anti-inflammatory property, continues to be recommended as the first line of treatment for patients with symptomatic and progressive disease. Patients with asymptomatic mass lesions or nonprogressive disease can be observed and treated at a later time if required. The dosage is typically 1 mg/kg (60 mg/d) for 1 to 3 months, then 40 mg/d for 3 months, then 10 to 20 mg/d or every other day for one year. Every-other-day scheduling can be successfully utilized for this disorder. A shorter 6-month course may be enough in certain situations.