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Bronchiolitis

Page last reviewed: 13/07/2011

Bronchiolitis is a common lower respiratory tract infection that affects babies and young children. The early symptoms are similar to those of a common cold, such as a runny nose and cough. As bronchiolitis develops, it can cause:

  • a slight fever (raised temperature)
  • a dry and persistent cough
  • difficulty feeding

Bronchiolitis is most commonly caused by an airborne virus known as the respiratory syncytial virus (RSV). This causes the smallest airways in the lungs (the bronchioles) to become infected and inflamed (swollen). The inflammation reduces the amount of air entering the lungs, making it more difficult for the child to breathe.

How common in bronchiolitis?

It is estimated that one-third of infants develop bronchiolitis in the first year of their life.  The condition is most common in infants who are three to six months old. By two years of age, almost all infants have been infected with RSV and 40-50% will have had bronchiolitis.  

Most cases of bronchiolitis occur during the winter months, from November to March, when the viruses that can cause bronchiolitis are more common. It is also possible to get bronchiolitis more than once during the same winter season. 

Outlook

There is no medication to kill the viruses that cause bronchiolitis, but the infection usually clears up within two weeks without any treatment. Most infants can be cared for at home by ensuring they get enough fluid and by monitoring their condition.

Around 3% of infants who are under one year of age and have bronchiolitis will need to be admitted to hospital. This is because they develop more serious symptoms, such as difficulty breathing. However, this is more likely to occur in premature babies (babies born before week 37 of pregnancy) and those born with a heart or lung condition.

Glossary

Respiratory tract
The respiratory tract is a general term used to describe all the parts of the body that are involved in helping a person breathe.

Bronchioles
The bronchioles are tiny airways found throughout the lungs.

Lungs
Lungs are a pair of organs in the chest that control breathing. They remove carbon dioxide from the blood and replace it with oxygen.

Inflammation
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.

Page last reviewed: 13/07/2011

Early symptoms

The early symptoms of bronchiolitis are similar to those of a common cold. The first symptom is usually a blocked or runny nose. Your child may also have a slight cough or fever (high temperature). A normal temperature is 36-36.8C (96.8-98.2F).

Later symptoms

The symptoms of bronchiolitis usually get worse during the first three days, then gradually improve. During this time, your child may experience some of the following symptoms:

  • a rasping and persistent dry cough
  • rapid or noisy breathing
  • brief pauses in their breathing
  • feeding less and having fewer wet nappies
  • vomiting after feeding
  • being irritable

Even though most cases of bronchiolitis are not serious, these symptoms can be very worrying for parents.

When to seek medical advice

Contact your GP or midwife if your child has the later symptoms of bronchiolitis described above. This is particularly important if your baby is under 12 weeks old or they have an underlying health problem, such as a congenital heart or lung condition. Congenital means that the condition is present from birth.

In all cases, be aware of any changes to your child's symptoms. Contact your GP again if you are worried or if your child develops any of the following symptoms:

  • increased difficulty breathing or wheezing as they breathe
  • poor feeding (if your child has taken less than half the amount that they usually do during the last two or three feeds)
  • no wet nappy for 12 hours or more
  • a rapid breathing rate of more than 40 breaths a minute
  • a high temperature (fever) of 38C (100.4F) or above
  • being very tired or irritable

When to call 112

While it is unusual for children to need hospital treatment for bronchiolitis, the symptoms can get worse very quickly.

Call 112 for an ambulance if:

  • Your child has severe breathing difficulties or exhaustion from trying to breathe. You may see the muscles under your child's ribs sucking in with each breath, your child may be grunting with the effort of trying to breathe, or they may be pale and sweaty.
  • Your child has a rapid breathing rate of more than 60 breaths a minute.
  • You are unable to rouse (wake) your child or, if roused, they do not stay awake. 
  • Your child's breathing stops for more than 10 seconds at a time (this is known as recurrent apnoea).
  • Your child's skin begins to turn ashen (very pale) or blue, particularly around the lips or fingernails (known as cyanosis).

Glossary

Fever
A fever is when you have a high body temperature (over 38C or 100.4F).

Vomiting
Vomiting is when you bring up the contents of your stomach through your mouth.

Wheezing
Wheezing is the whistling sound made during breathing when the airways are blocked or compressed.

Page last reviewed: 13/07/2011

Bronchiolitis is almost always caused by a viral infection. In 75% of cases, the virus responsible is the respiratory syncytial virus (RSV).

Respiratory syncytial virus (RSV)

RSV is a very common virus. Almost all children are infected with RSV by the time they are two years old. In older children and adults, RSV may cause a cough or cold, but in young children it can cause bronchiolitis.

