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Cystic fibrosis

Page last reviewed: 13/07/2011

Cystic fibrosis is a common inherited disease. Thre are over 1100 people registered as having cystic fibrosis in Ireland.

Cystic fibrosis affects the internal organs, especially the lungs and digestive system. It causes them to become clogged with thick, sticky mucus. It is caused by a faulty gene that controls the movement of salt and water in and out of cells in the body. When cystic fibrosis occurs, too much salt and not enough water pass into the cells and turn the body's secretions, which normally act as a lubricant, into a thick mucus. This mucus clogs up many of the body's tubes, ducts and passageways so they cannot work properly. In the lungs, this leads to frequent and severe infections.

The faulty gene that causes cystic fibrosis is recessive. This means that you need two faulty genes (one from each parent) to inherit the disease. Around 1 in 19 people in Ireland are carriers of the cystic fibrosis gene. Carriers do not have the disease but their children may inherit it.

Cystic fibrosis causes recurrent chest infections, poor growth and related health problems, such as diabetes and infertility.


There is no cure for cystic fibrosis, but many treatments and therapies can make cystic fibrosis easier to live with.

It is difficult to predict life expectancy for people with cystic fibrosis as the condition affects everyone differently. According to statistics, around half of all people with cystic fibrosis can expect to live beyond the age of 38.

Genetic disorder

A genetic disorder is a disorder caused by a fault in the genes. It is usually hereditary (runs in the family).


A carrier is a person or animal that spreads an organism that causes disease but does not become ill themselves.

Page last reviewed: 13/07/2011

There is no cure for cystic fibrosis, but many treatments and therapies can make cystic fibrosis easier to live with.

It is difficult to predict life expectancy for people with cystic fibrosis as the condition affects everyone differently. According to statistics, around half of all people with cystic fibrosis can expect to live beyond the age of 38.


When a child is born with cystic fibrosis, symptoms usually appear in the first year of life, although occasionally they can develop later.

The thick sticky mucus in the body affects a number of organs, particularly the lungs and digestive system.

The symptoms and related problems of cystic fibrosis can vary in severity from person to person.

The main symptoms and problems are detailed below.


It is common for people with cystic fibrosis to have difficulties such as:

  • Cough and wheeze. The body tries to shift the thick mucus in the lungs by coughing it up
  • Recurring chest and lung infections. Infections are caused by the continual build-up of mucus in the lungs, which provides an ideal breeding ground for bacteria

Cross infection

People with cystic fibrosis are vulnerable to harmful lung infections caused by certain strains of bacteria (these bacteria are rarely harmful to people without cystic fibrosis).

Two strains of bacteria that commonly infect people with cystic fibrosis are Pseudomonas aeruginosa and Burkholderia cepacia complex. They multiply in the thick mucus inside the lungs and may cause serious health problems, such as repeated chest infections. The danger is that a person with cystic fibrosis who has such an infection can easily pass it on to another person with cystic fibrosis through close personal contact or by coughing near them. This is known as cross-infection.

As more and more people with cystic fibrosis become infected with these bacteria, the bacteria may become resistant to antibiotic treatment, which is why cross-infection is such a problem.

There is a concern that people with cystic fibrosis are more likely to pick up strains from each other than from the environment. For this reason, it is recommended that people with cystic fibrosis do not come into close contact with each other. Patients infected with these dangerous bacteria may be treated in separate clinics to those without the bacteria, to avoid cross-infection.

