What is asthma really all about?
As many as nine million children in America below the age of eighteen have asthma.
Another seven to eight million adults suffer from asthma too. Around the world,
many times those numbers are afflicted with the disease, although estimates vary
widely. So just what is asthma?
Asthma is basically an inflammatory disease affecting the airways of the lungs. It is a chronic illness, meaning that it tends to persist over long periods of time. The inflammation has the effect of narrowing the airways, which causes breathing difficulties. The patient may start wheezing and may gasp for breath in some cases.
Asthma charactaristics
One of the characteristics of asthma is that the airway obstruction generally goes away on its own or else responds well to various types of medication. However, acute asthma attacks have also been fatal on occasion.
The airways in the lungs consist of the bronchi (or 'breathing tubes') and the bronchioles. In an asthma patient, they are hypersensitive to one or more kinds of stimuli. For example, they may be hypersensitive to pollutants, pollen, animal dander, cold air, dust mites or even internal triggers like anxiety and stress.
In non-asthmatic people, these stimuli do not usually produce an adverse effect
on the lungs. However in an asthmatic, the muscle tissues that line the walls of
the bronchi start to spasm when exposed to these triggers. Also, the cells along
the airways swell to more than their normal size and discharge mucus. These
responses have the effect of narrowing the bronchi, a phenomenon called
bronchoconstriction.
The net effect of bronchoconstriction is that the patient must make a much
greater effort to breathe normally. This gives rise to the symptoms of asthma.
The cells that line the walls of the bronchi are called mast cells. These cells
release groups of substances called histamines and leukotrienes. Both these
chemical groups cause mucus to form and also cause the bronchi to contract.
Histamines and leukotrienes are released in response to allergens - quite often,
with a delay after the initial exposure to the allergens. These allergic
responses can result in an asthma attack. At the same time, many asthma patients
do not exhibit allergic reactions and yet have asthma attacks.
Asthma usually (but not always) begins during childhood or adolescence.
Childhood asthma is thought to occur when a child becomes hypersensitive to
substances in the environment as a result of genetic reasons. Such children are
known as atopic persons.
Researchers in Finland have identified two genes that may predispose people to
become atopic. This is significant because it may help identify children who
have a greater chance of developing asthma.
It is estimated that one third to one half of the population may be atopic. When
such people are exposed to potential allergens in their environments, their
systems respond by producing an antibody to capture and destroy these foreign
substances. The effect of this response is that the airways become sensitive to
these allergens. Repeated or continued exposure to these substances can produce
an asthmatic response.
Since allergens are a common cause of the bronchoconstriction that leads to an
asthma attack, minimizing exposure to such substances is a crucial step in
managing asthma.
In asthma patients, inflammation of the nose lining - a condition called
rhinitis - can worsen asthma symptoms. So can sinusitis and even acid reflux,
which is a condition when acidic stomach contents back up into the esophagus.
Other illnesses like viral infections that affect the respiratory tract can set
off or worsen asthma attacks.
Severe asthma episodes are easy to spot because of wheezing and other symptoms.
But some attacks may be quite mild and the patient may only experience moderate
difficulty in breathing. In such cases, listening to chest sounds using a
stethoscope can help identify the presence of an asthmatic condition.
The good thing about asthma is that even in the case of severe attacks, the
patient will almost always recover completely.
Check out the other pages of this site for information on symptoms, treatment,
disease types and in general, additional information in answer to the question
"What is asthma?"