What Is Cystic Fibrosis?

Just 10 years ago, cystic fibrosis (CF) a life-threatening disorder that causes severe lung damage and nutritional deficiencies was a genetic mystery, and most people with the disease didn't live beyond their teens. Since then researchers have made real progress in unraveling the genetic basis of CF, which has led to earlier detection. Because of this and improved and more consistent treatments for the disease, many people with CF now live into their 30s and have fuller and more comfortable lives.

CF is an inherited (genetic) condition affecting the glands that produce mucus, tears, 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 may 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. Two-thirds of the infants born with CF will be diagnosed in the first year of life. In all, about 30,000 American adults and children are living with this disorder. Although there's still no cure, the emerging field of gene therapy may someday help correct lung problems in people with CF.

Children's Health Center

Signs and Symptoms

The specific signs and symptoms of CF can vary, depending on the severity of the disease. For example, one child with CF may have respiratory problems but not digestive problems, while another child may have both. In addition, the signs and symptoms of CF may vary with age.

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. Infants and young children tend to swallow their sputum, and parents may not be aware of it.
  
  
• Chronic coughing or wheezing.
  
  
• Frequent chest and sinus infections with recurring pneumonia or bronchitis.
  
  
• Growths (polyps) in the nasal passages.
  
  
• 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.
  
  
• Cirrhosis of the liver due to inflammation or obstruction of the bile ducts.
  
  
• 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 coughing.

Intussusception Cirrhosis

Causes

In CF, a defective gene alters a protein that regulates the normal movement of salt (sodium chloride) in and out of cells. This results in thick, sticky secretions in the respiratory and digestive tracts, as well as in the reproductive system. It also causes increased salt in sweat on the skin.

The affected gene, which is inherited from a child's parents, is known as a recessive gene. This means children need to inherit two copies of the gene, one from each parent, in order to have the disease. If children inherit only one copy, they won't develop CF, but they will be carriers and possibly pass the gene to their own children.

If two people who carry the defective gene conceive a child, there's a 25 percent chance the child will have CF, a 50 percent chance the child will be a carrier of the CF gene, and a 25 percent chance the child will neither be a carrier nor have the disease.

People who carry the CF gene are healthy and have no symptoms of disease. In fact, it's estimated that as many as 10 million people may be carriers of a CF gene and not know it. Currently, it's not possible to identify everyone who carries the gene. But researchers are working to develop a test for all carriers.

Although parents often blame themselves when a child is born with CF, it's important to remember that nothing a parent does causes this disease.

Risk Factors

The greatest risk factor for CF is a family history of the disease. If both parents come from families with CF, the chances are one in four that each of their children will also have CF. In addition, CF occurs mainly in whites of Northern European ancestry. It's relatively rare in black Americans and Asian-Americans.

When to Seek Medical Advice

See your doctor if you suspect your child has CF. Signs and symptoms in newborns may include failure to grow, chronic respiratory problems especially recurrent pneumonia and frequent bulky, greasy stools. Older children also may have diarrhea and frequent respiratory infections, including pneumonia. Failure to grow steadily on the growth percentile curve may also be a sign of CF, especially if other signs and symptoms are present. Call your doctor right away if, after diagnosis, your child develops fever, a worsening cough, breathing difficulties, change in level of tiredness or decreased appetite.

In addition, if your child has received a diagnosis of CF, arrange regular examinations at a CF clinical center. Your child will also need to see your family doctor on a regular basis to have medications and any lung or digestive problems monitored.

Diarrhea Fever

Screening and Diagnosis

The standard diagnostic test for CF is a sweat test, which measures the amount of sodium and chloride in a person's sweat. During the procedure a small amount of an odorless sweat-producing chemical is applied to a small area on the arms or legs. An electrode attached to the area stimulates a very weak electric current, causing a tingling or warm feeling. After several minutes, sweat is collected from the stimulated area and sent to a laboratory for analysis.

The sweat test is performed twice. A consistently high level of salt indicates CF. This test doesn't show whether someone has a mild or severe case of the disease, however, and it can't predict how well someone with CF will do.

In addition, the sweat test may not always be useful in newborns. That's because babies may not produce enough sweat for a reliable diagnosis in the first month of life. For this reason, doctors usually don't perform a sweat test until an infant is at least several months old.