Digestive system

Cystic fibrosis can also cause mucus to block the ducts in the pancreas. The pancreas produces essential food-digesting enzymes. When it is blocked, not enough of the enzymes reach the intestines (bowel) to help break down food, which can cause:

  • Large, smelly stools. If the digestive enzymes are not being produced, food is not adequately digested and excess fat is lost in the stools, making them bulky, oily, smelly and difficult to flush away.
  • Malnutrition. Because the body cannot digest essential nutrients in food (particularly fat), it is often difficult to gain weight and infants may struggle to put on weight and grow. Adults with cystic fibrosis often find it difficult to gain and maintain weight. In children with cystic fibrosis, this can result in delayed puberty if they are severely underweight.
  • Diabetes. In older people with cystic fibrosis, the pancreas can become more damaged. Diabetes can develop if the pancreas does not produce enough insulin, a hormone that controls the level of sugar in the blood. Diabetes in people with cystic fibrosis is different from diabetes in people without cystic fibrosis. Usually, the symptoms of diabetes include feeling constantly thirsty, frequently needing to pass urine and feeling extremely tired. These rarely occur in patients with cystic fibrosis. People with cystic fibrosis who develop diabetes may find it difficult to gain weight or may lose weight and see a decline in their lung function. Cystic fibrosis-related diabetes is usually controlled by regular injections of insulin. Diabetes rarely occurs in children with cystic fibrosis.

Ears, nose and sinuses

People with cystic fibrosis can be prone to sinusitis and hay fever, which may need to be treated with nasal sprays or antibiotics. Some older children and adults develop nasal polyps, which are fleshy swellings that grow from the lining of the nose or sinuses. If they become troublesome, they may need to be removed.

Bones and joints

Some older children with cystic fibrosis develop a form of arthritis (swelling and pain of the joints), usually in one or two large joints such as the knee. In most cases, symptoms improve with time and treatment.

Older children and adults may also be prone to osteoporosis (thin brittle bones) for many reasons, including repeated infection, poor growth or weight, lack of physical activity and lack of vitamins and minerals due to digestive problems. People with cystic fibrosis are more at risk of developing osteoporosis if they are taking steroids to help with lung infections.

Osteoporosis as a result of cystic fibrosis may cause joint pain and bones may fracture (break) more easily. Some people need to take drugs called bisphosphonates to help maintain their bone density.


Both men and women with cystic fibrosis can have problems conceiving children.

In virtually all men with cystic fibrosis, the tubes that carry sperm do not develop correctly, making them infertile. Women with cystic fibrosis may find that their menstrual cycle becomes absent or irregular if they are underweight. There is also an increased thickness of cervical mucus, which may reduce fertility. However, most women with cystic fibrosis can become pregnant without any difficulty.


In a few people with cystic fibrosis, the tiny bile ducts in the liver can become blocked by mucus. This can be serious as the disease progresses, and in some cases it may be necessary to have a liver transplant.


People with cystic fibrosis, especially females, are more likely to have incontinence. Urine usually leaks during coughing fits. It is important that people with cystic fibrosis are asked about this and encouraged to talk to a member of their cystic fibrosis team as soon as possible so they can get help.

Enzymes are proteins that speed up and control chemical reactions, such as digestion, in the body.
The liver is the largest organ in the body. Its main jobs are to secrete bile (to help digestion), detoxify the blood and change food into energy.
Stool (also known as faeces) is the solid waste matter that is passed from the body as a bowel movement.

Meconium ileus

One baby in ten with cystic fibrosis is born with a serious bowel obstruction, known as meconium ileus. This can make them very ill in their first few days.

All babies are born with meconium in their bowels. This is a thick, black substance that is normally passed out of the body a day or two after the birth.

However, in some babies with cystic fibrosis, the meconium is too thick to be passed through the bowels and causes a blockage. If a baby is born with meconium ileus, an operation to remove the blockage will probably be required.

Page last reviewed: 13/07/2011

Cystic fibrosis is an inherited condition. It is caused by a faulty gene that allows too much salt and not enough water into cells. This results in a build-up of thick, sticky mucus in the body's tubes and passageways. These blockages damage the lungs, digestive system and other organs, resulting in inflammation (swelling) and, in the lungs, repeated infections.

A child born with cystic fibrosis will have inherited the faulty gene from both their mother and father. In Ireland1 person in every 19 carries the faulty gene for cystic fibrosis, which is why it is so common. A carrier can be completely healthy and have no symptoms of cystic fibrosis.

