<unk>  is an inflammation of the bronchi (medium and large size airways). Acute<unk>  is a self-limiting disease usually caused by viruses or bacteria. Chronic<unk>  is a subtype of the chronic obstructive pulmonary disease (COPD), and it is defined as a chronic productive cough for at least three months in two consecutive years, after excluding other causes of chronic cough. The inflammatory response of the bronchial epithelium to infections or irritants that involve the medium and large-sized airways results in thickening of the bronchial and tracheal mucosa. Hallmark features of the pathophysiology of chronic<unk>  include hyperplasia and hypertrophy of the goblet cells of the airway, resulting in an increased mucus secretion, which contributes to the airway obstruction. Microscopically, there is infiltration of the walls of the airway with inflammatory cells, particularly neutrophils. Inflammation is followed by scarring and remodeling that thickens the walls, resulting in narrowing of the small airway. Further progression leads to metaplasia and fibrosis of the lower airway. The consequence of these changes is a limitation of airflow. Acute<unk>  affects young children and old people. Its overall incidence is approximately 5% in the U.S. There is no racial or gender predilection for this disease.Although chronic<unk>  is common among geriatric patients, it occurs more commonly among caucasian individuals compared to other races, and there is no sexual predilection.
Age, season of the year and the immunization status are the main determining risk factors for acquiring acute<unk> . The most potent risk factor in the development of chronic<unk>  is cigarette smoking. Other risk factors are occupational pollutants such as cadmium and silica, air pollutants, and genetic factors such as alpha 1 antitrypsin deficiency
Acute<unk>  is a self limiting lower respiratory tract infection that usually presents with cough that lasts for up to 3 weeks. Chronic<unk>  gradually worsens over time and can result in death. The rate of deterioration varies between individuals and depends on the level of airflow obstruction. The prognosis is dependent on early recognition and smoking cessation, which improves the outcome significantly. Smoking cessation, good hand hygiene, vaccination, and a reduction in occupational exposure to known risk factors, are important to ensure decreased severity and risk of<unk> .
Bronchitis
Tracheitis
Mediastinitis
Hydrothorax
Croup
Lung abscess
Bronchiolitis
Pleurisy