Bronchiolitis is an infection of the small breathing tubes (bronchioles) of the lungs. It occurs most often in infants. (The term bronchiolitis is sometimes confused with bronchitis, which is an infection of the larger, more central airways.)
Bronchiolitis is almost always caused by a virus, most commonly the respiratory syncytial virus (RSV). Other viruses that can cause this condition are parainfluenza, influenza, measles, and adenovirus. The infection causes inflammation and swelling of the bronchioles, which in turn, blocks the airflow through the lungs. Most adults and many children who are infected by RSV get only a cold. In infants, however, the infection is more likely to lead to bronchiolitis. This happens because their airways are smaller and are more easily blocked when infection and inflammation occur.
Almost half the infants who develop bronchiolitis go on to develop asthma later in life. We do not know why these youngsters are more susceptible, but it is likely that the RSV infection is the first trigger for the airway reaction.
RSV infection is the most likely cause of bronchiolitis from October through March. It is spread by contact with secretions from an infected person. It often spreads through families, child-care centers, and hospital wards. Careful hand washing can help prevent this.
If your infant has bronchiolitis, it will start with signs of an upper respiratory infection (a cold): runny nose, mild cough, and sometimes fever. After a day or two the cough becomes more pronounced, the child begins to breathe more rapidly, and with more difficulty:
- He may dilate his nostrils and squeeze the muscles under his rib cage in efforts to get more air in and out of his lungs.
- He will use the muscles between the ribs and above the collarbone to help him breathe.
- When he breathes he may grunt and tighten his abdominal muscles.
- He will make a high-pitched whistling sound, called a wheeze, each time he exhales.
- He may not take fluids well because he is working so hard to breathe that he has difficulty sucking and swallowing.
- As his breathing difficulty increases, you may notice a bluish tint around the lips and fingertips. This indicates that his airways are so blocked that an inadequate amount of oxygen is getting into the blood.
If your baby shows any of these signs of breathing difficulty, or if his fever lasts more than three days (or is present at all in an infant under three months), call your pediatrician immediately.
Call the pediatrician if your child develops any of the following signs or symptoms of dehydration, which also can be present with bronchiolitis.
- Dry mouth
- Taking less than his normal amount of fluids
- Shedding no tears when he cries
- Urinating less often than normal
Lastly, if your child has any of the following conditions, notify your pediatrician as soon as you suspect that he has bronchiolitis.
- Cystic fibrosis
- Congenital heart disease
- Bronchopulmonary dysplasia (seen in some infants who have been on a respirator as newborns)
- Low immunity
- Organ transplant
- A cancer for which he is receiving chemotherapy
There are no medications you can use to treat RSV infections at home. All you can do during the early phase of the illness is ease your child’s cold symptoms. You can relieve some of the nasal stuffiness with a humidifier, nasal aspirator, and perhaps some mild salt-solution nasal drops prescribed by your pediatrician. Make sure your baby drinks lots of fluid during this time so he does not become dehydrated. He may prefer clear liquids rather than milk or formula. Because of the breathing difficulty, he also may feed more slowly and may not tolerate solid foods very well.
If your baby is having mild to moderate breathing difficulty, your pediatrician may try using a bronchodilating drug (one that opens up the breathing tubes) before considering hospitalization.
Unfortunately, some children with bronchiolitis need to be hospitalized, either for breathing distress or dehydration. The breathing difficulty is treated with oxygen and bronchodilating drugs, which are inhaled periodically. Occasionally, another medicine, called theophylline, is used. The dehydration will be treated with a special liquid diet or by fluids given intravenously.
The best way to protect your baby from bronchiolitis is to keep him away from the viruses that cause it. When possible, especially while he’s an infant, avoid close contact with children or adults who are in the early (contagious) stages of respiratory infections. If he is in a child-care center where other children might have the virus, make sure that those who care for him wash their hands thoroughly and frequently.
(Adapted from “Caring for Your Baby and Young Child: Birth to Age” Bantam 1998,American Academy of Pediatrics)