Cystic fibrosis

Cystic fibrosis (CF) is an inherited disease, which is most common in white children and young adults, although it can affect people of any race. It used to be thought of as a disease of the lungs and digestive system, but it is now known to affect most organs in the body.

With improvements in diagnosis and care, life expectancy is increasing progressively and CF has become a disease of adults.

Last Update 17/05/2023
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Cystic fibrosis can affect several parts of the body:

  • The lungs
  • Digestive system
  • Ears, nose and sinuses
  • Bones
  • Liver

It results in various symptoms and other conditions which may include:

  • A cough producing phlegm or mucus, frequent respiratory infections and progressive breathlessness
  • Sinusitis
  • Difficulty absorbing food, leading to poor nutrition
  • Diabetes
  • Cirrhosis, or scarring, of the liver
  • Reduced fertility

Periods of worsening of symptoms are known as exacerbations or ‘lung attacks’.

They can have a negative impact on a person’s quality of life and are associated with a faster decline in lung function.

Chronic, or persistent, infection cause progressive damage to the airways and lungs, including bronchiectasis and eventually lead to failure of the lungs due to their inability to maintain normal levels of oxygen and carbon dioxide in the body.


CF is usually caused by problems with a gene called cystic fibrosis transmembrane regulator (CFTR), which plays a key role in regulating salt and water transport across cells lining the airway and gut, for example. If this gene isn’t working properly there is a build-up of thick mucus in the airways such that bacteria and particles cannot be removed effectively.

CF is an inherited (genetic) condition; a large number of variations of the faulty gene have been identified and the severity of the condition depends on the variation.

There are no known environmental causes of the disease, although exposure to tobacco smoke, air pollution and allergens, may all contribute to the long-term progression of the condition.


Diagnosis of CF can be achieved by screening new-born babies. A baby’s heel is pricked and a small sample of blood is taken. This is known as the heel-prick test. The genes in the blood sample can then be analysed. A sweat test should also be performed to confirm CF. This takes a sample of sweat that is sent to a laboratory for testing for high salt concentrations in the sweat.

Current treatment mainly focuses on alleviating the symptoms to help improve a person’s quality of life and slowing progress of the disease. However, new treatments correcting the basic defect are becoming available.

The best form of treatment is by a multidisciplinary team, including nurses, physiotherapists, dieticians, social workers and pharmacists. For the best results care should be provided in a specialist centre which should be have the expertise and facilities to manage all aspects of the disease.

Antibiotics, physiotherapy, avoiding smoking, and immunisation are all important aspects of management; physiotherapy is used to clear the abnormally thick mucus that accumulates in the lungs, with patients shown how to continue regular treatment at home. Some people with CF may also receive a lung transplant.

The cost of treatment is likely to increase as new drugs, targeting specific genetic mutations in different forms of CF, are being developed. Gene therapy, aimed at replacing the faulty gene in the airway cells is currently in clinical trial.