Bronchitis

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Bronchitis

Bronchitis is an obstructive pulmonary disease characterized by inflammation of the bronchi of the lungs. It is a common disease of habitual tobacco smokers and residents of polluted cities. Like many disorders, bronchitis can be acute (short-term), or chronic (long-lasting). Chronic bronchitis is defined clinically as a persistent cough that produces sputum for at least three months in two consecutive years.

Chronic bronchitis is predominantly caused by smoking, and has also been linked to pneumoconiosis, excessive alcohol consumption and exposure to cold and draught. 1

Symptoms

An expectorating cough (the colour of the mucus does not signify whether the infection is viral or bacterial)
Dyspnea (Shortness of breath)
Fatigue and/or malaise
Mild fever
Mild chest pains

Diagnosis

A physical examination will often reveal decreased intensity of breath sounds (rhonchi) and extended expiration. Most doctors rely on the presence of a persistent dry or wet cough as evidence of bronchitis.

A variety of lab test results may suggest chronic bronchitis, namely:

a chest x-ray that reveals hyperinflation and increased bronchovascular markings
a pulmonary function test that shows an increase in the lung's residual volume and a decreased vital capacity
arterial blood gases that show a decreased level of oxygen in the blood and an increased level of carbon dioxide
a sputum culture that has pathogenic microorganisms and/or neutrophils in it

Some of these findings may also be seen in acute bronchitis.

Pathophysiology

Acute bronchitis often follows a cold or infection. It may be viral or bacterial.

Another type of bronchitis is called chronic bronchitis. This is a bronchitis condition that lasts at least three months for two years. This long term problem is mostly likely due to environmental irritation of the bronchial tubes and is often caused by smoking. The initiating event in developing chronic bronchitis is chronic irritation due to inhalation of certain substances (especially cigarette smoke). The earliest clinical feature of bronchitis is increased secretion of mucus by submucousal 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. As bronchitis persists to become chronic bronchitis, a substantial increase in the number of goblet cells in the small airways is seen. This leads to further increased mucous production that contributes to the obstruction of the airways.

The role of infection in the pathogenesis of chronic bronchitis is secondary. However, although infection is not responsible for initiating bronchitis, it may have an important role in maintaining it. Acute exacerbations of the long-standing bronchitis may result from infections.

Treatment

Drinking lots of fluids is beneficial for sufferers of acute bronchitis. Many doctors now recognize that most acute bronchitis is caused by viruses, so antibiotics will not help treat this type of bronchitis.

Some bronchitis is bacterial, but since most bronchitis is viral, most patients will instead receive advice for rest, lots of liquids, and aspirin or Tylenol for fever. Occasionally, a doctor may prescribe a steroid to help open the bronchial tubes to help with coughing.

Coughing is an essential mechanism to help clear the mucus present in the irritated bronchial tubes. Expectorant cough medicine can help make such coughs more productive by thinning the mucus; suppressant cough medicine may help the patient sleep by suppressing the dry coughs so prevalent in the early stages of the illness.

Oxygen therapy, bronchodilator drugs, antibiotics, and lung volume reduction surgery are also used to treat chronic bronchitis.

Prognosis

Acute bronchitis usually lasts approximately 10 or 11 days. It may accompany or closely follow a cold or the flu, or it may arrive unaccompanied by any other condition. It is contagious, and it starts out with a dry cough, frequently waking the sufferer up at night. After a few days, it progresses to a wetter, productive cough, which may be accompanied by a low grade fever, fatigue, and headache. The fever, fatigue, and malaise may last only a few days, but the wet cough may last up to a few weeks to a few months. For some people, the cough may last as long as a few months as the bronchial tubes slowly heal.

Should the cough last longer than a month, many doctors recommend seeing a doctor to see if a cause other than bronchitis is causing the irritation. It's 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 up mucus tinged with blood, they should see a doctor. In rare cases, doctors may conduct tests to see if the cause is a serious condition such as TB or lung cancer.

The prognosis for patients with severe chronic bronchitis varies, but recovery is harder for those patients with additional severe illnesses (lung diseases or heart conditions). Pulmonary hypertension, cor pulmonale, and chronic respiratory failure are possible complications from chronic bronchitis.

Prevention

The best way to avoid acute bronchitis is to wash your hands frequently and thoroughly, to get lots of rest, and to drink lots of fluids. Acute bronchitis is most commonly caused by viruses or bacteria, which spread via coughing droplets in the air and/or from touching contaminated surfaces.

Chronic bronchitis is often preventable. The main action to reduce your risk is to eliminate exposure to cigarette smoke and other environmentally hazardous fumes. Smokers in the early stages of chronic bronchitis can change and improve the course of the disease by quitting smoking.

History

Bronchitis was originally named and described by Charles Bedham in 1808.

External links

Section Online medical references

Acute bronchitis Merck Manual of Diagnosis & Therapy
Bronchitis The Merck Manual - Second Home Edition
Chronic Obstructive Pulmonary Disease The Merck Manual - Second Home Edition
Chronic Obstructive Pulmonary Disease The Merck Manual of Geriatrics
Bronchitis Lungs OnLine
Acute Bronchitis FamilyDoctor.org (American Academy of Family Physicians)

References

"Chronic bronchitis." Springhouse Handbook of Diagnostic Tests, 2nd ed. (1999). ISBN 0-87434-982-6
"Chronic obstructive pulmonary disease." 2005 Current Medical Diagnosis and Treatment. ISBN 0-07-143692-8
Kumar, Vinay, Abul Abbas, and Nelson Fausto. Robbins and Cotran Pathologic Basis of Disease, 7th ed. (2005). ISBN 0-7216-0187-1
Skinner, Henry Alan. The Origin of Medical Terms. (1970).

Inflammations | Pulmonology

Deaths from Chronic Bronchitis: 1,172 deaths (NHLBI 1999)

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