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Cystic Fibrosis

What is cystic fibrosis?

Cystic fibrosis (CF) is an inherited life-threatening disease that affects many organs. It causes changes in the electrolyte transport system causing cells to absorb too much sodium and water. CF is characterized by problems with the glands that produce sweat and mucus. Symptoms start in childhood. On average, people with CF live into their mid to late 30.

CF affects various organ systems in children and young adults, including the following:

  • Respiratory system
  • Digestive system
  • Reproductive system

Some people can carry the CF gene without being affected by the disease. They usually do not know that they are carriers.

How does CF affect the respiratory system?

The abnormal electrolyte transport system in CF causes the cells in the respiratory system, especially the lungs, to absorb too much sodium and water. This causes the normal thin secretions in the lungs to become very thick and hard to move. These thick secretions increase the risk for frequent respiratory infections.

Recurrent respiratory infections lead to progressive damage in the lungs, and eventually death of the cells in the lungs.

Because of the high rate of infection in the lower respiratory tract, people with CF may develop a chronic cough, blood in the sputum, and often even have a collapsed lung. The cough is usually worse in the morning or after activity.

People with CF also have upper respiratory tract symptoms. Some have nasal polyps that require surgical removal. Nasal polyps are small protrusions of tissue from the lining of the nose that can block and irritate the nasal cavity. People with CF also have higher rates of sinus infections.

How does CF affect the gastrointestinal (GI) system?

CF mainly affects the pancreas. The pancreas secretes substances that aid digestion and help control blood sugar levels.

The secretions from the pancreas also become thick and can clog the ducts of the pancreas. This may cause a decrease in the secretion of enzymes from the pancreas that normally help digest food. A person with CF has trouble absorbing proteins, fats, and vitamins A, D, E, and K.

The problems with the pancreas can become so severe that some of the cells in the pancreas die. Over time, this may lead to glucose intolerance and Cystic Fibrosis-Related Diabetes (CFRD), a unique type insulin-dependent diabetes.

The symptoms of CF that may be due to involvement with the GI tract include:

  • Bulky, greasy stools
  • Rectal prolapse (a condition in which the lower end of the bowel comes out of the anus)
  • Delayed puberty
  • Fat in the stools
  • Stomach pain
  • Bloody diarrhea

The liver may also be affected. A small number of people may actually develop liver disease. Symptoms of liver disease include:

  • Enlarged liver
  • Swollen abdomen (belly)
  • Yellow color to the skin (jaundice)
  • Vomiting of blood

How does CF affect the reproductive system?

Most males with CF have blockage of the sperm canal. This is called congenital bilateral absence of the vas deferens (CBAVD). This results from the thick secretions clogging the vas deferens and keeping them from developing properly. It causes infertility because sperm can't travel out of the body. Women also have an increase in thick cervical mucus that may lead to a decrease in fertility, although many women with CF are able to have children.

What causes cystic fibrosis?

Cystic fibrosis (CF) is a genetic disease. This means that CF is inherited.

Mutations in a gene called the CFTR (cystic fibrosis conductance transmembrane regulator) gene cause CF. The CFTR mutations causes changes in the body’s cell’s electrolyte transport system. Electrolytes are substances in blood that are critical to cell function. The main result of these transport system changes are seen in the body secretions, such as mucus and sweat.

The CFTR gene is quite large and complex, there are many different mutations in this gene have been linked to CF.

A person will be born with CF only if two CF genes are inherited – one from the mother and one from the father.

Who is at risk for cystic fibrosis?

Cystic fibrosis (CF) is inherited, and a person with CF had both parents pass the altered gene to them. The birth of a child with CF is often a total surprise to a family, since most of the time there is no family history of CF.

What are the symptoms of cystic fibrosis?

All U.S. states require that newborns be tested for cystic fibrosis (CF). This means that parents can know if their baby has the disease and can take precautions and watch for early signs of problems.

The following are the most common symptoms of CF. However, people may experience symptoms differently, and the severity of symptoms can vary, too. Symptoms may include:

  • Abnormalities in the glands that produce sweat and mucus. This may cause a loss of salt, which can cause an upset in the balance of minerals in the blood. This can lead to abnormal heart rhythms, and, possibly, low blood pressure and shock.
  • Thick mucus that clogs certain organs, such as the lungs, pancreas, and intestines. This may cause malnutrition, poor growth, frequent respiratory infections, breathing problems, and chronic lung disease.

Many other medical problems can point to cystic fibrosis, as well. These include:

  • Sinusitis
  • Nasal polyps
  • Clubbing of fingers and toes. This means thickened fingertips and toes because of less oxygen in the blood.
  • Collapse of the lung often due to intense coughing
  • Coughing up blood
  • Enlargement of the right side of the heart due to increased pressure in the lungs (Cor pulmonale)
  • Abdominal pain
  • Excess gas in the intestines
  • Rectal prolapse. In this condition, the lower end of the bowel comes out of the anus.
  • Liver disease
  • Diabetes
  • Pancreatitis, or inflammation of the pancreas that causes severe pain in the belly (abdomen)
  • Gallstones
  • Congenital bilateral absence of the vas deferens (CBAVD) in males. This causes blockages of the sperm canal.

