Pleural effusion

Question 1

Define pleural effusion

Answer 1

Excess fluid in the pleural space

Question 2

Explain the difference between a pleural effusion which is an exudate vs transudate
Examples of when one is more likely

Answer 2

• exudate: higher protein content >30g/L (protein driven) | often associate with inflammation + increased permeability to protein
• e.g. parapnuemonic effusion, maligancy, TB, Pulmonary infarction from pulmonary embolism
  .
• transudate: reduced protein content <30g/L (fluid driven)
• e.g. heart failure, liver failure, kidney failure

Question 3

What can be used to establish whether a pleural effusion is exudative or transudative?

Answer 3

Light’s criteria
- analysis of pleural effusion fluid
Exudative if one or more of following:
- pleural fluid/serum protein >0.5
- pleural fluid/serum LDH >0.5
- pleural fluid LDH >2/3 of upper limit of normal

Question 4

Examples of causes of exudate pleural effusion

Answer 4

due to inflammation > protein leaks out of tissues + into pleural space
- Parapneumonic effusion (pneumonia)
- Malignancy
- TB
- Pulmonary infarction from pulmonary embolism
- RA

Question 5

Examples of causes of transudate pleural effusion

Answer 5

• due to increase pleural capillary hydrostatic pressure - heart failure
• due to decreased capillary oncotic pressure - liver failure + kidney failure
• Meigs syndrome
• hypoalbuminemia

Question 6

What is Meigs syndrome?

Answer 6

Triad of:
- benign ovarian tumour
- pleural effusion
- ascites

Question 7

Is high protein content fluid tranudate or exudate?

Answer 7

Exudate

Question 8

Investigations of pleural effusion

Answer 8

• CXR
• USS of chest
• ECG
• ECHO (if heart failure suspected)
• staging CT (with contrast) if suspect exudative cause
• FBC, U&E, LFT etc.
• pleural effusion analysis + light’s criteria

Question 9

Describe the radiological findings of a pleural effusion?

Answer 9

• loss of costo-phrenic angle of affected side
• dense homogenous opacities
• upper border of effusion higher laterally than medially
• meniscus: concave upper border to effusion
• tracheal + mediastinal deviation away from effusion

Question 10

What are some signs found on examination of pleural effusion

Answer 10

• dullness to percussion
• reduced breath sounds
• tracheal deviation away from effusion

Question 11

What would you find on percussion of pleural effusion?

Answer 11

Dull

Question 12

Treatment of pleural effusions

Answer 12

Remove the fluid:
- chest drain
- needle aspiration
- diuresis
- antibiotics: to remove pathogen causing inflammation
- treat cause