Cystic fibrosis: Background information and therapy

Cystic fibrosis (CF) is a genetic metabolic disease. Currently it cannot be cured, but intensive research means there are now effective treatments available. The outlook in terms of life expectancy is now much better. The most important thing to note is that only close collaboration with a CF treatment team can ensure that they can decide on the best available therapy for their patients.

Cystic fibrosis (CF) is a genetic metabolic disease caused by a gene defect, a mutation of the cystic fibrosis gene: the CFTR gene.

This mutation leads to the production of thick mucus in many organs of the body. For instance, it “blocks” the airways, leading to inflammation, infection and lung damage. The thick mucus is also what gives its names to an alternative term for cystic fibrosis - mucoviscidosis - from the Latin for viscous and mucus.

The CFTR gene leads to the expression of the “Cystic Fibrosis Transmembrane Conductance Regulator”. This kind of regulator is a protein is located on the surface of the cells of many of the organs in the body and acts like a channel. The mutation in the CFTR gene – which usually ensures that salt and water can move in and out of the cell – causes a defective channel and therefore a dysfunction in the salt and water balance. This means that too little water moves to the mucus coating the cells, making it thick.

Cystic fibrosis can trigger symptoms in any organ in which the CFTR channel protein acts. The symptoms may also vary from one patient to another. The airways and pancreas are especially often affected.

• A persistent cough to rid the body of the thick mucus
• Shortness of breath because the thick mucus “blocks” the airways
• Frequent airway infections through to pneumonia

The thick mucus in the pancreas blocks pancreatic enzymes from reaching the small intestine. This leads to:

• Abdominal pain
• Constipation
• Very low weight
• Failure to thrive in infants and young children

The genetic defect causing salt-water inbalance in the cell means that patients have very salty sweat. It is therefore important to keep a close eye on electrolyte intake.

Inhalation therapy is the cornerstone of symptomatic treatment for cystic fibrosis. The disease primarily affects the airways, where it prevents the thick mucus from transporting away pathogens, promotes their growth and so increases the risk of infections. Suitable inhalation devices deliver active ingredients directly to the target organs – the lungs. Inhalation therapy has a two-pronged approach:

• Inhalation to liquify the thick mucus, make it easier to cough up phlegm
• Inhalation of antibiotics to clear up or suppress existing infections

Further information on inhalation for cystic fibrosis is available here.

Respiratory therapy/physiotherapy is a more intensive and varied component in the treatment of cystic fibrosis. It involves various exercises to clear the mucus, exercises to prevent hyperinflation of the lungs and respiratory therapy equipment, such as PEP systems.

Over the past decades, a combination of respiratory therapy/physiotherapy and inhalation therapy has proven effective and is generally recommended.

The website of the organisation Mukoviszidose e.V. has a practical search function for addresses of physiotherapists for cystic fibrosis.

CFTR modulators are a group of drugs that have been especially developed for the treatment of cystic fibrosis. They therapeutically target the cause of the cystic fibrosis, the faulty CFTR channel. There are various types of CFTR modulators:

• Correctors are used to repair the defective CFTR channels and to move them to the cell membrane.
• Potentiators are used to increase the activity of CTFR channels that are already at the cell membrane.
• Combination preparations combine the mode of action of correctors and potentiators

The introduction of CFTR modulators, especially in triple combination (consisting of two correctors and one potentiator) has changed the treatment of cystic fibrosis.