Pathology Of Obstructive Lung Disease Flashcards
What percentage of the FVC if FEV1 in healthy patients?
70 - 80 %
What is the normal volume of FEV1?
3.5 - 4L
What is the normal volume of FVC?
5L
What is the normal peak expiratory flow rate?
400-600L/min
Normal range is 80-100% of predicted value.
Moderate fall is 50-80%
<50% is a marked fall
What happens in obstructive lung disease?
Airflow limitation, Peak expiratory flow rate is reduced, FEV1 is reduces and less than 70%, FVC may be reduced.
What is asthma?
It is airflow limitation due to bronchial constriction, the reduction in the luminal cross section area in the small airways in the lungs (smooth muscles).
What are the two effect that are made from mast cell granules?
- Inducing inflammation by attracting a number of inflammatory cell types in to the airways leading to swelling and oedema within the bronchial mucosa
- direct effect on bronchial smooth muscle leading it to constrict.
What are the aetiology of chronic bronchitis and emphysema?
- Smoking
- Atmospheric pollution
- Alpha-1-protease (emphysema)
- Age and susceptibility
- Men > Women
- Increasing in developing countries
What is the clinical definition of chronic bronchitis?
The patient has a cough productive of sputum most days in at least 3 consecutive months for 2 or more consecutive year.
Complicated chronic bronchitis when sputum turns mucopurulent (yellow or green) or FEV1 falls
What happens to the large airways during chronic bronchitis?
Mucous glands get bigger, number of goblet in the surface respiratory epithelia increases, inflammation and fibrosis.
What happens to the small airways during chronic bronchitis?
Goblets cells appear, inflammation and fibrosis in long standing disease.
What is the pathological definition of emphysema?
Increase beyond the normal in the size of the airspaces distal to the terminal, bronchial arising either from dilatation or from destruction of their walls and without obvious fibrosis.
What is acinus?
The gas exchange tissue part of the lung, everything distal to the terminal bronchiole.
What is centriacinar acinus?
The loss of of lung tissue is concentrated around the middle of the acinus.
What is panacinar acinus?
It takes out large areas of the lungs,
What is periacinar acinus?
Loss around the edges of the acinus.
What is bleb?
It is used to describe spaces underneath the plasma.
What is the pathogenesis of emphysema?
- Smoking
- Protease - Antiprotease imbalance
- Ageing
- Alpha-1-antitrypsin deficiency
What are the main mechanisms of airways obstruction in COPD?
- change in large airways has little contribution.
- inflammation in the small airways leads to change in the smooth muscle tone.
- In emphysema the loss of alveolar attachments is the most common factor
- fibrosis - partial collapse of airways on expiration.
How do the small airways remain open?
The intrathoracic pressure increase causes them to want to collapse but the radial pull and counterbalance from these elastic structures pulling the small airways open.