Cystic fibrosis (CF) is an inherited disease in which the body’s glands produce abnormally thick mucus. The mucus can cause problems with digestion, breathing, and regulating body temperature.
Cystic Fibrosis Overview
Cystic fibrosis (CF) is an inherited disease of the secretory glands, which produce mucus, sweat, and enzymes that aid in digestion. Normally, these secreted fluids are thin and slippery and they act as lubricants around the body. In people with CF, a defective gene causes the secretions to become thick and sticky. Instead of acting as a lubricant, the secretions clog tubes, ducts, and passageways, especially in the lungs, pancreas, liver, intestines, sinuses, and sex organs. The mucus also makes it easy for bacteria to grow, which can lead to repeated infections, especially in the lungs. When the ducts in the pancreas are clogged, digestive enzymes made in the pancreas cannot reach your small intestine. The enzymes help break down food and, without them, the intestines cannot fully absorb fats and proteins. This can cause vitamin deficiencies and malnutrition because nutrients pass through the body without being used. People with CF may also have bulky stools, intestinal gas, a swollen belly from severe constipation, and pain or discomfort.
CF also causes sweat to become very salty. This can disrupt the balance of minerals in the blood, which may cause health problems such as dehydration (a lack of fluid in your body), increased heart rate, fatigue (tiredness), weakness, decreased blood pressure, heat stroke, and, rarely, death.
CF is a common genetic disease among Caucasians in the United States, occurring in 1 in 2,500 to 3,500 newborns. CF is less common in other ethnic groups, affecting about 1 in 17,000 African Americans and 1 in 31,000 Asian Americans.
CF requires daily care, and there is currently no cure for the disease. However, people with CF are able to attend school and work, and have a better quality of life than in previous decades. Improvements in screening and treatments mean most people with cystic fibrosis now live into their 20s and 30s, and some are living into their 40s and 50s.
Cystic Fibrosis Symptoms
CF 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 CF have a higher than normal level of salt in their sweat.Most of the other signs and symptoms of CF affect the respiratory system or the digestive system. However, adults with CF are more likely to have atypical symptoms, such as pancreatitis, diabetes, and infertility.
The thick and sticky mucus associated with CF clogs the tubes that carry air in and out of your lungs. This can cause the following respiratory system signs and symptoms of CF include:
- A persistent cough that produces thick (sputum) mucus
- Exercise intolerance
- Repeated lung or sinus infections
- Inflamed nasal passages or a stuffy nose
The thick mucus can also block tubes that carry digestive enzymes from your pancreas to your small intestine. Without these digestive enzymes, your intestines cannot fully absorb the nutrients in the food you eat. The result is often the following digestive system signs and symptoms:
- Foul-smelling, greasy stools
- Poor weight gain and growth
- Intestinal blockage, particularly in newborns (meconium ileus)
- Severe constipation
As CF gets worse, other problems may occur, such as:
- Pancreatitis. This is a condition in which the pancreas become inflamed, which causes pain
- Rectal prolapse. Frequent coughing or problems passing stools may cause rectal tissue from inside you to move out of your rectum
- Liver disease due to inflamed or blocked bile ducts
The thick mucus can block the tubs of the reproductive system and CF is associated with several reproductive system signs and symptoms.
Men who have CF are infertile because they are born without a vas deferens. The vas deferens is a tube that delivers sperm from the testes to the penis. Women who have CF may have a hard time getting pregnant because of mucus blocking the cervix or other CF complications.
Other signs and symptoms of CF are related to an imbalance of minerals in your blood. CF causes sweat to become very salty. As a result, the body loses large amounts of salt when you sweat. This can cause dehydration, increased heart rate, fatigue, weakness, decreased blood pressure, heat stroke, and, rarely, death. CF also can cause clubbing and low bone density. Clubbing is the widening and rounding of the tips of your fingers and toes. This sign develops late in CF because the lungs are not moving enough oxygen into your bloodstream. Low bone density also tends to occur late in CF. It can lead to bone-thinning disorders called osteoporosis and osteopenia.
Cystic Fibrosis Causes
In CF, a defect (mutation) in the CFTR 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 1 copy of the gene from each parent in order to have the disease. If children inherit only 1 copy, they will not develop CF, but they will be carriers of the mutated gene and possibly pass the gene to their own children.
