[6] Pleural Effusion Flashcards
What is a pleural effusion?
When the volume of fluid in the pleural space is substantially greater than normal
What kind of disease can pleural effusions be caused by?
Disease that is pulmonary, pleural, or extrapulmonary
What covers the lungs?
A thin serious layer, called the visceral pleura
What covers the chest wall and pericardium?
The parietal pleura
How are the visceral and parietal pleura related?
The parietal pleura is a reflection of the visceral pleura, and they are connected at the lung hila
What is the space inbetween the visceral and parietal pleura called?
The pleural space
What is found in the pleural space?
A very small amount of fluid
What is the purpose of the fluid in the pleural space?
It lubricates movement between the layers
What can pleural effusions be classifed as?
Transudates or exudate
Other than transudates and exudates, what can accumlate in the pleural space?
- Blood
- Pus
- Chyle
What is it called when blood accumulates in the pleural space?
Haemothorax
What is it called when pus accumulates in the pleural space?
Empyema
What is it called when chyle accumulates in the pleural space?
Chylothorax
When does a transudative pleural effusion occur?
When there is disruption of the hydrostatic and oncotic forces operating across the pleural membranes
When does an exudative pleural effusion occur?
When there is increased permeability of the pleural surface and/or capillaries, usually as a result of inflammation
How are pleural effusions divided into transudative and exudative?
On the basis of the Light criteria
What does the Light criteria consist of?
The measureent of lactate dehydrogenase (LDH) and protein concentration in the pleural fluid and serum
What are the Light criteria?
Fluid is considered exudative if one of the following is present;
- Pleural fluid-to-serum protein ratio is >0.5
- Plueral fluid-to-serum LDH ratio is >0.6
- Pleural fluid LDH concentration > 2/3 upper limit of normal serum LDH
What are the most common causes of transudate pleural effusions?
- Heart failure
- Cirrhosis
- Hypoalbuminaemia
- Peritoneal dialysis
What are the less common causes of pleural effusion?
- Hypothyroidism
- Nephrotic syndrome
- Pulmonary embolism
- Mitral stenosis
What are the most common causes of exudate pleural effusions?
- Pneumonia
- Malignancys
What are the most common malignancies causing pleural effusion?
Lung cancer in men, breast cancer in women
What kind of pleural effusoins are most commonly due to malignancy?
Large, unilateral pleural effusions
What are the less common causes of exudate pleural effusions?
- Pulmonary infarction, resulting from pulmonary embolism
- Autoimmune disease, especially RA
- Asbestos exposure
- Pancreatitis
- TB
What is a chylothorax?
The presence of chyle in the pleural space
What does a chylothorax usually occur due to?
Disruption of the thoracic duct
What are the causes of a chylothorax?
- Neoplasm
- Trauma
- TB
- Sarcoidosis
- Cirrhosis
- Amyloidosis
What neoplasms can cause a chylothorax?
- Lymphoma
- Metastatic carcinoma
What trauma can cause a chylothorax?
Operative and penetrating injuries
When are pleural effusions symptomatic?
An effusion has to be quite large before it causes any symptoms, however most malignant effusions are symptomatic
What are the symptoms of a pleural effusion?
- Shortness of breath, especially on exertion
- Cough
- Pleuritic chest pain
What other history features should be noted with pleural effusion?
- Loss of weight, which may suggest malignancy
- Smoking and haemoptysis, which might suggest lung cancer
- History of another malignancy
How is a pleural effusion investigated?
- Examination
- CXR
- Other imaging, including CT, MRI, and ultrasound
- Pleural fluid analysis
What may be seen on inspection on examination in pleural effusion?
- Signs of lung pathology
- Chest expansion may be reduced, bilaterally or unilaterally
- Dyspnoea
- Signs of underlying cause
What signs of lung pathology may be seen on examination in pleural effusion?
- Nicotine staining on dfingers
- Accessory muscles of respiration use
- Finger clubbing
What signs of an underlying cause may be seen on examination in pleural effusion?
- Signs of weight loss
- Rheumatoid changes in hands
Describe chest expansion in pleural effusion
It is reduced on the side of the effusion
How is the trachea deviated in pleural effusion?
With a large, unilateral effusion, the trachea is deviated away from the lesion
If there is associated collapse, the trachea is deviated towards the lesion
What may be found on palpation in examination in pleural effusion?
May be decreased tactile vocal fremitus
What may be found on percussion in pleural effusion?
Effusion will cause stony dullness on percussion. Laterally, it will rise upwards towards the axilla
What will be found on ausculatation in pleural effusion?
- Breath sounds diminished or absent over effusion
- Vocal resonance lost over pleural effusion, except at it’s upper surface
What is the first-line investigation in suspected pleural effusion?
CXR
How big must a pleural effusion be to be visible on a CXR?
About 200ml to be seen on a PA, or 50ml to cause costophrenic blunting on lateral view
Other than detecting fluid, what can a CXR be useful for in pleural effusion?
May suggest an underlying cause, e.g. heart failure
What is the advantage of ultrasound over CXR in pleural effusion?
It is much more sensitive than CXRs in detecting pleural effusions, and can detect even very small effusions
What things are looked at when interpreting pleural fluid analysis
- If it is transudate or exudate
- Pleural fluid haematocrit
- pH
- Cytology
- Lipids
- Glucose
What is classification of transdate or exudate in pleural fluid analysis based on?
Pleural protein content
What can bloody pleural fluid be caused by?
- Malignancy
- Pulmonary embolus with infarction
- Trauma
- Benign asbestos pleural effusions
What can pleural fluid haematocrit help determine?
If a pleural effusion is a haemothorax
What can pH help determine in the analysis of pleural fluid?
If pleural effusion is a haemothorax
What is the normal pH of pleural fluid?
Around 7.6
What can cause a pleural pH of <7.2 with normal blood pH?
- Pleural infection and empyema
- Rheumatoid disease and SLE
- TB
- Malignancy
What is the importance of cytology in pleural fluid analysis?
It is required to diagnose malignant effusions
Why are lipids looked at in pleural fluid analysis?
Determine if chylothorax
Where may low pleural glucose levels be found?
- Empyema
- Rheumatoid disease and SLE
- TB
- Malignancy
What should the management of pleural effusion be aimed at?
The underlying disease
When should aspiration be avoided in pleural effusion?
If transudate is confirmed
How are small effusions that are not causing respiratory problems managed?
Observation
What is the advantage of tapping in pleural effusion?
- It can give symptomatic relief
- Useful for diagnosis
What is the disadvantage of tapping pleural effusions?
Effusion is likey to reform
Where may repeated tapping be used in pleural effusion?
In pallative care
How can controlled drainage of an effusion be achieved?
Insertion of a chest drain
When are chest drains removed in pleural effusion?
If/when the underlying disease is treated
In what kind of pleural effusions are chest drains often needed?
- Empyema
- Haemothorax
What is pleurodesis?
The injection of sclerosant to cause adhesion of the visceral and parietal pleura, and to help prevent reaccumulation of the effusion
What are some commonly used sclerosing agents in pleurodesis?
- Tetracycline
- Sterile talc
- Bleomycin
Where is pleurodesis most commonly used in pleural effusion?
In the management of recurrent malignant effusions
