Cystic Fibrosis (CF)

Cystic fibrosis (CF) is a genetic condition caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene.1,2 Abnormalities of CFTR protein lead to the production of thick, sticky mucus that accumulates in organs such as the lungs and pancreas.1 Symptoms commonly include persistent cough, shortness of breath, lung infections, and pancreatic and intestinal obstruction.1 Chronic lung damage due to CF can result in life-threatening complications. Even though no cure is currently available, treatment options have greatly improved, allowing patients a better quality of life. Approaches to treatment focus on reducing the quantity and thickness of mucus in the airways, as well as preventing intestinal and pancreatic blockage.1

Airway Clearance

In CF, thick mucus accumulates in the lungs, promoting infection, inflammation, and tissue damage.3 Patients with CF must use airway clearance techniques (ACTs) at least daily to dislodge the mucus.3 ACTs are commonly coordinated with the inhalation of bronchodilators (before), mucolytics (during), and antibiotics (after). Bronchodilators relax the airway muscles, and mucolytics thin the mucus so it can be removed from the airways more easily.4

Several airway clearance techniques are available. and these differ in regard to the equipment and assistance needed and in cost.3 Conventional chest physiotherapy (postural drainage with percussion and vibration) requires the assistance of a physical therapist. Methods such as active cycle of breathing techniques and autogenic drainage include breathing control and thoracic expansion exercises that can be done without a therapist or equipment.3 

A young man at home uses a machine to help with mucus buildup from cystic fibrosis. Credit: Getty Images

A device is used to create positive pressure in positive expiratory pressure (PEP) therapy or high-pressure PEP therapy, or to create vibrations.3 In PEP therapy, the patient uses a PEP mask or mouthpiece to exhale against a positive pressure of 10 to 25 cm H2O. This pressure is increased to 140 cm H2O in high-pressure PEP.3 Positive pressure oscillation and expiratory airflow acceleration assist in clearing mucus. With other techniques, such as mechanical percussion and external high-frequency chest compression, a vest is used for external chest wall compression, and no assistance is required.3

Each patient should use a technique that meets his or her needs, after considering factors such as age, comfort, and ease of use. Moderate evidence has indicated that PEP therapy and vibrating devices have similar effects on lung function after 6 months of treatment; however, because of a significant lack of studies in this area, further conclusions cannot be reached.3

After the lungs have been cleared as much as possible, inhaled antibiotics are typically used to prevent infections.4


The energy needs of patients with CF are typically greater than those of other people.5 Digestive problems that lead to malabsorption may arise as thick mucus prevents the release of digestive enzymes from the pancreas. Symptoms of malabsorption include failure to gain weight, frequent bowel movements, and stomachache. The mucus may also cause intestinal blockage.6 

The nutritional status of patients with CF affects disease outcomes. Studies have revealed an association between fat absorption and pulmonary outcomes, showing that children with normal fat absorption have milder symptoms, lower levels of sweat chloride, and a better prognosis than do children with steatorrhea.5 Maintaining optimal nutrition is therefore essential for the normal development of children.5

In patients with CF, an optimal nutritional status requires that normal levels of fat-soluble vitamins and essential fatty acids be maintained; levels can be compromised by deficient absorption.5 Patients must take specific multivitamin supplements that contain fat-soluble (A, D, E, and K) and water-soluble (C) vitamins so that their nutritional needs are met.7 Supplementation with pancreatic enzymes is also required for patients with pancreatic insufficiency.5 After ingestion, the enzymes are released into the small intestine as part of the digestive process. Supplements can be taken before every meal or snack, and the dose can be adjusted according to the type of meal consumed.6

In case of nutritional failure, supplementation via a nasogastric tube, gastrostomy tube, or gastrojejunal tube (enteral nutrition) may improve the growth status of children with CF.8


1. Cystic fibrosis. National Organization for Rare Disorders. Accessed January 13, 2022.

2. About cystic fibrosis. Cystic Fibrosis Foundation. Accessed January 13, 2022.

3. Wilson LM, Morrison L, Robinson KA. Airway clearance techniques for cystic fibrosis: an overview of Cochrane systematic reviews. Cochrane Database Syst Rev. 2019;1(1):CD011231. doi:10.1002/14651858.CD011231.pub2

4. Airway clearance techniques (ACTs). Cystic Fibrosis Foundation. Accessed January 13, 2022.

5. Brownell JN, Bashaw H, Stallings VA. Growth and nutrition in cystic fibrosis. Semin Respir Crit Care Med. 2019;40(6):775-791. doi:10.1055/s-0039-1696726

6. Enzymes. Cystic Fibrosis Foundation. Accessed January 13, 2022.

7. Vitamins. Cystic Fibrosis Foundation. Accessed January 13, 2022.

8. Sullivan JS, Mascarenhas MR. Nutrition: prevention and management of nutritional failure in cystic fibrosis. J Cyst Fibros. 201716(Suppl 2):S87-S93. doi:10.1016/j.jcf.2017.07.010

Reviewed by Kyle Habet, MD, on 1/13/2022.