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Bronchitis

Bronchitis is an obstructive pulmonary disorder characterized by inflammation of the bronchi of the lungs. Chronic bronchitis is often caused by smoking, and may be fatal. It is common in 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 matter that is coughed up from the respiratory tract, 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.

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 number of conditions are often misdiagnosed as, or lumped together as, acute 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. Other coughing conditions are often diagnosed as acute bronchitis.

Chronic bronchitis, however, is most 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.

Hyperplasia of submucosal glands is shown by an increase in Reid index, which can be measured in a bronchus section. A Reid index larger than 0.4 is indicative of chronic bronchitis.

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

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. One should get plenty of rest, especially until fever subsides, and plenty of non-caffeinated clear fluids such as water or juices (up to 3 or 4 L/day).

Bacterial bronchitis is commonly treated with a course of antibiotics.

To increase the humidity in the environment, one can use room humidifiers, or simply one of the home remedies such as putting wet towels or blankets around the house.

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 if possible), or at least try not to smoke in their house.

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 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 ENT Doctor to see if a cause 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 up 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.

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 sleep appropriately, and to drink lots of non-caffeine 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, so washing hands will help reduce this transmission of it.

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. Avoiding environmental hazards, such as car fumes, second-hand smoke, and air pollutants from factories and other sources, will also help reduce the chance of Chronic bronchitis.

Source: Wikipedia