Cystic Fibrosis Diagnosis
Every state in the U.S. now routinely screens newborns for CF. Early diagnosis means treatment can begin immediately. In the screening test, a blood sample is checked for higher than normal levels of a chemical released by the pancreas. However, levels of this chemical may be high because of premature birth or a stressful delivery. For that reason other tests are needed to confirm a diagnosis of CF:
- Sweat test. A sweat-producing chemical is applied to a small area of skin. The collected sweat is then tested to see if it is saltier than normal.
- Genetic testing. DNA samples from blood can be checked for specific defects on the gene responsible for CF.
The sweat test is usually done when the infant is a month old, to ensure the sample is large enough to be analyzed. The sweat test can determine if the infant carries the CF gene or has the condition.
CF tests may be recommended for older children and adults who were not screened at birth. Your doctor may suggest genetic and sweat tests for CF if you have recurrent episodes of an inflamed pancreas (pancreatitis), nasal polyps, chronic sinus or lung infections, bronchiectasis, or male infertility.
CF can also be detected in fetuses before birth. Prenatal genetic tests can show whether a fetus has CF. These tests include amniocentesis (AM-ne-o-sen-TE-sis) and chorionic villus (ko-re-ON-ik VIL-us) sampling (CVS).
Living With Cystic Fibrosis
People with CF should learn as much as possible about the disease. Work closely with doctors to learn how to manage CF. Practice good self-care and follow a healthy lifestyle. This includes eating a healthy diet that includes a variety of fruits, vegetables, and whole grains. Other lifestyle changes that can improve CF symptoms include:
- Not smoking and avoiding tobacco smoke
- Washing hands often to lower your risk of infection
- Exercising regularly and drinking lots of fluids
- Doing chest physical therapy
People with CF have a higher risk for diabetes and bone-thinning conditions including osteoporosis and osteopenia.
CF also causes infertility in men, and the disease can make it harder for women to get pregnant.
Living with CF may cause fear, anxiety, depression, and stress. Talk about how you feel with your health care team. Talking to a professional counselor also can help. If you are very depressed, your doctor may recommend medicines or other treatments that can improve your quality of life.
Joining a patient support group may help you adjust to living with CF. You can see how other people who have the same symptoms have coped with them. Talk with your doctor about local support groups or check with an area medical center.
Support from family and friends also can help relieve stress and anxiety. Let your loved ones know how you feel and what they can do to help you.
Cystic Fibrosis Treatments
CF has no cure. However, treatments have greatly improved in recent years. The goals of CF treatment include:
- Preventing and controlling lung infections
- Loosening and removing thick, sticky mucus from the lungs
- Preventing or treating blockages in the intestines
- Providing adequate nutrition
- Preventing dehydration (a lack of fluid in the body)
Medications used to treat CF include:
- Antibiotics to treat and prevent lung infections, including azithromycin (Zithromax, others) and tobramycin (Bethkis)
- Mucus-thinning drugs to help you cough up the mucus, which improves lung function, such as dornase alfa (Pulmozyme)
- Bronchodilators to help keep your airways open by relaxing the muscles around your bronchial tubes such as albuterol (AccuNeb, ProAir, Proventil HFA, Ventolin HFA)
- Oral pancreatic enzymes to help your digestive tract absorb nutrients, including pancrelipase (Creon, Ultresa, Pertyze, Viokace)
New options for the treatment of CF include drugs that enhance the activity of the enzyme that is deficient or missing in CF. These drugs include ivacaftor (Kalydeco, in Orkambi) and lumacaftor (in Orkambi).
Other treatment options for CF include:
- Chest physical therapy. Loosening the thick mucus in the lungs makes it easier to cough up. Chest physical therapy helps loosen mucus. It is usually done from 1 to 4 times a day. A common technique is clapping with cupped hands on the front and back of the chest. Mechanical devices such as a vibrating vest or a tube or mask you breathe into can also help loosen lung mucus.
- Pulmonary rehabilitation. Pulmonary rehabilitation is a long-term program to improve lung function and control CF symptoms. Programs include:
- Exercise training
- Nutritional counseling
- Breathing techniques
- Psychological counseling and group support
Surgical and other procedures may be necessary if CF symptoms do not improve with first-line treatments. Procedures may include:
- Nasal polyp removal.
- Oxygen therapy.
- Endoscopy and lavage to suction mucus from obstructed airways
- Feeding tube to deliver nutrition
- Bowel surgery to repair blockages in the digestive tract
If CF causes severe breathing problems or life-threatening lung complications, or if it presents increasing resistance to antibiotics used to treat lung infections, lung transplantation may be an option. Because both lungs are affected by cystic fibrosis, both need to be replaced. CF does not recur in transplanted lungs.