What is cystic fibrosis?
Cystic fibrosis is a life-threatening genetic disease that causes mucus to build up and clog some of the organs in the body, particularly the lungs and pancreas. When mucus clogs the lungs, it can make breathing very difficult. The thick mucus also causes bacteria (or germs) to get stuck in the airways, which causes inflammation (or swelling) and infections that lead to lung damage.
Mucus also can block the digestive tract and pancreas. The mucus stops digestive enzymes from getting to the intestines. The body needs these enzymes to break down food, which provides important nutrients to help people grow and stay healthy. People with cystic fibrosis often need to replace these enzymes with medicine they take with their meals and snacks, which helps them digest food and get proper nutrition.
How do people get cystic fibrosis?
Cystic fibrosis is a genetic disease. This means that people inherit it from their parents through genes (or DNA), which also determine a lot of other characteristics including height, hair color and eye color. Genes, found in the nucleus of all the body's cells, control cell function by serving as the blueprint for the production of proteins.
To have cystic fibrosis, a person must inherit two copies of the defective CF gene—one copy from each parent. If both parents are carriers of the CF gene (i.e., they each have one copy of the defective gene, but do not have the disease themselves), their child will have a 25% chance of inheriting both defective copies and having cystic fibrosis, a 50% chance of inheriting one defective copy and being a carrier, and a 25% chance of not having CF or carrying the gene.
Approximately 30,000 children and adults in the United States have cystic fibrosis. An additional ten million more—or about one in every 31 Americans—are carriers of the defective CF gene, but do not have the disease. CF is most common in Caucasians, but it can affect all races.
The severity of cystic fibrosis symptoms is different from person to person. The most common symptoms are:
- Very salty-tasting skin
- Persistent coughing at times producing phlegm
- Frequent lung infections, like pneumonia or bronchitis
- Wheezing or shortness of breath
- Poor growth/weight gain in spite of a good appetite
- Frequent greasy, bulky stools or difficulty in bowel movements
- Small, fleshy growths in the nose called nasal polyps
New research shows that the severity of CF symptoms is partly based on the types of CF gene mutations (defects) a person with the disease has. There are more than 1,400 different mutations of the CF gene.
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 boderline.
- 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.
Normally, the healthy CF gene makes a protein—known as CFTR (Cystic Fibrosis conductance Transmembrane 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 leads to infections that damage the lungs.
Is there a cure for cystic fibrosis?
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.
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.
What is a typical day for someone with CF?
Because the severity of CF differs widely from person to person, and CF lung infections flare up from time to time, there is no “typical” day. However, each day most people with CF:
- Take pancreatic enzyme supplement capsules with every meal and most snacks (even babies who are breastfeeding may need to take enzymes).
- Take multi-vitamins.
- Do some form of airway clearance at least once and sometimes up to four or more times a day.
- Take aerosolized medicines—liquid medicines that are made into a mist or aerosol and then inhaled through a nebulizer.