In some cases your doctor may perform a genetic analysis of a blood sample to confirm a diagnosis of CF. Researchers have identified more than 800 changes in a gene that when paired with another abnormal gene can result in CF. Testing is possible on approximately 30 of the most common genetic mutations. About 90 percent of people with CF can be detected through genetic analysis.

Tests may also help determine the extent and severity of CF. Among these are tests to measure how well the lungs, pancreas and liver are working.

Because CF is an inherited disease, your doctor may suggest testing of brothers and sisters of a child with CF, even if the siblings show no symptoms. Other family members, especially first cousins, also may want to be tested. In most cases family members can be screened with a sweat test, although in some cases genetic testing may be appropriate.

Complications

The most frequent complications of CF are chronic respiratory infections, including pneumonia, bronchitis and bronchiectasis an abnormal dilation of the walls of the bronchial tubes that makes it more difficult to clear your airways.

Respiratory infections are common because thick mucus blocks the airways and provides a perfect breeding ground for bacteria. The most common infective agent in people with CF is Pseudomonas aeruginosa a bacterium that can cause increased inflammation of the respiratory tract. Although antibiotics can decrease the frequency and severity of attacks, the bacteria are never completely eradicated from the airways and the lungs.

People with CF may also develop collapsed lung — a condition in which lung air leaks into the chest cavity (pneumothorax) — bleeding from the lungs (hemoptysis) or respiratory failure. Because of lung disease, the right ventricle of the heart also may fail (cor pulmonale). Ultimately, complications from lung problems may prove fatal for many people with CF.


In addition, cystic fibrosis makes you prone to chronic diarrhea and severe nutritional deficiencies. That's because thick secretions obstruct the ducts in the pancreas, preventing enzymes that digest fats and proteins from reaching your intestines. These secretions also prevent your body from absorbing the fat-soluble vitamins A, D, E and K.

CF affects the pancreas and because the pancreas controls the level of sugar in your blood, about 7 percent of people with CF may develop type 1 diabetes — formerly called juvenile or insulin-dependent diabetes. In addition, the bile duct, the duct that carries bile from your liver and gallbladder to your small intestine, may become blocked and inflamed, leading to liver problems.

CF also affects the reproductive system. Because thick secretions often block the tube connecting the testes and prostate gland (vas deferens), many men with CF are infertile. But certain fertility methods and surgical procedures may sometimes make it possible for men with CF to become fathers.

Although women with CF may be less fertile than other women are, it's possible to conceive and to have successful pregnancies. Discuss with your doctor the options and weigh carefully the possible risks. In addition, using oral contraceptives can sometimes aggravate certain symptoms of CF. Discuss your birth control options with your doctor.

Pneumonia Bronchitis Bronchiectasis Collapsed lung (pneumothorax) Diabetes Diabetes Center Infertility

Treatment

Many treatments exist for the symptoms and complications of CF. The main goal is to treat infections, keep the lungs free of sputum, 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. Oral and intravenous antibiotics have made antibiotic therapy available on an outpatient basis. And aerosolized antibiotics that can be inhaled, such as tobramycin (Tobi), provide medication directly into airways. The drawbacks to long-term antibiotic therapy include the development of bacteria that are resistant to antibiotics.
  
  
• Mucus-thinning drugs. DNA, the basic material in your white blood cells, is released when these cells attack bacteria in your airways, making the mucus in the airways even thicker. The aerosolized drug dornase alpha (Pulmozyme) is an enzyme that fragments DNA, making mucus thinner and easier to cough up. Side effects of Pulmozyme may include chest irritation and sore throat.
  
  
• Bronchodilators. Use of medications such as albuterol (Proventil, Ventolin) may help keep the airways in the lungs open by helping to clear thick bronchial secretions.
  
  
• 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. In some cases an electric chest clapper, known as a mechanical percussor, is used. Some people may use an inflatable vest with a machine attached that vibrates at high frequency to help 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 even older siblings.
  
  
• Oral enzymes and better nutrition. CF can result in your becoming malnourished because the pancreatic enzymes needed for digestion don't reach your small intestine. As a result you may need 50 percent to 100 percent more calories than you would if you were healthy. Supplemental high-calorie nutrition, special vitamins and enteric-coated oral pancreatic enzymes can enable you to maintain or even gain weight.

Using antibiotics sensibly

Future treatments

One of the biggest breakthroughs in CF research came in 1989, when researchers identified the gene that, when defective, causes the disease. Since then scientists have been studying ways to insert copies of the normal gene into cells of the respiratory tract.

