Pleural Pathology Flashcards
Describe the layers of the pleura from the lung to the intercostal muscles
- Lung
- Connective tissue
- Mesothelium
- Pleural cavity
- Mesothelium
- Connective tissue
- Intercostal muscles
What cells line the pleural cavity?
A single layer of mesothelial cells (either side)
What do the mesothelial cells of the pleura secrete?
Pleural fluid
What does pleural fluid consist of?
hyaluronic acid-rich mucinous pleural fluid
Function of pleural fluid?
lubricates the movement of the visceral and parietal pleura against each other during respiration
What are the 2 names for the inflammation of the pleura?
Pleurisy or pleuritis
Which type of 1ary inflammatory diseases can cause pleurisy?
Collagen vascular diseases:
- systemic lupus erythematosus (SLE)
- rheumatoid arthritis
Pleurisy can also occur 2ary to infections. Which 3 infections predispose to pleurisy?
- Pneumonias
- Pulmonary TB
- Viral: primary Coxsackie B infection (Bornholm disease)
Pulmonary infarction can give rise to pleurisy. What is this usually 2ary to?
Pulmonary arterial thromboembolus
What is a ‘bleb’ in the lung?
In the lungs, a bleb is a collection of air within the layers of the visceral pleura.
Lung bleb vs bulla?
If blebs become larger or come together to form a larger cyst, they are called bulla.
Which lung condition are bullae common complications of? What is the danger of this?
A giant bulla is a complication of emphysema. In areas of the lung completely damaged by the disease, air pockets can develop. These areas threaten the patient’s health not only because of the underlying emphysema. As an air pocket—a bulla—grows, it takes up space in the chest cavity and can encroach on the lungs.
Emphysema can lead to pleurisy. What is this usually 2ary to?
Ruptured bullae
Can neoplasms lead to pleurisy?
Yes
When would pleurisy be therapeutically induced?
Pleurodesis - talc is put into the pleural cavity to induce inflammation, causing the pleural cavity to seal up, preventing fluid (pleural effusions) or air (pneumothoraxes) from continually building up around your lungs.
What can iatrogenic pleurisy occur?
- Radiotherapy to the thorax
- Immune reactions to a drugs
Signs and symptoms of pleural inflammation if there is no associated pleural effusion?
- Symptom - Pleuritic chest pain, a sharp localised pain exacerbated by breathing
- Sign - Auscultation of a pleural rub during breathing
What is pleuritic chest pain?
Chest pain exacerbated by deep breathing, coughing, sneezing, or laughing. The pain is sudden and intense sharp, stabbing, or burning in nature.
What is a pleural rub? What is it caused by?
An adventitious breath sound heard on auscultation of the lung. The pleural rub sound results from the movement of inflamed and roughened pleural surfaces against one another during movement of the chest wall.
What is pleural fibrosis?
Pleural fibrosis and calcification are thickening and stiffening of the pleura
What 2 major factors predispose to pleural fibrosis?
- Pleural inflammation
- Asbestos exposure
What are the 2 types of asbestos associated pleural fibrosis?
- Parietal pleural fibrous plaques; related to low level asbestos exposure
- Diffuse pleural fibrosis; related to high level asbestos exposure
What are the effects of widespread thick pleural fibrosis? What symptom does this lead to?
Can prevent normal expansion and compression of the lung during respiration causing breathlessness. Fibrous adhesions can wholly or partly obliterate the pleural cavity.
What is pleural decortication?
Removal of the fibrous tissue to improve the expansion and compression of the lung during respiration
What are parietal pleural fibrous plaques associated with?
Associated with low level asbestos dust exposure
How do parietal pleural fibrous plaques present?
- Asymptomatic
- May be visible on chest radiographs
- Dense poorly cellular collagen
Are parietal pleural fibrous plaques a serious disease?
It is not a UK Government Prescribed Occupational Disease therefore it is not eligible for Industrial Injuries Disablement Benefit
What is diffuse pleural fibrosis associated with?
Associated with high level asbestos dust exposure
How does diffuse pleural fibrosis typically present?
- Usually bilateral
- Dense cellular collagen not extending into interlobar fissures
- Prevents normal expansion and compression of the lung during breathing causing breathlessness
Is diffuse pleural fibrosis recognised as a UK Government Prescribed Occupational disease?
Yes - is eligible for Industrial Injuries Disablement Benefit
What are the 6 major pathological fluids that can occur in the pleural cavities? What are the names of the disease that each causes?
- Serous fluid –> pleural effusion
- Pus –> empyema or pyothorax
- Blood –> haemothorax
- Bile –> cholethorax
- Lymph –> chylothorax
- Gas –> pneumothorax
What is empyema/pyothorax usually 2ary to?
Pneumonia
What is haemothorax usually 2ary to?
Usually traumatic or a ruptured thoracic aortic aneurysm
What is a chylothorax usually 2ary to?
Traumatic
If a patient with a pleural effusion has an CXR taken standing up, where does the fluid tend to accumulate?
At the bottom of the lung(s) - is a horizontal line between the fluid and the lung above
What are the 2 types of pleural effusion?
- Transudate
- Exudate
What are the 2 causes of a transudative pleural effusion?
- Increased pressure in blood vessles (high vascular hydrostatic pressure)
- Low protein blood count (low capillary oncotic/colloid osmotic pressure)
What is the plasma oncotic pressure?
The plasma oncotic pressure is that part of the total osmotic pressure of the plasma that is due to impermeant proteins.
Reduction in plasma proteins = reduction in oncotic pressure
How can a high vascular hydrostatic pressure lead to a transudative pleural effusion?
This pressure drives fluid out of the capillary (i.e., filtration) –> Forces fluid out of the vessels
What are the 2 major causes of a high vascular hydrostatic pressure (leading to a transudative pleural effusion)?
- Left ventricular failure
- Renal failure
How can a low capillary oncotic pressure lead to a transudative pleural effusion?
Filtering of fluid out of vessels (and into extravascular space) leads to an increase in protein concentration inside the vessel
What is the capillary plasma oncotic pressure determined by?
Plasma proteins that are relatively impermeable –> ALBUMIN