Constrictive bronchiolitis, also known as bronchiolitis obliterans, is a respiratory illness that affects the smallest air passages in the lungs, known as the bronchioles. Bronchioles normally control airflow in the lungs. Individuals with constrictive bronchiolitis have bronchioles that are compressed and narrowed by fibrosis (scar tissue) and/or inflammation (swelling). Symptoms may include shortness of breath, dry cough, or wheezing. Diagnositic testing may include a chest xray, chest cat scan (CT) and pulmonary function testing (measures the airflow in your lungs). Early inspiratory crackles may also be heard by your physician while listening to your lungs. Constrictive bronchiolitis may occur after a lung transplantation or a respiratory infection or due to exposure to certain toxic (poisonous) fumes or taking certain medications. Some connective tissue disorders also involve constrictive bronchiolitis. If the condition is due to inflammation, steriod treatments may be successful. If the condition is due to scarring, the damage is irreversible although steroid treatments may help manage the symptoms. The development of antifibrotic medications is rapidly progressing with advances in medical research. Talk with your doctor about treatment and management options if you or a family member has been diagnosed with constrictive bronchiolitis.