What Is Cystic Fibrosis?

Cystic fibrosis is a progressive genetic disease that affects the lungs, the pancreas and other organs.

01 Cystic fibrosis – incidence and age

Although cystic fibrosis is a rare disease overall, it is one of the most common inherited disorders: it is the most common genetic metabolic disease in Europe. Around four per cent of all people carry a gene defect through which they can pass on cystic fibrosis. However, the disease only occurs if the other parent also passes on this genetic change. This happens in one in 2,700 newborns. There are now more adults than children among people with cystic fibrosis, which reflects good survival rates.

Cystic fibrosis occurs only when both parents have passed on a gene affected by the mutation. Healthy people who inherit one altered gene do not develop cystic fibrosis, but they can pass on the predisposition to their children.

Only a few decades ago, the life expectancy of people with cystic fibrosis rarely exceeded twenty years. Today, thanks to modern treatment methods, including treatment in Switzerland, many people with cystic fibrosis live more than twice as long.

02 What are the symptoms of cystic fibrosis?

Thanks to newborn screening, cystic fibrosis can be diagnosed within the first month of life, before symptoms appear. People born before newborn screening became available, however, may not be diagnosed until the signs and symptoms of cystic fibrosis appear.

The signs and symptoms of cystic fibrosis vary depending on the severity of the disease. Even in the same person, symptoms may worsen or improve over time. Some people may have no symptoms until adolescence or adulthood. People who are not diagnosed until adulthood usually have a milder form of the disease and are more likely to have atypical symptoms, such as recurring bouts of inflammation of the pancreas (pancreatitis), infertility and recurrent pneumonia.

People with cystic fibrosis have higher than normal levels of salt in their sweat. Parents often taste the salt when they kiss their children. Most of the other signs and symptoms of cystic fibrosis affect the respiratory and digestive systems.

Classic cystic fibrosis

Children with classic cystic fibrosis have the following symptoms:

• Failure to thrive (inability to gain weight despite a good appetite and an adequate calorie intake).
• Loose or greasy stools.
• Difficulty breathing.
• Recurrent wheezing.
• Frequent lung infections (recurrent pneumonia or bronchitis).
• Recurrent sinus infections.
• Persistent cough.
• Slow growth.

Atypical cystic fibrosis

People with atypical cystic fibrosis may already be adults by the time they are diagnosed. Respiratory signs and symptoms may include:

• Chronic sinusitis.
• Breathing problems, possibly diagnosed as asthma or chronic obstructive pulmonary disease (COPD).
• Nasal polyps.
• Frequent bouts of pneumonia.

Other signs and symptoms of atypical cystic fibrosis may include:

• Dehydration or heatstroke revealing abnormal electrolyte levels.
• Fertility problems.
• Diarrhoea.
• Pancreatitis.
• Unintentional weight loss.

03 How is cystic fibrosis (CF) diagnosed?

In most cases CF is diagnosed in childhood. Doctors diagnose cystic fibrosis through a careful assessment and a range of tests. These include:

• Newborn screening: Your doctor takes a few drops of blood from the heel, usually while your newborn is still in hospital, and places the drops on a special card.
• Sweat test: The sweat test measures the amount of chloride in the body’s sweat, which is higher in people with cystic fibrosis. During the test, your doctor applies a chemical called pilocarpine to your skin and then uses a small amount of electrical stimulation to make the sweat glands produce sweat. The doctor then collects the sweat in a plastic coil, on a piece of filter paper or on gauze. People of any age can have a sweat test. It is painless and involves no needles. It is the most conclusive test for cystic fibrosis.
• Genetic tests: Blood samples are checked for the genes that cause cystic fibrosis.
• Chest X-ray. Your doctor will order a chest X-ray to support or confirm cystic fibrosis, but a chest X-ray alone is not enough to confirm the diagnosis. Other tests must also be carried out.

• Sinus X-ray: Like a chest X-ray, a sinus X-ray can confirm cystic fibrosis in people with certain symptoms. Other forms of testing are used alongside the sinus X-ray.
• Lung function tests: The most common lung function test uses a device called a spirometer. You breathe in fully, then breathe out into the spirometer’s mouthpiece.
• Sputum culture: Your doctor takes a sample of your sputum (phlegm) and tests it for bacteria. Certain bacteria, such as Pseudomonas, are found most often in people with cystic fibrosis.
• Nasal potential difference (NPD). This test uses a voltmeter and electrodes placed at two points inside the nose and at one point outside it to measure the electricity generated by the transport of ions in solution across the nasal tissue. Three different types of solution are used in the test.
• Intestinal current measurement (ICM): For this test you will need a biopsy of rectal tissue. The tissue is stimulated to secrete chloride, which is then measured.

In people with atypical cystic fibrosis, the sweat test may show normal chloride levels. Some people with atypical cystic fibrosis may have been born before testing became routine.

04 When to see a doctor

If you or your child have symptoms of cystic fibrosis, or if someone in your family has cystic fibrosis, talk to your doctor about testing for the disease. Consult a doctor who is experienced in cystic fibrosis.

Cystic fibrosis requires ongoing, regular follow-up with a doctor, at least every three months. See your doctor if you have new or worsening symptoms, such as more mucus than usual or a change in its colour, lack of energy, weight loss or severe constipation.

Seek medical help immediately if you cough up blood, have chest pain or difficulty breathing, or severe abdominal pain and bloating.