Bronchitis

WHAT IS BRONCHITIS?
Bronchitis is an inflammation of the bronchial tubes, or bronchi (the air passages that extend from the windpipe into the lungs). The inflammation may be caused by a virus, bacteria, smoking or the inhalation of chemical pollutants or dust. When the cells of the bronchial-lining tissue are irritated beyond a certain point, the tiny hairs (cilia) within them, which normally trap and eliminate pollutants stop functioning. Consequently, the air passages become clogged by debris and irritation increases. In response, a heavy secretion of mucus develops, which causes the characteristic cough of bronchitis.

Bronchitis is classified as either acute or chronic. In acute bronchitis, the causative agents are viruses, symptoms typically last 7- 21 days, are preceded by a “cold”, and resolve without treatment other than over the counter products. Chronic bronchitis is a component of chronic obstructive pulmonary disease. It is defined by the chronic nature of the cough, which usually is productive, and has lasted for at least 3 months per year for at least 2 years.

ACUTE BRONCHITIS
This is one of the most common disorders seen in clinical practice. Bronchitis is generally caused by a virus, and does not respond to antibiotic therapy. Unfortunately, seventy percent of the time, the diagnosis usually leads to a prescription for antibiotics. This diagnosis is one of the leading causes of antibiotic abuse. Bronchitis often evolves from a severe cold. This disorder may also follow or accompany the flu, or it may begin without having had an infection.

HOW IS BRONCHITIS DIAGNOSED?
Patients who have a persistent, productive cough, usually following an upper respiratory infection (a cold) are suspected of having bronchitis. The presence of fever, chills, muscle aches, or chest pain suggest a more serious infection such as pneumonia or influenza (the flu). If physical examination indicates serious lung involvement, a chest x-ray will help a health care provider distinguish between pneumonia and bronchitis.

Patients with chronic cough, but no history of recent upper respiratory infections should be evaluated for other possible causes of cough such as postnasal drip, asthma, and gastroesophageal reflux.

CHRONIC BRONCHITIS
Chronic bronchitis is defined as excessive mucus secretion in the bronchi and a chronic or recurrent mucus-producing cough that lasts three or more months and recurs year after year. In diagnosing chronic bronchitis, it is important to rule out heart disease, lung infections, cancer and other disorders that may produce bronchitis-like symptoms. Chronic bronchitis may result from a series of attacks of acute bronchitis, or it may evolve gradually because of heavy smoking or the inhalation of air contaminated with other pollutants in the environment. When the so-called smoker's cough is constant rather than occasional, the likelihood exists that the mucus-producing layer of the bronchial lining has thickened, narrowing the airways to the point where breathing becomes increasingly difficult. With the immobilization of the cilia that sweep the air clean of foreign irritants, the bronchial passages become more vulnerable to further infection and the spread of tissue damage.

The top left illustration shows the normal pulmonary tree, while the lower right illustration shows what happens during an attack of bronchitis. The inflammation of the bronchi and bronchial tubes produces a buildup of mucus. The thickened mucus forms a plug that can block bronchial tubes, the passages that carry air from the trachea (windpipe) to the alveoli (air sacs) of the lungs. This results in the difficult breathing characteristic of bronchitis.

SMOKING
There is no doubt that cigarette smoking is the chief cause of chronic bronchitis, and recent studies indicate that smoking marijuana causes similar damage. Unless some other factor can be isolated as the irritant that produces the symptoms, the first step in dealing with chronic bronchitis is to stop smoking. To alleviate any symptoms, a provider may prescribe a combination of medications that will both open up obstructed bronchial airways and thin obstructive mucus so that it can be coughed up more easily. A steam vaporizer near the bed can also be helpful in easing chest congestion at night.

EARLY DETECTION OF TISSUE DAMAGE
Gradual and progressive damage of bronchial tissue cannot be detected by chest x-rays. However, screening tests have been developed recently for measuring the early changes in respiratory function that eventually lead to chronic bronchitis and other respiratory disorders. Evaluation of these tests has shown that a high incidence of disease of the smaller airways is present in young people who have smoked for one to five years. Although completely free of obvious symptoms, these individuals are likely candidates for future respiratory diseases.

HELP FROM THE PROVIDER
For the heavy smoker suffering from chronic bronchitis, self-treatment is not recommended. Use of over-the-counter medicated inhalers and cough medications, unless specifically recommended by a doctor, may produce undesirable results. Also, there is no conclusive evidence that a massive dose of vitamin C is effective in preventing bronchitis. If smoking is the root of the problem and you have difficulty in stopping, ask your provider for guidance. There are numerous stop-smoking programs, ranging from peer-support groups to those involving hypnosis and behavior-modification techniques.

For patients who do not respond to dietary and other lifestyle changes, including a reduction of stress, medications may be prescribed. These may include an anticholinergic agent to reduce the intestinal overactivity, a mild tranquilizer or a sedative.

SUMMARY
Bronchitis - an inflammation of the bronchial tubes; may be caused by smoking, air pollution and viral or bacterial infections. Complications of a cold or flu may lead to acute bronchitis, which can be treated with over the counter cold remedies and by drinking plenty of fluids. Suffering from a series of acute bronchitis attacks, smoking heavily or inhaling contaminated air for prolonged periods may result in chronic bronchitis. Since chronic bronchitis can be serious, it should receive professional medical attention, no matter what its underlying cause.

References
Compendium of Patient Information (1987). New York: Biomedical Information Corporation.
UpToDate Online14.2

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