Cystic fibrosis: Description:
A congenital metabolic disorder in which secretions of exocrine glands are abnormal; excessively viscid mucus causes obstruction of passageways (including pancreatic and bile ducts, intestines, and bronchi), and the sodium and chloride content of sweat are increased throughout the patient’s life; symptoms usually appear in childhood and include meconium ileus, poor growth despite good appetite, malabsorption and foul bulky stools, chronic bronchitis with cough, recurrent pneumonia, bronchiectasis, emphysema, clubbing of the fingers, and salt depletion in hot weather. Detailed genetic mapping and molecular biology have been accomplished by the methods of reverse genetics; autosomal recessive inheritance, caused by mutation in the cystic fibrosis conductance regulator gene (CFTR) on chromosome 7q. Syn: fibrocystic disease of the pancreas, mucoviscidosis, Clarke-Hadfield syndrome, viscidosis.
Cystic fibrosis (CF) is a potentially life-threatening disease that causes thick, sticky mucus to build up in the lungs and digestive tract. Persons with cystic fibrosis need to eat high calorie and high protein foods throughout the day.
Mucus is a substance made by the lining of some body tissues. Normally, mucus is a slippery, watery substance. It keeps the linings of certain organs moist and prevents them from drying out or getting infected. However, if you have CF, your mucus becomes thick and sticky.
The mucus builds up in your lungs and blocks your airways—the tubes that carry air in and out of your lungs. The buildup of mucus makes it easy for bacteria to grow. This leads to repeated, serious lung infections. Over time, these infections can severely damage your lungs. The thick, sticky mucus also can block tubes, or ducts, in your pancreas. As a result, the digestive enzymes that your pancreas makes can’t reach your small intestine.
These enzymes help break down the food that you eat. Without them, your intestines can’t fully absorb fats and proteins. This can cause vitamin deficiency and malnutrition because nutrients leave your body unused. It also can cause bulky stools, intestinal gas, a swollen belly from severe constipation, and pain or discomfort.
This glue-like mucus builds up and causes problems in many of the body’s organs, especially the lungs and the pancreas. People who have cystic fibrosis can have serious breathing problems and lung disease. They can also have problems with nutrition, digestion, growth, and development. There is no cure for cystic fibrosis and the disease generally gets worse over time.
The life expectancy for people with cystic fibrosis has been steadily increasing over the past 40 years. On average, people who have cystic fibrosis live into their mid-to-late 30s, although new treatments are making it possible for some people to live into their 40s and longer.
Cystic fibrosis is a lifelong condition. With improved treatment there has been a dramatic increase in the survival of people with cystic fibrosis over the last 20 years or so.
In the 1960s and before, most babies born with cystic fibrosis only survived for a few months or years. Today, many people with cystic fibrosis are living into their 30s and beyond. With optimal care and treatment, it is estimated that about 8 in 10 of today’s children with cystic fibrosis should live into their mid 40s. With treatment, most people with cystic fibrosis can live reasonably normal and productive lives.
However, there will be times when symptoms are more severe, mainly when a chest infection develops. Even with treatment, the main risk is recurring chest infections, and pneumonia. This can have a repeated damaging effect on lung function which can get worse over time. Death in childhood or early adulthood is still not uncommon. Most people with cystic fibrosis die of lung complications, mainly respiratory and heart failure.
Recent research has focused on treating the cause as well as the symptoms of cystic fibrosis. Medical researchers are currently looking at gene transfer therapy, which tries to correct the result of the gene defect that causes cystic fibrosis. Gene transfer therapy involves introducing healthy genes into the lung cells of people who have cystic fibrosis.
Researchers are also investigating protein repair therapy, or protein assist therapy. This therapy involves taking medicines that help the defective protein work more normally to allow a small amount of salt and water to move out of cells.
Gene transfer and protein repair therapies are in the experimental, developmental stages; and clinical trials are being conducted. For more information, see the Other Places to Get Help section of this topic for organizations to contact.
Some common symptoms of a baby who has cystic fibrosis include:
A blocked small intestine at birth, which prevents the baby from passing his or her first stool.
- Very salty sweat or skin.
- Not growing or gaining weight the way that other children do.
- Breathing problems, lung infections, a cough that does not go away, and wheezing.
Other symptoms may also develop in childhood such as:
Clubbing (rounding and flattening) of the fingers.
- Rectal prolapse (when part of the rectum protrudes from the anus).
- Growths (polyps) in the nose or sinuses.
Causes and Risk factors:
Cystic fibrosis is a genetic disorder. If you have cystic fibrosis, a particular pair of genes (on chromosome 7) do not work properly. This pair of genes help to control the way the cells handle sodium and chloride ions (‘salt’). There are many different abnormalities (mutations) of the ‘cystic fibrosis gene’, but, basically, they all stop the cell from handling sodium and chloride properly.
