Acute bronchitis is generally caused by viral respiratory infections and typically appears just as the symptoms of the initial infection are waning. These viral infections may be caused by any number of respiratory viruses including the rhinoviruses which cause the common cold. These viruses produce bronchial inflammation which sets the stage for bronchitis and, in some cases, a secondary bacterial infection.
Early symptoms may include a tickle deep in the throat just above the sternal notch which progresses into an irritating dry cough. As the infection progresses, the cough may become productive with thick yellow sputum (purulent sputum) which is very rarely blood streaked. Associated symptoms may include fever, malaise, chest pain, and shortness of breath.
When affected, infants generally develop other respiratory complications, such as bronchiolitis or pneumonia, while older children and adolescents develop typical adult symptoms of bronchitis.
Risk factors for bronchitis include recent illnesses that have lowered resistance to infection, a preceding viral respiratory infection, smoking, or chronic lung problems. Acute bronchitis is one of the most common conditions seen in clinical practice..
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