If two carriers of the faulty gene have a baby, there is:

  • a one-in-four chance that the child will not inherit either of the faulty genes (the child will not have cystic fibrosis and will not be a carrier of the condition)
  • a one-in-two chance that the child will inherit one copy of the faulty gene from either their father or mother (the child will not have cystic fibrosis but will be a carrier of the condition)
  • a one-in-four chance that the child will inherit both copies of the faulty gene (the child will have cystic fibrosis)
Chromosomes are the parts of a body cell that carry genes. A human cell usually has 23 pairs of chromosomes.
Genes contain information that you inherit from your parents, such as eye or hair colour. They are carried by chromosomes.

Page last reviewed: 13/07/2011

Most cases of cystic fibrosis are now diagnosed through screening tests, which are carried out very early in life. However, some babies, children and even young adults are diagnosed later following unexplained illness.

There are four main ways of diagnosing cystic fibrosis:

  • newborn testing
  • antenatal testing
  • carrier testing
  • sweat testing

Newborn screening

Babies are screened for cystic fibrosis at birth as part of the newborn screening programme.

A small amount of the baby's blood is taken by a heel prick and transferred onto a card. The blood sample on the card is then analysed in the laboratory for cystic fibrosis and other inherited conditions, such as sickle cell anaemia and phenylketonuria.

The sooner cystic fibrosis is diagnosed, the sooner treatment can begin and the better the outlook.

For more information on the newborn screening programme, see the HSE Newborn Screening Centre website.

Antenatal testing

A test can be done on a woman when she is pregnant to see if her unborn baby has cystic fibrosis. This can be carried out from 10 weeks of pregnancy.

The test uses chorionic villus sampling (CVS), where a fine needle is passed through the abdomen into the womb. Sometimes, a fine tube is passed through the vagina into the cervix (neck of the womb) instead. A tiny piece of the developing placenta, known as the chorionic tissue, is taken and the chromosomes in the cells of the tissue are examined for the faulty gene that causes cystic fibrosis.

Antenatal testing for cystic fibrosis is usually only offered to mothers who are thought to be at high risk of having a child with the disease.

Carrier testing

There is a simple test that uses a mouthwash to identify whether a person is a carrier of cystic fibrosis. Swishing the mouthwash collects a sample of cells from the mouth. This sample is then sent to a laboratory and the cells it contains are checked for the faulty cystic fibrosis gene. It is important to have this test if the person's partner is a known carrier, or if someone in the family has cystic fibrosis or knows that they carry it.

Sweat test

If someone has cystic fibrosis, their sweat will have higher levels of salt than normal. A parent may first notice their child's symptoms of cystic fibrosis when they kiss them, as their skin can taste salty.

A sweat test measures the amount of salt in sweat. It is usually done by applying a very weak and painless electric current to a small area of skin to which pilocarpine has been applied. This causes that area of skin to sweat. A sample of the sweat is then collected and analysed. If the salt content in the sweat is abnormally high, this confirms cystic fibrosis.

A sweat test may be carried out if:

  • newborn screening tests are abnormal
  • a child has symptoms of cystic fibrosis
  • a child is born with a serious bowel obstruction known as meconium ileus
  • a child or adult has symptoms suggestive of cystic fibrosis

Genetic testing

A genetic test checks for the faulty cystic fibrosis gene by either analysing a saliva sample taken from inside the cheek using a swab or a blood sample. It can be useful to confirm cystic fibrosis if a sweat test gives a borderline result. It can also be useful to find out which members of a family are carriers of the cystic fibrosis gene.

