What Causes Cystic Fibrosis?
is Cystic Fibrosis?
Cystic fibrosis (CF) — a life-threatening disorder that
causes severe lung damage and nutritional deficiencies. CF is an inherited
(genetic) condition affecting the cells that produce mucus, sweat, saliva
and digestive juices. Normally, these secretions are thin and slippery,
but in CF, a defective gene causes the secretions to become thick and
sticky. Instead of acting as a lubricant, the secretions plug up tubes,
ducts and passageways, especially in the pancreas and lungs. Respiratory
failure is the most dangerous consequence of CF. Each year approximately
3,200 white babies are born in the United States with CF. The disease
is much less common among black and Asian-American children. Most babies
born with CF are diagnosed by age 3, although mild forms of the disease
may not be detected until the third, fourth or fifth decade of life. In
all, about 30,000 American adults and children are living with the disorder.
Although there's still no cure, the emerging field of gene therapy may
someday help correct lung problems in people with CF.
The symptoms of cystic fibrosis usually appear within the first year of
life, but may not appear until late childhood or adolescence. The specific
signs and symptoms of CF can vary, depending on the severity of the disease
and with age. For example, one child with CF may have respiratory problems
but not digestive problems, while another child may have both.
In some newborns the first sign may be a blockage of the intestines (meconium
ileus). This occurs when meconium — tarry, greenish-black stools
normally passed by an infant in the first day or two after birth —
becomes so thick it can't move through the intestines. Other signs in
newborns may include a failure to grow, bulky and greasy stools (steatorrhea),
and frequent respiratory infections.
The signs and symptoms of CF in children and young adults may include:
- Salty taste to the skin. People with CF tend to have two to five times
the normal amount of salt (sodium chloride) in their sweat. This may
be one of the first signs parents notice because they taste the salt
when they kiss their child.
- Blockage in the bowel.
- Foul-smelling, greasy stools.
- Delayed growth.
- Thick sputum. It's easy for parents to overlook this symptom because
infants and young children tend to swallow their sputum rather than
cough it up.
- Coughing or wheezing.
- Frequent chest and sinus infections with recurring pneumonia or bronchitis.
- Growths (polyps) in the nasal passages.
- Cirrhosis of the liver due to inflammation or obstruction of the bile
- Displacement of one part of the intestine into another part of the
intestine (intussusception) in children older than age 4.
- Protrusion of part of the rectum through the anus (rectal prolapse).
This is often caused by stools that are difficult to pass or by frequent
- Enlargement or rounding (clubbing) of the fingertips and toes. Although
clubbing eventually occurs in most people with CF, it also occurs in
some people born with heart disease and other types of lung problems.
It is most common in Caucasian-American children, occurring in about one
in every 2,000 births. It is less common among African-American children,
(about one in 17,000 births), and even more rare among Asian Americans
(one in 100,000 births).
The mode of inheritance is autosomal, which means that it does not involve
the x or y chromosomes, which determine sex. It is also recessive, which
means that the disease is inherited from both parents. About five percent
of Caucasian Americans (one in 28) are believed to carry the gene. Carriers
do not have symptoms of the disease, and often do not even realize that
they are one of more than 10 million people who carry cystic fibrosis.
The number of cystic fibrosis carriers is likely to increase in the future.
This chart can help you determine the genetic probability of having
a child with cystic fibrosis
Chance of Unaffected Child
Chance of Child Carrier
Chance of Child with CF
Unaffected + Carrier
Unaffected + CF Patient
Carrier + CF Patient
for Cystic Fibrosis
Many treatments exist for the symptoms and complications of CF. The main
goal is to prevent infections, reduce the amount and thickness of secretions
in the lungs, improve airflow, and maintain adequate calories and nutrition.To
accomplish these objectives, treatments for CF may include:
- Antibiotics. Newer antibiotics may more effectively
fight the bacteria that cause lung infections in people with CF. Among
these are aerosolized antibiotics that send medication directly into
airways. One of the major drawbacks of long-term use of antibiotics
is the development of bacteria that are resistant to drug therapy.
- Mucus-thinning drugs. When your white blood cells
attack bacteria in your airways, DNA in the cells is released, making
the mucus in your airways even thicker. The aerosolized drug dornase
alfa (Pulmozyme) is an enzyme that fragments DNA, making mucus thinner
and easier to cough up. Side effects of Pulmozyme may include airway
irritation and sore throat.
