Cystic Fibrosis


What Is It?

Cystic fibrosis is an inherited disorder that affects many organs in the body, including the lungs, liver, pancreas, urinary tract, reproductive tract and sweat glands. Specific cells in these organs normally produce mucus and other watery secretions. In cystic fibrosis, these cells produce secretions that are thicker than normal, causing disruptions in the body’s water balance and ability to handle salt. This creates other problems. For example, in the lungs, thickened secretions trap germs, causing repeated lung infections. In the pancreas, thickened 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 result in 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.

In order to develop cystic fibrosis, a person must have inherited two cystic fibrosis genes, one from each parent. People who have inherited only one cystic fibrosis gene are called cystic fibrosis carriers and 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, and another 6 million are carriers of the cystic fibrosis gene. The illness is most common in Caucasians, affecting approximately one in every 3,000 newborns. Cystic fibrosis is less common among African-Americans (fewer than one in 15,000), and even more rare in Asian-Americans (one in 50,000).


The symptoms of cystic fibrosis usually appear within the first year of life, but may not appear until late childhood or adolescence. The severity of symptoms varies from person to person. Some people have severe symptoms involving various parts of the body; others have much milder disease involving only one area of the body.

At birth, a child with cystic fibrosis can develop a swollen belly and vomiting due to a condition called meconium ileus, in which the bowel is plugged up with meconium, a thick, dark, sticky substance produced by the baby’s intestine while still in the uterus.

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 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 abdominal 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


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 his or her suspicions, your doctor will order a sweat test, a painless procedure that can diagnose cystic fibrosis by measuring the amount of salt in skin sweat. In newborns, who are too tiny to produce enough sweat for a sweat test, a blood test can be done to confirm the diagnosis. Many states now routinely screen newborns for cystic fibrosis.

Expected Duration

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


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 for cystic fibrosis depends on the severity of the disease and which parts of the body are affected. Regular monitoring is essential. Lung disease can be treated with antibiotics, mucus-thinning drugs and chest physical therapy, a form of physical therapy in which another person drums the patient’s chest and back with cupped hands to help clear mucus from the lungs. Older patients sometimes can do this therapy themselves, and machines are now available that can vibrate the chest to help loosen mucus. 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, which is made at the command of the cystic fibrosis gene. The defective CFTR protein is responsible for the abnormalities in salt and water regulation that lead to thickened secretions.

When To Call A Professional

Call your doctor if your child has symptoms suggestive of cystic fibrosis, including 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.


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. Between 1 percent and 2 percent of people with cystic fibrosis are affected only mildly, with minimal lung disease or no evidence of pancreas dysfunction. With regular monitoring and improved treatment, the average life span of a person with cystic fibrosis has increased to 32 years, although some people with mild symptoms live much longer.

Johns Hopkins patient information

Last revised:

Diseases and Conditions Center

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.