Bronchiolitis is swelling and mucus buildup in the smallest air passages in the lungs (bronchioles), usually due to a viral infection.
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. Respiratory syncytial virus (RSV) is the most common cause. Other viruses that can cause bronchiolitis include:
The virus is transmitted from person to person by direct contact with nasal fluids, or by airborne droplets. Although RSV generally causes only mild symptoms in an adult, it can cause severe illness in an infant.
Bronchiolitis is seasonal and appears more often in the fall and winter months. It is a very common reason for infants to be hospitalized during winter and early spring. It is estimated that by their first year, more than half of all infants have been exposed to RSV.
Risk factors include:
Some children have infections with few or minor symptoms.
Bronchiolitis begins as a mild upper respiratory infection. Over a period of 2 - 3 days, it can develop into increasing respiratory distress with wheezing and a "tight" wheezy cough.
The infant's breathing rate may increase (tachypnea), and the infant may become irritable or anxious-looking. If the disease is severe enough, the infant may turn bluish (cyanotic), which is an emergency.
As the effort of breathing increases, parents may see the child's nostrils flaring with each breath and the muscles between the ribs retracting (intercostal retractions) as the child tries to breathe in air. This can be exhausting for the child, and very young infants may become so tired that they have difficulty maintaining breathing.
Sometimes, no treatment is necessary.
Supportive therapy can include:
Antibiotics are not effective against viral infections. Most medications have little effect on bronchiolitis. Children in the hospital may need oxygen therapy and fluids given through a vein (IV) to stay hydrated.
In extremely ill children, antiviral medications (such as ribavirin) are used in rare cases.
Usually, the symptoms get better within a week, and breathing difficulty usually improves by the third day. The mortality rate is less than 1%.
Call your health care provider immediately, or go to the emergency room if the child with bronchiolitis:
Most cases of bronchiolitis are not easily preventable because the viruses that cause the disorder are common in the environment. Careful attention to hand washing, especially around infants, can help prevent the spread of respiratory viruses.
Family members with an upper respiratory infection should be especially careful around infants. Wash your hands often, especially before handling the child.
At this date, there is no RSV vaccine available. However, there is an effective product, called palivizumab (Synagis), for infants who are at high risk of developing severe disease from RSV. Ask your child's doctor whether this medication is right for your child.