Asthma - Types, Causes, and Treatment
Asthma can strike at any age, half of all cases first occur in
children under age 10; in this age group, asthma affects twice
as many boys as girls. It is one of the leading causes of
respiratory illness among children and young adults, however,
this condition may progress a lifetime. It's estimated
17-million Americans suffer from asthma.
Asthma is a reversible lung disease characterized by obstruction
or narrowing of the airways. It may resolve spontaneously or
with treatment. Its symptoms range from mild wheezing and
shortness of breathe (dyspnea) to life-threatening respiratory
failure. Symptoms may persist between acute episodes.
People with asthma do not have a problem inhaling, but rather, a
problem exhaling. Airways open up during inhalation with the
lowering of the diaphragm as the ribs move out making the lungs
bigger allowing air to move around any obstruction. However,
when the person exhales, as the rib cage relaxes, the diaphragm
slides up preventing the air from getting around the obstruction.
TYPES AND CAUSES
Extrinsic asthma results from sensitivity to specific external
allergens. In cases in which the allergen isn't obvious, it's
referred to as intrinsic asthma.
Extrinsic asthma usually begins in childhood and is accompanied
by other manifestations of atopy -- A hereditary disorder marked
by the tendency to develop immediate allergic reactions to
substances such as pollen, food, dander, insect venoms, house
dust or mold, kapok or feather pillows, food additives
containing sulfites, or similar allergic conditions. In
intrinsic asthma, no external allergen can be identified. Most
cases are preceded by a severe respiratory infection. Irritants,
emotional stress, fatigue, exposure to noxious fumes, changes in
temperature, and changes in humidity, may aggravate intrinsic
asthma attacks. In many asthmatics, intrinsic and extrinsic
asthma coexist.
Several drugs and chemicals may provoke an asthma attack.
Examples of these substances include aspirin, various
nonsteroidal anti-inflammatory drugs, and yellow food dye
(tartrazine). Exercise may also provoke an asthma attack. In
exercise-induced asthma, bronchospasm may follow heat and
moisture loss in the upper airways.
An asthma attack may begin dramatically, with simultaneous onset
of many severe symptoms, or insidiously, with gradually
increasing respiratory distress. It typically includes the
following signs or symptoms or some conbination of them:
- progressively worsening shortness of breath - cough - wheezing
- chest tightness.
During an acute attack, the cough sounds tight and dry. As the
attack subsides, thick mucus is produced (except in young
children, who don't expectorate). Between acute attacks, breath
sounds may be normal.
The intensity of breath sounds in symptomatic asthma is
typically reduced. A prolonged phase of forced expiration is
typical of airflow obstruction. Evidence of lung hyperinflation
(use of accessory muscles, for example) is particularly common
in children. Acute attacks may be accompanied by tachycardia,
tachypnea, and diaphoresis. In severe attacks, the patient may
be unable to speak more than a few words without pausing for
breath. Cyanosis (a bluish or purplish tinge to the skin and
mucous membranes), confusion, and lethargy indicate the onset of
respiratory failure.
TREATMENT
Treatment of acute asthma aims to decrease inflammation,
coughing, wheezing, and shortness of breath, bronchial airway
swelling, and increase pulmonary ventilation. After an acute
episode, treatment focuses on avoiding or removing precipitating
factors, such as environmental allergens or irritants.
If asthma is caused by a particular virus, bacterium, toxin, or
other foreign substance, it may be treated by desensitizing the
patient through a series of injections of limited amounts of the
antigen causing the attack. The aim is to curb the patient's
immune response to the antigen.
************************************** Copyright 2006 --
HealthClamour.com Larry Champlin Health Clamour Senior Editor
http://www.healthclamour.com