Term
| What is the main cause of COPD? |
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Definition
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Term
| Type of airway obstruction in COPD? |
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Definition
| Partially reversible, but will NEVER normalize |
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Term
| What are the 3 main pathologies associated with COPD? |
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Definition
Expiratory flow limitation
Air trapping
Hyperinflation of lungs |
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Term
| Pathogenic mechanisms of COPD |
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Definition
Neutrophilia - enhances elastase and protease activity to cause destruction of parenchyma
a1-antitrypsin deficiency (genetic) - w/o inhibitor get increased protease activity & alveolar wall destruction (contributes to parenchymal breakdown) |
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Term
| What are the 2 clinical identities of COPD? |
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Definition
| Emphysema & chronic bronchitis |
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Term
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Definition
| Abnormal & permanent enlargement of airways distal to terminal bronchioles; aveolar & parenchymal destruction |
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Term
| COPD - Chronic Bronchitis |
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Definition
| Productive cough for > 3 months, in 2 consecutive years w/o alternative diagnosis |
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Term
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Definition
Functional unit of the lung; all structures distal to terminal bronchioles
= respiratory bronchioles, alveolar ducts & sacs, alveoli |
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Term
| Types of tissue degeneration in COPD: |
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Definition
Panacinar - distal alveoli & acini
Centriobular - bronchiolar destruction |
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Term
| What is the cellular pathology involved in hyperinflation of the lungs & air trapping? |
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Definition
| Loss of elastic tissue due to parenchymal destruction (airways lose ability to recoil) |
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Term
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Definition
| Outpouchings of the lung seen in smokers w/ hyperinflated alveoli; caused by loss of alveolar tissue |
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Term
| Why does loss of alveoli cause airway closure/limited flow? |
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Definition
All alveoli are interconnected and interdependent; they are tethered together to keep the airways open
Loss of some alveoli, parenchymal attachments fall apart & airways collapse (limits flow) |
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Term
| What are the pathophysiological impacts of COPD? |
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Definition
Loss of area for gas exchange (loss of alveoli)
Mismatch between ventilation/perfusion & diffusion - lose O2 diffusion capacity
Loss of elastic fibers - air trapping & hyperinflation |
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Term
| What is the most preventable risk factor for COPD? |
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Definition
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Term
| What has the greatest effect on reducing respiratory disease in adults? |
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Definition
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Term
| What is essential for COPD diagnosis? |
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Definition
| Objective demonstration of airway obstruction by SPIROMETRY |
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Term
| What is the purpose of spirometry? |
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Definition
| To measure lung volumes as a measure of pulmonary function |
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Term
| What is the FEV1/FVC ratio which indicates obstruction? |
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Definition
| < 0.70; NEEDED for COPD diagnosis |
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Term
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Definition
| Normal amount of air entering lungs after normal breath = 500 mL |
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Term
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Definition
| Maximum amount of air that can be moved in/out of lungs = 4600 mL |
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Term
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Definition
| Amount left in lungs after maximal expiration = 1200 mL |
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Term
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Definition
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Term
| What are the two categories of respiratory disease? Where do asthma and COPD fall? |
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Definition
Restrictive
Obstructive - includes both COPD & asthma |
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Term
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Definition
| It is treatable at ANY stage |
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Term
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Definition
Mild = 1 or 2
Moderate = 3 or 4
Severe = 5 |
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Term
| Continuum of management strategies of COPD: |
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Definition
Start w/ smoking cessation & exercise
With progression, use SABD prn; may need LABD if necessary
More severe forms require ICS or LABA; possible O2 therapy/surgery with end-stage |
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Term
| What is the most effective intervention for COPD? |
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Definition
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Term
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Definition
| Ask, Advise, Assess, Assist, Arrange |
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Term
| Guidelines for exercise therapy in respiratory disease |
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Definition
Frequency = 3-5 times per week
Moderate shortness of breath
30-45 minutes/session
Activities = running, cycling, swimming |
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Term
| COPD Pharmacotherapy in MILD Cases: |
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Definition
| SABA prn -> LAAC/LABA + SABA prn |
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Term
