Bronchiolitis symptoms, causes, diagnosis, treatment

Bronchiolitis is an infection of the small air passages ( bronchioles) inside the lungs. It causes swelling and mucus build-up in these tubes that causes congestion in the airways.

The infection is usually triggered by a virus, most commonly by respiratory syncytial virus (RSV), which can also cause the common cold. It’s spread through the air by coughing and sneezing. The condition is most common among children under 2. One in every three children in the UK has had bronchiolitis by the end of their first year.

Causes of bronchiolitis

In 70 % of cases, bronchiolitis is caused by respiratory syncytial virus (RSV). Other viruses that can cause it include:

• Rhinovirus
• Flu virus
• Adenovirus
• Parainfluenza virus

These viruses are spread through the air by tiny droplets released during sneezing or coughing. They can also be picked up from surfaces where droplets land, such as a table or baby toy. RSV can survive on such a surface for 6 – 12 hours.

Once your child is infected, the virus acts on the respiratory system via the small airways (bronchioles). It causes inflammation, swelling and mucus production that can make breathing hard. Babies are more susceptible as their airways are so small and underdeveloped.

Symptoms of bronchiolitis

Early symptoms of bronchiolitis are much like those of the common cold and include a blocked or runny nose and a cough. Over a few days further symptoms develop including:

• A high temperature
• Breathlessness
• Wheezing or noisy breathing
• Small pauses in breathing
• A dry persistent cough
• Loss of appetite or difficulty feeding
• Fewer wet nappies
• Irritability
• Vomiting after feeds

When to seek medical advice

Most cases of bronchiolitis are mild and get better on their own. However, the above symptoms can cause worry and concern for parents. If symptoms don’t progress beyond those of a normal cold, there’s usually no need to get medical help and you can take care of your child at home.

Seek medical advice if you’re worried or if your child is:

• Struggling for breath
• Has a breathing rate of 50 to 60 breaths a minute
• Has no wet nappy for 12 or more hours
• Is consuming significantly less food / feeds than normal
• Has a persistent high temperature over 38C (100.4°F)
• Is irritable and unsettled or very fatigued

You should seek immediate medical advice if your child has these symptoms and is:

• Under 12 weeks old
• Has an underlying health issue such as a heart or lung condition

When to call 999

It’s rare for bronchiolitis to develop into a medical emergency, but call an ambulance if your child:

• Is breathing more than 60 breaths a minute
• Is having severe breathing problems and clearly struggling for breath
• Is pale, sweaty and exhausted
• Is unable to be woken from sleep or keeps falling asleep
• Is pausing for 5 to 10 seconds between breaths
• Has blue skin or lips and tongue turn blue