Most people with CF develop symptoms early in life, usually by age three. However, some people are diagnosed in their teenage and early adult years. The standard method is the sweat test, a painless procedure that measures the amount of salt in sweat. The Effects of CF on the Lungs Abnormal movement of salt in and out of the cells lining the lungs causes secretion of thick, sticky mucus. This mucus is not cleared from the airways and as a result bacteria begin to grow.
Chronic infection leads to a vicious cycle.
P. aeruginosa infections cause lung inflammation, which causes more mucus secretion. More mucus secretion and lung damage leads to further lung obstruction encouraging the growth of more bacteria, causing additional deterioration of lung function. Adolescents may lose even more lung function over the course of a year. People with CF sometimes experience acute flare-ups exacerbations of their pulmonary symptoms. These exacerbations often lead to more rapid decline in lung function.