Encyclopedia of Health and Medicine

asthma 187
CHEA (windpipe), injury to the brainstem affecting
the NERVOUS SYSTEM signals that regulate breathing,
compression of the neck or chest, electrical shock,
cardiovascular collapse, and other circumstances
that interfere with BREATHING. A person experiencing
asphyxia may require immediate CARDIOPUL-
MONARY RESUSCITATION (CPR) until medical care is
available.
See also HYPOXIA.
aspiration Drawing foreign matter, often food or
drink, into the airways (TRACHEA and bronchi). The
COUGH REFLEX typically activates to expel the matter,
though may not succeed if inhalation draws
the matter deep into the respiratory tract or the
cough reflex is weak. Food, drink, and other substances
that coughing does not expel can lodge in
the airway to create a partial or complete obstruction.
Aspiration is potentially life-threatening
and may require emergency intervention
such as the HEIMLICH MANEUVER.
A doctor should evaluate the condition
of the LUNGS when aspiration occurs.
Material that makes its way deep into the LUNGS
is likely to draw BACTERIA and fluid to the site,
establishing inflammation, edema, PNEUMONIA, or
LUNG ABSCESS. Physical movement such as sitting,
standing, and walking may help the respiratory
tract propel the substance outward, while inactivity
allows the matter to settle into the lungs. Near
drowning often results in aspiration of water into
the lungs.
A chest X-RAY typically shows the site of INFLAM-
MATION and fluid collection. Treatment may
require BRONCHOSCOPY to retrieve the object and
ANTIBIOTIC MEDICATIONS to treat INFECTION. Aspiration
pneumonia is a potentially serious condition, particularly
in the elderly, infants, and debilitated
people who cannot easily move around or who
may have trouble with the natural mechanisms
that protect the airway, resulting in foreign matter
getting into the lungs. Aspiration pneumonia
develops when the accumulated fluid becomes
infected or interferes with the ability of the lungs
to oxygenate the BLOOD.
See also BRONCHUS.
asthma A disease of the airways that results in
narrowing of the airways (bronchospasm) and
INFLAMMATION in response to a wide range of
inhaled irritants such as pollen, mold, smoke,
chemicals, and the airborne debris of pests ranging
from cockroaches to microscopic dust mites. This
narrowing, or airflow obstruction, is usually
reversible when the person can eliminate the
exposure or through treatment with medications
called bronchodilators. Repeated exposure to irritants
in susceptible people can result in repeated
episodes of inflammation. This pattern can ultimately
cause scarring of the airways that is not
reversible.
Nearly 18 million Americans have asthma, a
third of whom are under age 18. For many of them
asthma attacks are mild and infrequent, giving the
perception that asthma is a common and, though
annoying, harmless condition. However, lifethreatening
consequences can occur during a
severe asthma attack. If the person does not receive
rapid and effective treatment, the airway narrowing
and inflammation can completely block the
flow of air. The person cannot exhale (breathe out)
fully, lowering oxygen levels and potentially causing
death. Nearly 5,000 Americans die each year as
a consequence of asthma or its complications.
Symptoms and Diagnostic Path
An asthma attack generally follows a pattern of
symptoms that, though it varies among people
who have asthma, tends to be consistent for each
individual. Some people first experience DYSPNEA
(shortness of breath) or wheezing (a high-pitched
whistling sound with exhalation), for example,
while other people find a restless night with frequent
waking foreshadows an asthma attack that
manifests the following day. Common symptoms
of asthma attacks include
• dry, nonproductive COUGH
• sense of tightness in the chest
• dyspnea, especially during physical activity
• wheezing
• gasping for air
There are no definitive tests for asthma. The
diagnostic path may include tests and procedures,