Understanding Asthma

By Pierre P. Gagnon, MD

Pierre-Paul Gagnon, MD

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Understanding Asthma

People with asthma suffer from a condition that makes it hard for them to breathe. Asthma differs from emphysema in that asthma is described as a reversible obstruction, that is a temporary blockage of the bronchial airways. The obstruction is caused by constriction of the muscles that surround the airways, inflammation and swelling of the airways lining and an increase in mucus production, which blocks the passage of air.

The asthma patient has what is described as overreactive airways (or “twitchy” airways) responding not just to allergens, but to many factors which during an asthma attack will narrow and constrict the flow of air through the bronchial air tubes. Asthma is a constriction of the air tubes, not the air sacs. The inflammation is the inner lining of the airways being filled with cells and fluid and the increasing mucus, which normally lubricates the airways, clogging the passages (mucus plugs).

An asthmatic individual does not have a problem breathing in (inhalation) but a difficulty in breathing out (exhalation). During inhalation, the airway opens up with the lowering of the diaphragm and the ribs moving out making the lungs bigger. The air can then move around an obstruction. in exhalation, the relaxation of the ribs and the movement of the diaphragm sliding up prevents the air from getting around the obstruction.

Allergy is the primary cause of asthma. About 90% of children under 10 who have asthma and 50% of adults over 30 with asthma also have allergies. Studies of dust mite allergen have shown that exposure in early childhood increases the likelihood of the subsequent development of asthma and is a major risk factor for presentation to a hospital with an acute asthmatic attack. Chronic exposure to dust mite allergen can cause rhinitis, eczema and the bronchial hyper-reactivity characteristic of asthma.

Clinical studies have further demonstrated that in both childhood and adult asthmatics, avoidance measures resulted in decreased asthmatic symptoms and a reduction in medication requirements.

Asthma is a chronic disease and its treatment requires four components patient education, environmental control, comprehensive pharmacologic therapy, and objective measures to assess severity and monitor course of therapy.