What Is Cystic Fibrosis?
Cystic fibrosis (SIS-tik fi-BRO-sis), or CF, is an
inherited disease of your secretory glands, including the glands that make
mucus and sweat.
"Inherited" means that the disease is passed through
the genes from parents to children. People who have CF inherit two faulty CF
genes—one from each parent. The parents likely don't have the disease
themselves.
CF mostly affects the lungs, pancreas, liver,
intestines, sinuses, and sex organs.
Overview
Mucus is a substance made by the lining of some body
tissues. Normally, mucus is a slippery, watery substance. It keeps the linings
of certain organs moist and prevents them from drying out or getting infected.
However, if you have CF, your mucus becomes thick and sticky.
The mucus builds up in your lungs and blocks your
airways—the tubes that carry air in and out of your lungs. The buildup of
mucus makes it easy for bacteria to grow. This leads to repeated, serious lung
infections. Over time, these infections can severely damage your lungs.
The thick, sticky mucus also can block tubes, or
ducts, in your pancreas. As a result, the digestive enzymes that your pancreas
makes can't reach your small intestine.
These enzymes help break down the food that you eat.
Without them, your intestines can't fully absorb fats and proteins. This can
cause vitamin deficiency and malnutrition because nutrients leave your body
unused. It also can cause bulky stools, intestinal gas, a swollen belly from
severe constipation, and pain or discomfort.
CF also causes your sweat to become very salty. As a
result, your body loses large amounts of salt when you sweat. This can upset
the balance of minerals in your blood and cause a number of health problems.
Examples include dehydration (a condition in which your body doesn't have
enough fluids), increased heart rate, tiredness, weakness, decreased blood
pressure, heat stroke, and, rarely, death.
If you or your child has CF, you're also at
increased risk for diabetes or a bone-thinning condition called osteoporosis.
CF also causes infertility in men, and it can make it harder for women to get
pregnant.
Outlook
The symptoms and severity of CF vary from person to
person. Some people who have CF have serious lung and digestive problems. Other
people have more mild disease that doesn't show up until they're adolescents or
adults.
The symptoms and severity of CF also vary over time.
Sometimes, you will have few symptoms. Other times, your symptoms may become
more severe. As the disease gets worse, you will have more severe symptoms more
often.
Lung function often starts to decline in early
childhood in people who have CF. Over time, permanent damage to the lungs can
cause severe breathing problems. Respiratory failure is the most common cause
of death in people who have CF.
As treatments for CF continue to improve, so does
life expectancy for those who have the disease. Today, some people who have CF
are living into their forties, fifties, or older.
Early treatment for CF can improve both your quality
of life and lifespan. Such early treatment includes nutritional and respiratory
therapies, medicines, exercise, and other treatments.
Other Names for Cystic Fibrosis
- Cystic fibrosis of the pancreas
- Fibrocystic disease of the pancreas
- Mucoviscidosis (MU-ko-vis-i-DO-sis)
- Mucoviscidosis of the pancreas
- Pancreas fibrocystic disease
- Pancreatic cystic fibrosis
What Causes Cystic Fibrosis?
A defect in the CFTR gene causes cystic fibrosis
(CF). This gene makes a protein that controls the movement of salt and water in
and out of your body's cells. In people who have CF, the gene makes a protein
that doesn't work right. This causes thick, sticky mucus and very salty
sweat.
Research suggests that the CFTR protein also affects
the body in other ways. This may help explain other symptoms and complications
of CF.
More than a thousand known defects can affect the
CFTR gene. What type of defect you or your child has may influence how severe
CF is. Other genes also may play a role in how severe the disease is.
How Is Cystic Fibrosis Inherited?
Every person inherits two CFTR genes—one from
each parent. Children who inherit a faulty CFTR gene from each parent will have
CF.
Children who inherit a faulty CFTR gene from one
parent and a normal CFTR gene from the other parent will be "CF carriers." CF
carriers usually have no symptoms of CF and live normal lives. However,
carriers can pass the faulty CFTR gene on to their children.
The following image shows how two parents who are
both CF carriers can pass the faulty CFTR gene to their children.
Example of an Inheritance
Pattern for Cystic Fibrosis
The image shows how CFTR genes are
inherited. A person inherits two copies of the CFTR gene—one from each
parent. If each parent has a normal CFTR gene and a faulty CFTR gene, each
child has a 25 percent chance of inheriting two normal genes; a 50 percent
chance of inheriting one normal gene and one faulty gene; and a 25 percent
chance of inheriting two faulty genes.