The symptoms of CF differ for each person. Infants born with CF usually show symptoms by age two. Some children, though, may not show symptoms until later in life. The following signs are suspicious of CF, and infants having these signs may be further tested for CF:

  • Diarrhea that does not go away
  • Foul-smelling stools
  • Greasy stools
  • Frequent wheezing
  • Frequent pneumonia or other lung infections
  • Persistent cough
  • Skin that tastes like salt
  • Poor growth despite having a good appetite

The symptoms of CF may resemble other conditions or medical problems. See a health care provider for a diagnosis.

How is cystic fibrosis diagnosed?

Most cases of cystic fibrosis (CF) are found during newborn screening. In addition to a complete medical history and physical exam, tests for CF include a sweat test to measure the amount of sodium chloride (salt) present. Higher than normal amounts of sodium and chloride suggest CF. Other tests depend on which body system is affected and may include:

  • Chest X-rays, ultrasound, and CT scans
  • Blood tests
  • Lung function tests
  • Sputum cultures
  • Stool tests

For babies, who do not produce enough sweat, blood tests may be used.

How is cystic fibrosis treated?

There is no cure for CF. Goals of treatment are to ease symptoms, prevent and treat complications, and slow the progress of the disease.

Treatment generally focuses on the following two areas.

Management of lung problems

This may involve:

  • Physical therapy
  • Regular exercises to loosen mucus, stimulate coughing, and improve overall physical condition
  • Medications to thin mucus and help breathing
  • Antibiotics to treat infections
  • Anti-inflammatory medications

Management of digestive problems

This may involve:

  • A healthy diet that's high in calories
  • Pancreatic enzymes to aid digestion
  • Vitamin supplements
  • Treatments for intestinal blockages

Lung transplant may be an option for people with end-stage lung disease. The type of transplant done is usually a heart-lung transplant, or a double lung transplant. Not everyone is a candidate for a lung transplant. Discuss this with your health care provider.

What are the complications of cystic fibrosis?

CF has some serious complications, including:

  • Lung infections and other serious lung problems that don't go away or that come back
  • Inflammation of the pancreas (pancreatitis) that doesn't go away or that comes back
  • Cirrhosis or liver disease
  • Vitamin deficiencies
  • Failure to thrive. This means that the child does not grow and develop like he or she should.
  • Infertility in males
  • Cystic fibrosis-related diabetes (CFRD)
  • Gastroesophageal reflux disease (GERD). With this disease, stomach contents rise up into the esophagus and can cause serious damage.

Organ transplant may be needed for people with end-stage disease.

Can cystic fibrosis be prevented?

Cystic fibrosis (CF) is caused by an inherited gene mutation (change). Testing for the CF gene is recommended for anyone who has a family member with the disease, or whose partner is a known carrier of CF or affected with CF.

Testing for the CF gene can be done from a small blood sample or from a cheek swab, which is a brush rubbed against the inside of your cheek to get cells for testing. Labs generally test for the most common CF gene mutations.

There are many people with CF whose mutations have not been identified. In other words, all of the genetic errors that cause CF have not been discovered. Because not all mutations are known, a person can still be a CF carrier even if no mutations were found by testing.

There are limitations of CF testing. But, if both parents have the CF gene, they have some options:

  • Avoid pregnancy
  • Choose prenatal diagnosis (the fetus can be checked for CF at 10 to 12 weeks and 15 to 20 weeks gestation)
  • Terminate a pregnancy
  • Prepare for the birth of a child with CF
  • Avoid trouble diagnosing CF in an affected infant
  • Get early treatment for a child with CF

Living with cystic fibrosis

  • In addition to routine immunizations, regular flu vaccines, the pneumonia vaccine, and other appropriate vaccines are important to help reduce the chance of infection.
  • Long-term suppressive inhaled antibiotics may be recommended to prevent lung infections.
  • Medicines may be needed to help with digestion.
  • Vitamin and mineral supplements may be recommended.

Key points about cystic fibrosis

  • Cystic fibrosis (CF) is an inherited life-threatening disease that affects many organs. It causes changes in the electrolyte transport system which causes cells to absorb too much sodium and water.
  • CF is characterized by problems in the glands that produce sweat and mucus.
  • A person will be born with CF only if two CF genes are inherited — one from the mother and one from the father.
  • All U.S. states require that newborns be tested for cystic fibrosis (CF). This is how most cases are diagnosed.
  • CF causes thick mucus that clogs certain organs, such as the lungs, pancreas, and intestines. This may cause malnutrition, poor growth, frequent respiratory infections, breathing problems, and chronic lung disease.
  • There is no cure for CF. Goals of treatment are to ease symptoms, prevent and treat complications, and slow the progress of the disease.
  • CF can cause many different problems and long-term complications.
  • There is no way to prevent CF.
  • People with CF will work closely with a medical team to manage symptoms and stay as healthy as possible.

Next steps

Tips to help you get the most from a visit to your health care provider:

  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.
Online Medical Reviewer: Jones, Niya, MD
Online Medical Reviewer: Kidd, India, RN, BSN, MBA
Date Last Reviewed: 1/31/2014
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