Other viruses that may cause bronchiolitis include:

  • parainfluenza virus
  • influenza (flu) virus
  • adenovirus
  • rhinovirus

Catching a virus

Viruses are spread through tiny droplets of liquid from the coughs or sneezes of someone who is infected. The droplets can be breathed in directly from the air or picked up from a surface that they have landed on, such as a toy or table.

For example, your child can become infected if they touch a toy that has the virus on it and then touch their eyes, mouth or nose. RSV can survive on a surface for 6-12 hours.

Children can be infectious for up to three weeks after having the condition, even after their infection has cleared up.

The respiratory system

Once the virus has been caught, it enters the respiratory system through the windpipe (trachea). The virus makes its way down to the smallest airways in the lungs (the bronchioles).

The infection causes the bronchioles to become inflamed (swollen) and increases the production of mucus. The mucus and swollen bronchioles can block the airways, making it difficult to breathe. As babies and young children have small, underdeveloped airways, they are more likely to get bronchiolitis.

Risk factors

Bronchiolitis is very common in infants and is usually mild. However, some risk factors can make bronchiolitis more serious. These include:

  • being under 12 months of age
  • having congenital heart disease (a birth defect that affects the heart)
  • being born prematurely (before week 37 of pregnancy)
  • having chronic lung disease of prematurity (when injury to the lungs causes long-term respiratory problems in premature babies)
  • being breastfed for less than two months or not at all
  • being exposed to smoke, for example if parents smoke
  • having brothers or sisters who attend school or nursery (as they are more likely to come into contact a virus and pass it on)

Glossary

Respiratory tract
The respiratory tract is a general term used to describe all the parts of the body that are involved in helping a person breathe.

Bronchioles
The bronchioles are the tiny airways found throughout the lungs.

Lungs
Lungs are a pair of organs in the chest that control breathing. They remove carbon dioxide from the blood and replace it with oxygen.

Inflammation
Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.

Heart
The heart is a muscular organ that pumps blood around the body.

Useful Links

Page last reviewed: 13/07/2011

Visit your GP if your child has the symptoms of bronchiolitis. See Symptoms of bronchiolitis for advice about when to call an ambulance.

In the UK, a diagnosis of bronchiolitis is usually based on the presence of some of the symptoms combined with an examination of your child's breathing.

Your GP will ask about your child's symptoms, for example whether they have had a runny nose, cough or high temperature (fever). They will also listen to your child's breathing using a stethoscope (a medical instrument that transmits sounds). Your GP will listen for any crackling or high-pitched wheezing as your child breathes in and out.

If your child has not been feeding very well or has been vomiting, your GP may also look for signs of dehydration to determine whether the water content of their body is reduced. Signs of dehydration include:

  • a dipped fontanelle (the soft spot on the top of the head) in babies
  • dry mouth and skin
  • drowsiness
  • producing little or no urine

Further tests

Further tests for bronchiolitis are not usually necessary. However, some conditions cause similar symptoms to bronchiolitis, such as cystic fibrosis (a condition that makes the internal bodily secretions thick and sticky) and asthma (another condition that affects the lungs).

If it is not clear what condition your child has, your GP may recommend further tests to confirm the diagnosis.

Chest X-ray

X-rays use radiation to create images of the inside of the body. A chest X-ray can be used to check for any abnormalities in the lungs. This may be used if your child has any unusual symptoms or if the diagnosis is uncertain.

For example, a chest X-ray can be used to diagnose pneumonia or may reveal whether your child has inhaled something small that is affecting their breathing.

Mucus sample test

Your GP may use a swab to collect a sample of mucus from your child's nose. The sample can be tested to confirm the virus that is causing your child's bronchiolitis.

Glossary

Fever
A fever is when you have a high body temperature (over 38C or 100.4F).

Wheezing
Wheezing is the whistling sound made during breathing when the airways are blocked or compressed.

Lungs
Lungs are a pair of organs in the chest that control breathing. They remove carbon dioxide from the blood and replace it with oxygen.

Useful Links

Page last reviewed: 13/07/2011

If your child's bronchiolitis is not severe, the infection will usually last about two weeks and will not require treatment. A small proportion of children (up to 9%) may still have symptoms after four weeks.

To avoid the infection spreading to other children, take your child out of nursery or day care and keep them at home until their symptoms have improved (see below).

Treatment at home

There is no medicine that can kill the viruses that cause bronchiolitis. However, if your child's symptoms are mild, there are some treatments that you can provide at home. These may help to ease your child's symptoms and make them more comfortable.

