The Sunday Tribune - Spectrum

As an allergic disorder, asthma can be initiated by various factors known as triggers. For long it was believed that the main pathology in the respiratory tubes is the constriction or narrowing of these tubes by the contraction of smooth muscles in the walls of bronchi. This narrowing produces whistling noises when the air passes in and out of these narrowed tubes.

Wheezing, thus, is a hallmark of this disease. Other symptoms include cough and the constriction of chest. Apart from this constriction, there is also inflamation of the walls of bronchi.

A large number of cells infiltrate the walls in response to the allergic process and produce various chemicals which produce oedema and mucus plugging.

The modern treatment is directed at both the factors. A large number of persons suffering from asthma may have a family history of asthma or other allergic disorders. These people usually exhibit the symptoms early in life. The other group of asthmatics do not have this predisposition but can react to various allergens and stimuli. There is quite a bit of overlapping between both the groups and the treatment is similar.

Allergens/triggers of asthma

Given the predisposition of an individual, asthma can be triggered off by a variety of allergens. These include pollens of various plants, between the size of three to five microns. The bigger ones are trapped in the nose and thus cannot reach the lungs. The plants would vary from place to place, according to the ecology of the area. A study conducted by the Department of Paediatrics, PGI, suggests that in this area pollens of kikkar doov grass, arandi, neem and paper mulberry, are the common triggers. During the harvesting season, wheat husk serves as a trigger. Moulds which grow outdoors and even indoors in the humid environment can be the source of an allergy in the rainy season for many people. In the indoor conditions, house dust containing dust mites, animal danders and secretions (dogs, cats, rodents and others) can all be major triggers of Asthma. Cockroaches are suspected to be an important source of allergens also.

Infections are very important precipitating causes of an asthmatic attack not only in the predisposed people but sometimes in other individuals as well. After every outbreak of an upper respiratory infection, a large number of people keep coughing and wheezing for weeks after the infection is over. Most of these infections are viral in nature, but occasionally bacterial infections can bring on an attack. A very interesting observation has been made that some of the countries with hygienic conditions and less infections are more prone to allergic disorders in general.

The immunological response to various infections in children grooms the immune mechanism in such a way that they become more active against a person’s own tissues. During a discussion on this subject on BBC somebody said, "Should we then expose our children to diarrhoea and respiratory infections?" The answer is obviously "no". But the observation deserves a notice.

A large number of drugs can produce an allergic response. Most notorious being the commonly-used aspirin and other pain-killers. Theoretically, any drug is capable of producing such a response. Air pollution can play havoc. The presence of a large number of suspended dust particles, high concentration of nitrogen oxide, ozone and to some extent sulphur dioxide can trigger an asthmatic attack. Places like Delhi, Bombay, Kolkata and Ludhiana have these triggers in plenty. Various industries, including food processing, plastics, metallurgic, saw mills, diamond polishing etc of which have a lot of dust can predispose individuals to asthma. Finally, psychogenic factors like stress and anxiety can precipitate an attack.

Prevention and treatment

There has been a great improvement in understanding the causative factors and therefore, the prevention and treatment of asthma. It is now possible for a person suffering from this disorder to lead a near normal life by following the basic principles of its prevention, maintenance and treatment of acute attack. The first thing, therefore, for a patient and the family is to understand the nature of this disease and the underlying principles of prevention and cure. There is no need to get frustrated and have a feeling of helplessness.

In case of children particularly, it is important to protect them from various environmental factors, their growth, education and other developments should not suffer. They should be gradually educated about the nature of asthma and their teachers and outside contacts should be informed about their disease and thus be ready for an episode of asthma and not react with panic.

It would be logical to keep the environment of an asthmatic person free from possible triggers by freedom from smoke (and smoking), dust, pets in the house, offending plants in the environment, if known, any apparent food trigger or in the work environment. It is, however, easier said than done but an attempt should always be made.

The second logical step should be to make an attempt to desensitise a person against a known allergen by what is known as immunotherapy. According to this approach, a person is desensitised by repeated small doses of a known allergen or allergens found out by cutaneous injections. The Patel Chest Institute, New Delhi did a lot of work on the production of such antigens but results have been rather disappointing and by and large the cure is not achieved in most of the patients.

The main treatment of asthma, therefore, is pharmacological and very good drugs are now available. The basic approach in the drug therapy is to treat an acute attack with those drugs which produce relaxation of the smooth muscles of the respiratory tubes. These drugs are known as bronchodilators (sablbutamol, terbutaline, sulmetrol, theophylline) and can be given orally, by inhalers or injections. The other group of drugs is anti-inflammatory and primarily consists of corticosteroids which are given by injections or tablets in an acute attack, but by an inhaler (known as meter dose inhaler) for maintenance of the treatment over a long time. The patient needs to be educated by the doctor in the beginning about the method, cleaning and frequency of the use of various devices for inhalation therapy.

A small device known as "peak expiratory flow meter" is now available, with which a patient can himself monitor the progress of the disease and thus can help his doctor in the management of asthma. In this connection, the patient and the family need to remember certain emergencies which can arise in asthma. These include continuation of an attack beyond few hours, patient becoming drowsy or confused, feeble movements of the chest, slowing of the pulse rate, fall in blood pressure or bluish coloration of the lips and nails. Such a patient requires an urgent care in a hospital and would need intravenous medication and sometimes the help to carry on his respiration.

The education of the patient and the family, improvement in the environment, acute and maintenance therapy and recognition of an emergency are the key factors in the management of asthma. This can help the patient to lead a near normal life. It may be mentioned that a number of top sports persons achieving Olympic gold medals were patients of asthma.