Obstructive Lung Disease Flashcards
What are the shared features of obstructive lung disease?
Decreased rate of forced expiratory air volume due to EITHER increased airflow resistance OR decreased outflow pressure
Morphological differences between emphysema due to Cig smoking vs alpha antitrypsin deficiency
centrilobar vs panlobar emphysema (with excess PAS stained globules in hepatocytes)
What’s the definition of emphysema?
COPD with permanently enlarged air spaces, destruction of their walls WITHOUT fibrosis
What are potential pathological mechanisms that lead to emphysema?
increased pulmonary proteolysis
decreased ANTIproteolysis
How can cigarette smoke lead to decreased alpha-antritrypsin function?
Cig–>chemotaxis, netruophils, macs in alveoli–>release of elastase, proteases and ROS–>increased elastolytic activity and oxidation of alpha-antitryps
What do we see with centrilobular emphysema?
primarily respiratory bronchioles involved, more severe in upper lung fields, usually b/c of cig smoking
If we see uniform destruction of pulmonary lobule, what are we looking at?
Panlobular emphysema due to alpha antitrypsin deficiency (or end stage centrilobar), more severe in lower lobes
What type of emphysema is adjacent to areas of fibrosis?
paraseptal
Why are those with emphysema described as PINK PUFFERS?
Lungs are hyper inflated so barrel chest AND normal hemoglobin saturation (not hypoxemic)
What is the definition of chronic bronchitis?
presence of persistent productive cough without apparent cause for at least 3 months in at least 2 years
What are the two major causes of chronic bronchitis?
chronic exposure to toxic inhalants and recurrent respiratory tract infections
whats the pathogenesis of chronic bronchitis?
chronic exposure leads to increased mucus production and epithelial squamous metaplasia (both impair clearance) leads to chronic airflow obstruction and predisposition to pulmonary infections
How does chronic bronchitis manifest on the bronchial/bronchiolar level?
- Hyperplasia of goblet cells and hyperplastic glands
- increased ratio of thickness of mucous glands to the airway wall
- increased smooth muscle
- inflam infiltrate
Why are patients with chronic bronchitis known as blue bloaters?
Marked vent-perf mismatch so hypoxemic (cyanotic) and vasoconstrict in lung leads to pulmonary hypertension leads to peripheral edema (bloat)
Gross appearance of lungs in an asthmatic?
distended, overinflated, multiple airways obstructed by viscoid mucous plugs
Airway remodeling in asthma patients?
Too many goblet cells! subepithelial mucous gland hyperplasia!
BM fibrosis! too thick
Smooth muscle hyperplasia!
eosinphohil influx
What do to the luminal mucous plugs (asthma) “contain?”
Curschmann spirals, eosinophils, Charcot-Leyden crystals
What is Bronchiectasis?
Permanent airways dilatation due to recurrent infections with necrosis (dilated but floppy so act as obstruction)
what are the pathological features of bronchiectasis? both gross and micrscopic
markedly dilated PERIPHERAL airways extending out to pleura, especially within lower lobes, mixed inflamm cell infiltrate associated wit ulceration, necrosis, scarring.
complete airway obstruction might lead to…
acquired atelectasis! resportion of trapped o2 –> alveolar collapse
Besides obstruction, what other way can we get acquired atelectasis?
Compression (due to accum in pleural cavity), contraction (pulmonary fibrosis), patchy (loss of sufactant- RDS)
