Skip to Main Content

We have a new app!

Take the Access library with you wherever you go—easy access to books, videos, images, podcasts, personalized features, and more.

Download the Access App here: iOS and Android. Learn more here!

Patient Story

A 5-month-old full-term female infant presents to your office with 3 days of fever and cough. On examination, you note a frequent wet cough and appreciate bilateral wheezes. Pulse oximetry reveals a normal oxygen saturation. You reassure the mom that her daughter has bronchiolitis and needs supportive care only (Figure 48-1). She agrees to follow up with you in 1 to 2 days.


Bronchiolitis illustration with captions embedded. (Reprinted with permission, Cleveland Clinic Center for Medical Art & Photography © 2012. All Rights Reserved.)


Bronchiolitis is inflammation of the bronchioles typically caused by a viral illness that frequently affects young children.1


Respiratory Syncytial Virus (RSV) or lower respiratory tract infection (LRTI).


  • Most common lower respiratory tract infection in children less than 1 year of age.1

  • Annual hospitalizations for bronchiolitis account for greater than half a billion dollars in health care expenditures.2

Etiology and Pathophysiology

  • Viral etiology, most frequently RSV.

  • Other viruses implicated include influenza, parainfluenza, adenovirus, and human metapneumovirus.

  • Inflammation, edema, and necrosis of epithelial cells lining bronchioles (Figure 48-1).

  • Leads to increased mucus production and bronchospasm.

Risk Factors

  • Up to 90 percent of infants will have had an RSV infection by the age of 2 years.1

  • Infants with exposure to child care center populations, school-aged siblings, and smoke are at higher risk for developing bronchiolitis.3

  • Risk factors for severe disease include:

    • Prematurity of less than 35 weeks gestation.

    • Chronic lung disease or congenital airway malformations.

    • Cyanotic congenital heart disease.

    • Severe neuromuscular disease.

    • Immunocompromised state.4


Clinical Features

  • Bronchiolitis is a clinical diagnosis.

  • Signs and symptoms include rhinorrhea, cough, tachypnea, bilateral wheezing, and signs of increased work of breathing such as use of accessory muscles and/or nasal flaring.

Laboratory Testing

  • Laboratory testing is not routinely indicated.

  • Respiratory viral testing can be obtained if necessary for epidemiologic surveillance and research but the results do not change the management of the disease.


  • As most chest x-rays obtained in patients with bronchiolitis are found to be normal, routine chest radiography is not recommended for patients with bronchiolitis (Figure 48-2).

  • Nonspecific findings such as hyperinflation, perihilar markings, or central bronchial thickening can be seen in some patients (Figure 48-3 to 48-5).

  • Chest radiography may be necessary if the patient experiences a severe course or does not improve as expected based on the natural history of disease.


Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.