COPD - 103 Flashcards
What defines chronic bronchitis?
Patient must have a cough productive of sputum for at least 3 months of the year for 2 consecutive years.
Pathology - damage to cilia, increased number of goblet cells, increased mucus glands - more mucus in airway.
What are the 2 conditions that characterise COPD?
Chronic bronchitis
Emphysema
What defines emphysema?
Degenerative loss of radial traction of bronchial walls, lung tissue destruction distal to terminal bronchioles, loss of connective tissue and therefore dilated airspaces. Floppy airways that collapse on expiration.
What is the difference between smoking-related emphysema and alpha-1-antitrypsin deficiency related emphysema?
Smoking-related usually affects upper lobes
Alpha - usually affects lower lobes.
What drugs can you use to treat COPD?
B2 receptor agonists: Salbutamol and terbutaline (short acting). Salmeterol (long acting)
M receptor anatgonists (M1/M3): Ipratropium (short acting), tiotropium (long acting). Note: M2 blocking can result in increased ACh release.
How would you distinguish asthma from COPD?
Asthma: common in all ages (COPD older), not necessarily a smoker (COPD - almost always smoke), breathlessness variable (COPD - constant), night time waking common
What is the most important drive for breathing? What happens if this is compromised?
PaCO2 - body wants to keep it at 40mmHg. If it rises above 50mmHg then PaO2 becomes the main stimulus.
What happens to FEV1 in COPD?
It is reduced.
What will happen to FEV1 in a restrictive disease?
It will be lowered but not always significantly
What will happen to FVC in a restrictive disease?
It will be reduced
What will happen to FEV1 in an obstructive disease?
It will be significantly reduced.
What will happen to FVC in an obstructive disease?
It will be reduced
What is the normal bp in the lungs?
25/8
What is hypoxic pulmonary vasoconstriction and when does it occur?
When there isn’t enough O2 in the alveoli vessels constrict. It occurs at birth and in diseased lungs.
What does the renin angiotensin aldosterone system do?
Renin is produced in the kidneys when bp is low, the renin is secreted directly into the circulation. It then converts angiotensinogen (released by the liver) to angiotensin I. Angiotensin I is then converted to angiotensin II and it is this that causes blood vessels to constrict, thus increasing blood pressure. Angiotensin II also stimulates secretion of aldosterone which increases Na and H2O reabsorption, thus increasing blood volume which also increases bp.
