What Do You Know About Cystic Fibrosis?

The sweat glands and the reproductive system usually are involved, as well. A person with CF produces excessively thick, sticky mucus, which clogs the air passages in the lungs and makes them more susceptible to infection. The clogged passages also make breathing more difficult. The sweat of a person with CF often is abnormally salty. Thick secretions also clog the ducts of the pancreas, keeping digestive enzymes and bicarbonate produced by the pancreas from helping with digestion. Most men with CF are infertile and most women with CF have difficulty getting pregnant.

Most of the 12 million people who have this gene don't know that they are carriers, according to the National Heart, Lung, and Blood Institute (NHLBI). The abnormal CF gene has many variations, which means that the disease can range from very mild to severe. Although most of CF cases occur in whites whose ancestors came from northern Europe, the disease can affect other races and ethnic groups. About 1,000 newborns are born with CF in this country each year.

Symptoms can vary from child to child, the NHLBI says. An infant born with CF genes usually develops symptoms within its first year of life. More than 80 percent of patients are diagnosed by age 3, according to the Cystic Fibrosis Foundation. In some children, however, CF may not be diagnosed until adolescence.

An abnormality in the glands that produce mucus causes the mucus to be thick. The mucus accumulates in the intestines and lungs, causing malnutrition, poor growth, and breathing difficulties, the NHLBI says. The extra mucus becomes a place for bacteria to grow, leading to frequent respiratory infections. Researchers first thought that these lung infections caused the lung failure typical in CF patients. They now believe that it is chronic inflammation of the lungs, caused by an abnormal inflammatory response by the body, that does the most damage. People with CF also lose excessive amounts of salt when they sweat. A severe loss of salt can upset the heart's rhythm and may cause shock.

The pancreas helps in digestion by providing enzymes and bicarbonate to neutralize stomach acid. If the pancreas ducts are blocked, digestion is affected and bowel movements become bulky and foul-smelling; malnutrition and slowed growth and development also can occur. If the cells in the pancreas that make insulin are damaged, the person can develop type 1 diabetes. If the bile ducts in the liver are affected, biliary cirrhosis may result. Other medical problems associated with CF include sinusitis; nasal polyps; clubbing of fingers and toes; pneumothorax (rupture of lung tissue); abdominal pain; gassiness; gallstones; coughing blood; enlargement of the right side of the heart; and infertility.

The sweat test measures the amount of sodium chloride (salt) in a person's sweat. A person with higher than normal amounts of sodium and chloride may have CF. Because newborns don't produce a lot of sweat, they may instead be given a blood test called an immunoreactive trypsinogen test. For this test, the blood is checked for a protein called trypsinogen, which indicates CF. Testing for CF also can be done as a prenatal blood test to determine whether the developing child has the disease. Genetic testing also can be done to help determine the diagnosis and for couples with a family history of CF who are considering having children.

Bronchodilators widen the bronchial passages in the lungs. Antibiotics kill the bacteria that cause lung infections. Decongestants reduce the swelling of bronchial membranes. Mucolytics thin the mucus in the lungs. Physical therapy and exercise also can help manage CF. Chest therapy helps the mucus drain from the lungs by clapping the chest and back to dislodge the mucus from the airways. A small, hand-held device called a flutter also loosens the mucus. When a patient exhales through the flutter, a valve causes rapid air pressure fluctuations in the patient's airways, according to the National Institute of Diabetes and Digestive and Kidney Diseases. The fluctuations cause vibrations, which loosen the mucus. Exercise also helps loosen the mucus. For patients with advanced CF, a lung transplant may be an option, the NHLBI says. To help ease digestive problems in people with CF, doctors prescribe a well-balanced, high-calorie diet that is high in protein but low in fat. Vitamin supplements and enzymes are also often given.

Fatty acids are long molecules that serve as the building blocks of the cell membrane, the CFF says. Certain fatty acids play a key role in controlling the body's inflammatory response. The hallmark of CF is chronic inflammation of the lung tissue. CF patients appear to have high levels of arachidonic acid (AA) and low levels of docosahexaenoic (DHA) acid. This combination leads to tissue inflammation. This also explains why omega-3 oils reduce inflammation in general because they boost DHA levels and reduce AA levels.

To develop CF, a person must inherit two defective CF genes, one from each parent, the CFF says. Each time two carriers conceive, there is a 25 percent chance that their child will have CF; a 50 percent chance that the child will be a carrier of the CF gene; and a 25 percent chance that the child will be a non-carrier.