Bronchitis is an acute inflammation of the air passages within the lungs. It occurs when the trachea (windpipe) and the large and small bronchi (airways) within the lungs become inflamed because of infection or other causes. The thin mucous lining of these airways can become irritated and swollen. The cells that make up this lining may leak fluids in response to the inflammation. Coughing is a reflex that works to clear secretions from the lungs. Often the discomfort of a severe cough leads you to seek medical treatment. Both adults and children can get bronchitis. Symptoms are similar for both. Infants usually get bronchiolitis, which involves the smaller airways and causes symptoms similar to asthma. Bronchitis occurs most often during the cold and flu season, usually coupled with an upper respiratory infection. Several viruses cause bronchitis, including influenza A and B, commonly referred to as "the flu." A number of bacteria are also known to cause bronchitis, such as Mycoplasma pneumoniae, which causes so-called walking pneumonia. Bronchitis also can occur when you inhale irritating fumes or dusts. Chemical solvents and smoke, including tobacco smoke, have been linked to acute bronchitis. People at increased risk both of getting bronchitis and of having more severe symptoms include the elderly, those with weakened immune systems, smokers, and anyone with repeated exposure to lung irritants. Acute bronchitis most commonly occurs after an upper respiratory infection such as the common cold or a sinus infection.
You may see symptoms such as fever with chills, muscle aches, nasal congestion, and sore throat. Cough is a common symptom of bronchitis. The cough may be dry or may produce phlegm. Significant phlegm production suggests that the lower respiratory tract and the lung itself may be infected, and you may have pneumonia. The cough may last for more than two weeks. Continued forceful coughing may make your chest and abdominal muscles sore. Coughing can be severe enough at times to injure the chest wall or even cause you to pass out. Wheezing may occur because of the inflammation of the airways. This may leave you short of breath.