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About Cystic Fibrosis

In this section, you or a loved one can find out more about medical treatments, research studies and practical information about cystic fibrosis. Read on to find answers to some of your questions as well as links to other information. Being informed is an important first step towards becoming an active decision-maker in your care plan.

What Is Cystic Fibrosis?

Cystic fibrosis is an inherited disease that causes blockage of tubes or passageways in several organs, especially the lungs and digestive system.

Cystic fibrosis affects the cells that keep mucus and digestive juices thin and slippery. People with cystic fibrosis have defective genes that cause secretions to become thick and sticky. Instead of acting as a lubricant, the secretions plug up tubes, ducts and passageways in the lungs, sinuses, pancreas, liver, intestines and reproductive system. The two major consequences in most people with cystic fibrosis are poor digestion and worsening lung disease over time. The symptoms and severity of cystic fibrosis can vary widely from person to person.

What Causes Cystic Fibrosis?

Tiny channels located in the surface of many cells keep a healthy balance of salt and water across membranes in the body. These channels are called “CFTR”, which is short for Cystic Fibrosis Transmembrane conductance Regulator. In order to have cystic fibrosis, a person must have two defective CFTR genes (one from each parent) that result in the absence or poor function of the CFTR channels, leading to dehydration of secretions and high salt levels in sweat. In the lungs, thick, sticky mucus clogs the airways and traps germs, which leads to repeated infections, extensive lung damage and eventually, respiratory failure. Blockage of the ducts in the pancreas by mucus prevents the release of digestive enzymes to the intestines that allow the body to break down food and absorb vital nutrients, which results in poor nutrition if untreated. The enzymes that are retained cause damage to the pancreas itself.

How common is cystic fibrosis?

Cystic fibrosis is relatively uncommon, affecting about 1 in 2 500 babies born in the UK and >75,000 people worldwide. In the past, cystic fibrosis was considered a “childhood disease”, but with centralised care and improved survival, there are as many adults with cystic fibrosis as there are children. It is most common in Caucasians, although it can be found in every race. It is seen more in North America, Western Europe and Australia, and seen infrequently in Asia or Africa.

How Does One Test for Cystic Fibrosis?

A variety of tests are used to diagnose cystic fibrosis.

  • Newborn Screening test: A blood test is carried out to find out whether a newborn has cystic fibrosis. A positive blood screen is then followed by other tests that confirm the diagnosis. In recent years, newborn screening has become standard in most countries where cystic fibrosis is more common. 
  • Sweat Test: In the past, sweat testing plus the presence of symptoms or family history was the primary method of diagnosis. This test measures the amount of salt in the sweat. Sweat is collected from the person's forearm and the chloride levels are measured. High salt levels confirm the diagnosis of cystic fibrosis. Sweat tests should be done only in labs that perform the test routinely and according to standard guidelines.
  • Gene testing: Either blood or cells from a cheek swab can be tested for mutations in the CFTR gene. There are over 2000 identified CFTR mutations, but most of them are extremely rare. Gene panels that test for the most common 20-50 mutations are relatively fast and inexpensive. If there is any doubt about a diagnosis, gene sequencing can be performed.
How Does Cystic Fibrosis Affect the Body?

Cystic fibrosis can affect many parts of the body, including the lungs, pancreas, liver, intestines, sinuses, reproductive system and sweat glands. Cystic fibrosis is a complex disease and the types and severity of symptoms can differ widely from person to person. Many different factors, including age, gender, gene type and environment can affect an individual's health and the course of the disease.

