Pleural Effusion

Question 1

What are the causes of a pleural effusion?

Answer 1

Transudate:
Common: CCF, hypoproteinaemia, CKD
Rarer: Hypothyroidism, Obstructive (SVC) pericarditis

Can also cause pulmonary oedema.

Exudate:
Infective 
Lung Ca
Rheumatoid arthiritis
Asbestosis
Pancreatitis

Question 2

Describe the clinical features of a pleura effusion?

Answer 2

Presence of excess fluid in the pleural space.

Symptoms:
Dysopnea
Pleuritic Pain
Cough

Features which link to causes:
Infection: febrile?
Malignancy: wt loss
PMH: CCF, liver, kidneys
SH: (asbestos exposure)

O/e:
Dull percussion
V.quite or absent breath sounds
Reduced vocal resonance.

Question 3

What is an empyema, what are the clinical features?

Answer 3

An empyema is the presence of pus in the pleura space.
It may be a complication of bacterial LRTI or Tb.

An empyema should be suspected in the same way as an abscess – if a patient stays pyrexial despite treatment.

Symptoms include: fever, rigors, malaise + pleural effusion symptoms (dysopnea, pleuritic pain, cough).

Question 4

Discuss the investigations of a unilateral pleural effusion and the indications for performing a pleural tap and biopsy?

Answer 4

Is the cause likely to be a transudate?
YES treat the cause if not better proceed, however in transudate it is much more likely for the pleural effusions to be bilateral.

Take a pleural aspiration/tap. 
Send aspirated fluid for:
-cytology
-protein
-lactate dehydrogenase (LDH)
-gram stain, culture and sensitivity
-acid-alcohol fast bacilli  stains and culture.

Look for a malignancy:

• CT chest/abdo/pelvis
• Pleural biopsy
• Bronchoscopy

Question 5

What are the criteria used to differentiate a transudate and an exudate?

Answer 5

Protein content greater than 30g/l

OR

Lights Criteria: one of the following

• Pleural fluid protein divided by serum protein >0.5.
• Pleural fluid LDH divided by serum LDH >0.6.
• Pleural fluid LDH more than two thirds the upper limits of normal serum LDH.

Question 6

How should pleural effusions be managed?

Answer 6

Treat the underlying cause:
If it is a transudate then aspiration should be avoided .

Small effusions which are not causing respiratory distress can just be observed.

Pleural tapping can be useful for diagnostics and can provide some symptomatic relief but are likely to reform.

A chest drain can be used for controlled drainage.

In malignant effusions they are likely to reoccur after drainage, so pleurodesis can be used (involves an injection of a sclerosant which causes adhesion of the parietal and visceral pleura).

Question 7

How are empyemas managed?

Answer 7

Infection will not clear unless there is drainage therefore it needs drainage either with:

• percutaneous thoracentesis
• chest drain

Followed with antibiotic treatment