Bronchitis

Bronchitis

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ICD-10	J20-J21
ICD-O:	{{{ICDO}}}
ICD-9	490-491
OMIM	{{{OMIM}}}
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Conducting passages

Front view of cartilages of larynx, trachea, and bronchi

Bronchitis is an inflammation of the bronchi, the medium-sized and large airways in the lungs. There are two main types: acute bronchitis and chronic bronchitis. Acute bronchitis usually is of brief duration and is one of the more common illnesses impacting preschool and school-age children; among children under the age of five it is more commonly diagnosed than any other age group (Krapp and Wilson 2005). Chronic bronchitis involves a long course and is a signof serious lung disease that may be slowed but not cured (Longe 2006).

Bronchitis is different from brochiolitis, which is inflammation of the small airways that lack mucus-secreting glands and cartilage and from bronchiectasis, which is the permanent dilation and destruction of bronchi involving chronic cough (Breslow 2002). Some extend the definition of bronchitis to include inflammation of the air passages between the nose and the lungs, including the trachea (windpipe) and the bronchi (Longe 2006; Krapp and Wilson 2005), but technically the term refers to inflammation of the bronchi and trachiobronchitis is the term commonly used when there is inflammation of the trachea together with inflammation of the bronchi (Breslow 2002). Bronchial asthma is an inflammatory disease but is not classified as bronchitis.

smoking

Overview

A bronchus (plural bronchi, adjective bronchial) is a caliber of airway in the respiratory tract that conducts air into the lungs. No gas exchange takes place in this part of the lungs.

The trachea (windpipe) divides into two main bronchi (also mainstem bronchi), the left and the right, at the level of the sternal angle. The right main bronchus is wider, shorter, and more vertical than the left main bronchus. The right main bronchus subdivides into three segmental bronchi while the left main bronchus divides into two.

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), for at least three months in two consecutive years. The remainder of this article deals with acute bronchitis only. This is caused by a viral infection, such as a cold, or a bacterial infection. It also can result from breathing irritating fumes, such as those of tobacco smoke or polluted air. Constant coughing is the main symptom. Either type(chronic or acute) may lead to asthma or pneumonia.

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 wheezing. 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 wheezing and occasionally chest pains, fever, and fatigue or malaise.

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).

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

Antibiotics

In most cases, acute bronchitis is caused by viruses, not bacteria and it will go away on its own without antibiotics. To treat acute bronchitis that appears to be caused by a bacterial infection, or as a precaution, antibiotics may be given.

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.

Smoking cessation

To help the bronchial tree heal faster and not make bronchitis worse, smokers should completely quit smoking.

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. 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.

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 1985, University of Newcastle, Australia Professor Robert Clancy developed an oral vaccine for acute bronchitis. This vaccine was commercialised four years later as Broncostat.[1]

References

ISBN links support NWE through referral fees

• Breslow, L. 2002. Encyclopedia of Public Health. New York: Macmillan Reference USA/Gale Group Thomson Learning. ISBN 0028658884.

• Krapp, K. M., and J. Wilson. 2005. The Gale Encyclopedia of Children's Health: Infancy Through Adolescence. Detroit: Thomson Gale. ISBN 0787692417.

• Longe, J. L. 2005. The Gale Encyclopedia of Alternative Medicine. Farmington Hills, Mich: Thomson/Gale. ISBN 0787693960.

• Longe, J. L. 2006. The Gale Encyclopedia of Medicine. Detroit: Thomson Gale. ISBN 1414403682

External links

Wikisource has an original article from the 1911 Encyclopædia Britannica about:

Bronchitis

Online medical references:

• Bronchitis Lungs OnLine
• Acute Bronchitis FamilyDoctor.org (American Academy of Family Physicians)

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