Who Is At Risk for Cystic Fibrosis?
About 30,000 people in the United States have cystic
fibrosis (CF). CF is one of the most common inherited diseases among
Caucasians. About 1,000 new cases of CF are diagnosed each year.
CF affects both males and females and people from
all racial and ethnic groups. However, the disease is most common among
Caucasians of Northern European descent.
CF also is common among Latinos and Native
Americans, especially the Pueblo and Zuni. The disease is much less common
among African Americans and Asian Americans.
About 12 million Americans are carriers of a faulty
CF gene. Many of them don't know that they're CF carriers.
What Are the Signs and Symptoms of Cystic
Fibrosis?
The symptoms of CF vary from person to person and
over time. Sometimes you will have few symptoms. Other times, your symptoms may
become more severe.
One of the first signs of cystic fibrosis (CF) that
parents may notice is that their baby's skin tastes salty when kissed or the
baby doesn't pass stool when first born.
Most of the other signs and symptoms of CF develop
later. They are related to how CF affects the respiratory, digestive, or
reproductive systems of the body.
Cystic Fibrosis
Figure A shows the
organs that cystic fibrosis can affect. Figure B shows a cross-section of a
normal airway. Figure C shows an airway affected by cystic fibrosis. The
widened airway is blocked by thick, sticky mucus containing blood and bacteria.
Respiratory System Signs and Symptoms
People who have CF have thick, sticky mucus that
builds up in their airways. This buildup of mucus makes it easier for bacteria
to grow and cause infections. Infections can block the airways and cause
frequent coughing that brings up thick sputum (spit) or mucus that's sometimes
bloody.
People who have CF tend to have lung infections
caused by unusual germs that don't respond to standard antibiotics. For
example, lung infections due to bacteria called mucoid Pseudomonas are much
more common in people who have CF. An infection caused by this bacteria may be
a sign of CF.
People who have CF have frequent bouts of sinusitis,
an infection of the air-filled spaces behind your eyes, nose, and forehead.
Frequent bouts of
bronchitis
(bron-KI-tis) and
pneumonia
(nu-MO-ne-ah) also occur. These infections can cause long-term lung damage.
As CF gets worse, you may develop more serious
complications, such as
pneumothorax
(noo-mo-THOR-aks), or collapsed lung; or
bronchiectasis
(brong-ke-EK-ta-sis).
Some people who have CF also develop nasal polyps
(growths in the nose) that may require surgery.
Digestive System Signs and Symptoms
Mucus that blocks tubes, or ducts, in your pancreas
and prevents enzymes from reaching your intestines causes most digestive system
signs and symptoms.
Without these enzymes, your intestines can't fully
absorb fats and proteins. This can cause ongoing diarrhea or bulky,
foul-smelling, greasy stools. Intestinal blockage also may occur, especially in
newborns. Too much gas or severe constipation in the intestines may cause
stomach pain and discomfort.
A hallmark of CF in children is poor weight gain and
growth. These children are unable to get enough nutrients from their food due
to the lack of enzymes to help absorb fats and proteins.
As CF gets worse, other complications may occur,
such as:
- Pancreatitis (PAN-kre-a-TI-tis). This is a
condition in which the pancreas become inflamed, which causes pain.
- Rectal prolapse. Frequent coughing or problems
passing stools may cause rectal tissue from inside you to move out of your
rectum.
- Liver disease due to inflamed or blocked bile
ducts.
- Diabetes.
- Gallstones.
Reproductive System Signs and Symptoms
Men who have CF are infertile because they're born
without a vas deferens. This is the tube that delivers sperm from the testicle
to the penis.
A woman who has CF may have a hard time getting
pregnant because of mucus blocking her cervix or other CF complications.
Other Signs, Symptoms, and Complications
Other signs and symptoms of CF are related to an
upset of the balance of minerals in your blood.
CF causes your sweat to become very salty. As a
result, your body loses large amounts of salt when you sweat. This can cause
dehydration (a condition in which your body doesn't have enough fluids),
increased heart rate, tiredness, weakness, decreased blood pressure, heat
stroke, and, rarely, death.
CF also can cause clubbing and low bone density.
Clubbing is the widening and rounding of the tips of your fingers and toes. It
develops late in CF because your lungs aren't moving enough oxygen into your
bloodstream.
Low bone density also tends to occur late in CF. It
can lead to a bone-thinning disorder called osteoporosis.
How Is Cystic Fibrosis Diagnosed?
