The breathing tubes, or bronchi, leading to the air sacs (alveoli) are lined with cells that produce mucus. Normally, the cells produce a thin, runny mucus that coats the surface of the lungs.
Foreign particles, such as dust and germs, constantly enter the lungs and become trapped in the mucus. Tiny hairs called cilia on the surface of the breathing tubes sweep the mucus and foreign particles upward into the larger air passages and then up to the throat where they can be swallowed or coughed up.
Cystic fibrosis causes the mucus that coats the breathing tubes to become so thick and sticky that the cilia are unable to sweep the germs and other particles up and out of the lungs. The trapped bacteria lead to frequent, serious infections and permanent lung damage.
In response to infections, the body's immune system sends white blood cells to the lungs to attempt to destroy the infection. White blood cells release chemicals that kill both bacteria and surrounding normal cells. After attacking the bacteria, the white blood cells die, adding to the thickness of the mucus and destruction of the airways.
In the upper respiratory tract, thick, sticky mucus may also clog the nasal passages and sinuses. Small growths, or polyps, on the inner lining of the nose may develop from repeated infection and inflammation.
Complications of cystic fibrosis usually involve some aspect of long-term impaired respiratory function. These complications may include:
|Primary Medical Reviewer||John Pope, MD - Pediatrics|
|Specialist Medical Reviewer||Susanna McColley, MD - Pediatric Pulmonology|
|Last Revised||June 15, 2011|
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