Cystic Fibrosis

Overview

Cystic fibrosis (CF) is an inherited condition that affects how the body makes mucus, sweat and digestive juices. In CF, these fluids become thick and sticky instead of thin and slippery. Sticky mucus builds up in the lungs and makes it harder to breathe and easier for infections to take hold. It can also block tubes in the digestive system, so the body struggles to break down food and get the nutrients it needs. CF is present from birth and lasts a lifetime, but modern care helps people with CF live full, active lives.

CF is uncommon but not rare. Around 1 in 2,500 babies in the UK is born with it, and about 1 in 25 people carries one changed copy of the CF gene without having any symptoms. Because carriers are so common, CF can appear in families with no history of the condition.

CF affects people of all ethnic backgrounds, though it is most common in people of white European descent. It is usually found in babies, either through newborn screening or because of early symptoms. Both boys and girls are affected equally.

Symptoms

Common symptoms

• A cough that does not go away, often bringing up thick, sticky mucus
• Chest infections that keep coming back or are hard to clear
• Wheezing or a tight chest
• Getting out of breath more easily than other people, especially with exercise
• Salty-tasting skin — parents sometimes notice this when kissing their child
• Finding it hard to put on weight, even with a good appetite
• Frequent, oily or greasy stools that are hard to flush away
• Tummy pain, bloating and wind
• Feeling very tired or low on energy
• A blocked or runny nose, or repeated sinus problems
• The ends of the fingers becoming rounder and wider (called clubbing)

Symptoms in children

• Slow weight gain or growth, or dropping to a lower growth line than expected
• Loose, oily stools from early life, sometimes very frequent
• A bowel blockage in the first days of life (meconium ileus), which shows as a swollen tummy and no poo
• Chest infections that keep coming back
• A salty taste when the skin is kissed
• Being smaller or lighter than other children of the same age
• Puberty starting later than usual

Symptoms in older adults

• Breathlessness that slowly gets worse over time
• More frequent flare-ups of chest infection
• A cough that brings up mucus most days
• Tiredness that affects work or daily life
• Bone thinning (osteoporosis), which raises the risk of fractures
• A type of diabetes that is linked to CF
• Liver problems that are often found on routine tests
• Fertility difficulties — many men with CF cannot father children naturally, and some women need help to conceive

Causes

Main causes

• CF is caused by a change in the CFTR gene. This gene gives the body instructions for making a protein that controls the movement of salt and water in and out of cells.
• When the CFTR gene is changed, salt and water do not move properly. Mucus, sweat and digestive juices become thick and sticky instead of thin and slippery.
• CF is inherited in a pattern called autosomal recessive. This means a child must receive a changed copy of the gene from both parents to have CF.
• Parents who each carry one changed copy are called carriers. Carriers usually have no symptoms at all and often do not know they carry the gene.

Risk factors

• Both parents being carriers of a changed CFTR gene — each pregnancy then has a 1 in 4 chance of the baby having CF
• A family history of CF or of known CF gene carriers
• Parents who are closely related by blood, which makes it more likely that both carry the same rare gene change
• Being of white European descent, where the gene change is more common — but CF can affect anyone

When to see a doctor

See a doctor urgently if:

• A baby or child who is not gaining weight or is losing weight
• Frequent or ongoing chest infections, or a cough that will not go away
• Loose, oily stools that happen often and are hard to flush
• A newborn who has not passed their first poo within the first day or two, or who has a swollen tummy and is vomiting
• Skin that tastes very salty when kissed
• Any sudden worsening of breathing, or coughing up blood

Book a routine appointment if:

• You are planning a pregnancy and want to know about your risk of having a child with CF
• Someone in your family has CF or is known to carry the CF gene, and you would like advice
• You have questions about newborn screening results
• You want to talk through family planning options with a genetics service

Diagnosis

In the UK, every baby is offered a newborn blood spot test (the heel prick test), usually around 5 days old, which includes a check for CF. If that test suggests CF, or if a child or adult has symptoms, the next step is usually a sweat test. This measures how much salt is in the sweat. A genetic test can confirm the diagnosis by looking for changes in the CFTR gene. Diagnosis is made by a specialist CF team.

Tests that may be done

• Newborn blood spot screening (heel prick test), offered to all babies
• Sweat test — a small patch on the arm or leg collects sweat, which is then measured for salt. It is painless and takes about an hour
• Genetic (DNA) test using a blood or saliva sample to look for CFTR gene changes
• Stool tests to see how well the pancreas and digestion are working
• Lung function tests, where you breathe into a machine to measure how well your lungs work
• Chest X-rays or scans to look at the lungs
• Sputum (mucus) samples to check for infection
• Blood tests to check vitamin levels, blood sugar and liver function

What to expect at your appointment

Being told that you or your child may have CF can feel frightening. The tests themselves are quick and mostly painless, but waiting for results can be hard. You will usually be seen by a specialist CF team who will explain each step. If CF is confirmed, they will talk you through what it means, what treatment involves, and what support is available. You are always welcome to bring someone with you, write down questions beforehand, and ask for things to be repeated.

Treatment

CF is managed by a specialist team, usually at a CF centre, with regular check-ups. Treatment aims to keep the lungs clear, help the body absorb food properly, and prevent and treat infections early. Most of the day-to-day work happens at home, with a routine that is built around school, work and family life. Your team will tailor a plan to you or your child, and it will change over time as needs change.

