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Asthma Definitions |
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| Manifestation |
Definition |
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| Asthma |
Inflammatory disease of the airways characterized by: |
| • Infiltration by eosinophils, lymphocytes and neutrophils |
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| • Mast cell activation |
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| • Epithelial loss |
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| Associated reversible airway obstruction, recurrent symptoms and bronchial hyper-responsiveness |
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| Gene-by-environment interactions are important |
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| Inflammation |
Plays central role in asthma pathophysiology |
| Mediated by T cells, lymphocytes, mast cells, eosinophils and epithelium. Other resident cells such as fibroblasts and smooth muscle play a role |
|
| Airway remodeling |
As inflammation proceeds, other changes evolve leading to reparative or remodeling changes and include: |
| • Sub-basement membrane thickening |
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| • Subepithelial fibrosis |
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| • Smooth muscle hypertrophy |
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| • Angiogenesis |
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| Mucus gland hyperplasia and hypersecretion |
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| Bronchoconstriction |
Airway narrowing resulting in wheezing |
| Probably acutely due to release of mast cell mediators such as histamine, leukotrienes, and tryptase |
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| Obstruction could be mediated by multiple factors: |
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| • Smooth muscle contraction |
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| • Airway edema |
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| • Airway remodeling and fibrosis |
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| Bronchial Hyperresponsiveness |
Exaggerated bronchoconstrictive response to a wide variety of stimuli; best measured clinically by methacholine challenge testing; mediated by inflammation, remodeling and other airway changes that occur in asthma |
Miller et al. Clinical and Molecular Allergy 2008 6:4 doi:10.1186/1476-7961-6-4 |
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