Bronchitis is inflammation and irritation of the airways (bronchial tubes) of the lungs. Symptoms include a persistent cough that often produces mucus (sputum), fever, mild wheezing, and chest pain.
Bronchitis is usually caused by infection from a virus (less commonly with bacteria or a fungus). It can also develop after exposure to chemicals or air pollution, including tobacco smoke.
There are two types of bronchitis.
WebMD Medical Reference from Healthwise