Pleural effusion

Question 1

Define pleural effusion

Answer 1

Abnormal accumulation of fluid in the pleural space
Due to increased pleural fluid production or decreased pleural fluid drainage or combination of both

Question 2

Describe the basic physiology that contributes to pleural fluid regulation

Answer 2

Fluid is drained out through the lymphatics - commonly through parietal pleura
Fluid is produced from nearby capillaries including pulmonary capillaries through visceral pleura and systemic capillaries through parietal pleura.

Question 3

What factors can contribute to increased pleural fluid formation?

Answer 3

1. Dec plasma oncotic pressure (hypoproteinaemia - liver cirrhosis, nephrotic syndrome)
2. Inflammation in vascular permeability - pneumonia
3. Increased venous pressure - PE, HF,
4. Decreased pleural pressure - lobar collapse

Question 4

What factors can contribute to decreased pleural fluid drainage?

Answer 4

1. Compression of the lymphatic vessel or occlusion of stoma - malignancy or granuloma
2. Inc venous pressure in venous angles - HF
3. Dec contraction of resp muscles (dec lymph drainage) - opioid overdose etc.

Question 5

What is the basic different between a transudate and an exudate?

Answer 5

Transudate: systemic conditions that alter pressure in blood vessels resulting in fluid accumulation ‘failures’ HF, LF, NS etc

Exudate: leakage due to local inflammation or injury such as cancer or infection causing localised changes in blood vessels. Infection, malignancy, PE

Question 6

What are the key investigations for a pleural effusion?

Answer 6

Bloods: LFTs (protein), U&E, + urine dip (nephrotic syndrome), FBC,
Bedside: ultrasound and thoracocentesis, Obs, resp examination
Imaging: CXR (meniscal sign and blutning of costophrenic angles), high contrast CT (identify underlying cause)

Question 7

What are the key symptoms of a pleural effusion?

Answer 7

SOB
Chest pain
Cough

Question 8

What are the key signs of a pleural effusion on examination?

Answer 8

Dec chest expansion
Dec vocal fremitus
Dec air entry
Dullness on percussion

Question 9

What is the golden standard investigation in diagnosis of a pleural effusion?

Answer 9

Ultrasound and thoracocentesis
Consider pleural fluid appearance, LDH, protein levels
This is also treatment for pleural effusion

Question 10

What criteria is used to differentiate between an exudate and transudate fluid on thoracocentesis?
(pleural effusion diagnosis)

Answer 10

Lights criteria
General: >30g/L protein is a exudate
However if within 25-25g also consider
Exudate:
Pleural: systemic protein >0.5
Pleural:systemic LDH >0.6
P LDH >2/3 lab systemic norm

Question 11

When might a chest drain be required for a pleural effusion?

Answer 11

If pleural fluid is turgid/purlent
If pleural fluid is cloudy but an infection is suspected and pH is below 7.2

Question 12

What management can be used for a pleural effusion?

Answer 12

Identify and treat the underlying cause
Thoracocentesis
Chest drain
Pleurodesis - if recurrent
Pleurectomy - if recurrent
Indwelling pleural catheter
Drug management to alleviate symptoms - opioids for SOB

Question 13

What are the relevant risk factors for a pleural effusion?

Answer 13

Failure conditions for transudate: HF, liver cirrhosis, neprhotic syndrome
Trauma to the chest
Infection/inflammation to the pleura - pneumonia, malignancy
Autoimmune conditions - RA, SLE (exudate)
Medical procedure to the chest with local trauma - chest drain, biopsy, mechanical ventilation.