What's Happening Inside the Body

Cystic fibrosis can be a difficult disease to understand; it is not uncommon to be completely overwhelmed by all of the medical jargon and have a difficult time understanding exactly what is happening to you or a loved one. However, all of the problems that occur with CF come down a mutation in a single gene: the cystic fibrosis gene. This gene is responsible for the protein transmembrane conductance regulator (CFTR) gene. When the CF gene can't function properly, neither can the CFTR gene. Most of the problems seen with CF arise from this CFTR gene not working correctly. However, just because it can be identified that somebody has a defect with their CF gene and their CFTR gene does not mean we can tell what their disease will look like. All CFTR gene mutations look very different, which is one of the reasons why no two cystic fibrosis cases are exactly alike. So far, there have been 1,893 different CFTR mutations identified.

When the CFTR gene is not working like it should, there will be problems with chloride-transport across the surface of cells (specifically mucosal cells). This decreased secretion of chloride leads to an increased reabsorption of sodium and water, which leaves the mucus much more sticky than normal. This sticky mucus can attract bacteria which makes the person prone to infection and inflammation. This stickiness of the mucus is also what makes it so difficult to clear from the body.

The two most common complications experienced by cystic fibrosis patients are lung disease and intestinal disease. Typically, it is the severity of these two diseases that determine how long an individual can live with CF. Typically, with lung disease it will progress from bronchitis, to bronchiolitis, to bronchiectasis. This will eventually lead to cor pulmonale (abnormal enlargement of the right side of the heart) and end-stage lung disease. The cause of death is usually respiratory failure or cor pulmonale in an individual with cystic fibrosis.

References: 

Sharma, G. (2014). Cystic Fibrosis. Medscape.