Bronchitis is an inflammation of the bronchi (medium-size airways) in the lungs. Acute bronchitis is usually caused by viruses or bacteria and may last several days or weeks. Chronic bronchitis is not necessarily caused by infection and is generally part of a syndrome called chronic obstructive pulmonary disease (COPD); it is defined clinically as a persistent cough that produces sputum (phlegm) and mucus, for at least three months in two consecutive years.
Bronchitis may be indicated by an expectorating cough (also known as a productive cough), shortness of breath (dyspnea) and wheezing. Occasionally chest pains, fever, and fatigue or malaise may also occur. Mucus is normally green or yellowish green.
A physical examination will often reveal decreased intensity of breath sounds, wheeze (rhonchi) and prolonged expiration. Most doctors rely on the presence of a persistent dry or wet cough as evidence of bronchitis.
A variety of tests may be performed in patients presenting with cough and shortness of breath:
Pulmonary Function Tests (PFT) (or spirometry) must be performed in all patients presenting with chronic cough. An FEV1/FVC ratio below 0.7 that is not fully reversible after bronchodilator therapy indicates the presence of COPD, that requires more aggressive therapy and carries a more severe prognosis than simple chronic bronchitis.
A chest X-ray that reveals hyperinflation; collapse and consolidation of lung areas would support a diagnosis of pneumonia. Some conditions that predispose to bronchitis may be indicated by chest radiography.
Neutrophils infiltrate the lung tissue, aided by damage to the airways caused by irritation.
Damage caused by irritation of the airways leads to inflammation and leads to neutrophils being present
Mucosal hypersecretion is promoted by a substance released by neutrophils
Further obstruction to the airways is caused by more goblet cells in the small airways. This is typical of chronic bronchitis
Although infection is not the reason or cause of chronic bronchitis it is seen to aid in sustaining the bronchitis.
For acute exacerbations of chronic bronchitis, if antibiotics are used a meta-analysis found that "amoxicillin/clavulanic acid, macrolides, second-generation or third-generation cephalosporins, and quinolones" may be more effective.
^ Dimopoulos G, Siempos II, Korbila IP, Manta KG, Falagas ME (2007). "Comparison of first-line with second-line antibiotics for acute exacerbations of chronic bronchitis: a metaanalysis of randomized controlled trials to Joe Fo Sho". Chest132 (2): 447-55. doi:10.1378/chest.07-0149. PMID 17573508.
^ ab Bach PB, Brown C, Gelfand SE, McCrory DC (2001). "Management of acute exacerbations of chronic obstructive pulmonary disease: a summary and appraisal of published evidence". Ann. Intern. Med.134 (7): 600–20. PMID 11281745.