  • Lungs: The lungs are commonly affected in cystic fibrosis. The thick, dehydrated mucus in the airways obstruct the passages and create a place for germs to grow and cause infection. These recurrent infections are associated with high levels of inflammation, which causes progressive damage to the airways, called “bronchiectasis”. Symptoms include cough, production of sputum, wheezing, chest pain or tightness, and shortness of breath. Complications in a small number of adolescents and adults include coughing up blood (haemoptysis) and pneumothorax (abnormal collection of air between the lung and inside chest wall, due to popping of a lung bleb – a blister like air pocket). Over time, cystic fibrosis can damage lungs so badly that they no longer function. It eventually can become life-threatening, with some people choosing to get a lung transplant.
  • Sinuses : The sinuses, like the lungs, become filled with thick mucus in people with CF, trapping germs and causing inflammation and sinus infections. Nasal inflammation can lead to fleshy growths called polyps in the nose. Symptoms include headache, nasal congestion and snoring.
  • Pancreas: The normal pancreas releases digestive enzymes and juices that are necessary to break down food into the small intestine. In cystic fibrosis, the ducts of the pancreas are blocked by thick mucus, which blocks the pancreatic ducts, causing damage and scarring. Since digestive enzymes and juices rich in bicarbonate are unable to reach the intestine, the absorption of fat, nutrients and vitamins is significantly diminished. Resulting symptoms can include poor growth, inability to gain weight, malnutrition, bloating, excessive gas and large, foul-smelling, oily stools.
  • Cystic fibrosis related diabetes (CFRD): Insulin is a hormone that controls blood sugar. It is released by cells in the pancreas that are different from those that make digestive enzymes. In some people with cystic fibrosis, damage to the pancreas from digestive enzymes may affect the insulin-secreting cells too. This will decrease the secretion of insulin, causing a form of diabetes. The chances of getting CFRD increases with age.
  • Digestive tract: Abnormally thick mucus and stool can occasionally causes blockages in the intestine, usually where the small and large intestines meet. This is called meconium ileus in a newborn, or distal intestinal obstruction syndrome (DIOS) in an older child or adult. Symptoms include severe constipation, bloating and stomach pain. If the stool cannot be flushed out, surgery is sometimes necessary to relieve the obstruction.
  • Liver: In the liver, bile juice is produced that is then stored in the gall bladder. Bile helps to break down fat in the diet. Bile travels through small tubes from the liver and gallbladder to the small intestine. If those tubes become blocked and inflamed due to thick mucus, liver cells can be damaged and stones called “gallstones” may form in the gall bladder. Liver damage can often be detected by routine blood tests, and only in rare cases does cirrhosis (severe scarring of the liver) occur.
  • Reproductive tract: Almost all men with cystic fibrosis are infertile because the tube that connects the testes and prostate gland (“vas deferens”) is missing. Certain fertility treatments and surgical procedures sometimes make it possible for men with cystic fibrosis to become fathers. Women with cystic fibrosis may be less fertile than other women because of thicker mucus blocking the cervix, but it's possible for them to conceive and have successful pregnancies. Still, pregnancy can worsen the signs and symptoms of cystic fibrosis, so make sure that you discuss the possible risks with your cystic fibrosis health care team. Cystic fibrosis does not affect sexual development or the ability to have sex in either men or women.
  • Sweat glands: The absence of functioning CFTR channels in the sweat glands leads to sweat that is very salty. Before newborn screening was widely available, infants were sometimes brought to medical attention because they tasted salty when kissed. Normally, salty sweat is not dangerous, but in situations when heavy sweating can be expected (exercise, hot weather), it is crucial to stay well hydrated by drinking extra water, possibly supplemented with electrolytes (such as sport drinks).

Bone complications

  • Thinning of the bones (osteoporosis): People with cystic fibrosis are at higher risk of developing a dangerous thinning of the bones as they age.
  • Clubbing of the fingers or toes: The tips of the fingers and toes may widen and get thicker. This finding is more common with worsening disease. Severe swelling of knee and ankle joints is less common and may be related to increased inflammation in the body from lung disease.
Lifestyle Options

For most people, regardless of having cystic fibrosis or not, exercise, healthy eating and good sleeping habits are recommended. A healthy lifestyle can lead to an enhanced quality of life for most people. Talk to your doctor before making any lifestyle changes.


People with cystic fibrosis should have the annual influenza vaccine. Cystic fibrosis does not affect the immune system, but children with cystic fibrosis are more likely to develop complications when they become ill.


Regular exercise helps keep the airways clear and promotes good lung, body and mental health.

Eliminate smoke

Cystic fibrosis patients should not smoke and they should not allow other people to smoke around them. Passive smoke is especially harmful for people with cystic fibrosis.

Wash hands

Hand-washing is a good way to protect against infection.

Medical Treatment

Current therapies for cystic fibrosis can be broadly classified into 2 categories: 1) those that treat the symptoms and try to prevent disease progression, and 2) newer medicines that target the cause of cystic fibrosis, namely absent or CFTR channels that do not work properly.

