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24 Cards in this Set
- Front
- Back
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What is asthma?
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Airway obstruction that is REVERSIBLE, either spontaneously or with tx
Airway inflammation Inc'd airways responsiveness to variety of stimuli |
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What are possible causes of asthma?
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Atopy (allergies): eczema, hay fever, high IgE levels
Allergens Tobacco Infectious agents: RSV (respiratory syncytial virus), Rhinovirus, chlamydia, mycoplasm GERD Sinusitis Nasal Polyps Obesity **asthma is not likely one disease, and likely does not have a single cause. Smaller causes: Exercise, occupational, reactive airway dysfn syndrome (RADS), ASA, cough variant |
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Intrinsic vs Extrinsic Asthma
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Intrinisic:
Often no clear precipitating factor (viral) Attacks often longer and stronger and lifelong Chronic inflammation Extrinsic: Clear precipitating environmental factors (dust, allergens, chemicals) Short lived once exposure removed Behaves like allergy (histmaine/bradykinin) Most peopl ehave features of both |
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Which interleukins are secreted by T cells to recruit B cells in asthma?
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IL-4, IL-5 are most important
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What are the "big three" effects (anatomical problems) of asthma?
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Bronchospasm
Airway edema Mucous production Which can lead to V/Q mismatch from plugging and air trapping (dynamic hyperinflation) |
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Events of early and late phases of asthma.
Which phase is more reversible? |
Early phase:
Bronchoconstriction, mucous production, more reversibility Late phase: Airway edema Inflammatory cells Hyperresponsiveness Less reversibility |
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Asthma results in the narrowing of airways. Which in particular? Effect on resistance? Consequences of this?
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Dec'd radius = Inc'd resistance (to the 4th power)
Asthma narrows small, floppy airways and creates one way valves-->obstruction-->air-trapping (lung over-inflation) Thus: air goes in, but not out. leads to ASYMMETRIC resistance (worse when breathe out--prolonged expiratory breathing). Note: Resistance is asymmetrical (normally) bc in inhalation low intrathoracic pressures outside bronchi open the airways; and in exhalation, positive intrathoracic pressure outside bronchi collapse them (milk out the air) |
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What is dynamic hyperinflation and how does it come about?
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Asthmatics facing inc'd expiratory resistance. Normal response to hypoxia/hypercarbia/dyspnea is to breath faster.
This amplifies the problem because more air is going in, and less of it is coming out, thus increasing dead space and compressing lung. Don't breathe rapidly in asthma attack. Need more time to exhale! |
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Slide 34, 1:22:14
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xxx
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Diagnosing asthma
PFTs? |
Confirm wheezing (by healthcare professional)
Confirm normalcy between attacks Establish precipitating factors Obstruciton with change from bronchodilators >12% Low FEV1 (less force of expiration during first second) +methacholine provocation suggestive but NOT diagnostic; best for r/o asthma Peak flow variability between AM and PM of >20% |
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Asthma treatment:
Non-pharmacalogic |
-Allergen avoidance: remove rugs, encase pillows/mattresses, HEPA filters
-Avoid irritants -Avoid beta-blockers (may change) and ASA! |
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Heliox therapy:
Benefits Use |
Use as a 2nd line tx in severe asthma
Mix of O2 and He allows O2 to penetrate smaller airways and get trapped air out--also allows O2 into lung |
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Mild Intermittent Asthma:
Criteria Treatment |
Syx < 2x/week
Asyx between episodes Nocturnal syx <2x/month FEV1 >80% PEFR variability <20% Tx: as needed short acting beta agonist (albuterol) |
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Mild Persistent Asthma:
Criteria Treatment |
Syx > 2x/week, but <daily
Nighttime syx >2x month Normal PFTs PEFR variability 20-30% Rx: SABA + anti-inflammatory (inhaled steroid) |
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Moderate Persistent:
Criteria |
Daily syx
Daily use of rescue inhaler Exacerbations affect activity Nocturnal Syx >1/week Mild obstruction on PFTs |
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Severe Persistent:
Criteria |
Continual syx
Limited physical activity Frequent exacerbations |
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Long Acting Beta Agonists:
Controversy |
-Asthma-related death rate is higher in long-acting beta agonists!
-Only get it if not taking it with an inhaled corticosteroid |
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Disadvantages of chronic beta-agonist use.
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-Tachyreflexia
-Promotes inflammn |
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What viruses can trigger asthma in children under 2 years of age? Over 2 years?
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Under 2 years and WHEEZING:
Respiratory viruses, mostly RSV Over 2 years and WHEEZING: Rhinovirus predominant (common cold) |
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How do viruses act as an asthma trigger?
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Viruses enter cells and reproduce (auto-infect)
Asthma attacks due to viruses can last a long time! |
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What conclusions have been made about the role that childhood viral infections play in asthma?
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Childhood viral infections may play a role in asthma, but it's very complex and involves many host and viral factors.
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Genetic associations of asthma.
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Glucocorticoid receptor SNP
beta-adrenergic receptor mutation: Gly 16 mutation in steroid dependent asthmatics (down-regulates a lot faster) |
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Hygiene theory of asthma.
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Asthmatics tend to have a larger TH2 response than TH1 response (no longer balanced)
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Airway remodeling in asthma
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SM hypertrophy, loss of columnar epithelium, goblet cell hyperplasia, thickened BM
Much more poised to cause inflammatory response |
