Cystic fibrosis is a hereditary disease the symptoms of which usually appear shortly after
birth. These symptoms include faulty digestion,
breathing difficulties, and respiratory infections due to mucus
accumulation, and excessive loss of salt in sweat. Cystic fibrosis (CF)
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 the food that is eaten. Without them, the intestines
cannot absorb fats and proteins fully.
As a result:
The abnormal gene also causes the sweat to become extremely salty. As a
result, during perspiration, the body loses large amounts of salt. This
can upset the balance of minerals in the blood. The imbalance may cause
the individual to have a heat emergency.
- Nutrients leave the body unused, and the individual can become malnourished.
- The stools become bulky.
- The individual may not get enough vitamins A, D, E, and K.
- The individual may have intestinal gas, a swollen belly, and pain
CF can also 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, ultimately, a cure.
What causes cystic fibrosis?
Cystic fibrosis 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
the 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.
- Children who inherit an abnormal CFTR gene from each parent will have
- 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.
When two CF carriers have a baby, the baby has a:
- Usually have no symptoms of CF
- Live normal lives
- Can pass the abnormal CFTR gene on to their children
- One in four chance of inheriting two abnormal CFTR genes and having
- One in four chance of inheriting two normal CFTR genes and not having
CF or being a carrier.
- 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
Who is at risk for cystic fibrosis?
About 30,000 people in the United States have cystic fibrosis.
CF is one of the most common inherited diseases among Caucasians.
- It affects both males and females.
- It affects people from all racial and ethnic groups but is most common
among Caucasians whose ancestors came from northern Europe.
About 1 in every 3,000 babies born in the United States has CF.
CF is also common in:
CF is much less common among:
- Native Americans, especially the Pueblo and Zuni
- 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.
the signs and symptoms of cystic fibrosis?
Most of the symptoms of cystic fibrosis are caused by the thick, sticky
mucus. The most common symptoms include:
CF can also lead to other medical problems, including:
- Frequent coughing that brings up thick sputum, or phlegm.
- Frequent bouts of bronchitis and pneumonia. They can lead to inflammation and permanent lung damage.
- Salty-tasting skin.
- Infertility (mostly in men).
- Ongoing diarrhea or bulky, foul-smelling,
and greasy stools.
- Huge appetite but poor weight gain and growth. This is called "failure
to thrive." It is a result of chronic malnutrition because the individual
does not get enough nutrients from his or her food.
- Stomach pain and discomfort caused by too much gas in the intestines.
- 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.
- 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.
- Pancreatitis. Pancreatitis is inflammation in the pancreas that causes
- Episodes of intestinal blockage, especially in newborns.
- Nasal polyps, or growths in the nose,
that may require surgery.
- 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.
- Collapsed lung. This is also called pneumothorax.
- Rectal prolapse. Frequent coughing or problems passing stools may
cause rectal tissue from inside the body to move out of the rectum.
- Liver disease due to inflammation or blocked bile
- Low bone density because the individual does not get enough vitamin
How is cystic fibrosis diagnosed?
First, a doctor will obtain a detailed medical and family history and perform
a thorough physical examination. The doctor may order some tests to ensure
an accurate diagnosis.
The sweat test is the most useful test for diagnosing cystic fibrosis. It
measures the amount of salt in the sweat. For this test, a small amount
of a chemical called pilocarpine is rubbed on the patient's arm or leg.
An electrode is then attached to this spot. The electrode provides a mild
electric current that produces sweat. This may cause tingling or a feeling
of warmth. The area is then covered with a gauze pad or filter paper and
wrap in plastic. After 30 to 40 minutes, the plastic is removed so the sweat
that collected on the pad or paper can be analyzed. The test is usually
done twice. High salt levels mean CF.
The following tests may also be carried out to understand more about a patient's
condition and how to treat it:
If the patient is pregnant, prenatal genetic tests can find out if the baby
- Blood tests to look for an abnormal
CF gene or other things that indicate CF.
- Chest X-ray. A chest X-ray takes
a picture of the lungs. It can show scarring from inflammation in the
- Sinus X-ray. This test may show signs of sinusitis.
- lung function tests can
- How much air the lungs can hold
- How quickly the individual can breathe air out of his or her lungs
- How well the lungs add oxygen to and remove carbon dioxide from
- Sputum (phlegm) cultures. A sample of sputum is taken to see what
bacteria are growing in it.
Some States are now testing the blood of all newborns for CF.
- In amniocentesis, a hollow needle
is inserted through the abdominal wall into the uterus to obtain cells from the amniotic
fluid around the baby. The fluid is then tested to see if both of
the baby's CFTR genes are normal.
- In chorionic villus
sampling, ultrasound is used 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.
