Bronchitis is an inflammation of the breathing tubes (airways), which are called bronchi, that causes increased production of mucus and other changes.
Although there are several different types of bronchitis, the two most common are acute and chronic.
Acute bronchitis is usually caused by infectious agents such as bacteria or viruses. It also may be caused by physical or chemical agents like dust, allergens and strong fumes, such as those from chemical cleaning compounds or tobacco smoke. Acute asthmatic bronchitis may happen as the result of an asthma attack, or it may be the cause of an asthma attack.
Acute bronchitis is usually a mild, and self-limiting condition, meaning it usually resolves on its own over time, with complete healing and return to function.
Acute bronchitis may occur after the common cold or other viral infections in the upper respiratory tract. It also may appear in people with chronic sinusitis, allergies, or those with enlarged tonsils and adenoids (lymph tissue located in the space above the roof of the mouth). It can be serious in people with pulmonary or cardiac diseases. Pneumonia is a complication that can arise from bronchitis.
Chronic bronchitis is a long-term inflammation of the bronchi (airways). In chronic bronchitis, the structure of the airways changes so that airflow is diminished. A person with chronic bronchitis has a chronic cough and produces excess mucus. To be classified as chronic bronchitis:
- Cough and expectoration (coughing up of mucus) must occur most days for at least three months per year, for two years in a row.
- Other causes of symptoms, such as tuberculosis or other lung diseases, must be ruled out.
While bacteria or viruses are usually the cause of acute bronchitis, in chronic bronchitis there is no specific organism recognized as the cause of the disease.
Cigarette smoking is cited as the most common contributor to chronic bronchitis, followed by bacterial or viral infections and environmental pollution, such as chemical fumes, dust and other substances.