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| Cystic fibrosis (CF) is a chronic (persistent) genetic disease. It affects the: Lungs Pancreas Digestive system Liver and gallbladder Joints Sweat glands Reproductive organs exocrine glands
The current median age for survival is 37 years.
The exocrine glands usually secrete thin, slippery substances, such as: Sweat Mucus Tears Digestive fluids
Saliva
Normally, mucus flows easily, carrying with it bacteria and wastes that are eliminated from the body. But in most people with CF, the exocrine glands produce abnormally thick, sticky secretions. These thick secretions obstruct glands throughout the body, eventually causing disease or organ failure.
Within the lungs, the thick mucus secretions plug the airways and cause infections and inflammation, leading to obstruction of airflow and ultimately lung damage. Increased airway reactivity may also contribute to the obstruction. The results are:
In the Pancreas
Your pancreas is a large gland behind your stomach. The pancreas secretes digestive enzymes that enter the small intestines through a duct. These enzymes help you digest fats, proteins, and carbohydrates. The pancreas also releases the hormones insulin and glucagon into the bloodstream. These hormones play an important part in metabolizing sugar.
The pancreas is affected in almost all people with CF. Thick secretions characteristic of CF obstruct the ducts in the pancreas, preventing enzymes from reaching the intestines. Without enzymes, food cannot be digested. If food cannot be digested, nutrients cannot be absorbed (malabsorption) and your body does not get the nutrients it needs for normal growth and development. This malabsorption leads to poor weight gain and malnutrition. To ensure good nutrition and normal growth in people with CF, the following are essential: Well-balanced, high-calorie diet Pancreatic enzyme supplements to help digestion Supplements of vitamins A, D, E, and K Other vitamin and mineral supplements, as needed Nutritional supplements (including tube feedings) to add calories, as needed
In people with CF, the pancreas does not secrete enough enzymes for food to be broken down and absorbed. About half of all infants with CF have pancreatic sufficiency. That means that they have enough enzymes to digest and absorb food without needing extra enzymes. However, over time pancreatic functioning in these infants starts to deteriorate, so that by the age of 8 or 9 they develop pancreatic insufficiency. That means that they are not able to digest and absorb food unless they take supplemental pancreatic enzymes.
The thick secretions also accumulate in the intestines and can cause obstructions, such as meconium ileus and distal intestinal obstruction syndrome.
In the Liver and Gallbladder
Liver disease and gallbladder disease may develop in some people with cystic fibrosis, resulting in biliary cirrhosis, gallstones, fatty liver, or other complications.
In the Joints
Various forms of joint disease may occur in people with cystic fibrosis. Hypertrophic pulmonary osteoarthropathy (HPOA) is a complication of CF that affects the bones and causes joint pain. Clubbing of the fingers and toes may also occur in people with CF.
In the Sweat Glands
Although the sweat produced by people with CF is not thick or sticky, it does contain high levels of salt (sodium and chloride). People with CF can lose excessive amounts of salt when they sweat. This loss of salt may upset the balance of minerals in the blood, causing: Weakness, fatigue, and muscle cramps Dehydration (decreased urination) Heat stroke
In the Reproductive System
In males, the effects of CF are seen in the tube (vas deferens) that carries sperm from the testicles to the penis. The vas deferens in men with CF may not be formed properly or may be obstructed by secretions. Although men with cystic fibrosis produce normal sperm and can have sexual intercourse, the majority require assistance to have children, since sperm is not present in the semen. A select few do not have the blockage and may have sperm in their semen. Men with CF should not assume that they cannot cause a pregnancy. If you do have trouble with fertility, there are options available to assist you. You should discuss these options with your healthcare provider.
