Cystic fibrosis (CF) is an inherited genetic disorder of the mucus and sweat glands. Mutations occurring in the cystic fibrosis transmembrane conductance regulator (CFTR) gene cause disruption in the function of chloride channels, which then prevents the regulation of the flow of chloride ions and water across the cell membranes. As a result, cells that are found within the passageways of organs then produce mucus that is abnormally thick and sticky and clogs airways and ducts. CF mainly affects the lungs, pancreas, liver, intestines, sinuses, and sex organs. Symptoms and severity of CF may vary between patients; some individuals may have significant issues at birth, while others may have a less severe form of the disease and not show symptoms until the person is a teenager or young adult. There is currently is no cure for CF; however, close monitoring and aggressive, early treatment can improve its symptoms, reduce complications associated with it, and improve the quality of life of those with the disease. The overall goals of treatment are to prevent and control lung infections, loosen and remove mucus from the lungs, prevent and treat blockages in the intestine, and ensure that the individual is receiving sufficient nutrition.
Airway clearance therapy (ACT) is something that is usually required several times per day. This is done to help loosen thick, sticky mucus so that it can be removed from the lungs. Before performing ACT, a bronchodilator such as albuterol (Ventolin, ProAir, and Proventil) or levalbuterol hydrochloride (Xopenex) followed by a mucus thinner (hypertonic saline, dornase alfa (Pulmozyme)) may be used. Bronchodilators help to keep the airways open by relaxing the muscles around the bronchial tubes. Mucus-thinning drugs are used to thin the mucus in the airways so that it can be coughed out of the lungs more easily.
Some of the newer drugs being used to treat CF are classified as CFTR modulator therapies, which work to correct the malfunctioning protein made by the CFTR gene. There are currently four CFTR modulators with FDA approval: ivacaftor (Kalydeco), lumacaftor/ivacaftor (Orkambi), tezacaftor/ivacaftor (Symdeko), and the most recent one, elexacaftor/tezacaftor/ivacaftor (Trikafta), which was approved in October 2019. Trikafta is the first triple combination therapy approved for CF patients who have at least one F508del mutation in the CFTR gene, which is believed to represent 90% of the CF population. There are currently more CFTR modulators in developmental stages.
One of many issues CF patients have to contend with is the need to take oral pancreatic enzymes before every meal or snack due to their pancreas producing thick mucus that blocks the release of enzymes that help the body absorb food and nutrients. Individuals with CF also have issues absorbing fat. This results in a propensity for developing deficiencies to fat-soluble vitamins. CF patients may be required to take nutritional supplements specifically designed for their condition. Individuals with CF also have a larger amount of salt in their sweat than the average person. Since salt is critical for muscle function, digestion, and nerve cell health, people with CF must adjust their diet to replace the salt that is lost. Due to CF patients having a buildup of thick, sticky mucus in their lungs, they are prone to lung infections, and so to keep the infections under control, antibiotics a part of their daily therapy. Anti-inflammatory medications such as corticosteroids and ibuprofen are used to reduce inflammation in CF patients. Azithromycin, an antibiotic, is another therapy that is used as an anti-inflammatory drug in these patients. CF patients also may be more prone to have gastroesophageal reflux disease. As a result, they are often treated with a proton pump inhibitor (eg, omeprazole), an H2 blocker (eg, famotidine), or an antacid (eg, simethicone) in combination with a proton pump inhibitor. Use of H2 blockers and proton pump inhibitors may also help reduce acid in the intestine, which helps the pancreatic enzyme supplements CF patients take work better.
The pancreas typically releases 1-2 quarts of fluid daily into the intestines. However, this fluid is usually limited in CF patients. In addition, people with CF can have thick mucus in their intestines. Due to having thick mucus in addition to having decreased fluids in the intestine, constipation or a bowel obstruction may occur. CF patients may be treated with polyethylene glycol for constipation. Surgery may be necessary if a bowel obstruction develops.
About 5% of CF patients develop significant liver disease. This is due to the small ducts in the liver becoming blocked with thick, sticky bile, leading to liver damage. Ursodeoxycholic acid (ursodiol), which increases the bile flow in the liver, may be used when liver function tests are elevated. CF patients should be up to date with hepatitis B vaccination as well as made aware of substances that may worsen liver damage or function (eg, alcohol, acetaminophen, certain herbal supplements).
Despite the complexity of CF and its related treatments, patients continue to live longer and healthier lives. According to recent Cystic Fibrosis Patient Registry data, the life expectancy of CF patients was approximated to be 44-47 years or older. However, these forecasts do not take into consideration the benefits that CFTR modulator therapies or any of the other constant improvements that are continuing to occur with CF treatment. Hopefully, as advancements in CF treatment continue, the life expectancy and quality of life of CF patients will further improve.
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Cystic Fibrosis News Today website. Cystic Fibrosis and Vitamins. https://cysticfibrosisnewstoday.com/cystic-fibrosis-vitamins/. Accessed June 5, 2020.
FDA website. FDA approves new breakthrough therapy for cystic fibrosis. https://www.fda.gov/news-events/press-announcements/fda-approves-new-breakthrough-therapy-cystic-fibrosis. Updated October 12, 2019. Accessed June 5, 2020.
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Johns Hopkins Cystic Fibrosis Center website. Nutrition. https://hopkinscf.org/clinical-care/nutrition/. Accessed June 5, 2020.
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The National Heart, Lung, and Blood Institute website. Cystic Fibrosis. https://www.nhlbi.nih.gov/health-topics/cystic-fibrosis. Accessed June 5, 2020.