ASTHMA:

An Overview

What is asthma?

Asthma is a disease of the bronchial tubes or airways of the lungs. Air is normally taken into the body through the nose and windpipe and into the bronchial tubes. At the end of these tubes are tiny air sacs (alveoli) that deliver fresh air (oxygen) to the blood. The air sacs also collect stale air (carbon dioxide), which is exhaled out of the body.

During normal breathing, the bands of muscle that surround the airways are relaxed and air moves freely. During an asthma episode or "attack," there are three main changes that stop air from moving easily through the airways:

1. The bands of muscle that surround the airways tighten and make the airways narrow. This tightening is called bronchospasm.

2. The lining of the airways becomes swollen or inflamed.

3. The cells that line the airways produce more mucus, which is thicker than normal.

When the air passages that enable air to pass into and out of the lungs become periodically narrow during an asthma attack, symptoms such as coughing, wheezing and shortness of breath result.
This is termed bronchial asthma.
The narrowing is typically temporary and reversible, but in severe attacks, asthma may result in death.
Asthma occurs in males and females of all ages, ethnic groups, and socioeconomic levels.
Although for reasons not completely understood, asthma is generally more common in poor urban neighborhoods, in cold climates, and in industrialized countries.

Statistics:

More than 17 million Americans suffer from asthma, with nearly 5 million cases occurring in children under the age of 18.
In the United States, asthma causes 5,500 deaths each year.
Among all Americans, the prevalence of asthma increased more than 60% between 1982 and 1994, especially among children.
Deaths from asthma increased more than 55% from 1979 to 1992.
Scientists suspect that increased exposure to second-hand smoke, growing populations in polluted city centers, and new housing that is poorly ventilated contribute to the increase in asthma cases.

Signs and Symptoms:

· Symptoms of an asthma attack or asthma include wheezing, coughing, difficulty breathing, and shortness of breath.

Causes:

· Asthma attacks are caused by airway hyperresponsiveness – an overreaction of the bronchi and bronchioles to various environmental and physiological stimuli, known as triggers. Triggers enter the airways and cause an inflammatory response in the airway walls, resulting in an asthma attack.

· For some people environmental triggers are allergens. Such as plant pollen, mold spores, animal dander, dust mites, etc.

· Asthma also occurs in people who do not have allergies. In these people chemical irritants trigger an inflammatory response. Sensitivities to products such as perfumes, hairspray, cosmetic, household cleaners, industrial plastics and chemicals, air pollution from exposure to ozone, car exhaust, wood smoke, and sulfur dioxide. Indoor pollutants can also contribute to asthma development.

· There are also non-environmental triggers. Aggravations from physiologic triggers also occur from exercise, infections such as the common cold, eating or drinking of certain substances, chemicals in food or medicine - food sulfites found in beer and wine and medications such as aspirin or ibuprofen for example.

· Genetic factors may also increase the risk of developing the disorder. Children with a family history of asthma may have an increased chance of developing asthma, however asthma develops even in those with no family history of the disorder.

· Further research is continually being done to determine additional links and causes.

Diagnosis:

· Physicians typically diagnose asthma by looking at the classic symptoms: episodic problems with breathing that include wheezing, coughing, and shortness of breath. Spirometry, a test to measure airflow may also be used.

Treatment:

· Successful treatment is dependent on identification of the specific trigger that causes the symptoms. This can be difficult to determine, as the trigger is not always recognizable or consistent. Skin tests can be done for allergens, but are not always conclusive.

· There is no cure for asthma, but effective treatment is available for preventing attacks and for controlling and ending attacks soon after they have begun.

Medications:

· Medications can be taken orally or inhaled in vapor form using an inhaler.

· There are two kinds of medications

· Bronchodialators to reduce bronchospasm are the most widely used for controlling sudden attacks and for preventing attacks brought on by physical activity or exercise. They cause the muscles around the airway to relax.

· Anti-inflammatory medications work mainly by interfering with the activity and chemistry of immune cells that are the cause of the inflammation in the airway walls. They also work to relax airway muscles. Corticosteriods reduce asthma symptoms by suppressing the immune response and are often effective when no other treatment has been successful. There are side effects though including weakening of the bones and development of cataracts.

· Immunotherapy is also a treatment option for asthma caused by allergens. This form of therapy modifies a person’s response by repeated exposure to small amounts of allergens, “training” the body to react to allergens differently. Immunotherapy is especially effective in reducing allergic reactions to dust mites, animal dander, pollen, and fungi.

References:

“Asthma: An Overview” http://www.cchs.net/health/health-info/docs/1500/1525.asp?index=6424