Pleural effusion

Question 1

What is a pleural effusion?

Answer 1

Excess of fluid in pleural space (normally up to 25mL)

Question 2

What is the aetiology of pleural effusions?

Answer 2

Disruption of normal equilibrium between pleural fluid formation/entry and pleural fluid absorption/exit.

Question 3

What are the major classifications of pleural effusions?

Answer 3

Transudative: usually bilateral.
Exudative: can be uni or bilateral.

Question 4

How can transudative and exudative effusions be distinguished clinically?

Answer 4

Light’s Criteria”

• Protein
• LDH
• Pleural LDH

Question 5

What is the pathophysiology of transudative pleural effusions?

Answer 5

Alteration of systemic factors that affect the formation and absorption of pleural fluid (e.g. increased capillary hydrostatic pressure, decreased plasma oncotic pressure).

Question 6

What is the aetiology of transudative pleural effusions?

Answer 6

• CHF
• Cirrhosis
• Nephrotic syndrome
• PE

Question 7

What is the pathophysiology of exudative pleural effusions?

Answer 7

Increased permeability of pleural capillaries or lymphatic dysfunction.

Question 8

What is the aetiology of exudative pleural effusions?

Answer 8

Infectious
Malignant
Inflammatory
Intra-abdominal
Intra thoracic
Trauma

Question 9

What are the infectious causes of exudative pleural effusions?

Answer 9

• Parapneumonic effusion: e.g. pneumonia, lung abscess.
• Empyema (bacterial, fungal, TB)
• TB pleuritis
• Viral infection

Question 10

What are the malignant causes of pleural effusions?

Answer 10

• Lung carcinoma
• Lymphoma
• Metastases: breast, ovary, kidney

Question 11

What are the inflammatory causes of exudative pleural effusions?

Answer 11

Collagen vascular disease (RA, SLE).
PE
Post CABGs
Drug reaction

Question 12

What are the traumatic causes of pleural effusion?

Answer 12

• Chylothorax: when thoracic duct disrupted and chyle accumulates in the pleural space (trauma, tumour)
• Haemothorax: rupture of blood vessel
• Pneumothorax

Question 13

What are the signs of pleural effusions?

Answer 13

• Dyspnoea
• Pleuritic chest pain
• Inspection: trachea deviates away from effusion, ipsilateral decreased expansion
• Percussion: decreased tactile fremitus, dullness
• Auscultation: decreased breath sounds, bronchial breathing, pleural friction rub.

Question 14

What investigations for pleural effusion?

Answer 14

• CXR: dense opacification of lung fields with concave meniscus
• Thoracocentesis: if pleural effusion new finding
• Pleural biopsy: if suspect TB, mesothelioma or malignancy.
• +/- Ultrasound