| COPD Pharmacotherapy in MODERATE cases: |
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Definition
Infrequent AECOPD (<1/year)
LAAC/LABA + SABA prn -> LAAC + ICS/LABA + SABA |
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Term
| COPD Pharmacotherapy in SEVERE cases: |
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Definition
Frequent AECOPD (>1/year)
Same as moderate + theophylline |
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Term
| What is the normal function of ACh in the airways? |
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Definition
Causes smooth muscle contraction to NARROW the airways
Mediated by parasympathetic innervation to airways by CN X (vagus nerve) |
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Term
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Definition
| Block ACh receptors in the airway to prevent airway narrowing from smooth muscle contraction |
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Term
| Normal function of B2-adrenergics in airways: |
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Definition
| Function as BRONCHODILATORS to relax airway smooth muscle |
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Term
| How to B2-agonist drugs function: |
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Definition
| Cause relaxation of all airway smooth muscle to prevent narrowing (counteract the effects of ACh induced airway narrowing) |
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Term
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Definition
Sustained worsening of dyspnea, cough, or sputum production causing increased use of meds
Known as "heart attacks" of lung disease |
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Term
| What is the most frequent cause of hospital visits & death in COPD patients? |
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Definition
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Term
| What are related to the probability of surviving AECOPD episodes? |
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Definition
Age, length of exacerbation, frequency of exacerbations
Measured by Kaplan-Meier survival curve |
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Term
| What is the basis of expiratory flow limitation; i.e. what is the principle behind it? |
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Definition
As you increase expiratory effort, expiratory flow increases to a maximum after which further efforts are not matched by increased flow
At a given point, expiratory flow becomes independent of effort |
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Term
| Pulmonary volumes on the flow vs. volume curve of expiratory flow: |
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Definition
TLC on left side, RV on right side
Diameter of small circle = tidal volume
Entire length of curve = VC of lung |
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Term
| What is the difference in flow between normal breathing and maximum expiration? |
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Definition
| This is the expiratory flow reserve - present during quiet breathing; gives us the ability to increase breathing rate to increase expiratory flow |
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Term
| What is the difference in expiratory flow reserve in a normal individual vs. one with emphysema (COPD)? |
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Definition
| The flow reserve is greatly reduced in the COPD patient at ALL lung volumes, cannot increase their rates of respiration to increase flow |
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Term
| What is the compensation mechanism to increase flow in COPD patients? |
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Definition
They HYPERINFLATE their lungs to increase tidal volume and thereby increase flow (increase TLC)
This increases the work of breathing though, and worsens dyspnea |
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Term
| What causes expiratory flow limitations? |
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Definition
| DYNAMIC COMPRESSION of the airways |
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Term
| What is the physiology behind dynamic compression? |
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Definition
Chest wall exerts pressure on the lung to create a positive pleural pressure difference
As the airways move closer to the mouth, the pressure within them decreases as it is expended to overcome flow limitations
At a point the pressure outside the airways > pressure within airways - causes compression and limitation of flow |
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Term
| Factors affective dynamic compression: |
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Definition
Increased peripheral resistance = increased pressure loss -> this moves the equal pressure point further w/in the periphery of the lung (seen in COPD); more limitation
Loss of tissue recoil from low lung volume or parenchymal loss
Airway stiffness/rigidity |
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Term
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Definition
| Inflammatory disorder of the airways chracterized by paroxysmal or persistent symptoms - dyspnea, tightness in chest, wheezing - associated with VARIABLE airflow limitation & hyperresponsiveness of the airways to certain stimuli (hypersensitivity response) |
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Term
| Airflow limitation in COPD vs. ASTHMA |
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Definition
Asthma = VARIABLE limitation
COPD = persistent flow limitation |
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Term
| What inflammatory cell types are involved in asthma? |
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Definition
| Eosinophils (predominant), mast cells, neutrophils (acute episodes, smokers), T lymphocytes, macrophages, RTE |
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Term
| Flow limitation and reversibility in COPD vs. asthma: |
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Definition
Asthma = variable limitation; spontaneously reversible often
COPD = fixed limtation; only partially reversible |
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Term
| Gender ratios in asthma over time: |
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Definition
Childhood = 2:1 in favor of boys
Teenagers = more prevalent in girls
Adults = 1:1 ratio |
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Term
| What is the primary immunohistological characteristic of asthma? |
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Definition
| Inflammatory cell infiltration by eosinophils |
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Term
| Effects of inflammation in asthma: |
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Definition
