is due to an ACUTE infection – viral or bacterial – of the bronchi. This is distinguished from PNEUMONIA by the anatomical site involved: bronchitis affects the bronchi whilst pneumonia affects the lung tissue. The infection causes a productive cough, and fever. Secretions within airways may lead to wheezing. Sometimes the organism causing the episode may be identified from the sputum. The patient usually spontaneously recovers but, if treatment is advised, bacterial infections respond to a course of antibiotics.

is a clinical diagnosis applied to patients with chronic cough and sputum production. For epidemiological studies it is defined as ‘cough productive of sputum on most days during at least three consecutive months for not less than two consecutive years’. Chronic bronchitis is classified as one of the Chronic Pulmonary Obstructive Disorders (COPD); chronic ASTHMA and EMPHYSEMA are the others.

In the past, industrial workers regularly exposed to heavily polluted air commonly developed bronchitis. The main aetiological factor is smoking; this leads to an increase in size and number of bronchial mucous glands. These are responsible for the excessive mucus production within the bronchial tree, causing a persistent productive cough. The increased number of mucous glands, along with the influx of inflammatory cells, may lead to airway-narrowing; this slows the passage of air, producing breathlessness. Other less important causative factors include exposure to pollutants and dusts. Infections do not cause the disease, but frequently produce exacerbations with worsening of symptoms.