Blood test
During a blood test, a sample of blood is taken from a vein using a needle, so it can be examined in a laboratory.
Chorionic villus sampling
Chorionic villus sampling is a test during pregnancy to see if there are any genetic problems with the foetus. A small sample of tissue is taken from the placenta.
Counselling is guided discussion with an independent, trained person to help you find your own answers to a problem or issue.
Genes contain information that you inherit from your parents, such as eye or hair colour. They are carried by chromosomes.
Genetic is a term that refers to genes, the characteristics inherited from a parent.
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

People with cystic fibrosis should be treated with help and advice from a team of healthcare professionals at a cystic fibrosis centre. With regular visits, the patient or parent can learn how to best manage the condition. As each case is different, they can receive tailored care for their or their child's condition.

There is no cure for cystic fibrosis. The aim of treatment is to ease the symptoms and make the condition easier to live with. It can also prevent or reduce the long-term damage caused by infections and other complications.

The different types of treatment for cystic fibrosis are detailed below.


Medical treatments for cystic fibrosis can help clear and control infections in the lungs and digestive system. They can also be used to treat some of the other health problems related to cystic fibrosis.

Lungs and airways

  • Bronchodilator drugs are inhaled to help the person breathe more easily. They are used for asthma and relax the muscles that surround the airways in your lungs, helping them to open up.
  • Antibiotics are taken to fight infections in the lungs. They can be taken by mouth as pills or suspensions, be inhaled through a nebuliser (a device that turns drugs into a mist that can be breathed in), or they may be given intravenously (through a tube into a vein) if the infection is more severe. All young children diagnosed with cystic fibrosis will be started on a course of oral antibiotics to protect them from certain bacteria, which will be continued until they are three years of age.
  • Steroids reduce the swelling of the airways, which can help with breathing. Steroid nasal drops and sprays can also be used to treat nasal polyps (small growths inside the nostrils).
  • DNase is an enzyme, usually inhaled, which helps to thin and break down the sticky mucus in the lungs so it is easier to cough up.

Digestive system

  • Pancreatic enzymes should be taken before and during every meal and fat-containing snack or drink. They help the digestive system break down food so that it can be digested and absorbed. The number of enzyme capsules taken needs to be adjusted depending on the amount of fat in the meal, snack or drink. The enzymes should be taken with the meal and the timing may vary depending on the age of the person with cystic fibrosis. It is essential that people with cystic fibrosis receive advice about enzymes from a specialist cystic fibrosis dietitian.
  • Fat-soluble vitamin supplements (A, D, E and K) are taken to help replace lost vitamins and to prevent deficiencies. Because people with cystic fibrosis lose fat in their stools, they also lose the fat-soluble vitamins. 
  • Nutritional supplements can help compensate for poor digestion and give additional energy and nutrients.
  • Insulin. People who have diabetes as a result of their cystic fibrosis will need to take insulin and manage their diet to stabilise blood sugar levels. The dietary advice usually given to people with diabetes who do not have cystic fibrosis does not apply to most people with cystic fibrosis-related diabetes.

Other medicines

  • Bisphosphonates can be taken to treat osteoporosis (weak and brittle bones), which can occur as a result of cystic fibrosis. Bisphosphonates help maintain bone density and reduce the risk of fractures.
  • Vaccinations and flu jabs. It is particularly important that people with cystic fibrosis are up to date with all the required vaccinations. People with cystic fibrosis should make sure they have an annual flu jab, as they are more susceptible to complications as a result of infection.


The management of cystic fibrosis with physiotherapy differs for each person with the condition, and is specifically tailored to their needs.

Traditionally, physiotherapy for cystic fibrosis focussed mainly on airway clearance (clearing mucus from the lungs). This still makes up a large part of daily treatment, but the role of the physiotherapist in cystic fibrosis has expanded to include daily exercise, inhalation therapy, posture awareness and, for some, the management of incontinence.

There are many airway clearance techniques. A specialist cystic fibrosis physiotherapist will assess a person with cystic fibrosis and recommend the most appropriate technique to use. The technique may change as the person gets older or as their disease changes.

