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What Are Common Respiratory Complications of Cystic Fibrosis?

The respiratory system has two parts:

  • The upper respiratory system (the nose, sinuses, pharynx, and trachea)
  • The lower respiratory system (the lungs and bronchus)

Respiratory complications are the most common complications of cystic fibrosis (CF). That’s because CF’s faulty gene prevents the normal flow of salt and water in and out of the cells in the lungs and other organs, creating a thick, sticky mucus. This mucus provides an exceptional breeding ground for many bacteria and viruses. This makes lung and sinus infections among the most common symptoms of CF.1-5

Common causes of respiratory complications

A pathogen is a term for any infectious organism or germ that causes disease, such as a virus, bacteria, fungus, protozoa, or prion. The bacteria and viruses that people with CF get most often include:

  • Staphylococcus aureus (staph)
  • Haemophilus influenza (flu)
  • Pseudomonas aeruginosa
  • Methicillin-resistant staphylococcus aureus (MRSA)
  • Burkholderia cepacian
  • Mycobacteria (Mycobacterium abscessus and Mycobacterium avium-intracellulare)
  • Achromobacter (Alcaligenes or Acinetobacter) xylosoxidans
  • Stenotrophomonas maltophilia

These pathogens tend to lead quickly to exacerbations, or serious illness in people with CF. Because people with CF battle these infections so often, they tend to be at risk for antibiotic resistance, meaning these vital drugs stop working to fight the infections.

Lung infections and cystic fibrosis

The wet environment of the lungs makes it an attractive target for germs. Normally, the body removes bacteria and viruses as we breathe. However, in people with CF, thick mucus slows or prevents the efficient removal of pathogens, leaving these germs to settle in and grow in the lungs.

As the germ reproduces, the body’s immune system responds to the infection with inflammation. This inflammation causes the lining of the lungs to swell, which leads the immune system to respond by creating more mucus.

Infection weakens the immune system, which leads to more frequent lung infections. Over time lung infections can lead to bronchiectasis and other complications.

Bronchiectasis and cystic fibrosis

Bronchiectasis (brong-kee-EK-ta-sis) is a type of lung damage by infection and inflammation. It occurs when the bronchi (walls of the airways) that carry air in and out of the lungs thicken and widen, then become flabby and scarred. CF causes almost 50% of the cases of bronchiectasis in the U.S.2

As the bronchi become less able to clear mucus from the lungs, it creates an environment where dust, bacteria, virus and fungi stay too long in the lungs, leading to more serious lung infections.

Each infection damages the airways still more, leading to greater susceptibility for infection and declining lung function. Over time, this prevents enough oxygen from reaching the other vital organs, which puts a strain on the heart and lungs that can lead to respiratory failure and heart failure.

Sinusitis and cystic fibrosis

There are four pairs of air-filled spaces in the head called the sinus cavity. When these spaces become inflamed and clogged with mucus, the area can become infected. This is known as sinusitis, or a sinus infection. Sinusitis is common in people with CF.

Common symptoms include a stuffy nose, pain in the face, sore throat (from post-nasal drip), cough, headache, mouth breathing, poor sense of smell, reduced sense of hearing, and a constant need to clear the throat.

People with CF often also have nasal polyps, and about 20% of people with CF also experience allergies that make them more vulnerable to sinus infections.3

What is a pneumothorax?

Pneumothorax is a collection of air outside the lung between the lung and the chest wall. This condition can be painful and cause shortness of breath. It is a side effect of the lung infections common to CF. A small pneumothorax may not require hospitalization, but a large one does.4

Treatment for respiratory complications in people with cystic fibrosis

Respiratory complications, whether in the lungs or sinuses, are generally treated with a combination of therapies and may vary widely from person to person. These include: antibiotics, bronchodilators, inhaled steroids, increased frequency of airway clearance treatments, mucus thinners, and oral anti-inflammatory medicines. CFTR modulators do not attack the infection but may help the body work better by improving the function of the mutated CFTR protein.2,3

People with CF, and their friends and family can take many steps to reduce their risk of infection, including remaining at least six feet from other people with CF.

Written by: Jessica Johns Pool | Last reviewed: September 2019
  1. Cystic Fibrosis Foundation. Why Are Some Germs Particularly Dangerous for People With CF? Available at: https://www.cff.org/Life-With-CF/Daily-Life/Germs-and-Staying-Healthy/What-Are-Germs/Why-Are-Some-Germs-Particularly-Dangerous-for-People-With-CF. Accessed 4/29/2019.
  2. National Heart, Lung, and Blood Institute. Bronchiectasis. Available at: https://www.nhlbi.nih.gov/health-topics/bronchiectasis. Accessed 4/29/2019.
  3. Stanford Medicine-The Cystic Fibrosis Center at Stanford. Sinusitis. Available at: https://med.stanford.edu/cfcenter/facts/CFNews-Sinusitis.html. 4/29/2019.
  4. Cystic Fibrosis Foundation. Pneumothorax and Hemoptysis Clinical Care Guidelines. Available at: https://www.cff.org/Care/Clinical-Care-Guidelines/Respiratory-Clinical-Care-Guidelines/Pneumothorax-and-Hemoptysis-Clinical-Care-Guidelines. Accessed 4/29/2019.
  5. Elborn JS. Cystic fibrosis. Lancet 2016; 388: 2519–31. https://doi.org/10.1016/S0140-6736(16)00576-6.