Cystic fibrosis

Cystic fibrosis develops when a child inherits a faulty gene from both parents. This faulty gene makes it hard for some cells to move salt and water across the cell wall the way they should. Along with infections that keep coming back, this can lead to thick, sticky mucus building up in the tubes and passageways of the body, especially in the lungs and the digestive system.

For a child to be born with cystic fibrosis, they need to inherit two copies of this faulty gene, one from each parent. The parents themselves usually do not have the condition, because each of them carries only one faulty gene alongside one that works normally.

When both parents carry the faulty gene, each child they have carries a 25% chance of being born with cystic fibrosis.

Cystic fibrosis is present from birth. It is not something a person can catch from someone else who has it.

Most cases of cystic fibrosis are now picked up soon after birth through the newborn blood spot test.

This involves collecting a drop of blood from the baby's heel and testing it for signs that could point to cystic fibrosis.

More tests will be needed to confirm the diagnosis, such as:

• a sweat test, which measures the amount of salt in sweat, since the sweat of someone with cystic fibrosis has higher salt levels than normal
• a genetic test, where a sample of blood or saliva is checked for the faulty gene that causes cystic fibrosis

These tests can also be carried out in older children and adults with symptoms of cystic fibrosis who have not been screened before.

If cystic fibrosis runs in your family, you can be tested to find out if you are at risk of having a child with the condition, by checking if you carry the faulty gene that causes it.

Read more about how cystic fibrosis is diagnosed.

Diagnosing cystic fibrosis

Tests to diagnose cystic fibrosis can be carried out at any age.

Most cases are now found soon after birth through newborn screening, but older children and adults with symptoms of cystic fibrosis who were not screened can also be tested to check for the condition.

Tests to find out if you carry the faulty gene responsible for cystic fibrosis may also be recommended for some people.

Newborn screening

A newborn blood spot test is offered to all babies in Scotland to help catch problems early, including cystic fibrosis.

When your baby is five to eight days old, a health professional will prick their heel and collect a few drops of blood on a special card. The blood is then sent to a laboratory to be checked for signs that could point to cystic fibrosis.

You should get the results by the time your baby is six to eight weeks old. If a problem is found, you will be contacted sooner and asked to bring your baby to a hospital appointment.

The screening result is not 100% accurate, so more tests will be carried out to confirm the diagnosis. You, your partner, and any other children you have may also be tested to see if you carry the faulty gene that causes cystic fibrosis.

Confirming a diagnosis

Tests to confirm a diagnosis will be carried out if screening suggests your child may have cystic fibrosis, or if your doctor thinks you could have the condition and you have not been screened before.

Two main tests are used to diagnose cystic fibrosis:

• sweat test, which measures the amount of salt in sweat, since the sweat of someone with cystic fibrosis has higher salt levels than normal
• genetic test, where a sample of blood or saliva is checked for the faulty gene that causes cystic fibrosis

The sweat test is the one used most often, though genetic testing may be done if the sweat test result is unclear, or to pin down the exact genetic fault causing the condition.

Carrier testing

Testing to find out if you carry the faulty gene that causes cystic fibrosis can be useful if:

• you have a close relative, such as a child, sibling, or parent, who is a known carrier
• you have a close relative with cystic fibrosis
• your partner is known to carry the cystic fibrosis gene

This can be done with a blood test, or sometimes a special mouthwash, to collect a sample of cells. The sample is then sent to a laboratory to be checked for the faulty gene.

Finding out if you carry the faulty gene can help show if you are at risk of having a child with cystic fibrosis. A genetic counsellor will explain the test results to you and talk through what they mean, along with the options available for future pregnancies.

There is currently no cure for cystic fibrosis, but many treatments are available that help control symptoms, prevent or reduce complications, and make daily life easier. Some possible treatments include:

• antibiotics to prevent and treat chest infections
• medicines that make the mucus in the lungs thinner and easier to cough up
• medicines that widen the airways and reduce inflammation
• special techniques and devices that help clear mucus from the lungs
• medicines that help the body absorb food better
• a special diet, along with supplements, to help prevent malnutrition

If the lungs become badly damaged over time, a lung transplant may eventually be needed.

More about treating cystic fibrosis

There is currently no cure for cystic fibrosis, but with the right care it is possible to control symptoms, prevent or reduce complications, and make the condition much easier to live with.

A person with cystic fibrosis is usually supported by a team of healthcare professionals at a specialist cystic fibrosis centre, who will draw up a care plan suited to their individual needs. A range of treatments may be used, and sometimes a stay in hospital is needed too. Regular check up appointments to monitor the condition are also recommended.

Medicines for lung problems

People with cystic fibrosis often need several different medicines to treat and prevent lung problems. These may be swallowed, inhaled or given by injection. Some of the main ones are:

• antibiotics to prevent and treat chest infections
• medicines that thin the sticky mucus in the lungs, such as dornase alfa, hypertonic saline and mannitol dry powder
• a medicine called ivacaftor, which helps reduce mucus levels in the body, though it is only suitable for fewer than 1 in every 20 people (4%) with cystic fibrosis
• bronchodilators, which widen the airways and make breathing easier
• steroid medicine to treat nasal polyps (small growths inside the nose)

It is also important for people with cystic fibrosis to stay up to date with all routine vaccinations, and to have the flu jab every year once they are old enough for it.