Drink plenty of fluids

Make sure that your child drinks plenty of water or fruit juice to avoid dehydration (when the normal water content of the body is reduced). If your child is being breastfed or bottle fed, try giving them smaller feeds more frequently.

Paracetamol or ibuprofen

If your child has a high temperature (fever) that is making them miserable, consider using paracetamol or ibuprofen. These are available over-the-counter (OTC) from pharmacies without prescription. Always follow the manufacturer's instructions and do not give aspirin to children under 16 years of age.

Do not try to reduce your child's high temperature by removing their clothes or sponging them with cool water.

Monitor your child

Continue to monitor your child. Check on them regularly, including throughout the night. If their condition worsens, contact your GP. See Symptoms of bronchiolitis for advice about when to call an ambulance.

Once your child is feeding normally and no longer has difficulty breathing, they can return to nursery or day care. If your child is recovering well, there is no need to see your GP again.

Treatment in hospital

Approximately 3% of infants who are under one year of age and have bronchiolitis are admitted to hospital. 

Children are more at risk of being admitted to hospital if they were born prematurely (before week 37 of pregnancy) or with an underlying health problem. See Causes of bronchiolitis for a full list of risk factors.

Your child may be admitted to hospital if:

  • they are not getting enough oxygen into their blood because they have difficulty breathing
  • they are not eating or drinking enough

Once in hospital, your child will be monitored and treated in a number of ways, as explained below.

Oxygen level

The level of oxygen in your child's blood will be measured with a pulse oximeter. This is a small clip or peg that is attached to your baby's finger or toe. It transmits light through your baby's skin and the sensor uses this to detect how much oxygen is in your baby's blood.

If your child needs more oxygen, it can be given to them through a thin tube in their nose or a mask that goes over their face.

Feeding

If your child is having trouble feeding, they may be given fluids or milk through a feeding tube. This is a thin plastic tube that goes into your child's mouth or nose and down into their stomach. Alternatively, they may be given fluids intravenously (directly into a vein).

Mucus sample test

If it has not already been tested, a sample of your child's mucus may be tested to see which virus is causing the bronchiolitis (see Diagnosis of bronchiolitis). This will confirm whether the respiratory syncytial virus (RSV) is responsible.

If your child has RSV, they will need to be kept away from other children in the hospital who are not infected with the virus. This is to control the spread of the virus.

Nasal suction

If your child's nose is blocked and is causing them breathing difficulties, nasal suction may be used. This involves a small, plastic tube being inserted into their nostrils to clear out the mucus. 

Other hospital treatments

A number of other medicines have been tested to determine whether they benefit children with bronchiolitis, and most have been shown to have little or no effect. Current research also suggests that chest physiotherapy, where physical movements or breathing techniques are used to relieve the symptoms, are also of little benefit.

Nebulised hypertonic saline solution is one possible treatment that may be of benefit. Hypertonic saline solution is fluid that has a high concentration of salt. A nebuliser is a device that converts liquid into mist so that it can be breathed in.

One review of medical research found that nebulised hypertonic saline solution reduced the amount of time that children with bronchiolitis spent in hospital and also reduced the severity of their symptoms. Further research is needed, but nebulised hypertonic saline solution may be a possible treatment.

Leaving hospital

Most children who are admitted to hospital will need to stay there for two to four days. Your child will be discharged from hospital when:

  • they have enough oxygen in their blood without the need for medical assistance
  • they are able to take (and keep down) over 75% of their normal feeds

Glossary

Dehydration
Dehydration is an excessive loss of fluids and minerals from the body.

Lungs
Lungs are a pair of organs in the chest that control breathing. They remove carbon dioxide from the blood and replace it with oxygen.

Oxygen
Oxygen is an odourless, colourless gas that makes up about 20% of the air we breathe.

Useful Links

Page last reviewed: 13/07/2011

There are several complications associated with bronchiolitis. These include:

  • cyanosis: an ashen (very pale) or blue tinge to the skin that is caused by lack of oxygen
  • dehydration: when the normal water content of the body is reduced
  • fatigue: extreme tiredness and a lack of energy
  • severe respiratory failure: an inability to breathe unaided

If any of these complications occur, it is likely that your child will need hospital treatment. Contact your GP immediately. In some cases, you may need to dial 112 for an ambulance.

See Symptoms of bronchiolitis for more information about severe symptoms and when to call an ambulance.

Death

It is very rare for bronchiolitis to cause death. However, one UK study found that the respiratory syncytial virus (RSV) caused around eight deaths in infants under one year of age for every 100,000 people.

