Pleural Effusion

Question 1

Define pleural effusion

Answer 1

Abnormal collection of fluid within the pleural space, rupturing into the lungs

Question 2

What is the difference between transudate and exudate?

Answer 2

Transudate: Protein <25g/l

Exudate: Protein >35g/l

Question 3

What are causes of transudate effusions?

Answer 3

Left ventricular failure/HF

Liver cirrhosis

Ascites

Hypoalbuminaemia

Hypothyroidism

Meig’s Syndrome

Peritoneal dialysis

Renal failure

Question 4

What is Meig’s syndrome?

Answer 4

Defined as the triad of benign ovarian tumor with ascites and pleural effusion that resolves after resection of the tumour

Question 5

What are causes of exudate effusions?

Answer 5

Malignancy

Pneumonia

TB

RA

SLE

Pancreatitis

Drugs

• Methotrexate

PE

Question 6

Describe the presentation of a pleural effusion

Answer 6

Asymptomatic if small and accumulates slowly

Dyspnoea: Fluid in pleural space, squashing the lung

Dry Cough: Receptors attempting to re-inflate lung

Pleuritic Chest Pain

• Sharp chest pain upon inspiration
• This is early and may improve as fluid accumulates if inflammatory, but worsens if malignancy

Dull Ache

Systemically Unwell

• Weight loss
• Malaise
• Pyrexia
• Night sweats

Decreased chest expansion on affected side

Stony dull percussion: Due to fluid

Clubbing

Trachea moved away from large effusion

Peripheral oedema

Bronchial breathing

Question 7

What investigations are used in pleural effusion diagnosis?

Answer 7

CXR

• To confirm presence of effusion
• At east 200ml required before detectable

CT

• Determines underlying cause/differentiates between malignant and benign

Pleural Aspiration

• Work out maximum area of dullness, give local anaesthetic and insert 50ml syringe to remove/drain fluid

Pleural Biopsy

• Biopsy immediately above a rib and never upwards due to risk of vessel rupture
• Carry out at least 4

Thoracoscopy

• If still no diagnosis, direct inspection of the pleura

Question 8

What is looked for in pleural aspiration?

Answer 8

Protein

Microscopy

Gram stain

Culture

Cytology

Glucose

Lactate dehydrogenase (LDH)

pH

Acid- and alcohol-fast bacilli (AAFB) culture ± amylase/triglycerides

Question 9

What is the management of a pleural effusion?

Answer 9

Treatment directed at cause

Aspiration:

• Insertion at 4th intercostal space, make a hole big enough for tube to slip in and drain fluid into underwater seal
• Palliative: Drain fluid by repeated pleural aspiration 1-1.5 litres at a time

Pleurodhesis:

• Sealing the pleural membranes together using sterile tac to cause inflammation

Question 10

Describe Light’s Criteria

Answer 10

For pleural protein 25–35 g/L; the fluid is an exudate if:

Pleural fluid protein divided by serum protein > 0.5

Pleural fluid LDH divided by serum LDH > 0.6

Pleural fluid LDH > two-thirds the upper limit of normal serum LDH.

Question 11

What is a Parapneumonic effusion?

Answer 11

Type of pleural effusion that arises as a result of a pneumonia, lung abscess, or bronchiectasis

Question 12

What is the management of parapneumonic effusions?

Answer 12

Antibiotics

Chest drain is necessary if

• Pleural fluid pH <7.2
• Pleural fluid glucose <2.2 mmol/L
• Pleural LDH >1000 IU/L
• Positive Gram stain/culture
• Gross pus is aspirated (this is an empyema)

If the infection fails to resolve, refer to cardiothoracic surgery

Question 13

What pathogens most commonly cause parapneumonic effusions?

Answer 13

Streptococcus

Haemophilus influenzae

Escherichia coli

Pseudomonas

Klebsiella

Question 14

What is the most common cause of an exudative pleural effusion?

Answer 14

Pneumonia

Question 15

Give complications of pleural effusion

Answer 15

Re-expansion pulmonary oedema

• Occurs if pleural effusion is drained too quickly