CF carrier testing
Individuals may want to check whether they are a CF carrier, if:
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
9 out of 10 cases of CF. Some insurance plans cover genetic testing.
- They have a family history of CF.
- They are a partner of someone with CF.
- They are a couple planning a pregnancy.
How is cystic fibrosis treated?
There still is no cure for cystic fibrosis, but treatments have improved
greatly in recent years. The goals of CF treatment are to:
- 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:
- Antibiotics for infections of the airways
- Chest physical therapy
- Other medications
Most people with CF have ongoing, low-grade lung infections. Sometimes,
these infections become so serious that the individual may need to be hospitalized.
Antibiotics are the primary treatment.
Several different types of antibiotics may be given. The choice of antibiotics
The different types of antibiotics include:
- The strains of bacteria involved
- How serious the condition is
- Previous history of antibiotic use
- Oral antibiotics for relatively mild airway infections.
- Inhaled antibiotics, such as tobramycin. They may be used alone or
with oral antibiotics.
- Intravenous antibiotics for severe infections or when none of the
oral antibiotics work.
- 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 it 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 the individual
sitting or lying on their stomach with their head down while CPT is performed.
This allows gravity to help drain the mucus from the lungs.
Because CPT is hard or uncomfortable for some people, several devices have
been developed recently that may help with CPT. The devices include:
Several breathing techniques may also help dislodge the mucus. These techniques
- An electric chest clapper, known as a mechanical percussor.
- An inflatable therapy vest that uses high-frequency air waves to force
the mucus out of the lungs.
- A "flutter" device, a small hand-held device that the individual breathes
out through. It causes vibrations that dislodge the mucus.
- A positive expiratory pressure (PEP) mask that creates vibrations
that help break the mucus loose from the airway walls.
- Forced expiration technique (FET) – forcing out a couple of
breaths or huffs and then doing relaxed breathing
- Active cycle breathing (ACB) – FET with deep breathing exercises
that can loosen the mucus in the lungs and help open the airways
Aerobic exercise helps:
If an individual exercises regularly, he or she may be able to cut back
on the chest therapy. A doctor should be consulted before doing this.
- Loosen the mucus
- Encourage coughing to clear the mucus
- Improve overall physical condition
Anti-inflammatory medications may help reduce the inflammation in the lungs
that is caused by ongoing infections. These medications include:
Mucus-thinning drugs reduce the stickiness of mucus in the airways. They
- Inhaled or, sometimes, oral steroids. Steroids are the most effective
- Ibuprofen, a type of non-steroidal
anti-inflammatory medicine. It may slow the progress of CF in young
children with mild symptoms.
- 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.
- Human DNase (Dornase Alfa), a drug that loosens the mucus in the lungs.
It may lead to shorter hospital stays.
- Acetylcysteine and saline.
- Saline washes of the nasal passages, which may help clear sinuses.
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.
Surgery to replace one or both of the lungs with healthy lungs from a human
donor may help the individual. Some of the factors that determine whether
a person can undergo lung transplantation include:
- The type of bacteria in the lungs
- The patient's age and weight
- The medications being taken
- Whether the patient has 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 may also make an individual strong enough to resist some lung
infections. Nutritional therapy includes a well-balanced, high-calorie diet
that is low in fat and high in protein.
As part of your nutritional therapy, a doctor may:
Other treatments for the digestive problems caused by CF may include:
- Prescribe oral pancreatic enzymes to help the patient digest fats
and proteins and absorb more vitamins. The enzymes should be taken in
capsule form before every meal, including snacks.
- Recommend supplements of vitamins A, D, E, and K to replace the fat-soluble
vitamins that the patient's intestines cannot absorb.
- Recommend use of a feeding tube, called a gastrostomy tube or T-tube,
to add more calories at night while the person are sleeping. 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. It feeds the individual
while they sleep.
- Enemas and mucus-thinning medications to treat intestinal blockages
- Medicines that reduce stomach acid and help the oral pancreatic enzymes
Living with cystic fibrosis
People with cystic fibrosis should learn as much as they can about the disease
and work closely with their doctors to learn how to manage it.
Ongoing medical care is important. Individuals with CF 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
Good self-care includes:
People with CF can expect to have a normal sex life.
- Eating a healthy diet
- Avoiding tobacco smoke
- Washing hands often to reduce the 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.
- Most men with CF are infertile, but they may be helped with modern
- Although most women with CF may be less fertile than women who don't
have CF, they usually can have children.
Parents of someone with CF should not feel guilty about passing it on to
their children. And they should not be overprotective; children with CF
should be encouraged to be active and self-reliant.
Source: U.S. National
Heart, Lung and Blood Institute