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Cystic Fibrosis
What Is Cystic Fibrosis?
Cystic fibrosis (CF) is an inherited disease of the mucus and sweat glands. It affects mostly
the lungs, pancreas, liver, intestines, sinuses and sex organs.
Normally, mucus is watery. It keeps the linings of certain organs moist and prevents them
from drying out or getting infected. But in CF, an abnormal gene causes mucus to become
thick and sticky.
The mucus builds up in the lungs and blocks the airways. This makes it easy for bacteria to
grow and leads to repeated serious lung infections. Over time, these infections can cause
serious damage to the lungs.
The thick, sticky mucus can also block tubes, or ducts, in the pancreas. As a result,
digestive enzymes that are produced by the pancreas cannot reach the small intestine.
These enzymes help break down food. Without them, the intestines cannot absorb fats and
proteins fully.
As a result:
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Nutrients leave the body unused, which can lead to malnourishment
Stools become bulky
There may be a deficiency of vitamins A, D, E and K
Intestinal gas, a swollen belly, and pain or discomfort may result
The abnormal gene also causes sweat to become extremely salty. As a result, when people
with CF perspire, their bodies lose large amounts of salt. This can upset the balance of
minerals in the blood. The imbalance may cause a heat emergency.
CF also can cause infertility (mostly in men).
The symptoms and severity of CF vary from person to person. Some people with CF have
serious lung and digestive problems. Other people have more mild disease that doesn't
show up until they are adolescents or young adults.
Respiratory failure is the most common cause of death in people with CF.
Until the 1980s, most deaths from CF occurred in children and teenagers. Today, with
improved treatments, people with CF live, on average, to be more than 35 years old.
Research continues to look for better treatments and a cure.
What Causes Cystic Fibrosis?
CF is caused by a defect in a gene called the cystic fibrosis transmembrane conductance
regulator (CFTR) gene. This gene makes a protein that controls the movement of salt and
water in and out of the cells in your body. In people with CF, the gene does not work
effectively. This causes the thick, sticky mucus and very salty sweat that are the main
features of CF.
Each of us inherits two CFTR genes, one from each parent.
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Children who inherit an abnormal CFTR gene from each parent will have CF.
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Children who inherit an abnormal CFTR gene from one parent and a normal CFTR
gene from the other parent will not have CF. They will be CF carriers.
CF carriers:
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Usually have no symptoms of CF
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Live normal lives
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Can pass the abnormal CFTR gene on to their children
When two CF carriers have a baby, the baby has a:
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One in four chance of inheriting two abnormal CFTR genes and having CF.
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One in four chance of inheriting two normal CFTR genes and not having CF or being a
carrier.
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Two in four chance of inheriting one normal CFTR gene and one abnormal CFTR
gene. The baby will not have CF but will be a CF carrier like its parents.
Who Is At Risk for Cystic Fibrosis?
About 30,000 people in the United States have cystic fibrosis (CF).
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It affects both males and females.
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It affects people from all racial and ethnic groups but is most common among
Caucasians whose ancestors came from northern Europe.
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CF is one of the most common inherited diseases among Caucasians.
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About one in every 3,000 babies born in the United States has CF.
CF is also common in:
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Latinos
Native Americans, especially the Pueblo and Zuni
CF is much less common among:
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African Americans
Asian Americans
About 12 million Americans are carriers of an abnormal CF gene. Many of them do not know
that they are CF carriers.
What Are the Signs and Symptoms of Cystic Fibrosis?
Most of the symptoms of cystic fibrosis (CF) are caused by the thick, sticky mucus. The
most common symptoms include:
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Frequent coughing that brings up thick sputum, or phlegm (flem).
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Frequent bouts of bronchitis and pneumonia. They can lead to inflammation and
permanent lung damage.
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Salty-tasting skin.
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Dehydration.
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Infertility (mostly in men).
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Ongoing diarrhea or bulky, foul-smelling and greasy stools.
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Huge appetite but poor weight gain and growth. This is called "failure to thrive." It is
a result of chronic malnutrition from not getting enough nutrients from food.
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Stomach pain and discomfort caused by too much gas in the intestines.
CF also can lead to other medical problems, including:
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Sinusitis. The sinuses are air-filled spaces behind the eyes, nose and forehead. They
produce mucus and help keep the lining of the nose moist. When the sinuses become
swollen, they get blocked with mucus and can become infected. Most people with CF
develop sinusitis.
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Bronchiectasis. Bronchiectasis is a lung disease in which the bronchial tubes, or
large airways in the lungs, become stretched out and flabby over time and form
pockets where mucus collects. The mucus provides a breeding ground for bacteria.
