Obstructive Lung Disease Flashcards
What are the most common obstructive airway diseases?
Asthma.
Chronic bronchitis.
Emphysema.
Chronic bronchitis + Emphysema = COPD.
What are the different values of PEFR?
Normal - 400-600litres/min.
Normal range - 80-100% of best value.
Moderate fall - 50-80% of best value.
Marked fall - <50% of best value.
How is obstructive lung disease shown through different measurements?
Reduced FEV1 and PEFR.
Reduced FVC may also occur.
FEV1 being <70% of FVC.
What is bronchial asthma?
Type I Hypersensitivity in the airways.
Mast cell degranulation occurs from specific IgEs or chemicals.
What are the effects of bronchial asthma?
Smooth muscle contraction and inflammation occur (can be modified by drugs).
Generally reversible - spontaneous, or due to medical intervention.
What is chronic bronchitis?
Defined clinically by a cough productive of sputum most days in at least 3 consecutive months for 2 or more consecutive years.
What are common misconceptions surrounding chronic bronchitis?
Can be confused with chronic bronchial asthma.
Complicated chronic bronchitis is when sputum turns mucopurulent (acute infective exacerbation) or FEV1 falls.
What are the effects of chronic bronchitis?
Large airways have hyperplasia of mucous glands and goblet cells; inflammation and fibrosis are minor.
Small airways gain goblet cells; inflammation and fibrosis are long-standing.
What is emphysema?
An increase beyond the normal size of airspaces distal to the terminal bronchiole arising either from dilatation or from the destruction of their walls and without obvious fibrosis.
What are the different types of emphysema?
Centriacinar - central acinus is distended.
Upper lobes of lungs are affected.
Panacinar - all parts of the acinus are distended.
Lower lobes of lungs are affected.
Periacinar - peripheral acinus is distended.
Irregular.
Define bulla and bleb.
Bulla - an emphysematous space >1cm.
Bleb - bulla spaces underneath the pleura.
What is the pathogenesis for emphysema?
Smoking.
Protease and antiprotease imbalance.
Age.
Alpha-1-antitrypsin deficiency.
How does smoking cause emphysema?
Inhibits elastin synthesis and anti-elastase.
Promotes elastase and neutrophils (which promote elastase).
Causes tissue destruction of the elastin framework in alveolar tissue.
How does alpha-1-antitrypsin deficiency cause emphysema?
Promotes anti-elastase, which promotes elastase.
Causes tissue destruction of the elastin framework in alveolar tissue.
What is the aetiology of COPD?
Smoking.
Pollution.
Dust (occupation-related).
Age.
Prevalence (men; in developing countries).
Antitrypsin deficiency (rare).
