Lung Flashcards
(131 cards)
What are the 3 mechanisms of impaired alveolar oxygen diffusion?
- ↓ Surface area
- ↓ driving pressure
- diffusion distance
What 3 things can cause ↓surface area mediated alveolar-capillary oxygen diffusion impairment?
- alveolar destruction (COPD/emphysema)
- loss of capillaries (embolism, pulmonary HTN)
- alveolar filling defect (fluid, pus, blood)
What 2 things can cause alveolar-capillary oxygen diffusion impairment by ↓ driving pressure?
- bronchiole obstruction (asthma)
- alveolar filling defect (pneumonia)
What can cause alveolar-capillary oxygen diffusion impairment by ↑ diffusion distance?
wide alveolar capillary space (fibrosis, edema)
How does emphysema/COPD cause alveolar-capillary oxygen diffusion impairment? (i.e. via which mechanism)
alveolar destruction → ↓ surface area
How does a PE or pulmonary HTN cause alveolar-capillary oxygen diffusion impairment? (i.e. via which mechanism)
loss of capillaries → ↓ surface area
How does fluid, pus or blood cause alveolar-capillary oxygen diffusion impairment? (i.e. via which mechanism)
alveolar filling defect → ↓ surface area
How does asthma cause alveolar-capillary oxygen diffusion impairment? (i.e. via which mechanism)
bronchiole obstruction (inflammation) → ↓ driving pressure
How does pneumonia cause alveolar-capillary oxygen diffusion impairment? (i.e. via which mechanism)
alveolar filling defect→ ↓ driving pressure
How does fibrosis or edema cause alveolar-capillary oxygen diffusion impairment? (i.e. via which mechanism)
wide alveolar-capillary distance → ↑ diffusion distance
What is the MC pulmonary ssx?
dyspnea!
This spirometry reading, FEV1/FVC ratio < 70%, is dx of which type of lung dz?
obstructive
Is it possible to determine restrictive lung dz physiology from spirometry tests?
NO!! Need to do lung volume tests
subepithelial collagen deposition leading to ↑ bronchial wall thickness
severe asthma
Main inflammatory mediators of asthma
eosinophils
Airway inflammation is primarily mediated by CD4(+) T-cells and eosinophils in which airway dz?
asthma
Airway inflammation is primarily mediated by CD8(+) T-cells and M∅/ PMNs in which airway dz?
COPD
What are the 2 things necessary to dx COPD?
- evidence of airflow obstruction (FEV1/FVC < 70%)
- clinical ssx (cough, sputum prdn., or dyspnea)
2 useful tests (other than spirometry) used to dx asthma
- methacholine challenge test
- peak flow variation
What are the 4 pathologic locations restrictive thoracic disorders can occur?
- pleural cavity
- interstitium (lung parenchyma)
- Neuromuscular
- Thoracic/Extrathoracic
How are the timing of clinical ssx different b/w asthma and COPD?
- asthma: intermittent and variable
- COPD: persistent and progressive worsening
How does a patients cough differ b/w asthma and COPD?
- asthma: nocturnal cough or on exertion
- COPD: morning cough w/ sputum
What are the 2 broad categories of COPD? What are their characteristic pathologic findings?
- chronic bronchitis: inflammation & excess mucus d/t hyperplasia of mucous glands
- emphysema: breakdown of alveolar membranes
Compare the prevelance and mortality trends of asthma and COPD
- asthma: ↑prevelance, ↓mortality
- COPD: ↑prevelance, ↑mortality