As a result, cells in affected organs have a fault in the way sodium and chloride travel in and out of the cells. Basically, too much sodium travels into the cells. Water follows the sodium which leaves too little water outside the cells. This causes the mucus or watery secretions outside the cells to be too thick (for example, in the airways of the lungs).
About 1 in 2500 babies in the UK are born with cystic fibrosis. Cystic fibrosis is an autosomal recessive disorder. This means that in order to develop cystic fibrosis you need to inherit two cystic fibrosis genes, one from your mother and one from your father. If you inherit only one cystic fibrosis gene, you are called a carrier.
About 1 in 25 people in the UK of Caucasian decent (white European) are carriers of the cystic fibrosis gene. It is much less common in Afro-Caribbean and Asian people. Carriers do not have the disease as they have one normal gene which can control the salt transport in their cells. But carriers can pass the cystic fibrosis gene on to their children.
When two people who carry the cystic fibrosis gene have a child, there is a:
1 in 4 chance that the child will have cystic fibrosis (by inheriting the cystic fibrosis gene from both parents).
- 2 in 4 chance that the child will not have cystic fibrosis, but will be a carrier (by inheriting a cystic fibrosis gene from one parent but the normal gene form the other parent).
- 1 in 4 chance that the child will not have cystic fibrosis, and will not be a carrier (by inheriting the normal gene from both parents).
A medical history and a physical exam are often the first steps in diagnosing cystic fibrosis, followed by screening or lab tests.
Certain test for cystic fibrosis include:
Sweat (chloride) test – a test to measure the amount of chloride in the sweat. The test is performed by placing a solution on the forearm (or the thigh if the child is too small) and attaching electrodes. The skin is stimulated to sweat with a mild electric current, which does not cause pain or harm your child. The sweat is collected onto a gauze pad and analyzed. Higher than normal amounts of chloride may suggest cystic fibrosis. The sweat test is not painful and usually causes minor discomfort.
- Blood tests – blood or cheek scraping cells can be tested for mutations in the CFTR gene. Other blood tests can asses infection, and involvement of certain organs.
- Chest x-rays – a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
- Pulmonary function tests – diagnostic tests that help to measure the lungs’ ability to exchange oxygen and carbon dioxide appropriately. The tests are usually performed with special machines that a child must breathe into.
- Sputum cultures – a diagnostic test performed on the material that is coughed up from the lungs and into the mouth. A sputum culture is often performed to determine if an infection is present.
- Stool evaluations – to measure stool fat absorption.
- Pancreatic function tests.
Doctors may do certain tests to help find out what kinds of problems your child is having. These tests may include:
A sputum culture, to identify what kind of bacteria are present. This test helps your doctor prescribe the best type of antibiotic.
- Lung function tests, to see how healthy the lungs are by checking how well air moves into and out of the lungs.
- A stool analysis, to see how well the digestive system is working by checking how much fat is in the stool and whether certain enzymes are present.
- Blood sugar (glucose) tests, to check for diabetes.
- A chest X-ray, to look for signs of lung infection or other problems.
- A CT scan, to identify any serious disease in the lungs, pancreas, or other organs.
Prenatal Screening:If you’re pregnant, prenatal genetic tests can find out whether your fetus has CF. These tests include amniocentesis and chorionic villus sampling (CVS).
In amniocentesis, your doctor inserts a hollow needle through your abdominal wall into your uterus. He or she removes a small amount of fluid from the sac around the baby. The fluid is tested to see whether both of the baby’s CFTR genes are normal.
In CVS, your doctor threads a thin tube through the vagina and cervix to the placenta. The doctor removes a tissue sample from the placenta using gentle suction. The sample is tested to see whether the baby has CF.
Cystic Fibrosis Carrier Testing: People who have one normal CFTR gene and one faulty CFTR gene are CF carriers. CF carriers usually have no symptoms of CF and live normal lives. However, carriers can pass faulty CFTR genes on to their children.
If you have a family history of CF or a partner who has CF (or a family history of it) and you’re planning a pregnancy, you may want to find out whether you’re a CF carrier.
A genetics counselor can test a blood or saliva sample to see whether you have a faulty CF gene. This type of testing can detect faulty CF genes in 9 out of 10 cases.
Treatment is different for everyone but usually involves a combination of medicines and home treatment. Home treatments include getting rid of mucus, eating healthy foods, and exercising to help prevent infections and complications. It can be challenging to follow a treatment plan, but doing so will help your child live a longer, healthier life.
The best treatment available is generally found at cystic fibrosis multidisciplinary specialist centers. These centers address the medical, nutritional, and emotional needs of people who have cystic fibrosis. Many people with cystic fibrosis and their families need emotional support to help them live with this life-shortening genetic disease. Support groups, counseling, and educating yourself about the disease can be very helpful.
Initial treatment: Usually, cystic fibrosis causes problems with both the respiratory and digestive systems, although sometimes it causes problems only in one or the other. Other parts of the body may also be affected. Tests such as a stool analysis, sputum culture, or lung function tests can help your doctor know how serious the disease is and how it is affecting your child’s body.