Doctors diagnose cystic fibrosis (CF) based on the
results from various tests.
Newborn Screening
Most States screen newborns for CF using a genetic
test or a
blood
test. The genetic test shows whether a newborn has faulty CFTR genes. The
blood test shows whether a newborn's pancreas is working.
Sweat Test
If a genetic test or blood test suggests CF, a
doctor will confirm a diagnosis using a
sweat
test. This test is the most useful test for diagnosing CF. It measures the
amount of salt in sweat.
For this test, doctors trigger sweating on a small
patch of skin on an arm or leg. They rub the skin with a sweat-producing
chemical and then use an electrode to provide a mild electrical current. This
may cause a tingling or warm feeling.
Sweat is collected on a pad or paper and then
analyzed. The sweat test usually is done twice. High salt levels confirm a
diagnosis of CF.
Other Tests
If you or your child has CF, your doctor may
recommend other tests, such as:
- Genetic tests to find out what type of CFTR
defect is causing your CF.
- A
chest
x ray. This painless test creates pictures of the structures in your chest,
such as your heart and lungs. A chest x ray can show whether your lungs are
inflamed or scarred or whether they trap air.
- A sinus x ray. This test may show signs of
sinusitis, a complication of CF.
-
Lung
function tests. These tests measure the size of your lungs, how much air
you can breathe in and out, how fast you can breathe air out, and how well your
lungs deliver oxygen to your blood.
- A sputum culture. For this test, your doctor will
take a sample of your sputum (spit) to see what bacteria are growing in it. If
you have bacteria called mucoid Pseudomonas, you may have more advanced CF that
needs aggressive treatment.
Prenatal Screening
If you're pregnant, prenatal genetic tests can find
out whether your fetus has CF. These tests include amniocentesis
(AM-ne-o-sen-TE-sis) and chorionic villus (ko-re-ON-ik VIL-us) sampling (CVS).
In amniocentesis, your doctor inserts a hollow
needle through your abdominal wall into your uterus. He or she removes a small
amount of fluid from the sac around the baby. The fluid is tested to see
whether both of the baby's CFTR genes are normal.
In CVS, your doctor threads a thin tube through the
vagina and cervix to the placenta. The doctor removes a tissue sample from the
placenta using gentle suction. The sample is tested to see whether the baby has
CF.
Cystic Fibrosis Carrier Testing
People who have one normal CFTR gene and one faulty
CFTR gene are CF carriers. CF carriers usually have no symptoms of CF and live
normal lives. However, carriers can pass faulty CFTR genes on to their
children.
If you have a family history of CF or a partner who
has CF (or a family history of it) and you're planning a pregnancy, you may
want to find out whether you're a CF carrier.
A genetics counselor can test a blood or saliva
sample to see whether you have a faulty CF gene. This type of testing can
detect faulty CF genes in 9 out of 10 cases.
How Is Cystic Fibrosis Treated?
Cystic fibrosis (CF) has no cure. However,
treatments have greatly improved in recent years. The goals of CF treatment are
to:
- Prevent and control lung infections
- Loosen and remove thick, sticky mucus from the
lungs
- Prevent or treat blockages in the intestines
- Provide enough nutrition
- Prevent dehydration (a condition in which the
body doesn't have enough fluids)
Depending on how severe the disease is, you or your
child may be treated in a hospital.
Specialists Involved
If you or your child has CF, you may be treated by a
CF specialist. This is a doctor who is familiar with the complex nature of CF.
Often, a CF specialist works with a medical team of
nurses, physical therapists, dietitians, and social workers. CF specialists
often are located at major medical centers.
Treatment for Lung Problems
The main treatments for lung problems in people who
have CF are chest physical therapy (CPT), exercise, and medicines.
Chest Physical Therapy
CPT also is called chest clapping or percussion. It
involves pounding your chest and back over and over with your hands or a device
to loosen the mucus from your lungs so that you can cough it up.
You might sit down or lie on your stomach with your
head down while you do CPT. Gravity and force help drain the mucus from your
lungs.
Some people find CPT hard or uncomfortable to do.
Several devices have been developed that may help with CPT, such as:
- An electric chest clapper, known as a mechanical
percussor.
- An inflatable therapy vest that uses
high-frequency airwaves to force the mucus that's deep in your lungs toward
your upper airways so you can cough it up.
- A small handheld device that you breathe out
through. It causes vibrations that dislodge the mucus.
- A mask that creates vibrations that help break
the mucus loose from your airway walls.
