What is Asthma
The asthma that everybody talks about is bronchial asthma, so called because the trouble occurs in the bronchi (air passages in the lungs). The other type is cardiac asthma, in which the basic problem lies in the heart and breathlessness is due to heart failure. In bronchial asthma, whenever the person comes into contact with the allergen, he gets an attack of breathlessness and wheezing. Between two attacks, the person is normal. The following changes occur during an attack:
(1) Bronchial muscles are constricted to the extent of considerably lessening the inner diameter of the bronchi,
(2) The inner lining (mucous membrane) of the bronchi gets swollen, further narrowing the lumen of the bronchi,
(3) Secretions are poured out from the swollen mucous lining into the narrowed bronchi and bronchioles.
These changes result in difficulty in breathing, accompanied by a wheezing sound, which is louder during exhalation because then the bronchi get narrower.
Asthma attacks usually occur in the early morning. The sufferer is suddenly aroused from his sleep by the attack. He typically sits up, stoops forward, tightly holds to some object and gasps for breath. The attack subsides after a varying period, either on its own or due to the effects of the medicines administered.
Usually in asthma patients, the lungs are over-distended and less elastic than those of normal persons. The breathing capacity of the lung is decreased and the reserves are at their lowest. All these changes result in a disturbed ventilatory mechanism causing a decline in effective oxygenation of blood.
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