Bronchitis constricts and inflames the bronchial tubes, reducing airflow between the lungs and the trachea, or windpipe, according to Nemours. Tissue lining the bronchial tubes becomes irritated and overproduces mucus, making it difficult to circulate oxygen throughout the respiratory system.
Bronchitis may cause breathing complications, coughing, fatigue and symptoms associated with a fever, according to the Mayo Clinic. When there is inflammation of the respiratory tract, yellow or green discolored mucus may be produced. Viral infections or existing respiratory problems can stimulate bronchitis, but frequent exposure to smoke, fumes and other inhaled irritants increases the risk of developing lasting symptoms.
Acute bronchitis is short-term and typically lasts less than 90 days, while the chronic form may persist for years, according to Merck. People who smoke or suffer from allergies or chronic sinus infections are more likely to experience ongoing bouts of acute bronchitis. Repeated episodes of bronchitis may weaken the respiratory system and increase vulnerability to viral bacteria. The Mayo Clinic says that an extended case can lead to pneumonia or chronic obstructive pulmonary disease.
Physicians may take chest X-rays and perform breathing tests to examine the bronchial tubes and check for similar conditions, such as asthma and pneumonia, according to Nemours. While doctors may prescribe medications for bronchitis symptoms, the treatment may be ineffective if the patient remains in an environment with harmful irritants.