Asthma - A chronic respiratory disease. It can sometimes be worrisome and inconvenient,
however in most cases it is a manageable condition. It is also known as reactive
airway disease. With proper understanding, good medical care and monitoring, you
can keep asthma under control.
Asthma is defined as a chronic lung condition with inflammation (swelling) of the
airways, increased sensitivity of the airways to a variety of things that make asthma
worse, and obstruction of airflow that is reversible.
Inflammation of the lining of the airways is the most common feature of asthma. When
they are stimulated, certain cells lining the airways release chemical substances
(mediators) that lead to inflammation. This causes the airway lining to swell and
narrow.
Inflammation may last for hours, days or weeks following an episode. Most those with
asthma have some degree of inflammation all of the time. Some long-term control medications
can help prevent and reduce inflammation.
Another characteristic of asthma is increased sensitivity of the airways. When inflammation
occurs in the airways, the airways become more sensitive. The more sensitive your
airways, the less it takes to cause a problem.
When there is less inflammation, the airways are less sensitive and you are less
likely to have asthma symptoms when exposed to things that make asthma worse.
Swelling that occurs as a result of inflammation also may occurs with tightening
of muscles that surround the airways. This is also called bronchospasm. Bronchospasm
causes further narrowing of the inflamed airways.
The mucus glands in the airways produce excessive, thick mucus in those with asthma,
which further obstructs the airways and causes coughing.
Exercise-induced asthma - Triggering events in exercise-induced asthma are considered
to be rapid breathing and airway cooling associated with vigorous exercise
Nocturnal asthma - Very common. Factors that may contribute to increased symptoms:
Exposure to allergens in the bedroom, particularly dust mites
Delayed allergic response, which may occur three to eight hours after exposure
Chronic sinus problems and/or post-nasal drip
Gastroesophageal reflux
Airway cooling from a drop in body temperature
Decreased effect of medications during early morning hours
Sleep apnoea - brief, repetitive cessation of breathing during sleep caused by an
upper airway obstruction
Occupational asthma
Workplace exposure to certain chemicals or dusts
Some chemicals act as sensitizers, inducing allergic reactions in the airways.
Dusts, can be airway irritants, causing symptoms in employees who have underlying
asthma or who are exposed to high concentrations.
