COPD Flashcards
What is normal FEV1??
70-80% of FVC (3.5-4L)
What is normal FVC?
5L
What is the normal FEV1/FVC ratio?
0.7-0.8L
What happens to FEV1/FVC in obstructive lung disorders such as COPD?
FEV1 is reduced
FVC may be reduced
FEV1/FVC is <0.7
What is the normal peak expiratory flow rate?
400-600L/min
What happens to peak expiratory flow rate in obstructive conditions?
It is reduced
What is the clinical definition of chronic bronchitis?
Cough productive of sputum most days in at least 3 consecutive months for 2 or more consecutive years (without presence of TB, bronchiectasis etc)
What condition is chronic bronchitis most often confused with?
Chronic bronchial asthma
What two things clinically define COMPLICATED chronic bronchitis?
Mucopurulent sputum or a fall in FEV1
List the three large airway changes that occur in chronic bronchitis
- Mucous gland hyperplasia
- Goblet cell hyperplasia
- Inflammation and fibrosis is a minor component
Lit the two small airway changes that occur in chronic bronchitis
- Goblet cells appear in places where there should be no goblet cells
- Inflammation and fibrosis in long standing disease
What is the pathological definition of emphysema?
An abnormal increase in the size of airspaces distal to the terminal bronchiole arising either from dilatation or from destruction of their walls and without obvious fibrosis.
What is included in an acinus
Everything distal to the terminal bronchiole (the “bunch of grapes” made from branches of alveoli)
What causes the increase in the air spaces as seen in emphysema?
the loss of the elastic tissue in alveolar walls
Name the 5 types of emphysema and identify the most common type
- Centriacinar 9most common)
- Panacinar
- Periacinar
- Scar ‘ irregular’
- ‘Bullous emphysema’
What is centriacinar emphysema?
The loss of lung tissue is concentrated around the middle of the acinus causing a hole in the middle of the acinus.
This means that you end up with holes in the lung tissue surrounded by lung tissue
Which regions of the lung tend to be worst affected by centriacinar emphysema?
the upper sections (gough-wentworth sections)
Describe what happens in panacinarf emphysema
Degradation of large sections of the lung rather than small holes as in Centriacinar
The gas exchange tissue is completely lost leaving only blood vessels and bronchioles
Describe what happens in periacinar emphysema
Tissue is lost from around the bottom edge of the acinar
Where in the lungs is periacinar emphysema seen?
particularly prevalent in acinar around the closest to the pleura
Why is emphysema close to the pleura clinically dangerous?
air can leak into the space between the lung and the pleura (pleural space) and a pneumothorax can occur
What is scar emphysema?
Scar emphysema is not clinically significant and simply refers to the formation of scars around regions of emphysema in the lung
How many ribs is it normal to see on an x-ray?
9-10
What x-ray findings are associated with emphysema?
Hyperinflation
all posterior ribs visible and the heart appears suspended in the middle of the lung field
What finding may you see on a CT scan that could indicate emphysema?
“bubbling” caused by emphysemic air sacs
What is the pathological cause of emphysema?
protease-antiprotease imbalance
name three things that can cause a protease-antiprotease imbalance
- SMOKING*
- Ageing (to a lesser extent than smoking)
- Alpha-1-antitrypsin deficiency (genetic cause)
Explain how the elastic framework of a healthy individual is maintained
- residual inflammatory cells release elastase while they digest pathogens/foreign material
- Elastase (which breaks down elastin) is broken down by anti-elastase produced by the lung