Asthma Flashcards
asthma
chronic disease w/ acute, reversible episodes of air way obstruction
reversible episodes of airway obstruction d/t what
- muscle hyperactivity (bronchospasm)
- inflm (exudate + swelling)
chronic inflm of the a/w (URT) d/t what
- hyper-responsive a/w
- “known” trigger
hyper responsive a/w
structures are easily irritated
“known” trigger
recognizable trigger that would cause an episode of a/w obstr –> bronchospasm, inflm & hyper-responsive to unknown triggers
bronchospasm
reversible + recurrent spasm where a/w locks in constricted state
extrinsic (atopic) form
- genetic tendency to develop allergic diseases (ex. allergic rhinitis, asthma, dermatitis)
- commonly assoc w/ heightened IR to common allergies, esp inhaled + food allergens
intrinsic (non-atopic) form
responses to triggers that are not genetically based
etiology
- complex trait –> genetic factors + enviro factors
- hypersensitivity to triggers (hyper-responsiveness)
trigger examples
allergen, strong odor, a/w irritant, exercise
patho
a/w become more hyper-responsive to other allergens/triggers + leads to bronchospasm & airflow limitation
early phase of asthma
release of chemical mediators –> inc mucus prod from goblet cells –> creates mucosal intercellular junctions (gaps b/w epith cells) once allergen is exposed to mast cell –> bronchospasm
late phase of asthma
allergen moves in –> influx of inflm cells into submucosa that release more inflm mediators, epith cell injury w/ dec mucociliary Fx & accum of mucus, inc vascular permb & edema; results in dec a/w patency d/t bronchospasm
acute phase response
- can last upto 1h
- inhaled allergen –> prev sensitized mast cells degranulate & IgE mediated release inflm mediators –> irritation of inflm cells & bronchospasm (limiting airflow) but the inflm cells do not move into the submucosa
acute phase response sequence
- prior sensitization to allergen (T1 HS)
- subsequent exposure = IgE Abs bind to sensitized mast cells
- mast cells on mucosa (surface of a/w) release inflm mediators
- intercellular junctions open –> allergens enter submucosa
- inc cap permb (d/t inflm) and inc mucus secretion (exudate & edema in a/w)
- bronchospasm reflex (via PNS)
- bronchoconstriction to compensate but not beneficial