Asthma In Children And Adolescents In-Depth

The word asthma originates from an ancient Greek word meaning panting. Essentially, asthma is an inability to breathe properly. When any person inhales, the air travels through the following structures:

• Air passes into the lungs and flows through progressively smaller airways called bronchioles. The lungs contain millions of these airways.
• All bronchioles lead to alveoli, which are microscopic sacs where oxygen and carbon dioxide are exchanged.

The major features of the lungs include the bronchi, the bronchioles, and the alveoli. The alveoli are the microscopic blood vessel-lined sacks in which oxygen and carbon dioxide gas are exchanged.

Asthma is a chronic condition in which these airways undergo changes when stimulated by allergens or other environmental triggers. Such changes appear to be two specific responses:

• The hyperreactive response (also called hyperresponsiveness)
• The inflammatory response

These actions in the airway cause patients to cough, wheeze, and experience shortness of breath (dyspnea), the classic symptoms of asthma.

Hyperreactive Response

In the hyperreactive response, smooth muscles in the airways constrict and narrow excessively in response to inhaled allergens or other irritants. Airways in everyone's lungs respond by constricting when exposed to allergens or irritants but there are major differences  in the hyperreactive response that occurs in people with asthma:

• When people without asthma breathe in and out deeply, the airways relax and open in order to rid the lungs of the irritant.
• When people with asthma try to take those same deep breaths, their airways do not relax but instead narrow, causing the patients to pant for breath. Smooth muscles in the airways of people with asthma may have a defect, perhaps a deficiency in a critical chemical that prevents the muscles from relaxing.

Inflammatory Response

The hyperreactive stage is followed by the inflammatory response, which generally contributes to asthma in the following way:

• The immune system responds to allergens or other environmental triggers by delivering white blood cells and other immune factors to the airways.
• These so-called inflammatory factors cause the airways to swell, fill with fluid, and produce a thick sticky mucus.

Click the icon to see an image of a normal versus asthmatic bronchiole.

• This combination of events results in wheezing, breathlessness, inability to exhale properly, and a phlegm-producing cough.