What is Bronchiolitis?

Bronchiolitis is an inflammation of the bronchioles (small passages in the lungs) usually caused by a viral infection. The disease usually affects children under the age of 2, with a peak age of 3 to 6 months, and is a common, sometimes severe illness. Respiratory syncytial virus (RSV) is one common cause. Other viruses that can cause bronchiolitis include parainfluenza, influenza, and adenovirus. 


  • Cough, wheezing, shortness of breath, or difficulty breathing 

  • Rapid breathing (tachypnea) 

  • Nasal flaring in infants 

  • Fever (variable) 

  • Bluish skin due to lack of oxygen (cyanosis) 


Exams and tests to diagnose bronchiolitis include: 

  • A stethoscope examination of the chest to detect wheezing and crackling sounds. 

  • Chest X-ray and blood gases. 

  • Samples of nasal fluid may be cultured to determine what virus is present. 


Antibiotics are not effective against viral infections. Sometimes, no treatment is necessary. Supportive therapy may include oxygen, humidified air, chest clapping (postural drainage to remove secretions), rest, and clear fluids. Other medicines used in the hospital may include albuterol (a medication normally used in asthma) or steroids. 

In extremely ill children, antiviral medications (such as ribavirin) are sometimes used. Antiviral treatment may decrease the severity and duration of the illness. To be effective, it must be administered early in the course of the illness. 


Usually, the symptoms have resolved within a week, and difficulty breathing usually improves by the third day. The mortality rate is less than 1 percent.

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