Long-term effects of bronchiolitis

Bronchiolitis does not usually cause long-term breathing problems. However, it can cause damage to the cells in your child's airways. This damage can last from three to four months. Around 20% of infants with bronchiolitis remain wheezy or have a persistent cough for a few weeks.

Underlying health conditions

If your child was born with a health problem, such as a heart or lung disease, their bronchiolitis symptoms may come on very rapidly and are more likely to be severe. The infection may also make any symptoms of your child's underlying health problem worse.

Pneumonia

In rare cases, bronchiolitis can be accompanied by bacterial pneumonia, which infects the lungs. If this happens, the pneumonia will need to be treated separately.

Respiratory conditions in later life

There may be a link between bronchiolitis and developing respiratory conditions, such as asthma, in later life. However, the link is not fully understood.

It is not clear whether having bronchiolitis as an infant makes asthma more likely, or whether there are environmental or genetic (inherited) factors that cause both the bronchiolitis and asthma. 

If your child has repeated bouts of bronchiolitis, their risk of developing asthma later in life may be increased.

Glossary

Oxygen
Oxygen is an odourless, colourless gas that makes up about 20% of the air we breathe.

Dehydration
Dehydration is an excessive loss of fluids and minerals from the body.

Wheezing
Wheezing is the whistling sound made during breathing when the airways are blocked or compressed.

Lungs
Lungs are a pair of organs in the chest that control breathing. They remove carbon dioxide from the blood and replace it with oxygen. 

Page last reviewed: 13/07/2011

The viruses that cause bronchiolitis are very common and easily spread, so preventing the condition altogether is not possible. However, you can take steps to reduce the chances of your child catching a virus. If your child already has bronchiolitis, following these steps will help prevent spreading the virus further:

  • Cover your child's nose and mouth when they cough or sneeze.
  • Use disposable tissues rather than cotton handkerchiefs and throw them away as soon as they have been used.
  • Wash both your child's hands and your hands frequently, particularly after touching their nose or mouth or after feeding.
  • Ask anyone who comes into contact with your child, such as a relative or nanny, to wash their hands first.
  • Wash and dry eating utensils after use.
  • Wash or wipe toys and surfaces regularly.
  • Keep infected children at home until their symptoms have improved (they are feeding normally and do not have any difficulty breathing).
  • Keep newborn babies away from people with colds or flu, particularly during the first two months of life or if they were born prematurely (before week 37 of pregnancy).

High-risk children

In some cases, it may be possible for a child with a high risk of developing severe bronchiolitis to have monthly antibody injections. The injections can help limit the severity of the condition if the child becomes infected.

Children considered to be at high risk include those who:

  • were born very prematurely
  • were born with a heart or lung condition
  • have an immune deficiency (a weakened immune system)

Your GP can give you more information and advice if your child is at high risk.

Glossary

Heart
The heart is a muscular organ that pumps blood around the body.

Lungs
Lungs are a pair of organs in the chest that control breathing. They remove carbon dioxide from the blood and replace it with oxygen.

Immune system
The immune system is the body's defence system, which helps protect it from disease, bacteria and viruses.

Useful Links

Page last reviewed: 13/07/2011

As well as treating your child's bronchiolitis at home (see Treatment of bronchiolitis), using the following tips may help make your child more comfortable.

Humidify the air

If you have access to an air humidifier, using it to moisten the air may help to ease your child's cough.

Alternatively, run the hot tap of the shower or bath for several minutes to steam up the room, then sit your child in the room for a few minutes. Afterwards, your child's clothes may need to be changed if they have become damp. Be careful not to scald your child with the hot water or steam.

Your home should be heated to a comfortable temperature, but do not make it too warm as this will dry out the air.

Keep your child upright

Keeping your child in an upright position may help make their breathing easier. This may be useful when they are trying to feed. If your child has a nap in an upright position, make sure that their head does not fall forward by supporting it with something, such as a rolled up blanket.

Saline nasal drops

Saline (salt water) nasal drops are available over-the-counter (OTC) from pharmacies. Placing a couple of drops of saline inside your child's nose before they feed may help to relieve a blocked nose. However, always follow the manufacturer's instructions or check with your pharmacist before using saline nasal drops.

Keep a smoke-free environment

Smoke from cigarettes or other tobacco products may aggravate your child's symptoms. If you smoke, avoid doing so around your child.

Passive smoking can affect the lining of your child's airways, making them less resistant to infection. Therefore, keeping smoke away from your child may help prevent future episodes of bronchiolitis.

Useful Links

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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