BRONCHIAL ASTHMAThe term Asthma comes from the Greek
verb aazein, meaning to pant, to exhale with the open mouth, sharp breath.
Asthma is a disease of airways it is characterised by increased responsiveness of tracheobronchial tree toa variety of stimuli resulting in widespread narrowing of the air passages which may be relieved spontaneously or by therapy.
EPIDEMIOLOGY• All around the world 234 million people are
suffering from asthma.• India has an estimated 15-20 million
asthmatics.• Majority 50%asthmatics are below are 10
years of age.• Ratio between male:female =2:1
TYPES OF ASTHMABased on the stimuli initiating bronchial asthma, are of 3 types
EXTRINSIC ASTHMAAtopic ,allergic.Most common type of asthma Usually begins in childhood or in early adult life.Most patients of this type have personal or family
history of preceding allergic diseases.Hypersensitivity to various extrinsic allergic substances
or ALLERGENS is usually present in these cases.OCCUPATIONAL ASTHMA It is a variant of extrinsic asthmaAsthma is stimulated by fumes, gases and organic and
chemical dust.Allergic response is IgE mediated TYPE-1
ACUTE IMMEDIATE RESPONSE ALLERGEN
Stimulates the IgE sensitised mast cells
Mast cell degranulation occurs
Mediators like histamine Leukotriene prostaglandin, PAF and chemotactic factor for eosinophils and neutrophils.
Contd….. Results in Bronchoconstriction Oedema Mucus hypersecretion
and Accumulation of
LATE PHASE REACTIONIt follows the acute immediate response and is
responsible for prolonged manifestations of asthma, Mobilisation of blood leucocytes mainly Basophils
along with Eosinophils and Neutrophils
leads to further release of inflammatory mediators
which accentuates brochoconstriction , oedema,…..
• Inflammatory injury is caused by Neutrophils and MBP of Eosinophils.
INTRINSIC ASTHMAIdiosyncratic,non-atopic.Seen in lateral adult life with negative
personal or family history of allergy , negative skin test ,normal serum levels of IgE.
Most of these patients develop acute typical symptom complex of asthma after an upper respiratory tract infection by virus.
Commonly associated with nasal polyp,emphysema and chronic bronchitis.
10% patients become hypersensitive to drugs mostly to small doses of aspirin- ASPIRIN SENSITIVE ASTHMA
MIXED TYPE OF ASTHMA
Many patients do not clearly fit into either of the above categories.
They have mixed features of both.
SIGNS & SYMPTOMS Dyspnoea Wheezing Cough Limitation of activity