Local edema in mucosa
Bronchoconstriction of airway smooth muscle
Mucous secretion
ALL of the above contribute to a narrowing of the airways, with this being at least partially reversible |
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Term
| What are the two types of asthma? |
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Definition
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Term
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Definition
Type I hypersensitivity (IgE); inhaled allergens
Familial history of atopy
Childhood onset |
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Term
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Definition
Stimuli target hyperresponsiveness of airways - cold air, stress, infection, drugs (aspirin)
Adult onset |
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Term
| Symptoms suggestive of asthma: |
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Definition
Dyspnea, tight chest, wheezing, productive cough
Worse at night & early morning - chronobiological symptoms
Develops after exposure to irritant/allergen
Improves w/ bronchodilator or ICS |
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Term
| What is the preferred PF criteria for asthma diagnosis? |
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Definition
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Term
| Spirometry criteria for asthma diagnosis: |
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Definition
Reduced FEV1/FVC - children < 0.8-0.9; adults < 0.75-0.8
Increased FEV1 w/ bronchodilator - children >12%; adults >12% + > 200 mL |
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Term
| Alternative diagnostic measure for asthma diagnosis? |
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Definition
Peak expiratory flow (PEF) variability
Need to see PEF increase post-bronchodilator
Can use diurnal variation in ADULTS only |
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Term
| What does methacholine mimic? |
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Definition
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Term
| Name one drug unique to asthma treatment and one drug unique to COPD treatment: |
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Definition
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Term
| What becomes the main driving force for inspiration in emphysema? |
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Definition
The low pO2 (hypoxic drive)
Chronically elevated pCO2 downregulates central chemoreceptors, so peripheral receptors respond to hypoxia instead |
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Term
| How does air trapping lead to hyperinflation in COPD? |
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Definition
Air trapping is due to loss of elastic fibers in walls of airways - leads to higher RV
Higher RV progressively leads to hyperinflation (increased TLC) |
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Term
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Definition
| AT ANY STAGE - never too late to stop smoking or start pharmacotherapeutic intervention |
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Term
| Difference between moderate and severe COPD |
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Definition
Moderate = infrequent AECOPD
Severe = frequent AECOPD (>1/yr) |
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Term
| Example of anti-cholinergic & example of B-agonist |
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Definition
AC = Triotropium Bromide
BA = Salbutamol |
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Term
| What are AECOPD's also known as? |
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Definition
| The "heart attacks of lung disease" |
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Term
| How is the expiratory flow reserve used to increase expiratory flow? |
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Definition
| Use it INCREASE RATE of breathing (increases flow) |
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Term
| How do COPD patients try to increase expiratory flow? |
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Definition
| Increase TLC (hyperinflate lungs) to try to increase expiratory flow, leads to severe dyspnea |
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Term
| Why does the expiratory flow increase compensation mechanism lead to increased dyspnea? |
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Definition
Because the pt hyperinflates lungs to try and increase expiratory flow (increases tidal volume
However, this hyperinflation increases work of breathing, leading to worsening dyspnea |
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Term
| What are all symptoms of asthma associated with? |
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Definition
| Variable flow limitation (key aspect of pathology) |
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Term
| Onset of intrinsic vs. extrinsic asthma? |
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Definition
Extrinsic = childhood (IgE mediated)
Intrinsic = adult (hyperresponsive airways are targeted) |
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Term
| What 3 objective measures are needed for an asthma diagnosis? |
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Definition
Reversible airway obstruction (post-bronchodilator)
Variable flow limitation over time
Airway hyperresponsiveness |
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Term
| Difference of dose-response curve in asthmatics vs. normal for methacholine challenge |
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Definition
Normal - sigmoidal decrease in FEV1, get plateau (maximum decrease)
Asthma - linear decrease; no plateau is seen - with increasing concentrations will always see further decrease |
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Term
| What is the function of inhaled corticosteroids/LTRA? |
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Definition
| Prevent bronchoconstriction of airways |
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Term
| Difference between ICS & bronchodilator use in asthma vs. COPD: |
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Definition
ICS - essential for asthma, only helpful for AECOPD
BD - prn for asthma, regular for COPD |
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Term
| Course of progression of asthma vs. COPD: |
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Definition
Asthma - stable course (w/ exacerbations)
COPD - progressively worsening (downward spiral) |
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Term
| What is inflammation mediated by in asthma vs. COPD: |
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Definition
Asthma = EOSINOPHILS
COPD = NEUTROPHILS |
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