Pathology of Obstructive Lung Disease Flashcards
Which three conditions are obstructive airway diseases?
Chronic bronchitis
Emphysema
Asthma
Which two conditions together are called COPD?
Chronic bronchitis
Emphysema
What is FEV1?
Forced expiratory volume of air exiting the lung in the first second
What is FVC?
Final total amount of air expired
What percentage of FVC is FEV1 normally?
70-80%
What volume is usually expired in FEV1?
3.5-4L
What volume is FVC usually?
5L
What is the normal ratio of FEV1/FVC?
0.7-0.8
What is predicted FVC based on?
Age
Sex
Height
What is a marked fall in PEFR?
<50% of best
What is the normal range in PEFR?
80-100% of best
In obstructive lung disease what happens to PEFR, FEV1 and FVC?
Reduced (FVC might be reduced)
What is FEV compared to FVC in obstructive lung disease?
< 70%
What is causing narrowing of the airway in bronchial asthma?
Smooth muscle contraction/twitching
Inflammation
What are causes of bronchi bronchitis and emphysema?
Smoking
Atmospheric pollution
Occupation: dust
Alpha-1-antitrypisin deficiency (emphysema)
How can an individual be susceptible to developing COPD?
How your metabolism handles the chemicals in cigarettes or pollution
What is the clinical definition of chronic bronchitis
Cough productive of sputum in 3 consecutive months for 2 or more consecutive years
What are some causes which induces mast cells to release chemotactic factors and spasmogens?
Specific IgE Drugs Chemicals Stress Cold
What are the morphological changes that occur in the large airways of chronic bronchitis?
Mucous gland hyperplasia
Goblet cell hyperplasia
Inflammation and fibrosis is a minor component
What morphological changes that occur in small airways?
Goblet cells appear
Inflammation and fibrosis in long standing disease
What is emphysema?
Increased in the size of the airspaces distal to the terminal bronchiole arising either from dilatation or from destruction of their walls
And without obvious fibrosis
What is the terminal bronchiole?
The last conducting airway which is lined by resp. epithelium
What is the acinus?
The structure beyond the terminal bronchiole
What is centri-acinar emphysema?
Loss of alveolar tissue around the middle of the acinus (around the bronchioles)
What is panacinar emphysema?
Destruction of the air spaces (alveoli) distal to respiratory bronchioles
What is a bulla?
Emphysematous space > 1cm
What causes emphysema?
Smoking
Protease-antiprotease imblance
Ageing
Alpha-1-antitrypsin deficiency
What is the effect of alpha-1-antitrypsin deficiency?
Less inhibition of elastase which causes tissue destruction leading to emphysema
What is the effect of smoking that leads to emphysema?
Decrease in anti-elastase, therefore increase in elastase
Increase in neutrophils and macrophages which increases elastase
Decrease in repair mechanisms to resynthesis elastin
What is the reversible component of COPD?
Smooth muscle tone and inflammation in the small airways respond to pharmacological intervention
Why does hypoxaemia arise in COPD?
Airway obstruction
Reduced respiratory drive
Loss of alveolar surface area
Only during acute infective exacerbation
What does hypoxaemia due to low V/Q respond well to?
Small increase in FlO2