Breathing techniques also may help dislodge mucus so
you can cough it up. These techniques include forcing out a couple of short
breaths or deeper breaths and then doing relaxed breathing. This may help
loosen the mucus in your lungs and open your airways.
Exercise
Aerobic exercise that makes you breathe harder helps
loosen the mucus in your airways so you can cough it up. Exercise also helps
improve your overall physical condition.
However, CF causes your sweat to become very salty.
As a result, your body loses large amounts of salt when you sweat. Thus, your
doctor may recommend a high-salt diet or salt supplements to maintain the
balance of minerals in your blood.
If you exercise regularly, you may be able to cut
back on your CPT. However, you should check with your doctor before doing
this.
Medicines
If you have CF, you doctor may prescribe
antibiotics, anti-inflammatory medicines, bronchodilators, or mucus-thinning
medicines. These medicines help treat or prevent lung infections, reduce
swelling, open up the airways, and thin mucus.
Antibiotics are the main treatment to prevent or
treat lung infections. Your doctor may prescribe oral, inhaled, or intravenous
(IV) antibiotics.
Oral antibiotics often are used to treat mild lung
infections. Inhaled antibiotics may be used to prevent or control infections
caused by the bacteria mucoid Pseudomonas. For severe or hard-to-treat
infections, you may be given antibiotics through a tube inserted into a vein.
This type of treatment may require you to stay in the hospital.
Anti-inflammatory medicines can help reduce swelling
in your airways that's caused by ongoing infections. These medicines may be
inhaled or oral.
Bronchodilator medicines help open the airways by
relaxing the muscles around them. These medicines are inhaled and often are
taken just before CPT to help clear out mucus. You also may take
bronchodilators before inhaling other medicines into your lungs.
Your doctor may prescribe mucus thinners to reduce
the stickiness of your mucus and to loosen it up. These medicines can help
clear out mucus, improve lung function, and prevent worsening lung
symptoms.
Treatments for Advanced Lung Disease
If you have advanced lung disease and the level of
oxygen in your blood is low, you may need oxygen therapy. Oxygen usually is
given through nasal prongs or a mask.
If other treatments haven't worked,
lung
transplant may be an option if you have severe lung disease. A lung
transplant is surgery to remove a person's diseased lung and replace it with a
healthy lung from a deceased donor.
Treatment for Digestive Problems
CF can cause a number of digestive problems,
including poor growth and development, bulky stools, intestinal gas, a swollen
belly, severe constipation, and pain or discomfort.
Nutritional therapy can improve your strength and
ability to stay active. It also can improve growth and development in children.
Nutritional therapy also may make you strong enough to resist some lung
infections. A nutritionist can help you create a nutritional plan that meets
your needs.
In addition to having a well-balanced diet that's
rich in calories, fat, and protein, your nutritional therapy may include:
- Oral pancreatic enzymes to help you digest fats
and proteins and absorb more vitamins.
- Supplements of vitamins A, D, E, and K to replace
the fat-soluble vitamins that your intestines can't absorb.
- High-calorie shakes to provide you with
additional nutrients.
- A high-salt diet or salt supplements that you
take before doing vigorous exercise.
- A feeding tube to give you more calories at night
while you're sleeping. The tube may be threaded through your nose and throat
and into your stomach. Or, it may be placed directly into your stomach through
a surgically made hole. Before you go to bed each night, you will attach a bag
with a nutritional solution to the entrance of the tube. It will feed you while
you sleep.
Other treatments for digestive problems may include
enemas and mucus-thinning medicines to treat intestinal blockages. Sometimes
surgery is needed to remove an intestinal blockage.
Your doctor also may prescribe medicines to reduce
your stomach acid and help oral pancreatic enzymes work better.
Treatments for Cystic Fibrosis Complications
A common complication of CF is diabetes. The type of
diabetes that people who have CF develop often requires different treatment
than other types of diabetes.
Another common complication is the bone-thinning
disorder osteoporosis. Your doctor may prescribe medicines that prevent your
bones from losing their density.
Living With Cystic Fibrosis
If you or your child has cystic fibrosis (CF), you
should learn as much as you can about the disease. Work closely with your
doctors to learn how to manage CF.
Ongoing Care
Having ongoing medical care by a team of doctors,
nurses, and respiratory therapists who specialize in CF is important. These
specialists often are located at major medical centers.
It's standard to have CF checkups every 3 months.
