Bronchiolitis obliterans

Bronchiolitis obliterans (BO), also called obliterative bronchiolitis (OB) and constrictive bronchiolitis (CB), is a rare and life-threatening form of non-reversible obstructive lung disease in which the bronchioles (small airway branches) are compressed and narrowed by fibrosis (scar tissue) and/or inflammation. Bronchiolitis obliterans is also sometimes used to refer to a particularly severe form of pediatric bronchiolitis caused by adenovirus.

Bronchiolitis means inflammation of the bronchioles and obliterans refers to the inflammation or fibrosis of the bronchioles partially or completely obliterating the airways. Bronchiolitis obliterans has always been thought to be irreversible and progressive.

Signs and symptoms

Bronchiolitis obliterans is a lung disease characterized by fixed airway obstruction. Inflammation and scarring occur in the airways of the lung, resulting in severe shortness of breath and dry cough.

FEV1 (forced expiratory volume in 1 second) should be above 80% of predicted values to be considered normal. Bronchiolitis obliterans reduces this to 16% to 21%.