Cystic Fibrosis

Last Updated 05/08/2020

Author:Iman Sami, MD

About Cystic Fibrosis

Key facts about Cystic Fibrosis
  • Cystic fibrosis (CF) is inherited.
  • People with CF either don’t make enough or make an unusual kind of a protein called cystic fibrosis transmembrane regulator (CFTR).
  • CFTR is found on the cell surface of many organs.
  • CFTR makes sodium (Na), chloride (Cl) ions, and water normal as they move across the surface of cells.

Cystic fibrosis (CF) is an inherited (genetic) disease. This means it is given to children from their parents’ genes. Both parents must have the abnormal gene for their child to have CF.
A protein called cystic fibrosis trans-membrane regulator (CFTR) controls normal movement of sodium (Na), chloride (Cl), and water in and out of the cells in different parts of the body. People with CF either don’t have enough CFTR or their CFTR is abnormal.
Mucus is made in the body by cells in the lungs, pancreas, stomach and intestines, and reproductive organs. When there is no CFTR or it is abnormal, the mucus becomes thick. This thick mucus causes blockages, infections, and damage in the affected organs.

How Cystic Fibrosis affects your body

How serious is Cystic Fibrosis?

CF is a life-threatening condition. More than 30,000 people in the United States and more than 70,000 people worldwide have it. Around 1 in 30 Americans carries the gene. Sixty years ago, children diagnosed with CF typically didn’t live past childhood. However, as care has gotten better, life expectancy has increased and is now over 40 years. Almost half of those who have CF are now over 18 years of age. Although it is seen in all races, CF is most common in whites and not common in people from the Far East or Native Americans.

CF can affect the whole body:

  • Thick mucus in the lungs can block the airways. The mucus also allows germs to grow and infect the lungs. This leads to a vicious cycle of more mucus, more airway blockage, and more infections. After a number of years, this process harms the airways and the lung tissue.

CF also affects other parts of the body—for example:

  • Pancreas. Parts of the pancreas, called ducts, become blocked, which scars the pancreas and can decrease its functioning. It can also cause a type of diabetes called cystic fibrosis–related diabetes.
  • Stomach and intestines. Mucus can be much thicker than normal, which causes blockages in the intestines and may require surgery.
  • Liver. Ducts can be blocked and cause damage to the liver.
  • Reproductive organs. Increased mucus can cause problems becoming pregnant or decreased sperm count.
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Cystic Fibrosis patient guide

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Symptoms of Cystic Fibrosis

There is a wide range of CF symptoms. Even in the same family, siblings can have different levels of CF.

CF symptoms are divided into 2 main categories: symptoms of respiratory tract (lung) disease and symptoms of gastrointestinal disease (stomach and intestines).

The most common symptoms of CF respiratory tract disease are:

  • Constant coughing (dry or coughing up mucus);
  • Frequent chest colds;
  • Wheezing (that may not get better with regular asthma drugs);
  • Shortness of breath;
  • Frequent sinus infections; and
  • Allergies that last all year.

Symptoms of lung disease can start in childhood, especially following upper respiratory infections. As children grow up, the symptoms increase. However, some children stay healthy during childhood and only start to get more severe symptoms in their lungs when they are teenagers.

The most common symptoms of CF gastrointestinal disease are:

  • Frequent, large, greasy, and bad-smelling bowel movements;
  • Inability to gain weight despite being hungry all of the time;
  • Poor growth;
  • Constipation and intestinal blockage;
  • Frequent infection of the pancreas, called pancreatitis; and
  • Symptoms of high blood sugar, such as being thirsty and urinating frequently.

Other symptoms include:

  • Too much sweating; and
  • A salty taste when you kiss your child with CF.
Cystic Fibrosis and children infographic

Cystic Fibrosis Child Infographic

Cystic Fibrosis adult infographic

Cystic Fibrosis Adult Infographic

What causes Cystic Fibrosis?

People cannot catch CF. CF is an inherited disease caused by having two abnormal copies of the CF gene. CF can happen even if there is no family history, because people who only have one abnormal CF gene (called carriers) are healthy.

What are risk factors for Cystic Fibrosis?