Airway clearance

Some airway clearance techniques are done without any equipment and focus on specific breathing exercises, such as:

  • active cycle of breathing techniques (ACBT)
  • autogenic drainage

Other techniques use a device to help with the clearance of mucus. The devices use positive pressure to hold open the airways. Some also create vibrations in the airways. Techniques include:

  • positive expiratory pressure (PEP)
  • oscillating positive expiratory pressure 

Some techniques use large pieces of equipment, which can be very expensive and are usually only available for use in a hospital, such as:

  • high frequency chest wall oscillation (HFCWO), where an electric air compressor connects to an inflatable jacket (vest) to vibrate the chest

A physiotherapist will advise on the most appropriate technique to use and also on the length and frequency of treatment sessions. 

Daily physiotherapy is usually required and, if the person with cystic fibrosis has a chest infection, they may need to increase the amount of airway clearance they do.

To encourage independence, older children and adults should use a technique that they can do by themselves and not need help with.

Lung transplants

In severe cases of cystic fibrosis, when the lungs stop working properly and all medical treatments have failed to help, a lung transplant may be recommended.

Both lungs need to be transplanted as they will both be affected by the condition. A lung transplant is a serious operation that carries certain risks, but it can greatly improve the length and quality of life for people with severe cystic fibrosis.

Lung transplantation for cystic fibrosis has a good success rate: 70% of patients survive one or two years after transplantation and the longest surviving patients had their transplant operation over 15 years ago.  See Health A-Z: lung transplant for more information.

Antibiotics are medicines that can be used to treat infections caused by micro-organisms, usually bacteria or fungi. Examples of antibiotics include amoxicillin, streptomycin and erythromycin.
Bronchodilator medicines are used to widen the airways of the lungs to help with breathing difficulties. An example is salbutamol.
Enzymes are proteins that speed up and control chemical reactions, such as digestion, in the body.
Genes contain information that you inherit from your parents, such as eye or hair colour. They are carried by chromosomes.
The heart is a muscular organ that pumps blood around the body.
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.
Lungs are a pair of organs in the chest that control breathing. They remove carbon dioxide from the blood and replace it with oxygen.
Physiotherapy is a treatment that uses physical movements, massage and exercise to relieve illness or injury.

Page last reviewed: 13/07/2011

The symptoms of cystic fibrosis can be considerably relieved through diet and exercise, with guidance from staff at a specialist cystic fibrosis centre. 


For people with cystic fibrosis, getting the right nutrition is vital. A healthy body weight is necessary to help fight off infections, and it is important that there is enough reserve energy to rely on when the person is ill.

Cystic fibrosis causes mucus to build up and block the small channels that carry digestive juices and enzymes. Over time, this causes the pancreas to become damaged. The effect of cystic fibrosis on the pancreas varies from person to person, but most people have to take digestive enzymes from birth to help them digest food and get the nutrients they need.

The diet of someone with cystic fibrosis should be high in calories, as they will not be able to digest all the food they eat.

A special diet should start as soon as cystic fibrosis is diagnosed, which will need to be adapted as people get older.

Babies with cystic fibrosis

Babies with cystic fibrosis may be breastfed as usual, otherwise most baby milks and formulas will be suitable. In some cases, if the baby is not gaining enough weight, a high-energy formula may be needed or nutritional supplements added to milk feeds to give the baby more calories (energy). The parent should ask a dietitian at their cystic fibrosis centre if they are unsure about this.

Before a baby moves onto solid foods, they may need extra salt as both breast milk and baby milk are very low in salt. Cystic fibrosis makes sweat five times saltier, and more salt than normal is lost through skin. If the baby needs extra salt, the dietitian or doctor at the cystic fibrosis centre will advise on the appropriate amount and prescribe a salt solution. A parent should never add salt to their baby's food or drink without specific advice from their cystic fibrosis specialists.

A parent can feed their baby any normal solid baby foods, but they will need vitamin supplements to compensate for the loss of vitamins A, D, E and K in their stools. These are available in two liquid preparations. Vitamins A and D are usually combined in one, and there is usually a separate one for vitamin E. Vitamin K is now prescribed by many doctors.

