SciTech

Health Talk: Cystic Fibrosis

In the past few decades, rapid advances in technology have led to corresponding advances in medicine, which have then resulted in exponentially better treatment for people with diseases that had earlier been a certain death sentence.

One such disease is Cystic Fibrosis (CF); only a little more than 50 years ago, this diagnosis, according to the Cystic Fibrosis Foundation’s website, was a fatal sentence for the child who was diagnosed before he or she even reached elementary school. Now the median age of a person with CF is more than 37 years, a clear improvement over only a half century ago. CF is an inherited respiratory disease that results in thick, sticky mucus secretions in the respiratory and digestive tracts and the reproductive system and causes an increase in the amount of salt in sweat.

These symptoms are due to a defective gene that alters a protein that controls the normal movement of sodium chloride, or table salt, into and out of the cells. This gene is recessive, which means that a child must inherit it from both their mother and father in order to have CF; if they receive only one copy of the gene, they will not develop the disease, but there will be the possibility that they pass the gene on to their own child.

The main characteristic of CF is the thick secretions that are produced. In healthy people, the cells that produce mucus, sweat, saliva, and digestive juices produce thin, slippery secretions that act as lubricants. For people with CF, however, the thicker secretions actually plug up tubes in the pancreas and lungs, which results in frequent respiratory infections. In addition, the secretions stop the body from absorbing important vitamins by blocking pancreatic enzymes that aid in the digestion of fats and proteins.

Common respiratory infections experienced by patients with CF are bronchitis, pneumonia, and chronic sinusitis; asthma can also result. The respiratory infections occur so often for people with CF because the thick mucus that is secreted blocks the airways, and is also the perfect breeding ground for the bacteria that cause these infections. In addition to respiratory infections, respiratory failure can also result, as can a collapsed lung. With a collapsed lung, a small hole forms in the lung’s outer layer which leads to air leaking into the chest cavity. It is ultimately respiratory problems that prove fatal for those with CF.

Though respiratory issues are common for CF patients, they are not the only symptoms of the disease. The thick secretions that block the airways and lead to respiratory infections also block the ducts of the pancreas, which stops enzymes that digest fat and proteins from reaching the stomach. This keeps the body from absorbing vitamins A, D, E, and K, resulting in severe nutritional deficiencies.

People with CF also often develop cystic fibrosis-related diabetes, because the pancreas controls the level of blood sugar and the ducts of the pancreas are often covered. The bile duct, which takes bile from the liver and gallbladder to the small intestine, can also be blocked by the secretions, leading to liver problems such as cirrhosis.

Cystic fibrosis can also cause reproductive problems in both men and women, though treatment options are available for both that can make it possible for some people to have children. As explained on MayoClinic.com, a number of treatments exist to help patients with CF live with the disease, though there is currently no cure.

Antibiotics are used to treat the bacteria that cause the respiratory infections. Mucus thinning drugs can also help, because the thinner mucus is easier to cough up. Bronchodilators are also used; medicines such as albuterol help to open the bronchial tubes and clear the thick secretions.
Oral enzymes are often taken to help patients maintain weight, as people with CF often need more calories than healthy people do. For those with persistent, severe, and life-threatening respiratory problems, a lung transplant may be suggested, though due to the serious risks that accompany this procedure, it is often a last option.

Though no cure exists for CF presently, the genetic mutation that causes the disease has been identified, and scientists have been looking for ways to put copies of the healthy gene into the patient’s respiratory tract; clinical trials are being done to test the reliability and effectiveness of using modified viruses, fat capsules, and synthetic vectors. In addition, testing has been developed to check if a person is a carrier of the CF gene.