Family doctor

What is it?

Bronchiolitis is a name that sounds like bronchitis but it is a quite different condition. It happens in infants mostly within the first two years of life with the peak being between three and six months of age.

It is more common in winter and in male infants.

It is an inflammation of the lower part of the tubing that takes the air down from the nose and throat to the lungs.

What are the symptoms?

The child has difficulty breathing in and out. The first symptoms are the same as those of a common cold: stuffiness, runny nose, mild cough. These symptoms last a day or two and are followed by gradually increasing breathing difficulty with wheezing; cough, fast, shallow breathing (60 to 80 times a minute); fast heartbeat and the child's chest will be retracted inwards at the lower front part as he or she tries to breathe in.

The child may have a fever.

There usually is no vomiting or diarrhoea.

In mild cases, symptoms last one to three days.

In severe cases, symptoms may rapidly get worse and the infant may tire out from the work of breathing and need admission to hospital.

The infant can also become dehydrated due to the hard work of breathing and not being able to drink enough water.

What is the cause?

Bronchiolitis is usually caused by a viral infection. The commonest virus is the respiratory syncytial virus (RSV). This virus is most common in the winter and early spring but other causes include parainfluenza virus, influenza virus, mycoplasma, and some adenoviruses.

Bronchiolitis is more likely to happen to an infant who is a male aged between three and six months of age in winter who has not been breast-fed and who lives in a crowded house and who has to breathe in cigarette smoke from smokers also living in the house.

Once a susceptible infant has caught the virus it can take up to 7 days before bronchiolitis starts. On average it will then last 7 days but in more severe cases it can last for weeks. There can be quite a lot of wheezing with it making bronchiolitis hard to separate out from asthma both for parents and doctors.

The virus which triggers bronchiolitis can easily be passed on to other infants. Probably the coughing and sneezing makes tiny droplets full of virus which travel through the air and are breathed in by other infants. This make for the epidemics which tend to occur in winter every two or three years. Infants in day care centres are at greater risk.

What can be done?

Unfortunately antibiotics do not help bronchiolitis because they are not able to kill off viruses. Antibiotics can only kill bacteria such as those that cause pneumonia or bronchitis or ear infections. For most cases the only treatment is "time" and making sure the infant is drinking extra fluids.

For most cases the illness peaks at about the second to third day after the onset of cough and difficulty breathing.

For mild bronchiolitis it can help to keep some steam in the air that the infant breathes. A cool-mist vaporizer in the infant's room during the dry winter months is the best but these are expensive. Boiling water in an electric fry pan without the top can be done but there is the constant danger of the child getting scalded so this arrangement needs very good protection around the fry pan.

Asthma medicines usually do not help unless the infant also has asthma. This can sometimes be difficult to tell, as both conditions have similarities, including a wheezy sound to breathing. Sometimes a nebuliser is tried by the doctor as a trial to see if asthma is also present.

Infants who have severe bronchiolitis may need hospital admission for fluids, humidified oxygen, and close observation.

Getting help

It is important to stay in close contact with your doctor. Review of the condition may be needed to make sure the child is making good progress.