MD3001 Week 10/11 Flashcards
normal FEV1/FVC
> 0.7 is normal
lung volume changes in obstructive lung disease
this type of lung disease increases residual volume due to lost elasticity
lung volume changes in restrictive lung disease
this type of lung disease decreases all lung volumes
common restrictive lung disease
sarcoidosis is an example of this type of lung disease
define asthma
chronic inflammatory disorder of airways in susceptible individuals associated w/ an increase in airway response to variety of stimuli. Reversible.
changes in airway structure in asthma (8)
- mucous plug
- thickened BM
- oedematous submucosa
- smooth muscle hypertrophy and hyperplasia
- desquamation of epithelium
- cellular infiltration
- hyperplasia of mucous gland
- neovascularization
define COPD
preventable disease characterized by persistent airflow limitations usually progressive and associated w/ chronic inflammatory response in airways and lung to noxious substance
likely cause of early onset COPD w/ emphysema in lower lobe
a1 antitrypsin deficiency
a1 antitrypsin
enzyme produced in liver that counteracts proteinases
requirements to acquire domiciliary oxygen therapy
- patient w/ a PO2 <7.3kPa
- stopped smoking
- must agree with it breathed for >15h/day
describe case control study
compare histories of diseased and non-diseased
advantages of case control study
- simultaneously look at multiple risk factors
- good for studying rare conditions or diseases
- useful as initial studies to establish association
describe cohort study
follow smokers and non smokers and follow for outcome
define crossover in EBM
each subject receives both intervention and control treatment separated by a washout period
advantages of RCT
- unbiased distribution of confounders
- clearly identified pop
- more likely to be blinded
problems associated w/ RCTs
- impossible w/ rare diseases where patients are limited
- unnecessary when a treatment produces dramatic benefit
- stopping trials early
- expensive, lengthly
common features of inhaled allergens (4)
- a protein which induce T cell response
- low dose which favours IL4 producing CD4
- small size so can diffuse
- high soluble
example of an enzyme as allergen and how it works
Der p 1 in faces of house dust mite can cleave tight junctions b/w epithelial cells in airway. Taken up by dendritic cells, presented to T cells, which become Th2, and cause B cells to secrete IgE
how do inhaled allergens affect body?
they affect nasal epithelium, causing allergic rhinitis (ie. hay fever)
how do allergens further down airway affect body?
cause allergic asthma
chronic asthma
driven originally by specific allergen, but may result in hyperactive airways to other irritants
2 main symptoms of ingested allergens
- activation of GI mast cells results in transepithelial fluid loss and smooth muscle contraction (diarrhea/vomiting)
- if enters bloodstream, urticaria (hives)
explain desensitization to treat allergic reaction
inject patient w/ escalating doses of allergen to shift Th2 to Th1 T cells so IgG is made instead of IgE
how do Helminths control allergy?
they induce a set of T cells (Tregs) that actively suppress Th2
