Bronchiectasis

Understanding the airways

Usually air travels from our windpipes down into our lungs through small tubes. The tubes that come off the windpipe are called bronchi; then they split into bronchioles which are a bit smaller. Finally the small bronchioles split into tiny tubes called alveoli. In a normal person all these tubes are fairly small: up to 2 cm in diameter at the windpipe, all the way down to just a few millimetres for the alveoli. Our airways are a bit like a tree: the tree trunk is the biggest bit, but it gradually splits off into branches, then twigs.

In bronchiectasis the airways gradually become bigger than they are meant to be. So instead of the tiny alveoli being just a few millimetres in diameter, they might be a centimetre wide. And instead of bronchioles being about a centimetre wide, they become 1.5 centimetres in diameter.

The problem then is that mucus, which we all have in our lungs to some degree, can pool and collect in the airways. And because the airways aren't meant to be that wide in the first place, they produce more mucus than usual. Mucus is the same as sputum, or phlegm: sticky, slightly thick liquid that can be white, clear, green or yellow. It can usually be coughed up.

This picture shows what happens in bronchiectasis:

Lungs and airways - bronchiectasis

Generally the cause is something that has created infection or inflammation in the lungs:

• A bad infection with tuberculosis.

• A bad case of pneumonia.

• A blood clot in the lungs, called a pulmonary embolus.

• A bad infection with whooping cough (pertussis) as a child.

Or it could be from a problem with the immune system:

• Having HIV.

• Having a low immune system from birth.

Or a problem with how the lungs clear away mucus already, such as occurs with:

• Cystic fibrosis from childhood.

• Some other type of rare condition like Kartagener's syndrome.

There are other rare conditions that can cause bronchiectasis, such as:

• Alpha-1 antitrypsin deficiency.

• Yellow nail syndrome.

• Allergic bronchopulmonary aspergillosis.

These problems could have occurred in childhood, but it's only in adulthood or even older that you develop bronchiectasis.

In at least a third of cases of bronchiectasis, no cause is found.

Bronchiectasis is not particularly common: most family doctors in the UK will have some patients with the condition but will not see new cases very often. Around 1% of people have been diagnosed with bronchiectasis in the general population; but people with a chronic lung condition like asthma, cystic fibrosis or chronic obstructive pulmonary disease (COPD) will have a higher rate of bronchiectasis. The condition gets more common with old age.

It seems to be getting more common lately but that is probably because lung scans are more detailed and picking up on the lung changes of bronchiectasis more easily.

The symptoms are caused by there being too much mucus inside the lungs:

• A wet cough every day, despite taking antibiotics.

• Coughing up lots of sputum (also called phlegm or mucus).

• Feeling slightly breathless or unable to do as much exercise as you used to.

• Frequent chest infections, particularly with a bug called Pseudomonas aeruginosa.

• As a child: asthma that is difficult to control; or having recurrent chest or ear infections.

Bronchiectasis is usually diagnosed by a lung specialist rather than a family doctor. It is usually diagnosed by:

• The general clinical picture of someone with a long-term cough that produces large amounts of sputum.

• A CT scan of the lungs that shows enlargement (or what is often called 'dilatation') of the airways and usually thickening of the wall of the airways.

Once bronchiectasis sets in, it can't ever be reversed. However, it can be prevented from getting worse by:

• Not smoking at all.

• Taking regular exercise.

• Using 'airways clearance techniques' that help to drain off mucus from the lungs. This usually involves seeing a physiotherapist who is trained in treating the lungs: what is usually termed a respiratory physiotherapist or 'chest physio'. The patient can also be taught how to use postural drainage techniques themself, along with special breathing techniques to bring up the mucus.

• Nebulised saline can help to make the sputum thinner and easier to cough up.

• Nebulised bronchodilators can help the mucus to drain away too.

• Long-term macrolide antibiotics such as azithromycin, can help to prevent infections and dampen down inflammation in the lungs.

• Treating any underlying cause, like tuberculosis or cystic fibrosis, is also important.

• Inhaled steroids or nebulised steroids do not seem to help.

• If the bronchiectasis is confined to just one area of the lungs (which is unusual) then surgery can be considered.

Most people with bronchiectasis (with no underlying cause) have a good outlook (prognosis). Symptoms in many affected people do not become severe. Treatment, in particular with antibiotics when an infection occurs, or regularly when needed, keeps most people reasonably well.

The condition becomes worse in some cases and breathing problems may develop. In a small number of cases the condition becomes gradually worse over time as more and more of the airways become affected.

A life-threatening bleed from a damaged airway may also occur but is rare.

The outlook for people where bronchiectasis is part of another condition depends on the underlying cause. Generally it gets a little bit worse as you get older, but if you follow treatment plans then you should be able to stop it getting much worse.