Symptom type and severity can differ widely from person to person. Therefore, treatment plans are usually tailored to each individual's unique circumstances. It is important for people with cystic fibrosis to receive care from a medical team that specialises in the disease and that will work closely with their doctor. Specialised teams include doctors, nurses, dieticians/nutritionists, respiratory physiotherapists and social/mental health workers who understand the complex patient needs and work closely with patients and families to create individualised treatment plans.

Treatments for symptoms and to delay progression

Each day, people with cystic fibrosis complete a combination of the following therapies:

Treatment for lung problems

  • Airway clearance to help loosen and get rid of the thick mucus that can build up in the lungs. Some airway clearance techniques require help from family members, friends or respiratory physiotherapists. Many people with cystic fibrosis use an inflatable vest that thumps the chest at a high frequency to help loosen mucus. Vigorous exercise also helps keep airways clear.
  • Medicines: Doctors may prescribe bronchodilators, mucolytic (medications that break up or thin mucus), anti-inflammatory medicines or antibiotics. These medicines help to open up the airways and thin and clear the mucus, reduce airway swelling, and treat or prevent airway infections. These medicines may be inhaled or taken orally. Inhaled medicines are liquid or dry-powder medicines that are inhaled by means of a nebuliser or inhaler. Using inhaled therapies can take a lot of time, so it is important to discuss with your health care team any difficulties you have in using the treatments consistently.

Treatment for digestive problems:

  • Nutrition therapy: This includes a well-balanced diet that is rich in calories, fat and proteins. People with cystic fibrosis may need up to 50 percent more calories daily than people without the condition. Nutrition will help to improve strength, growth and development, and immunity to resist lung infection.
  • Oral pancreatic enzymes help the body to absorb important nutrients, fats, proteins and vitamins. They must be taken with every meal and with most snacks.
  • Supplements of vitamins A, D, E and K replace certain vitamins that the intestines cannot absorb well.
  • High-calorie nutritional supplements can be taken either by mouth or through a tube inserted into the stomach.

Medicines that reduce stomach acid may help the enzymes that break down food to work better.

Medications that treat the cause of cystic fibrosis (CFTR dysfunction)

In recent years, scientists have learned more about the cause of cystic fibrosis and how genetic changes (called mutations) in the CFTR channel affect its function. The hundreds of different mutations in the CFTR channel can be classified into 2 groups: 1) those that result in reduced or no CFTR in the cell membrane, and 2) those that have CFTR present in the membrane but do not allow salt to pass through (like a closed gate).

How Is the Progression of Cystic Fibrosis Monitored?

Newborn infants with cystic fibrosis and their families must visit a cystic fibrosis centre frequently to make sure that the baby is growing and gaining enough weight, to watch for early lung problems and to become educated about the condition, what to expect and what the treatment will be like as the child grows. The adjustment of having a child with a chronic illness is discussed with the family, and the care team looks for signs of anxiety or depression in the patients and family members. Older children and adults visit the cystic fibrosis centre every 3 months or so.

Various tests are routinely performed to monitor the child’s health. Chest x-rays (or CT scans) are done to look at the lung structure and to monitor for airway obstruction or damage. Lung function tests can usually be started when the child is 5 years old. These tests are performed often, because loss of lung function does not always result in symptoms. Also, tissue samples from the respiratory tract (usually a throat swab or sputum) are taken to look for germs that are known to be harmful to the lungs, so that more aggressive treatment can be started. Finally, blood tests are carried out to check a variety of things such as level of inflammation, and liver and kidney function.

Over time, teams that care for patients with cystic fibrosis have become much more aggressive in not only managing complications of the disease, but also in trying to prevent the progression towards respiratory failure. Health trends have improved as a result and there is a very full pipeline of new treatments being tested that may eventually be life-changers for people with cystic fibrosis.


Please note that the information on this website is intended for informational purposes only and should not be used as a substitute for seeking medical advice or treatment from a healthcare professional. You should not use this information to diagnose or treat a medical condition or health problem. Speak to a healthcare provider if you have any questions about your health, medical condition, symptoms or treatment options.


UK Cystic Fibrosis charity

NHS Choices

Mayo Clinic's mission is to inspire hope and contribute to health and well-being by providing the best care to every patient through integrated clinical practice, education and research. Mayo Clinic’s primary value is "The needs of the patient come first."

US Department of Health and Human Services – National Institute of Health (NIH), National Heart, Lung and Blood Institute


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