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Pathology – Asthma
Definition
• A chronic inflammatory condition of the major airways marked by recurring episodes of reversible airway constriction.
Epidemiology: Highly prevalent, impacting over 10% of children and 5% of adults.
Aetiology • The majority of cases are linked to atopy, a hereditary predisposition of the immune system to generate IgE in reaction to prevalent environmental allergens. • The aetiology of non-atopic asthma remains ambiguous; nevertheless, some propose a connection with gastro-oesophageal reflux syndrome.
Pathogenesis: Atopic individuals react to prevalent environmental allergens by generating substantial quantities of allergen-specific IgE, which attaches to the surface of mast cells. • Subsequent exposure to the allergen results in the cross-linking of allergen-specific IgE antibodies and the degranulation of mast cells. Degranulated mast cells provoke airway inflammation and bronchospasm. Chronic inflammation leads to hypersensitive airways that respond to many stimuli, such as physical exertion, cold air, and tobacco smoke. Presentation: Intermittent episodes of dyspnea, wheezing, and chest constriction. Coughing, especially during nocturnal hours, is prevalent.
Macroscopy • The lungs of the majority of asthmatics may appear macroscopically normal. • In severe illness, thick mucus plugs may be observed in the airways.
Histopathology • The airways exhibit signs of inflammatory activity characterized by the presence of eosinophils, which are typically absent in normal airways. • Additionally, there may be thickening of the basement membrane, hyperplasia of goblet cells, and pronounced smooth muscle.
Prognosis: Generally favorable with suitable treatment. • A minor fatality rate is linked to severe acute asthma.


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