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)
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Hallmarks of Asthma
*
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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
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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
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T cell environmental differentiation factors: Th2
5 Listed
- Widespread use of antibiotics
- Western Lifestyle
- Urban Environment
- Diet
- Aeroallergens
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Early Phase responses
4 Listed
- Bronchial smooth muscle contraction
- mucus secretion
- vascular leakage
- mucosal edema
Late Phase response
3 Listed
- Infiltration with eosinophils and neutrophils
- increase inflammation
- bronchial hyperreactivity
Early and LAte Phase response effects
4 Listed
- Obstruction of large and small airways
- air trapping
- respiratory acidosis
- hypoxemia
Genetics of Asthma
3 Listed
- Multifactorial with environmental factors with multiple susceptibility genes
- gene expression and the combination of various polymorphisms varies from patient to patient
- more than 100 genes have a reported association in various mechanisms (immune response, tissue remodeling, disease severity, response to therapy)
Specific examples of Genetics of Asthma
3 Listed
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Tissue/Pathology?
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normal airway wall
Tissue/Pathology?
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Normal respiratory bronchiole
Tissue remodeling in chronic asthma
At least 8
- luminal mucous plugging
- Epithelial goblet hyperplasia
- Epithelial injury
- Basement membrane thickening/fibrosis (AKA subepithelial fibrosis/subepithelial collagen deposition)
- Increased airway vascularity
- Smooth muscle hypertrophy
- Mucous gland hypertrophy
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Airway remodeling summary
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Epithelial-mesenchymal trophic unit
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Additional characteristic findings in asthma
3 Listed
- Creola Bodies
- Curschmann spirals
- Charcot-Leyden crystals
Creola bodies Description
5 Listed
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Curschmann Spirals
5 Listed
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Charcot-Leyden Crystals Description
5 Listed
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What is this?
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Creola Bodies
What is this?
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Curschmann Spirals
What is this?
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Creola Bodies
What’s This?
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Charcot-Leyden Crystals
What’s this?
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Charcot-Leyden Crystals
What’s This?
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Charcot-Leyden Crystals
What’s This?
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Charcot-Leyden Crystals
Clinical features of Asthma
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Asthma Treatment
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Status Asthmaticus
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Status asthmaticus autopsy findings?
Obstructive: Difficulty expelling air
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Asthma summary 1
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Asthma Summary 2
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Asthma Summary 3
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Subepithelial fibrosis AKA
Basement membrane thickening