This leads to repeated lung infections. Each infection does more damage to the
bronchial tubes. If not treated, bronchiectasis can lead to serious illness, including
respiratory failure.
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Pancreatitis. Pancreatitis is inflammation in the pancreas that causes pain.
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Episodes of intestinal blockage, especially in newborns.
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Nasal polyps, or growths in the nose, that may require surgery.
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Clubbing. Clubbing is the widening and rounding of the tips of the fingers and toes.
It develops because the lungs are not moving enough oxygen into the blood stream.
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Collapsed lung. This is also called pneumothorax.
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Rectal prolapse. Frequent coughing or problems passing stools may cause rectal
tissue from inside to move out of the rectum.
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Liver disease due to inflammation or blocked bile ducts.
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Diabetes.
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Gallstones.
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Low bone density because of a lack of Vitamin D.
How Is Cystic Fibrosis Diagnosed?
First, the doctor will obtain a detailed medical and family history and perform a thorough
physical examination. Next, the doctor may order some tests to ensure an accurate
diagnosis.
The sweat test is the most useful test for diagnosing cystic fibrosis (CF). It measures the
amount of salt in the sweat. For this test, doctors rub a small amount of a chemical called
pilocarpine on your arm or leg. They then attach an electrode to this spot. The electrode
provides a mild electric current that produces sweat. This may cause tingling or a feeling of
warmth. They then cover the area with a gauze pad or filter paper and wrap in plastic. After
30 to 40 minutes, they remove the plastic so the sweat that collected on the pad or paper
can be analyzed. The test is usually done twice. High salt levels mean CF.
Your doctor also may do the following tests to understand more about your condition and
how to treat it:
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Blood tests to look for an abnormal CF gene or other things that indicate CF.
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Chest X-ray. A chest X-ray takes a picture of your lungs. It can show scarring from
inflammation in your lungs.
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Sinus X-ray. This test may show signs of sinusitis.
Lung function tests can measure:
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How much air your lungs can hold
How quickly you can breathe air out of your lungs
How well your lungs add oxygen to and remove carbon dioxide from your blood
Sputum (phlegm) cultures. Doctors take a sample of your sputum to see what
bacteria are growing in it.
Testing During Pregnancy
If you are pregnant, prenatal genetic tests can find out if your baby has CF:
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Amniocentesis. The doctor inserts a hollow needle through the abdominal wall into
the uterus to obtain cells from the fluid (amniotic fluid) around the baby. The fluid is
then tested to see if both of the baby's CFTR genes are normal.
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Chorionic villus biopsy. The doctor uses ultrasound to guide a thin tube through
the vagina and cervix into the uterus and remove a tiny piece of the placenta to
biopsy. The cells of the placenta are then tested to see if the baby has CF.
Some States are now testing the blood of all newborns for CF.
CF Carrier Testing
You may want to check whether you are a CF carrier, if:
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You have a family history of CF.
You are a partner of someone with CF.
You are a couple planning a pregnancy.
A genetics counselor at your local hospital can take a blood or saliva sample to see if it
contains the abnormal CFTR gene that causes CF. It will detect nine out of 10 cases of CF.
Some insurance plans cover genetic testing.
How Is Cystic Fibrosis Treated?
There still is no cure for cystic fibrosis (CF), but treatments have improved greatly in recent
years. The goals of CF treatment are to:
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Prevent and control infections in the lungs.
Loosen and remove the thick, sticky mucus from the lungs.
Prevent blockages in the intestines.
Provide adequate nutrition.
Treatment for Lung Problems
The main treatments for lung problems in people with CF are:
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Antibiotics for infections of the airways
Chest physical therapy
Exercise
Other medications
Antibiotics
Most people with CF have ongoing, low-grade lung infections. Sometimes, these infections
become so serious that they require hospitalization. Antibiotics are the primary treatment.
Several different types of antibiotics may be given. The choice of antibiotics depends on:
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The strains of bacteria involved
How serious the condition is
Previous history of antibiotic use
The different types of antibiotics include:
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Oral antibiotics for relatively mild airway infections.
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Inhaled antibiotics, such as tobramycin. They may be used alone or with oral
antibiotics.
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Intravenous antibiotics for severe infections or when none of the oral antibiotics
work.
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Antibiotics, such as azithromycin, that also reduce inflammation.
Chest Physical Therapy
Chest physical therapy (CPT) is also called chest clapping or percussion. It involves
pounding the chest and back over and over again to dislodge the mucus from the lungs so
that the mucus can be coughed up. CPT for cystic fibrosis should be done three to four
times each day.