The only risk factor for getting CF is having two parents who carry abnormal CF genes and pass the abnormal gene to their child. However, certain factors control how severe the CF is:

  • Genes. CF gene abnormalities are divided into two classes based on how damaged the CFTR protein function is.:
    • Classes I, II, and III are more severe.
    • Classes IV and V are milder, and other genes—called modifier genes—can affect CF symptoms and outcome.
  • Environment and lifestyle. People with CF need to eat a lot of calories to maintain weight and grow. Physical activity can help keep lungs healthy. People with CF should not smoke or be around people who smoke because smoke makes lung disease worse. They should not drink much alcohol and shouldn’t drink at all if they have liver disease.
  • Age. CF gets worse with age. People with CF typically see a small decline in lung function each year.

Diagnosing Cystic Fibrosis

Because of symptoms, people with CF used to be diagnosed by 2 years of age. Now there is newborn screening in all 50 US states. This means that babies are diagnosed before they have symptoms, and treatment can start right away. Health care providers diagnose CF in children by asking their parents questions about symptoms and doing a physical examination. They usually don’t need other tests to diagnose this condition. If someone with CF has or has recently had a fever, that person’s provider may want to see a chest X-ray to rule out pneumonia. There are different ways to find out if people have CF:

  • Newborn screening. The newborn test shows babies who have a large amount of an enzyme called immunoreactive trypsin in their blood. High levels of this enzyme appear if there is an injury to the pancreas. The test is done again if it is abnormal at first. Some states combine this test with another test for the most common gene abnormality, called deltaF508. Next, the baby will need more tests because sometimes the test shows CF when there really isn’t CF (called a false-positive test). The provider takes a blood sample to check whether the baby has the two genes that cause CF or performs a sweat test.
  • Genetic testing. More than 2000 gene abnormalities are seen in CF. Most of them are rare, but some are common. The deltaF508 abnormality is found in about 70% of people. In most cases, genetic testing is able to determine the exact abnormality. For couples who want to have children, genetic testing is important. More than 10 million Americans have a CF gene. If both parents have a CF gene, there is a 1-in-4 chance that the baby will have CF.
  • Sweat test. The provider can use sweat from a small area on the baby’s arm, and then measure chloride (salt) levels. Children with CF have high levels of chloride in their sweat because they are missing CFTR. This means that the salt on the skin can’t return to the sweat glands.
  • Measuring nasal lining. Another way to test for CF is to use different chemicals and run a small electrical current across the nasal lining (called the epithelium). People with CF respond differently than those without CF to this test, and it may help confirm a diagnosis.

Treating Cystic Fibrosis

There are different ways to stop or slow down lung damage from CF:

  • Airway clearance therapy. People with CF need airway clearance therapy (ACT). ACT can be done manually with physical therapy or with a device called the VEST. The VEST is a jacket that vibrates and shakes the mucus in the lungs so that the patient can cough it up. Another handy device is called a flutter. It makes the mucus in the lungs vibrate, or “flutter,” when the patient breathes through it.
  • Mucus-thinning medication. A type of inhaler called a nebulizer is often used before doing ACT. Albuterol is a drug that relaxes the airway and helps clear mucus. Dornase alpha is a drug that thins the mucus so that the patient can cough it up more easily. Hypertonic saline solution is a drug that puts moisture and salt back into the cell surfaces in the lungs.
  • Enzymes and nutrients. Other drugs, called pancreatic enzyme replacement therapies, help the body absorb food and important nutrients. These drugs have to be given before every meal or snack. People with CF also have to take certain vitamins that are absorbed with fat. Additional salt also needs to be put in formula or in food.
  • Antibiotics. These drugs are often used to treat bacteria that grow in the mucus. There are three ways to take antibiotics:
    • Orally (by mouth), which is the easiest and cheapest route
    • Inhalation (or breathing in), which is more expensive but useful
    • Intravenously (IV), where a drug inserted through a vein for those who are sicker
  • Anti-inflammatory medications. Drugs that treat swelling can be used in CF. Two drugs currently in use are ibuprofen (not so common nowadays) and azithromycin (an antibiotic that’s used as an anti-inflammatory in CF).
  • New medications. A combination drug called Ivacaftor/Lumacaftor is used in children aged 2 years and older. This medication helps people who carry two genes of the common deltaF508 (class II). A second drug, called Tezacaftor/Ivacaftor, was also approved for these people. More drugs are being tested and could be approved soon. The triple combination drugs being tested will help those who carry 1 or 2 copies of the abnormal deltaF508 (class II) gene.

