Cystic Fibrosis and the Respiratory System

How does cystic fibrosis (CF) affect the respiratory system?

Cystic fibrosis (CF) is an inherited disease characterized by an abnormality in the body's mucus glands. It is chronic, progressive, and is usually fatal. In general, children with CF live into their 30s.

Children with CF have an abnormality in the function of a cell protein called the cystic fibrosis transmembrane regulator (CFTR). CFTR controls the flow of water and certain salts in and out of the body's cells. As the movement of salt and water in and out of cells is altered, mucus becomes thickened.

In the respiratory system, mucus is normally thin and can easily be cleared by the airways. With CF, mucus becomes thickened and sticky and results in blocked airways. Eventually, larger airways can become plugged and cysts may develop.

Lung infections are very common in children with CF, because bacteria that are normally cleared, remain in the thickened mucus. Many of these infections are chronic. Pseudomonas aeruginosa (PA) is the most common bacteria that causes lung infections. About 70 to 80 percent of respiratory infections are due to PA.

Children with CF also have involvement of the upper respiratory tract. About 10 to 20 percent of individuals have nasal polyps that need surgical removal. Nasal polyps are small protrusions of tissue from the lining of the nose that go into the nasal cavity. Children with CF also have a high rate of sinus infections.

Symptoms that may be present due to the effects of CF on the respiratory system include the following:

• chronic cough
• coughing up blood
• collapsed lung
• clubbing (rounding and enlargement of the fingers and toes)
• heart enlargement
• nasal polyps (fleshy growths in the nose)
• sinusitis (inflamed nasal sinuses)

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