Bronchitis is 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 COPD (chronic obstructive pulmonary disease); it is defined clinically as a persistent cough that produces sputum (phlegm), for at least three months in two consecutive years. The remainder of this article deals with acute bronchitis only.
Acute bronchitis is characterized by cough and sputum (phlegm) production and symptoms related to the obstruction of the airways by the inflamed airways and the phlegm, such as shortness of breath and wheeze. Diagnosis is by clinical examination and sometimes microbiological examination of the phlegm. Treatment may be with antibiotics (if a bacterial infection is suspected), bronchodilators (to relieve breathlessness) and other treatments.
Signs and symptoms:
Bronchitis may be indicated by an expectorating cough, shortness of breath (dyspnea) and wheeze and occasionally chest pains, fever, and fatigue or malaise. The color of the mucus will signify whether the infection is viral or bacterial.
Diagnosis:
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:
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. A sputum sample showing neutrophil granulocytes (inflammatory white blood cells) and culture showing that has pathogenic microorganisms such as Streptococcus spp. A blood test would indicate inflammation (as indicated by a raised white blood cell count and elevated C-reactive protein).
Pathophysiology:
Acute bronchitis often follows a cold or infection. The earliest clinical feature of bronchitis is increased secretion of mucus by submucosal glands of the trachea and bronchi. Damage caused by irritation of the airways leads to inflammation and infiltration of the lung tissue by neutrophils. The neutrophils release substances that promote mucosal hypersecretion.
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.
Treatment:
In most cases, acute bronchitis is caused by viruses, not bacteria and it will go away on its own after a few days without antibiotics. To treat acute bronchitis that appears to be caused by a bacterial infection, or as a precaution, antibiotics may be given.
To help the bronchial tree heal faster and not make bronchitis worse, smokers should cut down on the number of cigarettes they smoke, or quit altogether.
Prognosis:
Acute bronchitis usually lasts approximately 20 or 30 days. It may accompany or closely follow a cold or the flu, or may occur on its own. It is contagious. Bronchitis usually begins with a dry cough, including waking the sufferer at night. After a few days it progresses to a wetter or productive cough, which may be accompanied by fever, fatigue, and headache. The fever, fatigue, and malaise may last only a few days; but the wet cough may last up to several weeks. For some people, the cough may last as long as a few months, as the bronchial tubes heal slowly.
Should the cough last longer than a month, some doctors may issue a referral to an otolaryngologist (ear, nose and throat doctor) to see if a condition other than bronchitis is causing the irritation. It is possible that having irritated bronchial tubes for as long as a few months may inspire asthmatic conditions in some patients.
In addition, if one starts coughing mucus tinged with blood, one should see a doctor. In rare cases, doctors may conduct tests to see if the cause is a serious condition such as tuberculosis or lung cancer.
Prevention:
In those at risk for bronchitis, vaccination with pneumococcal polysaccharide vaccine (PPV) may reduce the risk of acute bronchitis
History:
Bronchitis was originally named and described by Charles Bedham in 1808
