Pleura Flashcards
Where does the parietal pleura become continuous with the visceral pleura?
At the hila
What lines the inside of each hemithorax?
Parietal pleura
What is the pleural cavity and what is in it?
A potential pace between the two layers of pleura
A film of fluid produced by the parietal surface (absorbed by parietal and lymphatic vessels)
What does the pleural fluid do?
Allows layers of pleura to slide over eachother which allows movement of the lungs against the chest wall while breathing
Provides surface tension so lungs can stay in contact with the thoracic wall
How much pleural fluid is produced and absorbed in a day?
15ml
How is pleural fluid produced?
By capillary filtration in parietal pleura, driven by Starling forces
What forces increase production of pleural fluid?
Increased by
- increased lung interstitial fluid
- high hydrostatic pressure
- high permeability caused by inflammation, sepsis or malignancy
- low oncotic pressure in blood eg liver failure
What factors affect lymphatic drainage?
Decreased by lymphatic blockage
Increased by systemic venous pressure
What is a pleural effusion?
Any collection of extra fluid in the pleural space
What is a haemothorax?
Collection of blood in the pleural space
What is a chylothorax?
Collection of chyle in the pleural space (lymph with fats in it)
What is empyema?
Collection of pus in the pleural space
What is a simple effusion?
Collection of serous fluid in the pleural space
Does transudate have high or low protein content?
Low - less than 30g per litre
Does an exudate have a high or low protein content?
High - more than 30g/L
When are transudates formed?
Increased hydrostatic pressure eg cardiac failure
Deceased capillary oncotic pressure eg hypoalbuminaemia, nephrotic syndrome
Increased capillary permeability eg sepsis
When are exudates formed in the pleura?
Neoplasm - cancer involving pleural surface/secondary from breast, lung…/primary tumour of pleura
Infection eg pneumonia or TB
Immune disease eg CT disease eg rheumatoid arthritis, SLE
Abdominal disease eg pancreatitis, as cities, subphrenic abscesses causing diaphragmatic inflammation
What is pleurisy?
Inflammation of the pleura
Signs and symptoms of pleurisy?
Sharp pain on inspiration/coughing/sneezing/laughing…
Patient takes small breaths and holds affected side of chest
Involvement of diaphragmatic pleura causes pain in the shoulder
Pleural rub - a creaking noise heard through stethoscope
Causes of pleurisy?
Infection eg TB, pneumonia Autoimmune eg SLE, RA Lung cancer Pneumothorax Pulmonary embolism
How does pleural fibrosis occur?
If there an unabsorbed pleural effusion
Why happens if there are widespread effects of fibrosis of the pleura? (Small amount of thickening has no effects)
Restricted expansion
Reduction in lung volume
Reduction in compliance
What congenital chest wall abnormalities can affect breathing?
Deformation ribs, sternum, T spine, scoliosis and kyphosis - cause function impairment of thoracic cage
What muscular and neurological diseases can affect breathing?
Muscular dystrophy and many other muscular diseases
Polio
Get muscle weakness with lower resistance to respiratory tract infections due to poor clearance of secretions
