Cystic Fibrosis (CF)

What Is Cystic Fibrosis?

Cystic fibrosis (CF) is an inherited, lifelong genetic disease that primarily affects the lungs and digestive system. About 40,000 children and adults in the United States and more than 105,000 worldwide have cystic fibrosis, according to the Cystic Fibrosis Foundation. Thanks to modern therapies — including CFTR modulators that target the underlying protein defect — people with CF are living longer, healthier lives than ever before.

CF is a progressive disease, meaning it gets worse over time. It causes persistent lung infections and makes breathing difficult. People with CF have a defective CFTR gene that produces unusually thick, sticky mucus. This mucus builds up in the lungs and pancreas, making it hard to cough out and increasing the risk of severe infections. It also blocks ducts in the pancreas, leading to problems digesting food and absorbing nutrients.

Causes

CF is most common in individuals of northern European descent, but people of all ethnicities can carry CFTR mutations.

When diagnosed with CF, a person has two defective CFTR genes—one inherited from each parent. If both parents are carriers, each child has a one-in-four chance of having cystic fibrosis. People with only one copy of a CFTR mutation are carriers and typically have no symptoms.

There are approximately 40,000 people with CF in the U.S., according to the Cystic Fibrosis Foundation, although many do not know they carry the gene. Genetic testing can identify common CFTR mutations and is recommended for individuals planning a pregnancy or those with a family history of CF.

When the CFTR protein does not function correctly, it cannot transport salt and water across cells. This leads to thick, dehydrated mucus in the airways, pancreas, sweat glands, sinuses and bowels.

Signs and Symptoms

Cystic fibrosis is a progressive disease that involves a number of different organs. Symptoms of cystic fibrosis can vary, depending age and disease severity. The severity of disease is largely determined by the specific CFTR mutations. Disease severity can also be related to the type of infections that are present in the airways and several “modifier” genes, which can cause CF symptoms. Respiratory Symptoms

• Chronic coughing, sometimes with phlegm
• Coughing up blood during severe infections
• Fatigue or reduced exercise tolerance
• Frequent lung infections (pneumonia, bronchitis)
• Very salty-tasting skin
• Wheezing or shortness of breath

Digestive Symptoms

• Constipation or bowel obstruction, especially in newborns
• Frequent bulky, greasy stools
• Poor growth or weight gain despite a good appetite

Other Systemic Symptoms

• Male infertility
• Nutrient deficiencies due to poor absorption
• Weakness and fatigue

Coughing up blood is a common sign of increased infection and usually is resolved with antibiotics. More severe complications include collapse of lobes or leaking of air outside of the lungs. These complications are associated with advanced lung disease and can be a cause of sudden worsening of respiratory symptoms. Urgent medical evaluation and treatment are required in these cases.

Associated Conditions

When the CFTR gene is defective, many organ systems are affected. While damage to the lungs and pancreas is the most critical, CF can involve other organ systems and greatly impact the lives of people with CF.

Adults with cystic fibrosis may also develop:

• Bronchiectasis: Abnormal widening and inflammation of the airways in the lungs 
• Clubbing: Rounded and enlarged ends of the toes and fingers
• Diabetes, CF-related diabetes (CDFD): Blood sugar that is too high 
• Osteoporosis: Weakened bones
• Pancreatitis: Inflammation of the pancreas 
• Sinus disease: Inflammation of the sinuses, chronic sinusitis

In people with cystic fibrosis, thick and dehydrated mucus prevents the normal clearance of bacteria and other microbes from the lungs. Chronic infections often occur.

Aggressive medical treatment of CF sinus disease is very important. Poorly controlled sinusitis can greatly worsen the severity of CF lung disease and impact quality of life. Although sinus surgery is sometimes needed, this should only be performed by an otolaryngologist (ear, nose and throat (ENT) specialist) experienced in the treatment of cystic fibrosis-related sinus disease.

The most important complication of CF is the progressive destruction of the lungs. This can cause respiratory failure and death. Fortunately, steady advances in medical treatments for cystic fibrosis have provided a range of therapies to slow or prevent complications. New therapies have improved quality of life and extended the lifespan of children and adults.

Diagnosis

Children are most often diagnosed with cystic fibrosis through state-run newborn screening programs, according to the National Institutes of Health. However, in people with less severe symptoms born before widespread implementation of newborn screening, the diagnosis may be delayed for decades.

