Cystic Fibrosis

Content provided by the Faculty of the Harvard Medical School

Cystic Fibrosis

What Is It?

Cystic fibrosis is an inherited disease that affects many parts of the body, including the lungs, liver, pancreas, urinary tract, reproductive organs and sweat glands. Certain cells in these organs normally make mucus and other watery secretions, but in cystic fibrosis, these cells produce secretions that are thicker than normal. This causes trouble with the body's water balance and its ability to handle salt, which leads to other problems. For example, in the lungs, thick secretions trap germs, causing repeated lung infections. In the pancreas, thick secretions block the normal flow of pancreatic juices, making it more difficult for the body to digest and absorb fats and fat-soluble vitamins. This can lead to nutritional problems, especially in babies. Other problems related to cystic fibrosis include sinusitis, nasal polyps, esophagitis, pancreatitis, cirrhosis of the liver, rectal prolapse, diabetes and infertility, especially in males.

To develop cystic fibrosis, a person must inherit two cystic fibrosis genes, one from each parent. People who inherit only one cystic fibrosis gene are called cystic fibrosis carriers. They can pass the cystic fibrosis gene to their children, but they do not have the disease themselves.

About 30,000 people in the United States have cystic fibrosis. Another 12 million are carriers of the cystic fibrosis gene. The disease is most common in Caucasians, affecting approximately 1 in every 3,000 newborns. Cystic fibrosis is less common among African Americans, Asian Americans and Native Americans.

Symptoms

Symptoms of cystic fibrosis usually appear within the first year of life, but sometimes appear in late childhood or adolescence. The severity of symptoms varies from person to person. Some people have severe symptoms involving various organs. Others have a much milder form of the disease involving only one area of the body.

At birth, a child with cystic fibrosis can develop a swollen belly and will vomit due to a condition called meconium ileus, in which the bowel is plugged up with meconium, a thick, dark, sticky substance produced by the intestines of all babies while in the uterus. It is just stickier in a newborn with cystic fibrosis.

As the child grows, other symptoms can develop, including:

• Poor weight gain in spite of a good appetite, usually because of problems with digestion and the absorption of food, especially poor absorption of fats and fat-soluble vitamins (vitamins A, D, E and K)

• Large, foul-smelling, fat-filled, "greasy" stools

• Frequent episodes of diarrhea

• A swollen belly with gas and discomfort

• Repeated lung infections, leading to poor lung function

• Repeated sinus infections

• Wheezing and shortness of breath

• Chronic cough, which can produce heavy, discolored mucus or blood

• A salty "frosting" on the skin, or a salty taste when kissed

• Delayed sexual development

Diagnosis

Your doctor may suspect cystic fibrosis based on your child's symptoms and medical history, a family history of cystic fibrosis, and the results of a physical examination. To confirm the diagnosis, your doctor will order a sweat test, a painless procedure to diagnose cystic fibrosis by measuring the amount of salt in skin sweat. In newborns, who are too tiny to make enough sweat for a sweat test, a blood test can confirm the diagnosis. Many states now routinely screen newborns for cystic fibrosis.

Expected Duration

Cystic fibrosis is a lifelong illness that requires constant monitoring. The severity of the illness typically varies over time, with periods of worsening symptoms that may require more intense medical treatment and even hospitalization.

Prevention

There is no way to prevent cystic fibrosis. People with a family history of cystic fibrosis can seek genetic counseling to determine their chance of passing this disease on to their children. A blood test can detect most, but not all, of the genetic mutations that cause cystic fibrosis.

Treatment

Treatment for cystic fibrosis depends on the severity of the disease and the body parts involved. Close regular monitoring is essential. Lung disease can be treated with antibiotics, mucus-thinning drugs and chest physical therapy, in which a therapist or family member drums the person's chest and back with cupped hands to help clear mucus from the lungs. Older people with cystic fibrosis sometimes can do this therapy themselves. Special vests that attach to machines can vibrate the chest, too. In severe cases, a lung transplant may be an option. Digestive problems are treated with high-calorie diets, pancreatic enzymes and vitamin supplements.

Other treatments are being tested, including gene therapy, which involves using an inhaled spray to deliver normal copies of the cystic fibrosis gene to the lungs. Gene therapy is being tested in several medical centers nationwide, but has not been approved for general use. Also, medications are being tested to correct a defective protein, called the CFTR protein. The defective CFTR protein is responsible for problems with salt and water regulation that lead to thickened secretions.

When To Call a Professional

Call your doctor if your child has any of these symptoms: frequent respiratory infections, persistent abdominal discomfort and gas, repeated episodes of diarrhea, greasy foul-smelling stools or poor weight gain in spite of a good appetite.

Prognosis

The life expectancy of people with cystic fibrosis depends on the severity of disease and the parts of the body involved. Lung disease has the strongest impact on the severity of the illness, and death usually is caused by lung complications. With regular monitoring and improved treatment, the average life span of a person with cystic fibrosis has increased to 35 years, although some people with mild symptoms live much longer.

Additional Info

National Heart, Lung, and Blood Institute (NHLBI) P.O. Box 30105 Bethesda, MD 20824-0105 Phone: 301-592-8573 TTY: 240-629-3255 Fax: 301-592-8563 E-mail: nhlbiinfo@rover.nhlbi.nih.gov http://www.nhlbi.nih.gov/

Cystic Fibrosis Foundation 6931 Arlington Road Bethesda, MD 20814 Phone: 301-951-4422 Toll-Free: 1-800-344-4823 Fax: 301-951-6378 E-mail: info@cff.org http://www.cff.org/

Last updated:	April 09, 2009