Gastrointestinal and respiratory systems

Cystic fibrosis is the UK's most common life-threatening inherited disease. It usually affects the lungs and digestive system, making it difficult to breathe and absorb food properly.

As an inherited disease, cystic fibrosis shows racial differences. It is more common in people of white European descent than it is in people of Afro-Caribbean or Asian descent. The chances of a baby having cystic fibrosis are about 1 in 3,300 in families of European descent and about 1 in 15,300 in families of African descent. On average, an estimated 1 out of every 2500 babies born in the UK, about 5 children per week, are affected with the disease. Three children die each week because of cystic fibrosis.

When the Cystic Foundation Trust was founded in 1964, it was exceptional for a child to live for over 5 years. Now, because of improvements in the management of the disease, around half of the 8,500 people in the UK with cystic fibrosis can expect to live over 38 years of age.

Cystic fibrosis is an inherited disease caused by a faulty gene (the Cystic Fibrosis Transmembrane Conductance Regulator - or CFTR gene). This gene is responsible for producing a channel in cell membranes through which salts and water pass. A faulty CFTR gene can alter the function of many organs, but especially the lungs, pancreas and gastrointestinal tract. Mucus secreted by these organs lacks water and becomes thick and sticky, causing a blockage and preventing the organ from working properly.

Cystic fibrosis is an autosomal recessive disease. This means that in order to develop the disease a baby has to inherit two cystic fibrosis genes from its parents, one from the mother and one from the father. If the baby inherits only one cystic fibrosis gene the baby does not develop any symptoms but becomes a carrier of the disease, able to pass the gene on to his or her children. There are around 2 million people in the UK - about one person in 25 of the population - who carry the faulty CFTR gene, but they show no symptoms of cystic fibrosis.

Cystic fibrosis is a multi-system disease meaning that many organs throughout the body are affected, but those most affected by the faulty CFTR gene are the cells lining the gastrointestinal system, pancreas and lungs.

In the pancreas, the thick mucus prevents the normal secretion of enzymes that are responsible for the digestion of food. Important nutrients such as proteins and fats are not absorbed and the child will fail to gain weight and to develop properly. The fat which is not absorbed is excreted as very foul smelling oily faeces.

In the lungs, the thick sticky mucus clogs the airways and makes breathing difficult. The child may develop a persistent cough or a wheeze. The lungs become a breeding ground for bacteria, especially a bacterium called Pseudomonas aeruginosa, leading to severe chronic chest infections such as pneumonia.

The severity of symptoms may vary from child to child and in those children with mild symptoms, cystic fibrosis was sometimes only suspected when they failed to gain weight or they developed breathing problems. Other symptoms include a very salty sweat and, later in life, complications such as diabetes, liver disease, infertility and osteoporosis may develop.

If a child has cystic fibrosis then he or she will be referred to a Paediatric Centre with a team of doctors, nurses, dieticians and physiotherapists that specialise in the management of cystic fibrosis. They will work with the parent(s) to devise a management and treatment plan to ensure that the child has a full and healthy life as possible. Regular tests and monitoring will be performed to keep a check on the child's growth, development and well-being.

Treatment is aimed at controlling the symptoms of the disease and prolonging life, there is no cure for cystic fibrosis. There are two main types of treatment: to improve nutrition and to reduce lung infections.

Improving nutrition - Good nutrition is vital for children with cystic fibrosis to enable them to grow and develop properly and to remain healthy. They generally need a diet higher in calories and protein than children without cystic fibrosis. The reason is that a lot of calories and protein are not absorbed but are lost in the child's faeces. Consequently, in contrast to dietary advice that is normally given to other children, they should be encouraged to eat plenty of fatty and sugary foods and protein-rich foods.

In addition, as the pancreas becomes blocked with mucus and is unable to secrete the enzymes needed for the proper digestion of food, pancreatic enzymes containing lipase, protease and amylase have to be added to the child's meals. These enzymes breakdown fats, proteins and carbohydrate present in foods helping these essential substances to be absorbed for use by the body. Additional fat-soluble vitamins A, D and E may also be given to make up any deficiencies. The dietician will decide how much of the pancreatic enzymes and which vitamins are to be used and will make adjustments to the child's diet as he or she matures.

Reducing lung infections - Chest physiotherapy helps dislodge the sticky mucus from the lungs, enabling air to reach all areas of the lungs and reducing the risk of infection. Percussion involves chest clapping to loosen secretions. The physiotherapist explains how and when to perform the technique. As the child develops, the physiotherapist will adapt techniques to suit the child. All children should be encouraged to take part in physical activity.

Drug treatment using mucolytic agents such as carbocisteine, erdosteine or mecysteine breaks down the mucus and helps it to be expelled more easily from the lungs. Similarly, dornase alfa, breaks down the very high concentrations of extracellular DNA that are found in the viscous pus containing sputum of people with cystic fibrosis, greatly reducing the viscous and elastic nature of the mucus and allowing it to be removed by coughing.

Should an infection develop, the most likely cause of the infection is a bacterium called Pseudomonas aeruginosa. Treatment usually involves the use of an antibiotic called tobramycin which is administered by a nebuliser, a special type of inhaler. Other antibiotics may be given intravenously if the infection becomes particularly serious.

In addition to these treatments, bronchodilators such as salbutamol, and inhaled steroids such as beclometasone are used to help make breathing easier. Children must also be vaccinated against influenza and pneumonia to reduce the risk of their catching these diseases and their developing a severe chest infection.

Lung transplantation is a form of treatment for some patients with cystic fibrosis, and is being performed in the UK and in other parts of the world in both children and adults. Lung transplantation is major surgery and therefore carries considerable risks. It is appropriate only for a patient who is severely ill and for whom all other forms of conventional treatment are no longer helpful. Not all patients at this stage of the disease are suitable for a transplant.

Growing up - One consequence of the improved management of cystic fibrosis is that the life expectancy of children is increasing and many will develop into adults. As the child gets older and matures, he or she will be transferred from a Paediatric Centre to an Adult Centre. A major difference between the Paediatric Centre and the Adult Centre is that the person affected by cystic fibrosis becomes more involved in decisions about care and treatment, whereas in the Paediatric Centre decisions are made for the child.

The Adult Centre has a multi-disciplinary team with experience of the long term management of cystic fibrosis who develop a partnership with the person helping him or her to balance the demands of health and treatment with their education, career and social life.

Excellent factsheets about making the transition from Paediatric Centres to Adult Centres are available from the Cystic Fibrosis Trust on: http://www.cftrust.org.uk/aboutcf/publications/factsheets/

Talk to your pharmacist if you need help on any of the medicines for cystic fibrosis that have been prescribed for your child. If you are not sure what the medicines are for or how to give them, your pharmacist will be able to help. The pancreatic enzymes are available in a variety of different forms and strengths and your pharmacist will be able to advise you how to add them to the child's meals. Your pharmacist will also be able to show you how to use any inhalers correctly.

Talk to your doctor or your Paediatric Centre if you have any concerns about your child's wellbeing. Remember to keep your child's vaccinations up to date and to have the influenza vaccination each year.

Cystic Fibrosis Trust

The Cystic Fibrosis Trust is the UK's only national charity dedicated to all aspects of cystic fibrosis. It funds research to treat and cure cystic fibrosis and aims to ensure appropriate clinical care and support for people with the condition.

Further information can be found on the website www.cftrust.org.uk. Help and advice for those affected by cystic fibrosis is available through the Helpline on 0845 859 1000. For all other inquiries the switchboard is 020 8464 7211.


Reviewed on 10/01/2010