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Recognising worsening CF

Symptoms of CF can get worse quickly or over a longer period of time. Lung function, measured with FEV1 and FVC, can indicate the severity of lung disease or presence of an exacerbation, and you may have symptoms such as breathlessness, decreased ability to exercise, and wheezing or coughing with increased production of phlegm (mucus). You may need additional treatment if you are experiencing an exacerbation, and should notify your CF team if you feel like your symptoms are getting worse.1,2

FEV1 = forced expiratory volume in 1 second; essentially how much air you can get out of your lungs in 1 second after a maximal intake of breath. Usually measured in litres per second.

FVC = forced vital capacity; the maximum amount of air that can be exhaled when blowing out as fast as possible, usually measured in litres.


You may also see lung function represented like this, in a graph called a ‘flow volume loop’:

Other lung complications that can occur in CF include asthma and collapsed lung (pneumothorax).3

Signs of an emergency:

  • Fever, coughing up blood, sudden change in breathing3,4  
  • DIOS (See Symptoms of CF) can cause extreme pain (generally felt on the right side of your abdomen) bloating, nausea and vomiting.5

What to do in an emergency

Contact your specialist CF team, who may arrange for you to stay as an inpatient if treatment is needed. If you go to a general Accident and Emergency Department, try and notify your CF team as soon as possible in case extra care is required.3,5

Approval code: RESP-IE-NP-00038

Date of preparation: November 2020

  1. Moore V C. Breathe. 2012; 8: 233–240. Last accessed: November 2020
  2. Smyth A, Elborn J S. Thorax. 2008; 63: 180–184. Last accessed: November 2020
  3. Lungs and cystic fibrosis. CF Trust. Available at: Last accessed: November 2020
  4. 4 Common Symptoms of Chest Infections. Cystic Fibrosis News Today. Available at: Last accessed: November 2020
  5. CF Health Matters – Distal Intestinal Obstruction Syndrome. Cystic Fibrosis Canada. Available at: View PDF
  6. Cystic fibrosis statistics. British Lung Foundation. Available at: File goes here Last accessed: November 2020

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