- Bronchodilators. Use of medications such as albuterol
(Proventil, Ventolin) may help keep open the bronchial tubes by clearing
- Bronchial airway drainage. People with CF need a
way to physically remove thick mucus from their lungs. This is often
done by manually clapping on the front and back of the chest —
a procedure that's best performed with the person's head over the edge
of the bed so that gravity helps clear the secretions. In some cases
an electric chest clapper, known as a mechanical percussor, is used.
An inflatable vest that vibrates at high frequency can also help people
with CF cough up secretions. Both adults and children with CF need to
have bronchial airway drainage at least twice a day for 20 to 30 minutes.
Older children and adults can learn to do this themselves, especially
if they use mechanical aids such as vests and percussors. Young children
need the aid of parents, grandparents or older siblings.
- Exercise. Children with CF should be active. They
can swim, ride bikes, run, play sports and games. Most children with
CF can do any exercise they want.
- Loosen mucus in the lungs so it can be coughed up easier;
- Cause coughing, which helps clear the lungs;
- Strengthen breathing muscles and the heart.
- Oral enzymes and better nutrition. CF can cause you
to become malnourished because the pancreatic enzymes needed for digestion
don't reach your small intestine, preventing food from being absorbed.
As a result, you may need many more calories than you otherwise would.
Supplemental high-calorie nutrition, special vitamins and enteric-coated
oral pancreatic enzymes can help you maintain or even gain weight.
Lung transplantation. Your doctor may suggest lung transplantation
if you have severe breathing problems, life-threatening pulmonary complications
or increasing resistance to antibiotics used to treat lung infections.
Whether you're a good candidate for the procedure depends on a number
of factors, including your overall health, certain lifestyle factors and
the availability of donor organs. Because both lungs are affected by CF,
both need to replaced. If your chest isn't large enough to hold two adult
donor lungs, your surgeon is likely to use two lower lobes contributed
by two living donors. However it's performed, lung transplantation is
a major operation and may lead to serious complications, especially post-surgical
infections. The five-year survival rate has increased in the last 10 years,
CF Caregiver Well-Being
If you have a child with CF, one of the best things you can do is to
learn as much as possible about the disease. Diet, medication and early
recognition of infection are important.Also important is performing daily
chest percussion to drain mucus from your child's lungs. Your doctor or
respiratory therapist can show you the best way to perform this lifesaving
procedure. In addition, the following steps can help aid your child's
- Keep your child's immunizations up-to-date. This
includes your child's pneumococcal and influenza vaccines. CF doesn't
affect the immune system, but children with CF are more likely to develop
complications when they become sick.
- Encourage your child to lead as normal and active a life
as possible. Exercise is extremely important for people of
all ages who have CF. Regular exercise helps loosen mucus in your airways
and strengthens your heart and lungs. And for many people with CF, participating
in sports can improve confidence and self-esteem.
- Make sure your child eats a healthy diet. Be sure
to discuss your child's dietary needs with your doctor or a nutritionist.
Use nutrition supplements. Provide the fat-soluble
vitamin supplements and pancreatic enzymes your child needs to stay
as healthy as possible.
- Emphasize liquids. Encourage your child to drink
plenty of liquids to help loosen the mucus. This is especially important
in the summer when children are active and tend to lose a lot of fluids.
- Eliminate smoke. Don't smoke in your home or car,
and don't allow other people to smoke around your child. Secondhand
smoke is harmful for everyone, but especially for people with CF.
- Encourage hand washing. Teach everyone in your family
to wash their hands thoroughly before eating, after using the bathroom,
when coming home from work or school, and after being around a person
who is sick. Hand washing is the best way to protect against infection.
To stay healthy, those with cystic fibrosis need regular visits and
examinations at a Cystic
Fibrosis Foundation-accredited care center. These centers provide
specialized care for those with cystic fibrosis. Usually patients
are seen every six to eight weeks by the specialized cystic fibrosis
team. This team consists of a doctor, nurse, respiratory therapist,
dietitian, physical therapist, social worker and in some cases a psychologist.
Knowing the change or increase in symptoms is helpful. It is important
for patients with cystic fibrosis to exercise, eat healthy high calorie
diets, and take their medications and treatments as directed even
though the treatments take up a great deal of time.