Talk to your doctor about whether you should get an annual flu shot and other
vaccines. Take all of your medicines as your doctor prescribes. In between
checkups, be sure to contact your doctor if you have:
- Blood in your mucus, increased amounts of mucus,
or a change in the color or consistency of your mucus.
- Decreased energy or appetite.
- Severe constipation or diarrhea, severe abdominal
pain, or vomit that's dark green.
- A fever, which is a sign of infection. (However,
you may still have a serious infection that needs treatment even if you don't
have a fever.)
Lifestyle Measures
In between medical checkups, you can practice good
self-care and follow a healthy lifestyle.
An important part of a healthy lifestyle is
following a healthy diet. A healthy diet includes a variety of fruits,
vegetables, and whole grains. Talk to your doctor about what types and amounts
of foods you should include in your diet.
Other lifestyle measures include:
- Not smoking and avoiding tobacco smoke
- Washing your hands often to lower your risk for
infection
- Exercising regularly and drinking lots of fluids
- Doing chest physical therapy (as your doctor
recommends)
Other Concerns
Although CF requires daily care, most people who
have the disease are able to attend school and work.
Adults who have CF can expect to have a normal sex
life. Most men who have the disease are infertile. However, modern reproductive
techniques may help them. Men who have CF should still have protected sex to
avoid sexually transmitted diseases.
Women who have CF may find it hard to get pregnant,
but they usually can have children. If you have CF, you should talk to your
doctor if you're planning a pregnancy.
If your child has CF, encourage him or her to learn
about the disease and take an active part in his or her treatment.
Emotional Issues
Living with a chronic disease may cause fear,
anxiety, depression, and stress. It's important to talk about how you feel with
your health care team. Talking to a professional counselor also can help. If
you're feeling very depressed, your health care team or counselor may prescribe
medicines to make you feel better.
Joining a patient support group may help you adjust
to living with cystic fibrosis. You can see how other people who have the same
symptoms have coped with them. Talk to your doctor about local support groups
or check with an area medical center.
Support from family and friends also can help
relieve stress and anxiety. Let your loved ones know how you feel and what they
can do to help you.
Key Points
- Cystic fibrosis (CF) is an inherited disease of
your secretory glands, including your mucus and sweat glands. CF mostly affects
the lungs, pancreas, liver, intestines, sinuses, and sex organs. It doesn't
affect the brain.
- If you have CF, your mucus becomes thick and
sticky. It builds up in your lungs and blocks your airways. This leads to
repeated, serious lung infections that can damage your lungs.
- Lung function often starts to decline in early
childhood in people who have CF. Over time, permanent damage to the lungs can
cause severe breathing problems.
- The thick, sticky mucus also can block tubes, or
ducts, in your pancreas. As a result, the digestive enzymes that your pancreas
makes can't reach your small intestine. Without these enzymes, your body can't
absorb fats and proteins. This can cause vitamin deficiency and
malnutrition.
- CF also causes your sweat to become very salty.
As a result, your body loses large amounts of salt when you sweat. This can
upset the balance of minerals in your body and cause a number of health
problems. Examples include dehydration, increased heart rate, tiredness,
weakness, decreased blood pressure, heat stroke, and, rarely, death.
- A defect in the CFTR gene causes CF. This gene
makes a protein that controls the movement of salt and water in and out of your
body's cells. Every person inherits two CFTR genes—one from each parent.
Children who inherit a faulty gene from each parent will have CF.
- Children who inherit one faulty gene and one
normal gene will be "CF carriers." CF carriers usually have no symptoms of CF,
but they can pass the faulty gene on to their children.
- About 30,000 people in the United States have CF.
It is one of the most common inherited diseases among Caucasians. About 1,000
new cases of CF are diagnosed each year.
- The symptoms of CF vary from person to person and
over time. Sometimes, you will have few symptoms. Other times, your symptoms
may become more severe.
- Doctors diagnose CF based on the results from
various tests. Most States screen newborns for CF.
- CF has no cure. However, treatments have greatly
improved in recent years. Treatment may include nutritional and respiratory
therapies, medicines, exercise, and more. Early treatment for CF can improve
both your quality of life and your lifespan.
- If you or your child has CF, you should learn as
much as you can about the disease. Ongoing care and lifestyle measures can help
you manage the disease.
- As treatments for CF continue to improve, so does
life expectancy for those who have the disease. Today, some people who have CF
are living into their forties, fifties, or older.
Links to Other Information About Cystic
Fibrosis
NHLBI Resources
Non-NHLBI Resources
Clinical Trials
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