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Cystic Fibrosis


The Manual's Editorial Staff

Reviewed/Revised Sep 2023
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What is cystic fibrosis?

Cystic fibrosis is a disease that is passed down through families (a hereditary disease). It makes fluids in your lungs, digestive system, and many other organs thick and sticky. Children with cystic fibrosis have many health problems, such as difficulty breathing, lung infections, and poor growth. Cystic fibrosis is more common in White people and is equally common among boys and girls.

  • Cystic fibrosis happens when both parents pass on a defective gene to their child

  • The defective gene causes fluids in the lungs, liver, pancreas, and digestive system to be thicker and stickier than usual

  • Symptoms usually start in babies or young children and include throwing up, not gaining weight, and coughing

  • Doctors test blood and sweat and do genetic testing to diagnose cystic fibrosis

  • Treatment is with medicine to help with breathing, infections, and digestion

  • In the United States, people with cystic fibrosis who were born in the year 2019 are expected to live to about 48 years old.

Cystic Fibrosis: Not Just a Lung Disease

Cystic fibrosis affects the lungs and also several other organs.

In the lungs, thick bronchial secretions block the small airways, which become infected and inflamed. As the disease progresses, the bronchial walls thicken, the airways fill with infected secretions, areas of the lung contract, and lymph nodes enlarge.

In the liver, thick secretions block the bile ducts. Stones may develop in the gallbladder.

In the pancreas, thick secretions may block the gland completely so that digestive enzymes cannot reach the intestine. The pancreas may produce less insulin, so some people develop diabetes (usually in adolescence or adulthood).

In the small intestine, meconium ileus (a type of intestinal blockage) can result from thick secretions and may require surgery in newborns.

The reproductive organs are affected by cystic fibrosis in various ways, usually resulting in infertility in males.

The sweat glands in the skin secrete fluid containing more salt than normal.

Cystic Fibrosis: Not Just a Lung Disease

What causes cystic fibrosis?

Cystic fibrosis happens when a baby inherits two defective copies of a certain gene—one copy from each parent. The parents may not know they carry a defective copy of this gene. People who carry one defective copy of the gene are called carriers. Carriers have no symptoms of cystic fibrosis.

If you're trying to get pregnant, doctors can do blood tests to see if you and your partner are carriers. If you both carry the gene for cystic fibrosis, then your baby has a 1 in 4 chance of getting cystic fibrosis.

The defective genes cause body fluids to be thick and sticky instead of thin and flowing easily. The thick, sticky fluids clog up passageways in the lungs, pancreas, and intestines. The clogged passageways cause problems with breathing, getting energy from food, and passing stool (poop).

What are the symptoms of cystic fibrosis?

Newborn babies who have cystic fibrosis may:

  • Be born with a blocked or twisted intestine

  • Throw up

  • Have a bloated belly

  • Not gain enough weight by 4 to 6 weeks after birth

Breathing symptoms start with:

  • Coughing

  • Wheezing

  • Difficulty breathing

  • Frequent lung infections

After many years of breathing problems, your child may have long-term lung damage, which can cause:

  • A barrel-shaped chest

  • Blue color under the fingernails

  • Shortness of breath with normal activities

Digestive symptoms occur because a child with cystic fibrosis can't adequately digest and absorb food and vitamins. At first your child will have:

  • Poor weight gain

  • Below-normal growth

  • Belly cramps and constipation

  • Heartburn

After a few years, digestive problems get worse and your child may have bad-smelling, oily poop (stool) and lose weight.

Cystic fibrosis can cause other health problems, such as:

How can doctors tell if my child has cystic fibrosis?

Screening tests for cystic fibrosis using a drop of blood are done on all newborns in the United States. If the screening test shows the baby may have cystic fibrosis, the baby will have sweat testing and/or genetic testing to confirm the diagnosis. Most cases of cystic fibrosis are identified by newborn screening tests.

Doctors may do other tests to see if cystic fibrosis has caused problems with other organs, such as the digestive system or lungs.

How do doctors treat cystic fibrosis?

To help with breathing, doctors may:

  • Give medicines to help thin the fluid in your child's lungs and open up the airways

  • Give medicine to help your child's lungs work better

  • Teach you chest exercises to help move the fluid out of your child's airways so your child can breathe better

  • Give antibiotics for lung infections

A child with a very bad lung infection will need treatment in a hospital. Your child may need to be on a breathing machine. A breathing machine lets the lungs rest so they can heal better.

Children with cystic fibrosis can have problems taking in nutrients from food. To make sure your child gets enough energy and nutrients from food, doctors may:

  • Tell you to feed your child more food than normal

  • Give your child vitamins

  • Give your child medicine to help digest food

To help with breathing and nutrient absorption, doctors may also give your child a medicine that helps your child's defective gene work better.

A person with cystic fibrosis may have constipation or blocked intestines. Medicines can help with constipation. The medicine may be one that your child drinks or one that you can place in your child's anus (where poop comes out) as an enema.

Sometimes, doctors may do surgery to:

  • Fix a problem with the lungs

  • Stop bleeding

  • Remove a blockage in the intestine

Surgery may also be done if your child needs a liver or lung transplant. A transplant may be needed if your child's liver or lungs are badly damaged. With a transplant, a failing liver or lung is replaced with a healthy one from a donor.

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