Cystic fibrosis (CF) is an inherited chronic disease that affects the lungs and digestive system of about 30,000 children and adults in the United States (70,000 worldwide). A defective gene and its protein product cause the body to produce unusually thick, sticky mucus that:
- clogs the lungs and leads to life-threatening lung infections; and
- Obstructs the pancreas and stops natural enzymes from helping the body break down and absorb food.
Symptoms of Cystic Fibrosis (source: http://www.cff.org/AboutCF/)
People with CF can have a variety of symptoms, including:
- very salty-tasting skin;
- persistent coughing, at times with phlegm;
- frequent lung infections;
- wheezing or shortness of breath;
- poor growth/weight gain in spite of a good appetite; and
- frequent greasy, bulky stools or difficulty in bowel movements
How is CF diagnosed?
Most people are diagnosed with CF at birth through newborn screening, or before the age of 2. A doctor who sees the symptoms of CF will order a sweat test or a genetic test to confirm the diagnosis.
A sweat test is the most common test used to diagnose cystic fibrosis and is considered the diagnostic “gold standard.” A small electrode is placed on the skin (usually on the arm) to stimulate the sweat glands. Sweat is then collected and the amount of chloride, a component of salt in the sweat, is measured. A high level of chloride means that the person has cystic fibrosis.
For children who are less than six months old:
- Chloride levels at or above 60 mmol/L (a measure of concentration) means the child has CF.
- Chloride levels between 30 and 59 mmol/L are considered borderline and need to be examined on a case-by-case basis.
- Chloride levels below 30 mmol/L are considered negative for CF.
For people over the age of six months:
- Chloride levels at or above 60 mmol/L means the person has CF.
- Chloride levels between 40 and 59 mmol/L are borderline.
- Chloride levels below 40 mmol/L are considered negative for CF.
The best place to receive a reliable sweat test is at a Cystic Fibrosis Foundation-accredited care center.
In a genetic test, a blood sample or cells taken from the inside of the cheek are sent to a laboratory that specializes in genetic testing. Most labs only test for the most common mutations of the CF gene. Because there are more than 1,400 mutations that cause CF, screening for all mutations is not possible. A genetic test is often used if the results from a sweat test are unclear.
How does CF affect the lungs?
Normally, the healthy CF gene makes a protein—known as CFTR (Cystic Fibrosis conductance Trans membrane Regulator)—that is found in the cells that line various organs, like the lungs and the pancreas. This protein controls the movement of electrically charged particles, like chloride and sodium (components of salt) in and out of these cells.
When the protein is defective, as in cystic fibrosis, the salt balance in the body is disturbed. Because there is too little salt and water on the outside of the cells, the thin layer of mucus that helps keep the lungs free of germs becomes very thick and difficult to move. And because it is so hard to cough out, this mucus clogs the airways and lead to infections that damage lungs.
Thick mucus production results in frequent lung infections. Diminished secretion of pancreatic enzymes is the main cause of poor growth, fatty diarrhea, and deficiency in fat-soluble vitamins. Males can be infertile due to the condition congenital bilateral absence of the vas deferens. Often, symptoms of CF appear in infancy and childhood but not always the case. Many have been diagnosed much later in life. Meconium ileus is a typical finding in newborn babies with CF.
Individuals with cystic fibrosis can be diagnosed prior to birth by genetic testing. Newborn screening tests are increasingly common and effective (although false positives may occur, and children need to be brought in for a sweat test to distinguish disease vs. carrier status).
Currently, there is no cure for cystic fibrosis. However, specialized medical care, aggressive drug treatments and therapies, along with proper CF nutrition, can lengthen and improve the quality of life for those with CF. As of October 2013 the life expectancy of babies born now is 41 years. With that said, when I was born the life expectancy was 12 years. I have obviously have surpassed that. I have met and surpassed many life expectancies and I plan to continue on doing so.
The best way for people with cystic fibrosis to fight their disease is to work with their medical caregivers at a CF Foundation-accredited care center. The care center partners with people who have CF to help keep them in the best health possible.