UNILATERAL PLEURAL EFFUSION

Question 1

What is a pleural effusion?

Answer 1

Excess fluid in the pleural cavity.

Question 2

What is it categorised by?

Answer 2

Divided by their protein concentration: transudates (<25g/L) and exudates (>35g/L)

Question 3

What is a heamothorax?

Answer 3

blood in the pleural cavity – usually due to trauma

Question 4

What is a Haemopneumothorax?

Answer 4

blood and air in the pleural cavity

Question 5

What is an Empyema/pyothorax ?

Answer 5

pus in the pleural cavity – usually due to pneumonia

Question 6

What is a Chylothorax?

Answer 6

chyle (lymph and fat) in the pleural cavity – usually caused by rupture of the thoracic duct

Question 7

Aetiology of transudates

Answer 7

• May be due to increased venous pressure (HF, constrictive pericarditis, fluid overload)
• Or hypoproteinaemia (liver failure, cirrhosis, malabsorption, nephrotic syndrome)
• Hyperthyroidism
• Meig’s syndrome (right pleural effusion and ovarian fibroma)

Question 8

Aetiology of exudates

Answer 8

• Mostly due to increased ‘leakiness’ of pleural capillaries secondary to infection, inflammation, malignancy
Due to pneumonia, TB, pulmonary infarction, RA, SLE, lymphoma, lung Cancer

Question 9

Symptoms

Answer 9

• Asymptomatic – effusion has to be quite large to cause symptoms; approx >500ml
• Dyspnoea
• Pleuritic chest pain

Question 10

Signs

Answer 10

• Decreased chest expansion
• Stony dull to percussion
• Diminished breath sounds
• Tactile vocal fremitus and vocal resonance decreased
• Tracheal deviation away from effusion – in large effusions; if associated lung collapse then deviated towards
• Mediastinal shift – suggests effusion >1L
• Bronchial breathing – where lung is compressed above effusion
• Signs of associated disease
• Above the effusion, the lung is compressed – may be bronchial breathing
• Look for aspiration marks and signs associated disease (Cachexia, clubbing, lymphadenopathy, radiation marks, mastectomy scars – malignancy; signs cardiac failure, RA, SLE (butterfly rash))

Question 11

What are the investigations?

Answer 11

CXR
USS
Diagnostic aspiration
Pleural biopsy

Question 12

What would expect a CXR to show?

Answer 12

• Small effusions blunt the costophrenic and costocardiac angles
• Larger effusions are seen as water-dense shadows with concave upper borders (a meniscus); a completely horizontal upper border = pneumothorax as well!

Question 13

Why do we do a USS?

Answer 13

useful in guiding diagnostic or therapeutic aspiration

Question 14

What is a diagnostic aspiration?

Answer 14

• Percuss upper border of effusion and go 1-2 intercostal spaces below it
• Local anaesthetic
• Insert needle just above rib (to avoid neurovascular bundle) and aspirate 10-30ml
• Send to lab for clinical chemistry, bacteriology, cytology and immunology if indicated
• Transudate = protein <30, exudate = protein >30
• Light’s criteria – more accurate diagnosis of transudate and exudate; compares blood protein vs fluid protein as some things like diuretics can affect protein content
• Empyema = pH <7.2 (acidotic), can sometimes also look like pus

Question 15

What is LIGHTS criteria?

Answer 15

Satisfying any ONE criterium means it is exudative):
Pleural Total Protein/ Serum Total Protein > 0.5
Pleural LDH/ Serum LDH > 0.6
Pleural LDH > 2/3s of the upper limit of normal for serum LDH

Question 16

When would you do a pleural biopsy?

Answer 16

if pleural fluid analysis still inconclusive; thoracoscopic or CT-guided biopsy with Abram’s needle

Question 17

What is the management/treatment?

Answer 17

Treat underlying cause, drainage and pleurodesis

Question 18

What is the only treatment for transudate?

Answer 18

Treat underlying cause

Question 19

Why do you drain?

Answer 19

if symptomatic; best remove fluid slowly (<2L/24hrs); either via pleural tap or intercostal drain. Fluid is best removed slowly (<2L/24hr). Aspirate via IC drain or in same way as diagnostic tap

Question 20

When do you do pleurodesis?

Answer 20

• if recurrent effusions with tetracycline, bleomycin or talc – may be helpful for recurrent effusions
  Chemical injected into pleural space and causes inflammation of the membranes, helping them to stick together

Question 21

Differential diagnosis?

Answer 21

Pneumothorax – hyperresonant to percussion; black on CXR; different underlying pathology

Question 22

Prognosis

Answer 22

If cause is malignancy, the outlook is generally poor