Mild forms of CF can remain undiagnosed until adulthood. Most people with cystic fibrosis diagnosed in adulthood will have normal pancreatic function. The life expectancy of people diagnosed as adults with mild CF is significantly longer than for people diagnosed in childhood. The people diagnosed later in life also respond well to standard CF care.

Reliable testing is one of the most significant advances in our understanding and treatment of CF. Testing is important for children and adults suspected of having the disease. It is also important for individuals without symptoms who are concerned about the risk of being a CF carrier and passing the CF gene to their children, sometimes with a single mutated gene. 

Newborn Screening

Newborn screening for cystic fibrosis is now required in all 50 states and the District of Columbia. Many studies have proven that CF diagnosed early in life results in healthier children and increased survival rates when compared to children with a delayed diagnosis. The United States Centers for Disease Control and Prevention (CDC) and the Cystic Fibrosis Foundation recommend newborn screening. The test detects elevated quantities of trypsinogen in a drop of blood collected from the heel. This procedure (in which blood is collected from the heel) is already widely performed to test for other congenital disorders. Newborn screening is not a definitive diagnostic test for cystic fibrosis. If the test is positive, a sweat test and genetic testing may be done.

Lab Tests

Blood Test

Blood testing can help diagnose cystic fibrosis by looking for changes in the CFTR gene, which is responsible for the condition. A genetic blood test analyzes DNA to identify mutations in this gene that interfere with how salt and water move in and out of cells. If disease-causing mutations are found, it supports the diagnosis of cystic fibrosis, especially when combined with other tests such as a sweat chloride test and evaluation of symptoms.

Genetic Testing

Genetic testing for CF analyzes a person’s DNA from a blood sample or from cells that are gently scraped from inside the mouth. Genetic testing looks for the most common CFTR mutations, which account for up to 90 percent of all cases in specific ethnic groups. There are more than 1,700 known CFTR mutations.

Several tests can identify the presence of defective CFTR genes in newborns with positive screening results, as well as children and adults with symptoms of CF. These tests can also identify symptomless carriers of an abnormal CF gene.

The American College of Obstetricians and Gynecologists recommends that all pregnant women and their partners, as well as couples planning to have children, have genetic testing to screen for carriers of CF.

Patients confirmed to have CF by the sweat test can benefit from genetic testing. It can identify the specific CFTR mutations and help predict the future severity of the condition. Newer treatments are also focused on specific CFTR mutations.

The availability of reliable testing is one of the most significant advances in our understanding and treatment of CF. Testing is important not only for children and adults suspected of having the disease, but for individuals without symptoms that are concerned about the risk of being a CF carrier, with the potential to pass the gene to their children. Several different tests are currently available. 

Sweat Test

This test is the gold standard for diagnosing CF. Sweat tests must be performed by trained technicians and evaluated in a Cystic Fibrosis Foundation-accredited care center where strict guidelines help ensure accurate results. National Jewish Health is an approved diagnostic laboratory for cystic fibrosis. The sweat test is performed on children and adults who show symptoms of cystic fibrosis or babies who have a positive newborn screen for CF. It is a painless test that looks for high chloride levels: 

• Less than or equal to 29 mmol/L = CF is unlikely regardless of age.
• Between 30-59 mmol/L = CF is possible, and additional testing is needed.
• Greater than or equal to 60 mmol/L = CF is likely to be diagnosed.

If sweat test results are between 30-59 mmol/L, the sweat test is usually repeated. Testing must be performed at a CF Foundation–accredited center.

Treatment

Cystic fibrosis is treated with a personalized plan that includes symptom management techniques, a fitness plan nutritional therapy and medications. Following your treatment plan will help you to keep your disease under control. Since cystic fibrosis is a complex disease, it requires a team approach. 

Your CF care team will work with you to create a treatment plan that meets your needs and goals. Treatment plans can include:

• Airway clearance techniques
• Avoiding infections
• Fitness plans
• Lung transplant
• Medications
• Nutrition plans
• Regular visits to CF care center
• Treating infections

Medications 

A variety of inhaled medications may be used along with the airway clearance techniques. Your CF team will review the medications recommended for you. Medications for CF can include: 

• Antibiotics to treat bacteria and other infectious organisms causing infection and damage and airways.
• Bronchodilators to improve airflow.
• CFTR modulators : Targeted therapies, such as Trikafta, correct specific CFTR protein defects and have dramatically improved survival and quality of life for many people with CF. Eligibility depends on your specific mutation.
• Enzyme replacement therapy to help digest food.
• Inhaled antibiotics to treat chronic lung infections.
• Mucolytics and airway-hydrating agents to thin mucus.