CPT is also often referred to as postural drainage. This involves your sitting or lying on your
stomach with your head down while you do CPT. This allows gravity to help drain the mucus
from your lungs.
Because CPT is hard or uncomfortable for some people, several devices have been
developed recently that may help with CPT. The devices include:
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An electric chest clapper, known as a mechanical percussor.
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An inflatable therapy vest that uses high-frequency air waves to force the mucus out
of the lungs.
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A "flutter" device, a small hand-held device that you breathe out through. It causes
vibrations that dislodge the mucus.
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A positive expiratory pressure (PEP) mask that creates vibrations that help break the
mucus loose from the airway walls.
Several breathing techniques also may help dislodge the mucus. These techniques include:
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Forced expiration technique (FET) — forcing out a couple of breaths or huffs and
then doing relaxed breathing
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Active cycle breathing (ACB) — FET with deep breathing exercises that can loosen
mucus in the lungs and help open the airways
Exercise
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Aerobic exercise helps:
Loosen the mucus
Encourage coughing to clear the mucus
Improve overall physical condition
With regular exercise, some people with CF are able to cut back on their chest therapy. A
doctor should be consulted before doing this.
Other Medications
Anti-inflammatory medications may help reduce inflammation in the lungs caused by
ongoing infections. These medications include:
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Inhaled or, sometimes, oral steroids. Steroids are the most effective antiinflammatory medicines.
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Ibuprofen, a type of nonsteroidal, anti-inflammatory medicine. It may slow the
progress of CF in young children with mild symptoms.
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Bronchodilators, which are inhaled drugs that relax the muscles around the airways
so that the airways can open up. They should be taken just before CPT to help clear
mucus.
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Mucus-thinning drugs reduce the stickiness of mucus in the airways. They include
o Human DNase (Dornase Alfa), a drug that loosens the mucus in the lungs. It
may lead to shorter hospital stays.
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Acetylcysteine and saline.
Hypertonic saline, a solution of very salty sterile water taken by nebulizer two
times a day, can help clear mucus and improve lung function. Some doctors
are now giving it to select patients older than 6.
Oxygen Therapy
If the level of oxygen in the blood is too low, oxygen therapy may be needed. Oxygen is
usually given through nasal prongs or a mask.
Lung Transplantation
Surgery to replace one or both of the lungs with healthy lungs from a human donor may
help. Some of the factors that determine whether a patient can undergo lung
transplantation include:
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Type of bacteria in the lungs
Age and weight
Medications being taken
Other medical conditions, including osteoporosis
How well the lungs are functioning
Management of Digestive Problems
Nutritional therapy can improve growth and development, strength and exercise tolerance.
It also may help a person with CF resist some lung infections. Nutritional therapy includes a
well-balanced diet that is rich in calories, fat and protein.
As part of nutritional therapy, the doctor may:
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Prescribe oral pancreatic enzymes to help with digestion of fats and proteins and
absorption of more vitamins. The enzymes are taken in capsule form before every
meal, including snacks.
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Recommend supplements of vitamins A, D, E and K to replace the fat-soluble
vitamins that the intestines of someone with CF cannot absorb.
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Recommend the use of a feeding tube, called a gastrostomy tube or T-tube, to add
more calories at night during sleep. The tube is placed in the stomach. Before bed
each night, a bottle with a nutritional solution is attached to the entrance of the
tube.
Other treatments for the digestive problems caused by CF may include:
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Enemas and mucus-thinning medications to treat intestinal blockages
Medicines that reduce stomach acid and help the oral pancreatic enzymes work
better
Living With Cystic Fibrosis
If you or your child have cystic fibrosis (CF), you should learn as much as you can about the
disease and work closely with doctors to learn how to manage it.
Ongoing medical care is important. You should seek treatment from a team of doctors,
nurses and respiratory therapists who specialize in CF. These specialists are often located
at CF Foundation Centers in major medical centers.
Good self-care includes:
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Eating a healthy diet
Avoiding tobacco smoke
Washing hands often to reduce chances of infection
Exercising frequently
Drinking lots of fluids
Doing chest physical therapy every day
Having annual flu and other appropriate vaccinations
Taking medicines as prescribed
Having a positive attitude is also helpful.
If you are a parent of someone with CF, do not feel guilty about passing it on to your child.
And do not be overprotective; encourage your child to be active and self-reliant.
Source: National Heart, Lung and Blood Institute, National Institutes of Health
Updated: July 2008