Managing Cystic Fibrosis

Management of CF focuses on diet and lung health:

  • Maintain a normal weight. People with CF need to take in enough calories to keep their lungs healthy. This is sometimes hard without using diet supplements or other methods, such as a feeding tube. Patients may also need to take in more salt, especially if they’re sweating. Correct enzymes and vitamins are also important in taking care of CF.
  • ACT, inhaled medications, antibiotics, and exercise. It is important for people with CF to exercise and stay active to keep their lungs healthy. They should also make sure that any respiratory tract infections are treated right away. If an infection is suspected, the provider should be called so that he or she can prescribe medications.
  • New classes of CFTR-modifying medications. New drugs improve lung health in older patients but also maintain it when given to younger patients. People with CF will still need to take enzymes to help absorb food and will sometimes need antibiotics for infections, but the frequency should be much less.


The American Lung Association suggests that patients and caregivers join its Living With Lung Disease Support Community to connect with others who face this disease. Call the American Lung Association’s Lung HelpLine at 1-800-LUNGUSA to talk to a trained respiratory professional who can help answer questions and connect patients and caregivers with additional support.

Parent support groups and the local CF chapters of the CF Foundation are also available to help support parents of newly diagnosed CF in children as well as in older individuals with CF. Also, the social worker on the CF care team can provide counseling on many issues, including:

  • School concerns. The child’s school needs to be aware of the diagnosis so that correct actions are in place and the child can receive the support he or she needs.
  • Insurance. It’s important to get good advice on insurance policies to make the drugs used to treat CF affordable.
  • Jobs. It’s important to get good advice on talking with employers, retirement, and disability.

The CF Patient Assistance Foundation helps people with CF afford drugs and the devices needed to stay healthy. They can help patients apply for supplemental Social Security and Social Security disability benefits.

A CF legal hotline provides information for individuals with CF about their rights.

Frequently Asked Questions of Health Care Providers

Making notes before your visit and taking a trusted family member or friend with you can help you through the first appointment with your provider. For example, ask:

  • My newborn infant has been diagnosed with CF. Can I still breastfeed him?

    We encourage mothers to nurse their infants as long as they are able to gain adequate weight because breastfeeding gives the baby additional immunity. If the infant’s weight gain is not enough, then the mother can express her milk, and it can be supplemented to provide additional calories.

  • Can my infant with CF go to daycare?

    If at all possible, parents are encouraged to spend the first 6 months with their infant and not send them to daycare. When the infant needs to go to daycare, then in-home daycare or a very small daycare is preferable to limit the exposure to infections. The daycare provider must also be trained to give the enzymes before every feeding.

  • How can my child with CF receive enough nutrition and their enzymes during the school day?

    The child needs to go to the nurse’s office before lunch to take their enzymes. He or she also needs to be allowed to have an extra snack during the school day and additional time at lunch to finish their meal, if needed.

  • Can my child with CF be in the same classroom as another child with CF?

    It is recommended that children with CF not be in the same classroom, although they can be in the same school. They should not be in the same physical exercise or recess session, either.

  • Can we have pets at home if my child has CF?

    Yes, pets are allowed but should not sleep on the child’s bed.

  • I have 2 children with CF. Do I need to keep them apart?

    It is not possible to keep siblings who live in the same household apart, but what is recommended is that they do not perform their ACT in the same room.

  • How long do people with CF live?

    The lifespan of individuals with CF has been steadily increasing, and the median is now more than 40 years. As newer therapies come on the market, it is expected that longevity will continue to increase.

  • Can a lung transplant cure CF?

    Not really, because CF affects other organs, as well. However, a lung transplant can give an individual a new pair of lungs that can enable them to survive longer if their own lungs were very damaged.

  • Do people with CF need treatment daily, or can they skip days?

    Unfortunately, the therapies to keep the lungs healthy are needed every day, and the enzymes are needed with every meal unless the meal doesn’t contain any fat.

  • Will there be a cure for CF?

    Currently, there is no cure for CF. However, 2 medications that modify the function of the CTFR protein have been approved, and more are in clinical trials or awaiting approval. These medications have the potential to really change the function of the defective CFTR protein so that it works much better and individuals stay healthy. The future for people with CF is much brighter today than it was 50 years ago.