Definition of Bronchiolitis
Bronchiolitis is swelling and mucus buildup in the smallest air passages in the lungs (bronchioles), usually due to a viral infection.
Causes, incidence, and risk factors
Bronchiolitis usually affects children under the age of 2, with a peak age of 3 – 6 months. It is a common, and sometimes severe illness. (RSV) is the most common cause. Other viruses that can cause bronchiolitis include:
Symptoms
Some children have infections with few or minor symptoms.
Signs and tests
Signs include:
Treatment
Sometimes, no treatment is necessary.
Expectations (prognosis)
Usually, the symptoms get better within a week, and breathing difficulty usually improves by the third day. The mortality rate is less than 1%.
Review
Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 11/2/2009










