Cystic fibrosis is an inherited disease that causes thick, sticky mucus to build up in the lungs and digestive tract. It is one of the most common type of chronic lung disease in children and young adults, and may result in early death.

Cystic fibrosis (CF) is caused by a defective gene which tells the body to produce abnormally thick and sticky fluid, called mucus. This mucus builds up in the breathing passages of the lungs and the pancreas, the organ that helps to break down and absorb food.

This collection of sticky mucus results in life-threatening lung infections and serious digestion problems. The disease may also affect the sweat glands and a man's reproductive system.

Millions of Americans carry the defective CF gene, but do not have any symptoms. That's because a person with CF must inherit two defective CF genes -- one from each parent. An estimated 1 in 29 Caucasian Americans have the CF gene. The disease is the most common, deadly, inherited disorder affecting Caucasians in the United States. It's more common among those of Northern or Central European descent.

Most children with CF are diagnosed by age 2. A small number, however, are not diagnosed until age 18 or older. These patients usually have a milder form of the disease.

Because there are more than 1,000 mutations of the CF gene, symptoms differ from person to person. But in general they include:

• Belly pain from severe contipation
• Coughing or increased mucus in the sinuses or lungs
• Delayed growth
• Fatigue
• Infants may have salty-tasting skin
• No bowel movements in first 24 to 48 hours of life
• Stools that are pale or clay colored, foul smelling, or that float
• Recurrent respiratory infections such as pneumonia or sinusitis
• Weight loss, or failure to gain weight normally in childhood

A blood test is available to help detect CF. The test looks for variations in a gene known to cause the disease. Other tests use to diagnose CF include:

• Immunoreactive trypsinogen (IRT) test is a standard newborn screening test for CF. A high level of IRT suggests possible CF and requires further testing.
• Sweat chloride test is the standard diagnostic test for CF. A high salt level in the patient's sweat is a sign of the disease.

Other tests that identify problems that can be related to cystic fibrosis include:

• Chest x-ray or CT scan
• Fecal fat test
• Lung function tests
• Measurement of pancreatic function
• Trypsin and chymotrypsin in stool
• Secretin stimulation test
• Upper GI and small bowel series

An early diagnosis of CF and a comprehensive treatment plan can improve both survival and quality of life. Specialty clinics for cystic fibrosis may be helpful and can be found in many communities.

Treatment for lung problems includes:

• Antibiotics to prevent and treat lung and sinus infections
• Inhaled medicines to help open the airways
• DNAse enzyme replacement therapy to thin mucus and make it easier to cough up
• Lung transplant, in some cases

Treatment for intestinal and nutritional problems may include:

• A special diet to help with nutrition (see: Cystic fibrosis nutrional considerations)
• Pancreatic enzymes to replace those that are missing
• Vitamin supplements, especially vitamins A, D, E, and K

For additional information and resources, see: Cystic fibrosis support group

Today, the average life span for persons with CF who live to adulthood is approximately 35 years, a dramatic increase over the last three decades.

Death is usually caused by lung complications.

• Coughing up blood
• Chronic respiratory failure
• Cor pulmonale
• Diabetes
• Liver disease
• Malnutrition
• Osteoporosis and arthritis
• Pneumonia, recurrent
• Pneumothorax

Call your health care provider if an infant or child has symptoms of cystic fibrosis.

Call your health care provider if a person with cystic fibrosis develops new symptoms, particularly severe breathing difficulty or coughing up blood.

There is no way to prevent cystic fibrosis. Screening those with a family history of the disease may detect the cystic fibrosis gene in 60 - 90% of carriers, depending on the test used.

Farrell PM, Rosenstein BJ, White TB, et al. Guidelines for diagnosis of cystic fibrosis in newborns through older adults: Cystic fibrosis consensus report. Journal of Pediatrics. Aug 2008;153(2).

Stallings VA, Stark LF, Robinson KA, Feranchak AP, Quinton H. Evidence-based practice recommendations for nutrition-related management of children and adults with cystic fibrosis and pancreatic insufficiency: Results of a systematic review. Journal of the American Dietetic Association. May 2008;108(5).

Boat TF, Acton JD. Cystic fibrosis. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 400.