What is cystic fibrosis?

Cystic fibrosis is a genetic disease that causes thick, sticky mucus to build up in the lungs, digestive tract and other areas of the body. It’s one of the most common chronic lung diseases in children and young adults and is a life-threatening disorder.

Alternative names

CF.

Causes

Cystic fibrosis (CF) is a disease that is passed down through families. It’s caused by a defective gene that interrupts or decreases the transport of chloride in the surface of the cells. By doing this, the amount of water on the surface of cells decreases, making the mucus abnormally thick and sticky. This mucus builds up in multiple organs, including the lungs and pancreas.

The buildup of mucus results in bacteria proliferation and destruction of the airways (breathing pipes), leading to life-threatening lung infections and serious digestion problems. The disease may also affect the sweat glands and a man's reproductive system.

Many people carry a CF gene but don’t have symptoms. This is because a person with CF must inherit two defective genes, one from each parent.

Most children with CF are diagnosed by age 2. For a small number, the disease is not detected until later in life. These patients often have a milder version of the disease.

Symptoms

Symptoms in newborns may include:

• Delayed growth
• Failure to gain weight normally during childhood
• No bowel movements in first 24 to 48 hours of life
• Salty-tasting skin

Symptoms related to bowel function may include:

• Belly pain from severe constipation
• Increased gas, bloating or a belly that appears swollen (distended)
• Nausea and loss of appetite
• Stools that are pale or clay-colored, foul smelling, have mucus or that float
• Weight loss

Symptoms related to the lungs and sinuses may include:

• Coughing or increased mucus in the sinuses or lungs
• Fatigue
• Nasal congestion caused by nasal polyps
• Repeated episodes of pneumonia (symptoms of pneumonia in someone with cystic fibrosis include fever and loss of appetite as well as increases in coughing, shortness of breath and mucus)
• Sinus pain or pressure caused by infection or polyps

Symptoms that may be noticed later in life:

• Infertility (in men)
• Repeated inflammation of the pancreas (pancreatitis)
• Respiratory symptoms
• Clubbed fingers

Exams and tests

A blood test is done to help detect CF. The test looks for changes in the CF gene. A sweat chloride test is the standard diagnostic test for CF. A high salt level in the person's sweat is a sign of the disease.

Other tests that identify problems that can be related to CF include:

• Chest X-ray or CT scan
• Fecal fat test
• Lung function tests
• Measurement of pancreatic function
• Secretin stimulation test
• Trypsin and chymotrypsin in stool
• Upper GI and small bowel series

Treatment

An early diagnosis of CF and subsequent treatment plan can improve both survival and quality of life. Follow-up and monitoring are very important. When possible, care should be received at a cystic fibrosis specialty clinic. When children reach adulthood, they should transfer to a cystic fibrosis specialty center for adults.

Treatment for lung problems includes:

• Antibiotics to prevent and treat lung and sinus infections. They may be taken by mouth, given in the veins or by breathing treatments. People with CF may take antibiotics only when needed or all the time. Doses are often higher than normal.
• Inhaled medicines can be taken to help open the airways.
• Other medicines that are given by a breathing treatment to thin mucus and make it easier to cough up are DNAse enzyme therapy and highly concentrated salt solutions (hypertonic saline).
• Flu vaccine and pneumococcal vaccine.
• Lung transplant is an option in some cases.
• Oxygen therapy may be needed as lung disease gets worse.

Another component in the management of CF lung disease is airway clearance. The goal is not only to make the mucus thinner, but to help expectorating the mucus.

These methods include:

• Activity or exercise that causes you to breathe deeply
• Devices that are used during the day to help clear the airways of too much mucus
• Manual chest percussion (or chest physiotherapy), in which a family member or a therapist lightly claps the person's chest, back and area under the arms

Treatment for bowel and nutritional problems may include:

• A special diet high in protein and calories
• Pancreatic enzymes to help absorb fats and protein, which are taken with every meal
• Vitamin supplements, especially vitamins A, D, E and K
• Other treatments advised by your provider if you have very hard stools

Ivacaftor, Ivacaftor/Lumacaftor and Tezacaftor/Ivacaftor are new medicines that treat different patients with CF based on their gene mutations. These medications improve the transport of chloride in the surface of the cell. As a result, there is less buildup of thick mucus in the lungs. Patients taking these medications have an improvement in their lung function that ranges from 4 to 10 percent. Other CF symptoms are improved as well.

Care and monitoring at home should include:

• Avoiding smoke, dust, dirt, fumes, household chemicals, fireplace smoke and mold or mildew
• Giving plenty of fluids, especially to infants and children in hot weather, when there is diarrhea or loose stools or during extra physical activity
• Exercising two to three times each week. Swimming, jogging and cycling are good options.
• Clearing or bringing up mucus or secretions from the airways. This must be done one to four times each day. Patients, families and caregivers must learn about doing chest percussion and postural drainage to help keep the airways clear.

Support groups

You can ease the stress of illness by joining a cystic fibrosis support group. Sharing with others who have common experiences and problems can help your family to not feel alone.

Outlook (Prognosis)

Most subjects with CF stay in good health through adulthood. They are able to take part in most activities and attend school. Many adults with CF finish college or find jobs.

Lung disease can eventually get worse to the point where the person is disabled. Today, the average life span for people with CF who live to adulthood is about 39 years.

Death is most often caused by lung complications.

Possible complications

The most common complication is chronic respiratory infection.

Other complications include:

• Bowel problems, such as gallstones, intestinal blockage and rectal prolapse
• Coughing up blood
• Chronic respiratory failure
• Diabetes
• Infertility
• Liver disease or liver failure, pancreatitis, biliary cirrhosis
• Malnutrition
• Nasal polyps and sinusitis
• Osteoporosis and arthritis
• Pneumonia that keeps coming back
• Pneumothorax
• Right-sided heart failure (cor pulmonale)

When to contact a medical professional

Call your provider if you experience any of the following symptoms:

• Fever, increased coughing, changes in sputum or blood in sputum, loss of appetite or other signs of pneumonia
• Increased weight loss
• More frequent bowel movements or stools that are foul-smelling or have more mucus
• Swollen belly or increased bloating

Call your provider if a person with CF develops new symptoms or if symptoms get worse, particularly severe breathing difficulty or coughing up blood.

Prevention

CF cannot be prevented. Screening those with a family history of the disease may detect the CF gene in many carriers.

Images

References

Accurso FJ. Cystic fibrosis. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 89.

Cutting GR. Cystic fibrosis. In: Rimoin DL, Pyeritz RE, Korf BR, eds. Emery and Rimoin's Principles and Practice of Medical Genetics. 6th ed. Philadelphia, PA: Elsevier; 2013:chap 58.

Egan ME, Green DM, Voynow JA. Cystic fibrosis. In: Kliegman RM, Stanton BF, St Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 403.

Review Date

5/24/2018

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