FMS Week 9: Pathology of Asthma Flashcards
What is Asthma?
basically a reduction of airflow through a variety of processes that is
bronchoconstriction
airflow limitation
airway hyperreactivity
least partly reversible (in order to be asthma must be partly reversible)
Hallmarks of Asthma
*
Airway remodeling is?
Changes in the proportions of histologic constituents that make up the airways
Atopy classification
genetic predisposition towards IgE-mediated hypersensitivity reaction (eczema, allergic rhinitis, etc.)
Most common type of asthma
- Atopic Asthma
Classic example of Type I IgE-mediated hypersensitivity reaction
Atopic Asthma
Atopic Asthma begins when?
Typically in childhood
Atopic Asthma is triggered by?
4 Listed
environmental allergens
- pollen
- dust
- foods
- animal dander
Does Atopic Asthma have a family history component?
Yes, often see a family history of asthma
Tests for atopic asthma
2 Listed
Weal and flare
RAST (Radioallergosorbent test)
RAST description and name
Identifies serum IgE specific for a panel of allergens
Radioallergosorbent test
Non-Atopic Asthma test
No evidence of allergen sensitization (negative RAST, skin test)
Non-Atopic Asthma family history component?
Less common than in atopic asthma
Non-Atopic Asthma underlying cause?
- increased airway hyperirritability
- viral respiratory infections are a common cause
Aspirin-sensitive asthma
- seen in conjunction with recurrent rhinitis and nasal polyps
- special type of non-atopic asthma
Occupational Asthma
- A special type of non-atopic asthma
- caused by dusts (wood, platinum), fumes, gases; generally occurs after repeated exposure
Asthma Pathogenesis
Pollen meets tissue dendritic cell to Th2 cell
Th2 cell activates B cell with IL-4
B cell produces IgE
IgE coats mast cells
IgE cross-linking on mast cells
degranulation recruits eosinophils
histopathologic changes in asthma
- Type I hypersensitivity
- A genetic predisposition + environmental triggers
- thickening of the basement membrane
- smooth muscle cells thickening
- lamina propria macrophages, eosinophils, mast cells, neutrophils
- goblet cell hyperplasia
- eosinophils in the mucus
Atopic Asthma Early phase or immediate phase:
4 Listed
- vagus nerve stimulated
- vagus nerve parasympathetic nervous system
- get bronchoconstriction
- increased vascular permeability
Atopic Asthma: Late Phase
- Increased inflammation
- causes epithelial damage (raggedness and cell dropout of epithelial layer)
T cell environmental differentiation factors: Th1
5 Listed
- Presence of older siblings
- early exposure to daycare
- viral infection
- farm environment
- Tuberculosis