Bronchitis is the name for the condition that results when the bronchial tubes (the passageways that carry air to your lungs) become inflamed, according to the National Heart, Lung, and Blood Institute. Those tubes swell, making it more difficult for air to move through them and making it more challenging to breathe, per the American Academy of Family Physicians.
Mostly, bronchitis is caused by viruses. These can be spread through the air when someone coughs. You can also catch viruses if you touch a surface with virus on it (for example, a doorknob) and then touch your eyes, nose or mouth. Sometimes bronchitis may be caused by a bacterial infection
Signs and Symptoms of Bronchitis