is a recessive, genetic disease. A defective gene must come from each the mother and the father in order for the child to be born with CF. Carriers of the defective gene (those who have only one copy of the faulty gene) do not have CF. When two carriers come together to have a child, there is a one in four chance of having a child with cystic fibrosis with each pregnancy.
Cystic Fibrosis cells do not function normally. Sodium and chloride are not moved in and out of the cells as they are supposed to be. The mucus that the body makes is therefore thicker than normal. Thicker mucus in the lungs can be hard to get out and can provide an ideal home for bacteria. People with cystic fibrosis need chest physiotherapy to help them clear the thick mucus from their lungs. This can be done by "clapping" the chest and back with cupped hands or percussors, or it can be done using a special vest that is attached to an air compressor which causes vibrations which loosen lung secretions. Some people with CF use other airway clearance techniques. The important thing is to get the mucus out of the lungs.
In order to open airways, people with cystic fibrosis often use aerosolized prescription bronchodilators, such as albuterol. This is the same medication that many asthma patients use to open their airways. Bronchodilators used before chest physiotherapy can help clear mucus from the lungs.
Thicker than normal mucus is not confined to the lungs in CF. Mucus can block the ducts that carry enzymes from the pancreas to where they help digest food. Because the enzymes that the body makes cannot get where it needs to be, fat and protein in food goes undigested causing bulky, foul stools. Due to this absorption problem, children with cystic fibrosis are often very thin with huge appetites before they are diagnosed. Once they have been diagnosed with cystic fibrosis, enzyme therapy can begin to alleviate the digestion problems. People with CF take prescription enzymes when they eat or drink anything that contains fat or protein. The enzyme pills aid digestion and help people with CF gain weight and have normal stools.
Most men with cystic fibrosis are sterile and most women with cystic fibrosis have difficulty conceiving. Again, the thick mucus is the culprit. While men with CF produce sperm, the path the sperm must travel is blocked. Women have thicker secretions causing reproduction problems. Adults with cystic fibrosis funtion normally sexually, it is just conception of a child that is hindered.
Some other factors attributed to cystic fibrosis are nasal polyps (which may or may not occur, and which may appear and vanish in CF patients without explanation), digital clubbing (a condition where the fingertips are a little thicker than normal), and salty sweat.
The salty sweat is a hallmark of cystic fibrosis. Because of the cellular problem of moving sodium and chloride properly, most people with cystic fibrosis have very salty sweat. In fact, the test usually used to diagnose cystic fibrosis is called the sweat test and measures the salt content of sweat to determine if it is a high level.
A sweat test with results at 60 milliequivalents per liter or higher is positive for cystic fibrosis. Anything under 40 mEq/L is considered negative for CF. Test results between 40 and 60 mEq/L are rare and considered to be in the gray area and would require further testing.
Sweat tests should only be done at a lab that is associated with a CF Center. The test can easily be botched by labs that don't perform it regularly. This is really important! Many mistakes are made in CF diagnoses by labs that do not perform the test correctly. Both false-positives and false-negatives occur. Make sure that your child is tested by a lab that is associated with a CF Clinic, this is usually a hospital lab where a CF Clinic is located.
Salt is added to the food of people with cystic fibrosis to compensate for salt loss in perspiration.
If you or your doctor suspect that your child has cystic fibrosis, a sweat test should be done. If the sweat test is inconclusive, or if you don't live near a CF Center, genetic testing can be done to search for known CF mutations. There are about a thousand different mutations of the CF gene, and many genetic tests only look for a few of the most common mutations. Ambry Genetics does a much more extensive test and the genetic samples can be sent to them for testing by your doctor.
Some of the symptoms of cystic fibrosis follow. Bear in mind that CF varies greatly from one individual to another, and some people with CF have many of the symptoms, while some people with CF have a few symptoms.
If you suspect that your child may have cystic fibrosis, ask your family doctor for a sweat test to be done. It's painless, not terribly expensive, and produces results in just a few hours.
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