Pleural effusion

Question 1

What is pleural effusion?

Answer 1

Fluid between visceral and parietal pleura

Question 2

What are the categories of pleural effusion?

Answer 2

Based on protein content in the fluid:

1. Transudative = <30g protein/L
2. Exudative = >30g protein/L

Question 3

How do transudative pleural effusions occur?

Answer 3

Imbalance between hydrostatic and oncotic pressure - fluid leaks into pleural space

A) Hydrostatic pressure too high: congestive heart failure (heart can’t pump effectively and therefore the blood ends up in pulmonary vessels)

B) Low oncotic pressure: cirrhosis (can’t make albumin), hypothyroidism

Question 4

What are exudative pleural effusions?

Answer 4

Effusion due to infection/ inflammation/ excessive production

• Local factors influence pleural fluid formation and reabsorption
• Bacterial pneumonia
• Cancer
• PE
• TB

Question 5

What would the fluid of an exudative pleural effusion look like?

Answer 5

Cloudy, purulent

Question 6

Which cancers are associated with pleural effusion?

Answer 6

Breast, bronchial, lymphoma, leukaemia

Question 7

How much fluid in general has to accumulate before a pleural effusion becomes symptomatic?

Answer 7

500mL

Question 8

What is pleurodesis?

Answer 8

Mildly irritant drug is put between visceral and parietal pleura to stick the two pleural membranes together and prevent fluid collection

Considered a long term/ permanent treatment option

Question 9

Signs on x-ray in pleural effusion

Answer 9

• Blunting of costophrenic angles
• White areas in lung base

Question 10

Most common cause of transudative effusion (<30g/L protein)?

Answer 10

Heart failure

Question 11

Most common exudative cause of pleural effusion

Answer 11

>30g/L protein

Pneumonia is the most common cause

Question 12

Features of pleural effusions

Answer 12

Dyspnoea

Non-productive cough

Chest pain

Examination: dullness to percussion, reduced breath sounds and reduced chest expansion

Question 13

Investigations for patient with suspected pleural effusion

Answer 13

Imaging: PA CXR in all patients, USS can be used for guidance during aspiration, contrast CT if considering a malignant cause

Aspiration: USS used for guidance, fluid sent for pH, protein, LDH, cytology and microbiology

Light’s criteria: used to differentiate between a transudative and exudative pleural effusion

Exudates: >30g/L protein

Transudates <30g/L protein

If levels are between 25-30, the Light’s criteria should be used

Exudate = LDH levels > 2/3 the upper limit of normal serum LDH

Question 14

Differentials for a blood-stained pleural effusion

Answer 14

Mesothelioma, PE, TB

Question 15

Management of recurrent effusions

Answer 15

• Repeated aspiration
• Pleurodesis
• Indwelling pleural catheter
• Drug management to alleviate symptoms e.g. opioids for dyspnoea