Bronchial asthma, commonly called asthma, consists of repeated attacks of breathlessness and wheezing. When the patient is not in an attack, he feels normal. When an asthma patient comes in contact with an allergic substance, it behaves, as an antigen and reacts with the corresponding antibodies already present in his body. The histamine and other substances liberated during the allergic reactions cause the following changes in the bronchi:
□ Bronchial muscles are constricted to the content of lessening the diameter (calibre) of the bronchi.
□ Mucous membrane of the bronchi gets swollen, which further restricts the lemen of the bronchi.
□ Secretions are poured out from the swollen mucous lining into the constricted lumen of the bronchi.
When the bronchi are constricted and are full of secretions, the patient has difficulty in breathing and his breath has a wheezing sound in it, which is more on breathing out because then the bronchi get narrower.
Asthma is a disease of the larger and medium-sized airways of the lungs and there is obstruction of outflow of air from the lungs. Since enough air does not reach the lungs for the exchange of gases, there is hurried breathing to compensate it.
Cough is a frequent symptom in asthmatics. This occurs in order to throw out the excessive secretions produced in the lungs. This is particularly so in those who have respiratory infection as well. Cough gets relieved by the same measures as breathlessness.
The airways of the asthmatics are over-reactive to pollens, air pollution, changes in temperature, physical excercise, etc., and they react strongly to those factors. Persons who are asthmatics find it extremely difficult to tolerate smoking or air-pollution. Smoke or strong fumes, smell of fresh paint, white-washing, house-dust, or dust from old files, or the opening of dusty almirahs or trunks cause symptoms in some patients.
Asthma patients are liable to some complications such as thoracic deformity in children, diminished growth, recurrent infection or pneumonia, chronic bronchitis and hyper-inflation of the lung tissues (emphysema).