Cystic fibrosis is an inherited disorder that causes severe damage to the lungs, digestive system and other organs in the body.
Cystic fibrosis affects the cells that produce mucus, sweat and digestive juices. These secreted fluids are normally thin and slippery. But in people with cystic fibrosis, a defective gene causes the secretions to become sticky and thick. Instead of acting as a lubricant, the secretions plug up tubes, ducts and passageways, especially in the lungs and pancreas.
Although cystic fibrosis requires daily care, people with the condition are usually able to attend school and work, and often have a better quality of life than people with cystic fibrosis had in previous decades. Improvements in screening and treatments mean people with cystic fibrosis now may live into their mid- to late 30s, on average, and some are living into their 40s and 50s.
Cystic fibrosis care at Mayo Clinic
Screening of newborns for cystic fibrosis is now performed in every state in the United States. As a result, the condition can be diagnosed within the first month of life, before symptoms develop. For people born before newborn screening was performed, it's important to be aware of the signs and symptoms of cystic fibrosis.
Cystic fibrosis signs and symptoms vary, depending on the severity of the disease. Even in the same person, symptoms may worsen or improve as time passes. Some people may not experience symptoms until adolescence or adulthood.
People with cystic fibrosis have a higher than normal level of salt in their sweat. Parents often can taste the salt when they kiss their children. Most of the other signs and symptoms of cystic fibrosis affect the respiratory system and digestive system. However, adults diagnosed with cystic fibrosis are more likely to have atypical symptoms, such as recurring bouts of inflamed pancreas (pancreatitis), infertility and recurring pneumonia.
Respiratory signs and symptoms
The thick and sticky mucus associated with cystic fibrosis clogs the tubes that carry air in and out of your lungs. This can cause signs and symptoms such as:
- A persistent cough that produces thick mucus (sputum)
- Exercise intolerance
- Repeated lung infections
- Inflamed nasal passages or a stuffy nose
Digestive signs and symptoms
The thick mucus can also block tubes that carry digestive enzymes from your pancreas to your small intestine. Without these digestive enzymes, your intestines aren't able to completely absorb the nutrients in the food you eat. The result is often:
- Foul-smelling, greasy stools
- Poor weight gain and growth
- Intestinal blockage, particularly in newborns (meconium ileus)
- Severe constipation
Frequent straining while passing stool can cause part of the rectum — the end of the large intestine — to protrude outside the anus (rectal prolapse). When this occurs in children, it may be a sign of cystic fibrosis. Parents should consult a physician knowledgeable about cystic fibrosis. Rectal prolapse in children may sometimes require surgery. Rectal prolapse in children with cystic fibrosis is less common than it was in the past, which may be due to earlier testing, diagnosis and treatment of cystic fibrosis.
When to see a doctor
If you or your child has symptoms of cystic fibrosis — or if someone in your family has cystic fibrosis — talk with your doctor about testing for the disease.
Seek immediate medical care if you or your child has difficulty breathing.
In cystic fibrosis, a defect (mutation) in a gene changes a protein that regulates the movement of salt in and out of cells. The result is thick, sticky mucus in the respiratory, digestive and reproductive systems, as well as increased salt in sweat.
Many different defects can occur in the gene. The type of gene mutation is associated with the severity of the condition.
Children need to inherit one copy of the gene from each parent in order to have the disease. If children inherit only one copy, they won't develop cystic fibrosis. However, they will be carriers and possibly pass the gene to their own children.
- Family history. Because cystic fibrosis is an inherited disorder, it runs in families.
- Race. Although cystic fibrosis occurs in all races, it is most common in white people of Northern European ancestry.
Respiratory system complications
- Damaged airways (bronchiectasis). Cystic fibrosis is one of the leading causes of bronchiectasis, a condition that damages the airways. This makes it harder to move air in and out of the lungs and clear mucus from the airways (bronchial tubes).
- Chronic infections. Thick mucus in the lungs and sinuses provides an ideal breeding ground for bacteria and fungi. People with cystic fibrosis may often have sinus infections, bronchitis or pneumonia.
- Growths in the nose (nasal polyps). Because the lining inside the nose is inflamed and swollen, it can develop soft, fleshy growths (polyps).
- Coughing up blood (hemoptysis). Over time, cystic fibrosis can cause thinning of the airway walls. As a result, teenagers and adults with cystic fibrosis may cough up blood.
- Pneumothorax. This condition, in which air collects in the space that separates the lungs from the chest wall, also is more common in older people with cystic fibrosis. Pneumothorax can cause chest pain and breathlessness.
- Respiratory failure. Over time, cystic fibrosis can damage lung tissue so badly that it no longer works. Lung function usually worsens gradually, and it eventually can become life-threatening.
- Acute exacerbations. People with cystic fibrosis may experience worsening of their respiratory symptoms, such as coughing and shortness of breath, for several days to weeks. This is called an acute exacerbation and requires treatment in the hospital.
Digestive system complications
- Nutritional deficiencies. Thick mucus can block the tubes that carry digestive enzymes from your pancreas to your intestines. Without these enzymes, your body can't absorb protein, fats or fat-soluble vitamins.
- Diabetes. The pancreas produces insulin, which your body needs to use sugar. Cystic fibrosis increases the risk of diabetes. Around 30 percent of people with cystic fibrosis develop diabetes by age 30.
- Blocked bile duct. The tube that carries bile from your liver and gallbladder to your small intestine may become blocked and inflamed, leading to liver problems and sometimes gallstones.
- Intestinal obstruction. Intestinal obstruction can happen to people with cystic fibrosis at all ages. Children and adults with cystic fibrosis are more likely than are infants to develop intussusception, a condition in which a section of the intestines folds in on itself like an accordion.
- Distal intestinal obstruction syndrome (DIOS). DIOS is partial or complete obstruction where the small intestine meets the large intestine.
Reproductive system complications
Almost all men with cystic fibrosis are infertile because the tube that connects the testes and prostate gland (vas deferens) is either blocked with mucus or missing entirely. Certain fertility treatments and surgical procedures sometimes make it possible for men with cystic fibrosis to become biological fathers.
Although women with cystic fibrosis may be less fertile than other women, it's possible for them to conceive and to have successful pregnancies. Still, pregnancy can worsen the signs and symptoms of cystic fibrosis, so be sure to discuss the possible risks with your doctor.
- Thinning of the bones (osteoporosis). People with cystic fibrosis are at higher risk of developing a dangerous thinning of bones.
- Electrolyte imbalances and dehydration. Because people with cystic fibrosis have saltier sweat, the balance of minerals in their blood may be upset. Signs and symptoms include increased heart rate, fatigue, weakness and low blood pressure.
If you or your partner has close relatives with cystic fibrosis, you both may want to undergo genetic testing before having children. The test, which is performed in a lab on a sample of blood, can help determine your risk of having a child with cystic fibrosis.
If you're already pregnant and the genetic test shows that your baby may be at risk of cystic fibrosis, your doctor can conduct additional tests on your developing child.
Genetic testing isn't for everyone. Before you decide to be tested, you should talk to a genetic counselor about the psychological impact the test results might carry.