content:
- Definition of Asthma
- Classification
- Symptoms
- Treatment
Definition:
Asthma is a chronic inflammatory disorder of the bronchial tree (airways in lungs), in which breathing becomes difficult . It is characterised by obstruction in expiratory airflow due to widespread narrowing of bronchi (reversible bronchoconstriction). It produces symptoms such as wheezing (high pitched whistling sound during breathing), breathlessness, tightness of the chest and cough.
It is common, but is relatively rare cause of death. It usually develops at night and/or in the early morning.
Classification:
According to type of antigen:
- Early- onset asthma (atopic, allergic and extrinsic)
- Late- onset asthma (non-atopic, idiosyncratic and intrinsic)
According to the agents or events that trigger bronchoconstriction:
- Seasonal
- Exercise induced
- Drug induced
- Occupational
- Asthmatic bronchitis in smokers
Common types of Asthma:
Atopic Asthma:
- Most common type of Asthma.
- Usually begins in childhood.
- Family history of Asthma or allergic diseases are common.
- It is a classic example of type 1 IgE (immunoglobulin E) mediated hypersensitivity reaction.
- Allergens (substances causing alergy) resulting in asthma can be recognized. Examples: dust, pollen, animal dander and food.
- Skin test with the causative allergen results in an immediate wheal-and-flare reaction.
Non-atopic Asthma:
- A positive family history of Asthma is less common in these patients.
- Skin tests are usually negative.
- No causative exogenous factors can be identified and it does not show allergen sensitization.
- Triggering events can be respiratory infections due to viruses (e.g., rhinovirus, parainfluenza virus) and inhaled air pollutants (e.g., smoke, fumes).
- It may be due to hyperirritabilty of the bronchial tree.
Drug-induced:
- Several pharmacological agents provoke asthma.
- Aspirin sensitive asthma is an uncommon type, occurring in individuals with recurrent rhinitis and nasal polyps. These individuals are intensely sensitive to small doses of aspirin as well as other non-steroidal anti-inflammatory medications, and they experience not only asthmatic attacks but also urticaria (skin rash triggered by a reaction to food, medicine or other irritants).
Occupational:
Triggering occupational agents:
- Fumes (gas or vapour that smells strongly or is dangerous to inhale): e.g., epoxy resin, plastics
- Organic and chemical dusts: e.g., wood, cotton, platinum
- Gases: toluene
- Other gases: formaldehyde, penicillin products.
Symtoms of Asthma:
- Increase in respiratory rate (heavy breathing)
- wheezing (high pitched whistling sound made while breathing)
- Tightness of chest
- Shortness of breath
- Cough
These symptoms can be experienced by the patient at particular period of time in the day or night and also induced due to exercise , drugs and occupation of the patient.
Treatment and management of Asthma:
There is no complete and permanent cure for it. The patient can only manage it by limiting to an extent that he achieves good control of Asthma symptoms and maintain normal activities.
First, the patient needs to limit the risk factors like
- Cessation of smoking; avoidance of passive smoke inhalation
- Control of Obesity
- Control of associated rhinitis
- Avoid major psychological problems
- Inadequate use of inhaled corticosteroids
- Avoid overuse of inhaled short-acting beta-agonist
Avoidance of Allergens:
- In cases where a single allergen is found responsible, it is easy to reduce or avoid exposure to it.
- In cases where multiple allergens are found responsible avoidance becomes a difficult task.
Drug therapy:
There are drugs that useful in asthma. Often, a single drug may not be adequate when a combination of drugs is required:
- Catecholamines
- Sal butanol, Levosalbutamol, Terbutaline and Fenoterol
- Bambuterol
- Theophylline
- Aminophylline
- corticosteroidsteroids
- Anticholinergic
When the above drugs are taken as and when prescribed by a medical practitioner, the patient can curb the asthmatic symptoms efficiently.
Patients also use Asthma inhalers, which provides quick relief.
How to use an Asthma inhaler:
The cannister of inhaler is shaken well, then the patient exhales till the end of normal expiration, the nozzle of the inhaler is kept near the open mouth; It may also be kept inside the mouth. The patient activates the inhaler by pressing it and simultaneously inhales rapidly but smoothly till full inspiration. The breath is held for 10 seconds and then released. Mouth is then rinsed with plain water.
Souce:
Robbins and cotran
Mathew and Agarwal Medicine
Ramdas Nayak