Airway clearance techniques

Alongside medicines, special techniques can help keep the lungs and airways clear. A physiotherapist can guide you through these. The main ones include:

• active cycle of breathing techniques (ACBT), a sequence of relaxed breathing followed by deep breathing exercises and then huffing
• autogenic drainage, a series of gentle breathing techniques that help clear mucus from the lungs
• modified postural drainage, changing body position to make it easier to bring mucus up from the lungs
• airway clearance devices, handheld devices that use vibration and air pressure to help remove mucus from the airways, usually costing somewhere in the range of 45 to 60 pounds

Your care team can explain more about each of these techniques and help decide which suits you best.

Diet and nutrition

Getting the right nutrition is vital for people with cystic fibrosis, both for normal growth and to avoid becoming ill often. However, most people with cystic fibrosis struggle to digest food and absorb nutrients from infancy, and in some cases the pancreas becomes damaged over time, causing the same difficulty.

A dietitian can advise on how to avoid malnutrition, and may recommend:

• digestive enzyme capsules taken with all meals and snacks, with the number needed varying by person and by what is being eaten
• a special balanced diet high in calories, fat and protein
• vitamin and mineral supplements

Lung transplants

In severe cases, where the lungs stop working properly and other treatments no longer help, a lung transplant may be recommended. It is a serious operation with real risks, but it can greatly improve both the length and quality of life for someone with severe cystic fibrosis.

People with cystic fibrosis often do better than many other transplant patients, since they tend to be younger and in better general health otherwise. It is estimated that up to 9 out of 10 people survive for at least a year after the transplant. The Cystic Fibrosis Trust has more information on lung transplants for people with cystic fibrosis.

Treating related problems

Cystic fibrosis can bring other problems that also benefit from treatment. For example:

• regular exercise helps keep bones and joints healthy and is recommended for everyone with cystic fibrosis; most sports and activities are fine, but a physiotherapist can advise if you are unsure about a particular one
• bisphosphonate medicines can help treat weak, brittle bones that sometimes develop when a person does not get enough vitamin D and calcium from diet or supplements
• insulin treatment along with a special diet can help someone with cystic fibrosis related diabetes manage their blood sugar levels

Cystic fibrosis is a progressive illness, which means it usually worsens as time goes on.

In serious cases, it can eventually become fatal if it leads to a severe infection or if the lungs stop working the way they should.

The outlook for people with cystic fibrosis has improved a great deal in recent years thanks to advances in treatment, though most people with the condition still tend to have a shorter than average lifespan.

At present, around half of people with cystic fibrosis live past the age of 40, and children born with it today are likely to live even longer than that.

Lung problems

Cystic fibrosis causes thick, sticky mucus to build up and clog the lungs and airways. Over time this can lead to:

• repeated chest infections, since the mucus sitting in the lungs makes an ideal breeding ground for bacteria
• ongoing inflammation of the airways, which can cause them to widen abnormally (a condition called bronchiectasis)
• more frequent coughing
• occasional wheezing and breathlessness

As time passes, the lungs can become more and more damaged and may eventually stop functioning properly.

Digestive system problems

The mucus can also block parts of the digestive system, affecting how food moves through the gut and how well it is broken down and absorbed.

This can lead to:

• a serious blockage in the bowel within the first few days of life (known as meconium ileus), which usually needs surgery to clear
• jaundice
• diarrhoea, or stools that are unusually large or foul smelling
• trouble gaining weight and growing normally, since the body has difficulty digesting and absorbing nutrients (malnutrition)
• diabetes appearing from the late childhood or early adult years, which can develop if the pancreas becomes badly damaged

Other problems

People with cystic fibrosis may also face a number of other issues, including:

• sinusitis
• nasal polyps
• weak, thinning bones (osteoporosis), which can result from repeated infections, poor growth, low physical activity and malnutrition
• swelling and pain in the joints (arthritis or arthralgia), usually from late childhood onward
• difficulty having children, since most men with cystic fibrosis cannot father children naturally because the tubes carrying sperm do not develop as they should, though certain fertility treatments may still help; women with the condition are able to become pregnant
• liver problems, caused when the tiny bile ducts in the liver become blocked with mucus
• leaking of small amounts of urine, especially during coughing fits (known as stress incontinence)

How cystic fibrosis is inherited

Genes are inherited in pairs, one set from the mother and one from the father.

For a child to be born with cystic fibrosis, they must inherit a faulty copy of the gene from both parents.

This happens when both parents are carriers of the faulty gene. Being a carrier means a person does not have cystic fibrosis themselves, but they can pass the condition on to a child if their partner is also a carrier.

It is estimated that about 1 in every 25 people in the UK carries the faulty gene responsible for cystic fibrosis.

When both parents are carriers, for each child there is a:

• 25% chance the child will not inherit the faulty gene at all, and so will not have cystic fibrosis or be able to pass it on
• 50% chance the child will inherit just one copy of the faulty gene from one parent, making them a carrier
• 25% chance the child will inherit a faulty copy from both parents and will have cystic fibrosis

This pattern of inheritance is known as autosomal recessive inheritance.