Pleural Effusion

Question 1

What is Pleural effusion? What can it be broadly categorized into?

Answer 1

Pleural effusion is a collection of fluid in the pleural space. It can be broadly categorized into:

• exudative- a high protein content
• transudative- a lower protein content

Question 2

What is Light’s criteria for establishing an exudative effusion using protein or lactate dehydrogenase (LDH)?

Answer 2

• Pleural fluid protein/serum protein greater than 0.5
• pleural fluid LDH/ serum LDH greater than 0.6
• Pleural fluid LDH greater than 2/3 of the normal upper limit of the serum LDH

Question 3

What are the exudative causes of pleural effusion?

Answer 3

Related to inflammation. The inflammation results in proteins leaking out of the tissues into the pleural space. The top causes of this occuring are- cancer (lung cancer or mesothelioma), Infection (pneumonia or TB), rheumatoid arthritis.

Question 4

What are the transudative causes of pleural effusion?

Answer 4

Related to fluid moving across or shifting into the pleural space. Can be caused due congestive cardiac failure, hypoalbuminaemia, hypothyroidism, meigs syndrome.

Question 5

What is Meigs syndrome?

Answer 5

Involves a triad of a benign ovarian tumor (usually a fibroma), pleural effusion and ascites. The pleural effusion and ascites resolve with the removal of the tumor.

Question 6

What are the typical presentations of pleural effusion and examination findings?

Answer 6

• SOB
• dullness to percussion over the effusion
• reduced breath sounds
• tracheal deviation away from the effusion in very large effusions.

Question 7

List the investigations you would do when you suspect pleural effusions, and what they would show.

Answer 7

1) Chest x-ray- blunting of the costophrenic angle, fluid in the lung fissures, larger effusions will have a meniscus, tracheal and mediastinal deviation away from the effusion in ery large effusions.

2) Ultrasound and CT- detect smaller effusions than a chest x-ray, estimate the volume and identify potential causes.

3) Pleural fluid analysis- requires a sample to be taken by aspiration or chest drain. This helps establish the underlying cause by measuring the protein content, LDH, cell count, pH, glucose and microbiology testing.

Question 8

Treatment for pleural effusions:

Answer 8

1) conservative management- may be appropriate for small effusions- will resolve with treatment of the underlying cause.

2) Pleural aspiration- involves sticking a needle through the chest wall into the effusion and aspirating the fluid. Aspiration can temporarily relieve the pressure, but the effusion may recur, and further drainage may be required.

3) Chest drain- can be used to drain the effusion and prevent it from recurring.

Question 9

What is empyema? When would you suspect it? How is empyema treated?

Answer 9

Refers to an infected pleural effusion. You would suspect empyema in a patient with improving pneumonia but a new or ongoing fever.

Chest drain and antibiotics.

Question 10

What would a pleural aspiration in empyema show?

Answer 10

• pus
• low pH
• low glucose
• high LDH