Your doctor will ask you about your child’s immunizations and schedule any necessary shots. Children with cystic fibrosis should have all the recommended shots in addition to pneumococcal and flu shots. For more information on the recommended schedule of immunizations for children.
Your doctor will want to make sure that your child is eating properly and is gaining weight and growing at a normal rate. He or she will record your child’s weight, height, and head size in order to keep track of how your child is developing over time.
Respiratory therapy: Respiratory therapy refers to any treatment that slows down lung damage and improves breathing. The focus of this therapy is on reducing infection and getting rid of mucus to keep the lungs healthy. Medicines used in respiratory therapy include:
Bronchodilators (such as albuterol or salmeterol), which are used to make breathing easier. Bronchodilators may also make it easier to cough up mucus.
- DNase (such as Pulmozyme), which is used to thin mucus in the lungs.
- Mucolytics (such as Mucomyst), to thin mucus in the lungs and also in the intestines. These are not used very much, because they can irritate the lungs.
- An inhaled saltwater solution (hypertonic saline), sometimes used to help clear mucus from the lungs. It is low-cost, and it may help reduce inflammation in the airways.
- Deep breathing exercises, to help your child breathe out completely and strengthen the muscles used for breathing.
- Aerobic exercise can actually improve how well the lungs work. Ask your doctor about what kinds of exercise your child should do.
- Alternate methods of airway clearance, such as using a positive expiratory pressure (PEP) mask, high-frequency chest compression vest, or Flutter valve. These methods use mechanical equipment to help clear mucus from the lungs.
Digestive Therapy: It is another important part of initial treatment. This therapy works to replace certain digestive enzymes, to make sure the body absorbs all the vitamins and minerals it needs, and to prevent or treat intestinal blockages. Digestive therapy involves:
Digestive enzyme replacement therapy (such as with Creon or Pancrease), to help the intestines absorb nutrients from food.
- Nutritional therapy to help replace lost nutrients. This may include taking vitamins; eating high-calorie, high-fat foods; drinking nutritional drinks; receiving intravenous nutrient supplementation; and, in some cases, getting fed through a tube in the stomach.
- Preventing intestinal blockages with stool softeners (to avoid constipation) and enemas.
If complications develop, one or more of the following medications may be needed:
Antibiotics, to treat infection.
- Anti-inflammatories, (including nonsteroidal anti-inflammatory drugs (NSAIDs), membrane stabilizers, and corticosteroids, to reduce inflammation.
- Bronchodilators and anticholinergics, to open airways in the lungs.
- DNase (such as Pulmozyme) or, in rare cases, mucolytics, to control the amount and thickness of mucus and to reduce the chance of infection.
Sometimes surgery is needed to treat complications of cystic fibrosis. Procedures may include:
Chest tube drainage and possible thoracoscopy, to treat a collapsed lung (pneumothorax).
- A lung transplant.
- Repair of an intestine that has collapsed inside itself or the removal of a bowel obstruction.
- Removal of nasal polyps or endoscopic sinus surgery.
- Abdominal or perineal (anal) surgery for rectal prolapse, in rare cases.
Other treatments used to treat complications from cystic fibrosis may include:
Blood transfusions and medicines to treat the bleeding (embolization therapy), if your child is coughing up large amounts of blood. Coughing up small amounts of blood is normal for people who have cystic fibrosis, but coughing up large amounts of blood can be life-threatening.
- Placement of a feeding tube into your child’s stomach.
- Placement of a semipermanent intravenous (IV) tube in order to give your child antibiotics frequently without having to place a line in the vein each time.
- As they grow older, adults who have cystic fibrosis can develop other serious conditions such as infertility or diabetes. These problems will also require treatment.
Medicine and medications:
Medicines for cystic fibrosis help keep the lungs as healthy as possible, reduce and control mucus in the lungs, and replace digestive enzymes.
Antibiotics (such as azithromycin, Keflex or Cipro, and TOBI [tobramycin]), to treat infection.
- Bronchodilators (such as albuterol or salmeterol).
- Anticholinergics (such as Atrovent).
- DNase (such as Pulmozyme).
- Mucolytics (such as Mucomyst).
- Nonsteroidal anti-inflammatory drugs (NSAIDs) (such as Motrin).
- Membrane stabilizers (such as cromolyn or nedocromil).
- Corticosteroids (such as prednisone, Medrol, or Flovent Diskus).
- Enzyme replacement therapy (such as Creon or Pancrease)
Antibiotics-medicines that kill bacteria that cause infections-are often used to treat cystic fibrosis. Some antibiotics may be prescribed to help prevent infections (such as TOBI [tobramycin] or Zithromax). Others may be prescribed to help fight infections (such as Cipro).
Note: The following drugs and medications are in some way related to, or used in the treatment. This service should be used as a supplement to, and NOT a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.