Cystic Fibrosis

Cystic fibrosis is an inherited, life threatening disorder. It damages the lungs and causes digestive problems. About 30,000 American adults and children have cystic fibrosis.

In the past, people with cystic fibrosis were not expected to live beyond their teens. Today, cystic fibrosis is diagnosed earlier and treated more effectively. As a result, people live fuller lives into their 30s, 40s and beyond.

The disease affects the cells that produce mucus, sweat, saliva and digestive juices. In a person with cystic fibrosis, these secretions are thick and sticky. Instead of smoothing the surfaces that these secretions are on, they plug up tubes, ducts and passageways, especially in the lungs and pancreas. Respiratory failure is the most dangerous complication of cystic fibrosis.

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Symptoms

There are more than 1,000 mutations of the gene for cystic fibrosis. The disease affects nearly all the body's glands that secrete fluids into a duct. It also affects many organs.

Some symptoms of cystic fibrosis include:

  • Mucus blocks the small airways of the lungs, which become inflamed and sometimes infected.
  • Frequent sinus infections because the sinuses fill with thickened mucus
  • The lymph nodes swell
  • Thick secretions can block the bile ducts in the liver. This can lead to swelling and tenderness (inflammation) of the liver and eventual scarring (cirrhosis). Cirrhosis can put pressures on the veins of the liver, causing the veins at the lower end of the esophagus to get large and fragile. These veins can rupture and bleed.
  • The gall bladder can become blocked
  • Thick secretions can block the pancreas entirely preventing digestive enzymes from reaching the intestines to help break down and absorb food. This can cause nutritional deficiencies as fats, proteins and vitamins are poorly absorbed. Children with cystic fibrosis grow more slowly than other children.
  • Thick secretions that require surgery to remove in some newborns can block the small intestine. Between 15 and 20% of newborns with cystic fibrosis have meconium ileus, a serious blockage of the small intestine. They are also more prone to twisting of the intestine on itself or an incompletely developed intestine.

Other possible symptoms include:

  • A big appetite that does not lead to weight gain
  • Delayed puberty
  • Excessive sweating in hot weather or during a fever (This sweating puts the patient at greater risk of dehydration.)
  • Frequent lung or respiratory infections and a greater risk of developing a collapsed lung
  • Greasy, bulky stools
  • Loss of physical endurance
  • Persistent coughing that sometimes produces phlegm
  • Skin that tastes very salty or carries salt crystals
  • Wheezing or shortness of breath

One of the first signs of cystic fibrosis in a baby is slowness to gain weight in the weeks after birth. Because of a lack of pancreatic enzymes for proper digestion, the baby does not get enough nutrition to thrive. The baby may also have a distended stomach and small muscles.

Nearly half the children with cystic fibrosis are diagnosed when they are taken to the doctor because of frequent coughing, wheezing and respiratory tract infections. The coughing can be accompanied by gagging, vomiting and disturbed sleep.

Over time, the chest becomes barrel-shaped. The lack of oxygen causes the fingers to be bigger at the tips. The area under the fingernails looks bluish.

Because of the digestive problems that cystic fibrosis creates, a variety of nutritional complications can develop. These include night blindness, rickets, anemia (a lack of iron in the blood) and bleeding disorders. About 15% of adults with cystic fibrosis develop diabetes that requires treatment with insulin.

The condition also affects the reproductive system. More than 95% of men with cystic fibrosis are sterile. Although many women with cystic fibrosis are able to conceive children, the impact of the disease on their lungs and health may make carrying a child to term quite difficult.

 

Causes and Risk Factors

A defective gene causes cystic fibrosis. The gene controls the production of a protein that controls how salt is carried across the membranes that separate cells. People with one copy of the defective gene carry it but have no symptoms, which is the case for more than 10 million Americans. However, those who receive a copy of the defective gene from both parents will develop cystic fibrosis.

Cystic fibrosis affects Caucasians five times more often than it does African Americans. It is rare in Asian-American children. It affects boys and girls equally.

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Diagnosis

Cystic fibrosis is a condition a person is born with. More than 80 percent of the people who have cystic fibrosis are diagnosed by the age of three. Some mild forms may not be diagnosed until someone is in his or her 40s or 50s.

A sweat test is used to diagnose cystic fibrosis. Simple and painless, this test involves putting a drug that causes sweating on the skin. Filter paper or tubing is used to collect the sweat. Having a lot of salt in the sweat confirms cystic fibrosis.

In a newborn, a blood test is used to test for the amount of a digestive enzyme (trypsin) in the blood. A high level shows the presence of cystic fibrosis.

Genetic testing can be used to confirm a diagnosis of cystic fibrosis in a person who has one or more of the typical symptoms or has a sibling with cystic fibrosis. However, genetic testing can only confirm a small percentage of the more than 1,000 different types of genetic mutations that can lead to cystic fibrosis. Genetic testing can be done prenatally by using chorionic villus sampling or amniocentesis.

Since cystic fibrosis affects so many organs, other tests may be helpful, including:

  • Analysis of a stool sample to see if pancreatic enzyme levels are low, especially levels of trypsin and chymotrypsin or whether levels of fat are high
  • Blood glucose test because if not enough insulin is getting to the body from the pancreas, blood sugar will be high
  • Lung function tests to show if breathing is normal
  • Chest X-rays, which can show the presence of a lung infection or damage
  • Computed tomography (CT scan), which also can show lung infections or damage
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Treatments

There is no cure yet for cystic fibrosis. Treatment is aimed at preventing complications, such as lung infections or digestive problems. How the condition is treated depends on the stage of the disease and the organs affected. Following a daily program for clearing mucus from the lungs is necessary. This can be done by:

  • Chest physical therapy in which the back and chest are clapped on vigorously to break up the thick mucus in the lungs
  • Taking a mucus-thinning drug, such as Pulmozyme┬«, to improve how the lungs work and to prevent lung infections
  • Using an aerosol antibiotic, such as tobramycin, to prevent lung infections
  • Using azithromycin, an antibiotic that is effective for people with cystic fibrosis whose lungs are chronically infected with Pseudomonas aeruginos bacteria

Because of the effects of cystic fibrosis on a person's digestive system, pancreatic enzyme replacements may need to be taken with each meal. Patients may also need to take double the recommended daily amounts of fat-soluble vitamins (A, D, E and K) in a form that is easier to absorb.

Children with cystic fibrosis need psychological and social support because they may not be able to participate in normal childhood activities and may feel isolated. Infants and toddlers should have immunizations against pneumonia as part of their regular care.

As a person with cystic fibrosis gets older, additional health challenges can develop, such as diabetes and osteoporosis.

At some point, surgery may be needed to treat severe infections, bleeding in the esophagus, gallbladder disease or intestinal blocks. Liver transplantation or double lung transplantation may be done in some cases.