Antibiotics may be taken as a routine chronic regimen. These can be oral or inhaled for specific bacteria in the lungs. Occasionally the bacterial burden in the lungs becomes overgrown and a course of oral or IV antibiotics is needed. The typical amount of time for a course of antibiotics for an acute infection is two to three weeks.

Although there is not yet a cure for cystic fibrosis, there have been many treatment advances that have improved digestion, lung function and longevity, while enhancing mucus clearing and restoring CFTR function.

See the Cystic Fibrosis Foundation website for up-to-date information about approved CF medications and those under development.

Procedures

Lung Transplantation

Cystic fibrosis may progress despite therapy. If this happens, discuss with your health care provider if lung transplantation may be an option for you. Lung transplant surgery replaces one or two diseased lungs with healthy lungs from a non-living donor. With improved surgical techniques and post-transplant care, this may offer you improved quality of life and longer survival. Cystic fibrosis doesn’t recur in transplanted lungs.

Lung transplantation is performed only at specialty medical centers. Your health care team may determine that lung transplant is the best option for you and that you are healthy enough for surgery. After an extensive evaluation, appropriate candidates are placed on a waiting list. A position on the waiting list is determined by disease severity. Wait times vary from transplant center to transplant center. After surgery, long-term anti-rejection medications and strong emotional support are essential.

Therapies

Airway clearance measures are treatments designed to clear trapped mucus from the airways. They can include the following: 

• Applying postural drainage and clapping: This involves the use gravity to promote drainage of mucus from the lungs.
• Using oscillating positive expiratory pressure devices (OPEPD): These include devices such as the Aerobika®, Acapella® or the Flutter Valve® that help clear mucus from your lungs. These are small devices you inhale and/or exhale into.
• Wearing high-frequency chest wall oscillation vests: These include The Vest®, SmartVest®, AffloVest®, InCourage® Vest and Monarch® Vest.  Inflatable vests that you put on. The vest shakes your chest to help dislodge the mucus from the airway walls. Sometimes the Aerobika® or Acapella® is used after the inflatable vest. Once the mucus is dislodged, the device can help clear the mucus.

Different techniques can be prescribed by your health care provider. Correct technique using these devices is very important. Make sure a health care provider shows you how to use your device. It is also important to have your technique checked periodically to make sure you receive the most benefit.

Lifestyle Management

There are a number of measures that can help people with CF avoid infections:

• Avoid contact with others when they are sick.
• Avoid touching your eyes, nose and mouth. Germs are often spread this way.
• Good hand washing with soap and water is also very important to help prevent the spread of germs and infections. Alcohol-based gels are also effective. Use a quarter-sized dollop in your palm, and rub your hands together until they are dry.
• Remember the six-foot rule. All people with CF should stay six feet away from each other in all settings, unless living in the same household. The thick mucus seen with CF leads to a person being more at risk of infection. This will help decrease the risk of transmitting germs seen with CF from person to person.
• Vaccines are recommended. The influenza or flu vaccine is recommended yearly, often in the fall. There are two recommended pneumonia vaccines. These vaccines help prevent severe infection from a bacterium that is a common cause of pneumonia.

Exercise

Staying physically active helps the lungs function better, reduces pulmonary exacerbations, slows the rate of lung function decline and helps you maintain a normal life. Make physical activity an important part of your lifestyle, like sleeping and eating. Choose activities that you can do consistently despite the weather, such as walking, running and cycling. Keep hydrated while you are exercising to maintain your salt level.

Nutrition 

People with CF often need to eat a high-calorie, high-fat diet. Medicines may be recommended to help with digestion. Vitamin and mineral supplements may also be recommended. Each person’s nutritional needs are different, so your care team will help create a nutritional plan just for you.

Clinical Trials

Clinical trials help determine new treatment options for diseases and conditions. Patients with CF have access to clinical trials and should speak with their physician to determine what trials might work best for them.

When to See a Specialist

It’s important to be evaluated by a pulmonologist who specializes in CF if you or a loved one: 

• Has symptoms of CF
• Would like strategies to help improve your current treatment of CF

At National Jewish Health in Denver, Colorado, we have the largest adult cystic fibrosis center in the United States. Learn more about our Cystic Fibrosis Program or use the button below to make an appointment.