Self-care at home

• Do airway clearance physiotherapy every day, as taught by your physiotherapist — this helps shift mucus out of the lungs
• Take prescribed medicines exactly as your team advises, including those taken with meals and snacks to help digestion
• Keep active — regular exercise helps clear the lungs and supports general health
• Eat a high-calorie, high-protein diet, and add extra salt in hot weather or after heavy exercise if your team advises it
• Stay away from cigarette smoke, vaping and other lung irritants
• Wash hands often and follow your team's advice on avoiding people who are unwell with infections
• Keep up with routine check-ups, even when you feel well
• Clean and store physiotherapy and nebuliser equipment as instructed

Medical treatments

Treatment usually combines several approaches. Physiotherapy and special breathing devices help clear mucus from the lungs. Inhaled medicines help thin mucus, open the airways or reduce inflammation. Antibiotics are used to treat chest infections, sometimes at home and sometimes in hospital, and some people take them regularly to prevent flare-ups. Because thick mucus blocks the release of digestive enzymes, most people take enzyme capsules with every meal and snack so the body can absorb food, along with extra vitamins. Some people benefit from newer medicines that target the underlying cause of CF, but these only work for certain gene changes, so your team will tell you whether they are suitable. Some people are offered extra oxygen or help with breathing. Your CF team will explain exactly what is being recommended and why, and will review it regularly.

When is surgery considered?

Surgery is not routine in CF, but it can help in some situations. Lung transplant may be considered if the lungs are severely damaged despite treatment. Some people need surgery on the sinuses for persistent sinus problems, or an operation for a bowel blockage. Your team will discuss benefits and risks in detail if surgery is ever suggested.

Living with this condition

Living with CF means building a routine around treatment. Most days include physiotherapy, medicines with meals, and often inhaled treatments. It can feel like a lot, especially at first. Many families find a rhythm that works — for example, doing physiotherapy while watching a favourite programme, or linking medicines to mealtimes. Your CF team can help you fit treatment around school, work, travel and hobbies, and can adjust plans when life gets busy.

Lifestyle tips

• Keep up regular exercise you enjoy — walking, swimming, cycling or team sports all help
• Avoid smoking and vaping, and keep your home smoke-free
• Stay up to date with recommended vaccinations — ask your team which ones are right for you
• Plan travel ahead: carry enough medicines in hand luggage and ask your team for a letter about your equipment
• Tell your team about any new hobbies or jobs that involve dust, fumes or heavy physical work
• Get enough sleep, and pace yourself during flare-ups
• Stay connected with friends and interests — CF should be part of your life, not all of it

Diet and exercise

People with CF usually need more calories and protein than others because the body uses energy differently and some food is not fully absorbed. A dietitian on your team can give practical advice — often this means larger portions, nourishing snacks, and adding cream, cheese or healthy oils where you can. Extra salt may be needed, particularly in hot weather or after exercise. Enzyme capsules taken with food help your body absorb what you eat, so it is important to take them with every meal and snack. Exercise is one of the most useful things you can do: it helps clear mucus, strengthens breathing muscles, builds strong bones and lifts mood. Any activity counts, and your physiotherapist can help you find something that suits you.

Mental health and emotional wellbeing

Living with a long-term condition like CF can affect how you feel. Many people experience worry, low mood, frustration or tiredness from the constant demands of treatment, and this is completely understandable. Children may feel different from their peers, and parents and partners often carry their own stress. These feelings are common and treatable. Talking to your CF team is a good first step — they can offer counselling or connect you with psychological support. If you or someone you care for ever feels unable to cope, or has thoughts of harming themselves, contact your local emergency number or a crisis support service straight away. You do not have to manage alone.

Prevention

CF cannot be prevented once a child has inherited the gene changes that cause it, and nothing a parent does or does not do during pregnancy causes it. What can be done is to understand the risk before pregnancy. If you have a family history of CF, or you know you or your partner carry a changed CF gene, a genetics service can explain your options. These conversations are private, non-judgemental and can happen at any stage.

Vaccines

Vaccinations are an important part of staying well with CF. Your CF team will usually recommend routine childhood vaccinations plus yearly flu vaccination, and vaccinations against common lung infections such as pneumococcal disease. COVID-19 vaccination is also generally advised. Ask your team which vaccinations are right for you or your child, and when.

Screening programmes

In the UK, all babies are offered newborn blood spot screening, which includes a check for CF. This means most cases are found before symptoms appear, allowing treatment to start early. If you are planning a pregnancy and have a family history of CF, you can ask your GP or a genetics service about carrier testing. Some countries offer similar newborn screening programmes; ask your local health service what is available.

Complications

If left untreated

• Repeated chest infections that damage the lungs over time
• Bronchiectasis — where the airways become widened and scarred, making mucus harder to clear
• A collapsed lung (pneumothorax) or coughing up blood from damaged airways
• Poor growth and malnutrition because the body cannot absorb enough nutrients
• Bowel problems, including blockages and severe constipation
• CF-related diabetes, liver disease and bone thinning
• Fertility problems, particularly in men
• Increasing breathlessness that limits daily activities

Long-term outlook

The outlook for people with CF has improved enormously over the past few decades. Better physiotherapy, earlier treatment of infection, nutritional care and newer medicines mean that many people now live well into adulthood, with careers, relationships and families. Everyone's course is different, and your CF team can give you a realistic picture for your own situation. Research into CF continues at pace, and new treatments are being developed. It is reasonable to feel hopeful.

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