Bronchiolitis

In children, the term bronchiolitis refers to an acute respiratory illness caused by bronchiolar infection, typically by respiratory syncytial virus (RSV) or other viruses. In adults, the term refers to a primarily bronchiolar pattern of infection or inflammation caused by many pulmonary infections, systemic inflammatory conditions, inhaled irritants, certain systemic conditions, and accompanying several congenital diseases. Imaging may be helpful to assess the extent and severity of bronchiolitis and to establish a differential diagnosis based on the distribution of imaging findings, their respective morphologies, and any ancillary findings. Presence of cavities or architectural distortion with a bronchiolitis pattern, especially in the upper lungs, should prompt consideration of tuberculosis. Aspiration bronchiolitis is a common finding in patients with severe reflux or with impaired swallowing mechanisms. Early diagnosis of hypersensitivity pneumonitis can lead to prompt identification of the offending antigen. In cases with pure centrilobular nodules, smoking history is paramount – smokers get RB, non-smokers have a higher likelihood of hypersensitivity pneumonitis.