The challenge has been to find a reliable way to deliver the normal genetic material to affected cells that line the airways. Several methods have been developed as delivery systems, including using modified viruses, fat capsules (liposomes) and synthetic vectors. Clinical trials are under way to test the effectiveness of these delivery systems.

Other research is focusing on modifying the protein that the CF gene produces. This may help normalize the movement of salt and water in and out of the cells.

Prevention

If you have a family history of CF, you may want to consider genetic counseling before starting a family. In many cases carriers of this disorder can be identified through testing.

Self-Care

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 health:

• Keep your child's immunizations up-to-date. This includes your child's pneumococcal and influenza vaccines. CF doesn't affect the immune system itself, 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 his or her 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 his or her 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.

Things you need to know about children's immunizations Secondhand smoke Childhood illnesses: Prevent the 7 usual suspects

Coping Skills

After you or someone you love receives a diagnosis of cystic fibrosis, you may experience many emotions, including anger, concern, guilt and fear. These are all normal responses. Allow yourself to experience these feelings, but also to recognize and work through them. Talking openly about how you feel can help. It may also help to talk with others who are dealing with the same issues.

That might mean joining a support group for parents of children with CF. Or, if your child is older, he or she may want to join a CF group to meet and talk with others who have the disease.

Support groups aren't for everyone. But often members of these groups can share information, experiences and solutions about the unique challenges associated with CF. If a support group isn't available in your area, you might want to join Cystic-L, an e-mail support group for people with CF.

A social worker at your CF treatment center may also be able to put you in touch with another family who is dealing with CF. Learning how other meet certain challenges may help you find solutions that work for you.

Helping a child live normally

It's natural for parents to want to protect their children. This is even truer when the child has a chronic illness. But the best gift you can give a child with CF is a sense of normalcy. And in fact, most children with CF go to school, participate in sports and have active social lives. In time they may graduate from college and embark on careers, and many marry and raise families. Encouraging your child to be independent and self-reliant can help him or her have the fullest life possible.

Preparing for the future is also key. Parents of a child with CF need to plan for their child's education and financial future, just as they would for any other child.

Still, no matter how hard parents try to make life normal, children with CF often feel different. Even young children soon learn that not everyone has chest physical therapy or takes a handful of pills before each meal. But teenagers, who can be agonizingly self-conscious anyway, may feel their difference the most.

You can help a child by telling him or her about CF as soon as he or she is able to understand. Just what you say will depend on your child's age and personality. In general, help your child understand what CF is, and why eating a healthy diet, taking enzymes and having chest physical therapy are important. Also teach your child to talk to others about CF in a straightforward way. Have your child explain that coughing helps clear the lungs and enzymes help digest food.

Teenagers, especially, may feel embarrassed about their cough, their slenderness and their medications. Most of all, they may worry that their illness will keep them from having a normal social life. And in fact, all the turbulence and difficulty of adolescence is compounded for teenagers with CF. Yet many teens find that being frank and open about CF can ease some of their concerns.

Still, adolescents understandably may want to pretend they don't have CF. They may rebel against dietary restrictions, treatments and medications. And like other teenagers they may start to smoke. But normal rebelliousness can be life-threatening for young people with CF. If your teen is resisting treatment, a counselor or social worker may be able to help.

At the same time, you can boost your child's confidence and sense of normalcy by not being overly rigid. Don't be concerned if your child misses a chest therapy session now and then in order to participate in some activity. The goal is to help your child learn to live with CF, not to make it a way of life.

Marriage and family

Adults with CF face special issues around marriage and family. Often, they may have problems with fertility. They may have to help educate concerned in-laws and other family members. In addition, they need to consider how marriage may affect any benefits they receive.

Unfortunately, young adults with CF can't always be as carefree and spontaneous in their relationships as other young people. But many resources are available that can make dealing with issues of marriage and intimacy easier. These include genetic counseling, fertility evaluation and financial counseling. Be sure to discuss your concerns with your doctor or a CF social worker.

Some of the most difficult challenges facing people with CF and their families are financial ones. Many people with CF find it difficult to get health care coverage that meets their needs. If you're having trouble finding health insurance, talk to a social worker at your CF treatment center. In many cases he or she may be able to help.

— May 14, 2002 —