In females, the effects of CF are seen in the vagina, cervix, and ovaries. The secretions in the vagina and cervix (opening of the womb) may be so thick and sticky that sperm from the male partner cannot move through it and into the uterus to reach the egg. Ovulation (the release of eggs from the ovaries) may be less frequent. Women with CF can and do have children, although they may be less fertile than women without CF. Even if your periods are irregular, or you haven't yet begun to menstruate, it is still possible for you to become pregnant. It is most important to discuss with your healthcare provider:
The risk you may have of giving birth to a child with CF. The implications of pregnancy on your current health status Methods to prevent pregnancy should you decide not to become pregnant
Causes of Cystic Fibrosis Genes are responsible for every one of your inherited characteristics. Genes are made of deoxyribonucleic acid (DNA) and are located on structures called chromosomes within cells. Humans inherit 23 chromosomes from each parent for a total of 46. On these 46 chromosomes are an estimated 50,000 separate genes. Diseases such as cystic fibrosis are called genetic diseases because they are caused by inherited genes. With CF, each parent carries at least one abnormal CF gene but shows no evidence of the disease.
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| You must inherit two abnormal genes, one from each of your parents, to have CF. If you inherit only one abnormal (also called mutant or defective) CF gene, you are a CF carrier. You will not inherit cystic fibrosis, but you will carry the CF gene (called a recessive gene) on your chromosomes. If you are a carrier for CF and marry someone who also is a carrier for CF, your baby has a 1 in 4 chance of inheriting both mutant CF genes, one from each of you.
Both boys and girls are born with CF. The recessive CF gene can occur in both boys and girls because it is located on a non-sex-linked chromosome called an autosomal chromosome. Cystic fibrosis is therefore called an autosomal recessive genetic disease.
Symptoms of Cystic Fibrosis
People with cystic fibrosis have the following symptoms: Excessive production of thick, sticky mucus in the airways Persistent, sometimes frequent cough Frequent lung infections Failure to gain weight, sometimes even with a good appetite Frequent, foul-smelling, bulky stools Recurrent wheezing
The symptoms of cystic fibrosis gradually worsen over time and increase in severity. On average, people with CF have a lifespan of approximately 36.5 years. This means that some people do not live to 37 years of age, and others live much longer.
Diagnosis
Your healthcare provider will need the following information to make a diagnosis of cystic fibrosis: Testing
Your healthcare provider may order one or more of the following tests to confirm that your child has cystic fibrosis:
Prenatal tests. Two special prenatal tests can be done to detect cystic fibrosis in an unborn child: Amniocentesis Chorionic villus biopsy
However, these tests cannot detect all of the variations of CF gene mutations. Because these tests carry certain risks for the mother and are very expensive, they are not used for all pregnant women.
Sweat test. The most common test for CF in children and adults is the sweat test. It measures the amount of salt (sodium and chloride) in your sweat. Before having this test performed, ask your healthcare provider which laboratory in your area has the most experience in performing sweat tests.
Additional tests. Your healthcare provider may ask that other types of tests be performed. For example: Treatment
Treating cystic fibrosis means treating several types of problems that the disease causes. Lung disease. One important CF treatment focuses on relieving obstructed breathing, which causes frequent lung infections. Physical therapy, exercise, and medications help to reduce the mucus blockage of the lung's airways. Newer antibiotic therapy for lung infections has also been developed. Digestive problems. Management of digestive problems focuses on using pancreatic enzyme supplements to increase the amount of nutrients absorbed by the intestines. Nutritional care emphasizes adequate energy and protein intake to improve growth and overall health. With adequate nutrition, people with CF grow normally. Salt depletion. Salt lost in the sweat is replaced with high dietary salt intake. Lung surgery. Lung transplantation may be an option for people with advanced disease.
This article was written by Mary Virginia Corkle, RN, MN, a former assistant professor at Creighton University, Nebraska, who has extensive experience in emergency nursing. It was reviewed and revised in 2007 by James W. Wallace, MD.
References
Cystic fibrosis. MedlinePlus Medical Encyclopedia. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/000107.htm. Accessed March 9, 2005.
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