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).
What is not asthma?
There are several conditions, which cannot be asthma, but some symptoms are same. Here is a difference :
Chronic Bronchitis
In an elderly patient, the main difficulty arises in distinguishing asthma from chronic bronchitis and emphysema; sometimes asthma and chronic bronchitis may coexist in a patient. A patient may begin with asthma because of an allergy to pollens, etc., and if improperly or inadequately treated he may develop chronic bronchitis and later on emphysema, as well. On the other hand, a patient may begin with chronic bronchitis, and after many years, develop so-called intrinsic asthma, without any apparent allergic background or known cause and end up as a case of emphysema. Many a time, it is difficult to establish which is the primary disease, and which the complicated one.
Cardiac Asthma
An important disease which simulates bronchial asthma is cardiac asthma. In this condition the breathlessness is, primarily, due to heart disease. This condition also occurs in paroxysms of breathlessness, usually in sleep, but at times also due to exertion. An attack, usually rises to a prak, is accompanied by difficulty in breathing both during inspiration and expiration, and frequently by a terrifying sense of suffocation which causes the patient to sit up or stand erect and even to go to the window for air. The attacks last from a few minutes to a few hours, averaging about an hour, and leave the patient in an exhausted condition for hours or even days.
Cardiac asthma is precipitated by acute failure of the pumping action of the left ventricle of the heart. It is a common feature with hypertensive heart disease and coronary artery disease.
During an attack, the presence of cardiac asthma should be suspected if the patient is more than 40 years old; if he has a previous history of hypertension or heart disease; if he is sweating profusely; if he seeks for fresh air; and if he has a sudden fear of death.
Hysterical Asthma
Some patients, in particulary young girls, claim the complaint of asthma but history and examination reveal that all they have is sighing respiration; there is no wheeze and no difficulty in either breathing in or breathing out. Such cases present no serious problem in differential diagnosis.
Other Conditions
Diseases which at some stage may simulate bronchial asthma are malignant tumors of the chest, such as lymphosarcoma and Hodgkin’s disease. Pressure of enlarged glands in lung cancer may also give rise to wheezing and breathlessness. The same may happen with the dilatation and swelling (aneurysm) of the wall of the aorta in the chest. Aorta is the most important blood vessel which carries the pure blood from the heart for the rest of the body.
