Cystic fibrosis or CF is an inherited disease involving epithelial cells. Epithelial cells are found lining the skin, sweat glands, and respiratory, gastrointestinal and genitourinary tracts. In people with cystic fibrosis, the epithelial cells do not function properly. These impaired cells cause abnormal regulation of the flow of salts and water. The result is abnormal secretions such as a thick, sticky mucus that clogs the lungs. It is a life-threatening disorder that causes severe lung damage and nutritional deficiencies. The affected gene, which is inherited from a child’s parents, is a recessive gene. With recessive genes, children need to inherit two copies of the gene, one from each parent, in order to have the disease. If children inherit only one copy, they won’t develop cystic fibrosis, but will be carriers and possibly pass the gene to their own children. In normal airways, secretions work to help us remove germs and particles we breathe in with the outside air. In the airways of a person with CF, the secretions are abnormal and become thicker, actually trapping germs (mostly bacteria). This results in chronic infection. With time, infection leads to airway destruction and lung damage that progressively worsens.
Cystic fibrosis happens most often in white people of northern European ancestry, occurring in about 1 out of 3,000 live births. In the past, most people with cystic fibrosis died in their teens. Improved screening and treatments now allow many people with cystic fibrosis to live into their 50s or even longer. The changes in epithelial cell function which cause the abnormal cellular secretions in CF are the result of an abnormal cell membrane protein called the cystic fibrosis transmembrane regulator (CFTR). Roughly 1 in 30 Caucasians carry one copy of an abnormal CFTR gene. The disease is also seen, though much less frequently, in African American and Asian populations. This means a child will be born with CF only if the child receives one defective gene from each parent. After a child with CF is born, symptoms may be delayed for weeks, months or even years.
One of the first signs of cystic fibrosis is an excessively salty taste to the skin. People with cystic fibrosis tend to have higher than normal amounts of salt in their sweat. Parents often can taste the salt when they kiss their child. Most of the other signs and symptoms of cystic fibrosis affect the respiratory system or the digestive system. Many different genes for CF exist; as a result, clinical characteristics and symptoms vary. Symptoms may range from mild to severe in different individuals with CF. The following symptoms generally represent classic or severe forms of the disease:
- Recurrent or persistent lung infection
- Chronic cough
- Recurrent wheezing
- Trouble breathing
- Frequent need for antibiotics
- Poor weight gain
- Large, frequent, bulky and/or foul smelling stools
- Appetite which may vary from large to very poor
- Salty taste, sweating
- Fingers and toes with “clubbing”
People with cystic fibrosis are often on antibiotics to treat and prevent lung infection. In addition, they use mucus-thinning drugs to reduce the stickiness of the mucus, making it easier to cough up secretions which allows for better lung function. Bronchodilators, such as albuterol, are used as an inhaler or a nebulizer to help keep the airways open by relaxing the muscles around the bronchial tubes. Finally, people with cystic fibrosis need a way to physically remove thick mucus from their lungs. This is usually done by manually clapping with cupped hands on the front and back of the chest. This procedure should be performed with the person’s head over the edge of the bed so that gravity helps clear the secretions. There also are mechanical devices that help loosen lung mucus. Finally, numerous surgical and other procedures may be needed, including the placement of a feeding tube, a lung transplant and bowel surgery. CF patients are also encouraged to eat nutritious meals, drink plenty of fluids, keep immunizations up to date, exercise, stay away from smoke and wash hands thoroughly to prevent infections.
The future outlook for those with CF is optimistic. While cystic fibrosis is a life-shortening disease, the outlook is continually improving. Over the period from the 1950s and 1960s to the present, the median life expectancy has risen from 5-10 years to over 35 years, with some patients surviving into the fifth and sixth decades. In fact, some patients even survive into their seventies. And even these figures probably underestimate current survival rates. Much of this improved survival is attributed to hard work by families, intensive medical monitoring and care in CF centers, as well as increased options in antibiotics that can manage infection. Due to the intensive research efforts to defeat this disease, the expectation of added treatment options stemming from clinical trials at CF centers, and the refinement of lung transplantation for CF, continued progress is expected if combined with aggressive day-to-day therapy at home.