A baby with cystic fibrosis will also need pancreatic enzymes to help them digest food. These take the place of the food-digesting enzymes missing from their digestive system. They usually come in the form of microspheres or minimicrospheres (granules), which can be mixed with a little formula, expressed breast milk or fruit puree and spoon fed ideally at the start, during and after the feed. The granules should never be given dry as they can be a choking hazard. A dietitian can advise on the amount to use and the most suitable way to give the enzymes.

Children with cystic fibrosis

Children who have cystic fibrosis should eat a varied diet, but they should also eat a large amount of protein and calories. They should eat plenty of protein such as meat, fish and eggs, as well as starchy foods like bread and pasta. If a child's appetite is poor, give them food little and often, and offer snacks in between meals. Children who find it particularly hard to gain weight can be given dietary supplements in the form of milk shakes or fruit juices. You can talk to a cystic fibrosis dietitian about these.

Like babies, children with cystic fibrosis will need to continue taking vitamin A, D, E and K supplements to compensate for the vitamins they lose.

Children also need to continue taking pancreatic enzymes with all fat-containing meals, snacks and drinks. The capsules should be taken before and during the meal and the number of capsules will vary depending on the fat content of the meal. Enzymes can be taken in easy-to-swallow capsules. 

A dietitian may recommend salt supplements for a child with cystic fibrosis, especially in hot weather or if they are going on holiday to a country with a warm climate, where sweating may cause a loss of salt.

Children with cystic fibrosis may eat more sugary foods than normal due to their high-calorie diet, so it is important to make sure they brush their teeth properly and visit the dentist regularly.

If a child cannot gain enough weight and dietary supplements have not helped, they may need to be tube fed. This will usually be either nasogastric (the tube is inserted through the nose and goes down to the stomach), or gastrostomy (the tube is inserted directly into the stomach). The other end of the tube is attached to a bag of high-calorie/nutrient food that is delivered straight to the stomach, usually while the child sleeps.

Adults with cystic fibrosis

Adults who have cystic fibrosis do not need to avoid any particular food, but it is important they have a diet high in protein and energy to maintain their weight. They should eat regular meals and snacks as this helps to maintain energy intake. They should eat three meals a day, including plenty of meat, fish and eggs, and eat several high-calorie snacks in between.

If someone with cystic fibrosis wants to be a vegetarian, they should talk to their dietitian about alternatives to meat. A vegan diet is not advised for people with cystic fibrosis as it tends to be especially low in energy.

Most adults with cystic fibrosis need to continue taking pancreatic enzymes with all fat-containing meals, snacks and drinks. The capsules should be taken before and during the meal and the number of capsules will vary depending on the fat content of the meal. There are different types and strengths so talking to the cystic fibrosis specialist team will help the person find one that suits them. Creon is the usual preparation used in Ireland. People with cystic fibrosis should not stop taking pancreatic enzymes unless they are told to do so by their dietitian or doctor, as this can lead to a serious blockage of the bowel.

Most adults need to continue taking vitamin A, D, E and K supplements. These come in the form of prescribed multivitamin tablets.

People with cystic fibrosis who lose a lot of weight due to an infection or illness may need to be tube fed to help them gain weight. As in tube feeding for children, this will be either nasogastric or gastrostomy, depending on how long the tube must stay in for. A gastrostomy tube (which is inserted directly into the stomach) is best for longer periods of time or repeated courses of treatment as it is unlikely to be dislodged during coughing or physiotherapy.


Exercise is recommended for everyone with cystic fibrosis. This may vary from taking part in normal school activities to individualised exercise programmes. Infants and toddlers with cystic fibrosis should have some exercise included in their normal daily routine. Any sport or exercise that gets a person with cystic fibrosis moving is good, but if there are any concerns or worries, they should ask their physiotherapist.

Children and adults are also encouraged to include stretching exercises into their routine to mobilise the joints and muscles around their chest, back and shoulders, and to be aware of maintaining good posture.

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

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