Empyema

Question 1

What is the management of a small pleural effusion?

Answer 1

if small and causes no respiratory distress, can be managed conservatively without need for aspirating a sample

Question 2

What are 4 indications for obtaining a fluid sample of pleural effusion/empyema?

Answer 2

1. Large effusion
2. Significant hypoxia/ respiratory distress
3. No clear underlying diagnosis
4. Persistent fever despite antibiotic treatment

Question 3

What are the 3 aspects of management of a pleural effusion when fluid aspiration/sampling is indicated?

Answer 3

1. Ultrasound scan of the chest
2. Check blood clotting studies (prior to drain insertion)
3. Small chest drain (or pigtail drain) should be inserted into the pleural space

Question 4

What are 2 groups of things that samples should be sent for when obtaining a fluid sample from a pleural effusion?

Answer 4

1. Microbiology: bacterial culture and sensitivity, acid fast bacilli
2. Cytology: presence of pus cells and microscopic assessment of aberrant cell types

Question 5

What are 2 types of microbiological tests to perform on an effusion sample?

Answer 5

1. Bacterial culture and sensitivity
2. Acid-fast bacilli (for TB)

Question 6

What are 2 aspects of cytological tests performed on pleural effusion samples?

Answer 6

1. Presence of pus cells
2. Microscopic assessment of aberrent cell types

Question 7

In what proportion of cases may cytology for lymphoma in pleural effusion samples give false negative results?

Answer 7

up to 10% of cases

Question 8

What are the 2 key aspects that a diagnosis of empyema is based upon?

Answer 8

1. The fluid sample: pH <7.2, glucose <3.3 mmol/L, protein >3g/L, pus cells
2. USS: loculation or fibrin strands seen

Question 9

What are the 4 criteria for the fluid aspirate to be considered an empyema?

Answer 9

1. pH <7.2
2. glucose < 3.3 mmol/L
3. Protein >3g/L
4. Pus cells

Question 10

What are 2 features on ultrasound suggestive of empyema?

Answer 10

1. Loculation or fibrin strands seen

Question 11

What should be done after inserting a small-bore drain or pigtail catheter, in order to allow fluid drainage from the pleural cavity?

Answer 11

allow fluid to drain into a standard commercially available system e.g. underwater seal system

Question 12

At what point can a chest drain for pleural effusion be removed?

Answer 12

if draining <50ml in 24 hours

Question 13

How does removal of empyema differ from a simple pleural effusion?

Answer 13

need to instil urokinase via the chest drain, then use suction

Question 14

What dose of urokinase may be given to help remove an empyema?

Answer 14

40 000U urokinase in 40ml (10 000 U in 10ml if <1y) given 12 hourly for 3 days

Question 15

What is the method when giving urokinase to help drainage of an empyema?

Answer 15

instil the urokinase via the chest drain then clamp the drain and encourage the patient ot move and roll around over the next 4 hours

Question 16

How does suction following urokinase administration for empyema drainage work?

Answer 16

use a low-pressure suction device e.g. Robert’s pump to maintain suction of 20cm H₂O bewteen doses

Question 17

What can help control pain when managing empyema with urokinase and suction?

Answer 17

local anaesthetic: bupivacaine aronud drain site for pleural pain

consult pain control team

Question 18

At what point should you get a surgical referral for removal of effusion or empyema?

Answer 18

if it fails to resolve over a period of 7 days

Question 19

What can help identify loculated areas/ abscess formation in pleural effusion/empyema?

Answer 19

chest CT

Question 20

What are 2 possible intervention options for empyema or effusion that has not resolved after 7 days?

Answer 20

1. Definitive surgical procedure
2. Large bore drain and manual disruption of loculation

Question 21

What is the definition of empyema?

Answer 21

presence of frank pus in the pleural space

Question 22

What is the mortality of empyema?

Answer 22

15-20%

Question 23

What is the aetiology of how empyema arise?

Answer 23

• initially inflammation of the pleural space leads to a simple parapneumonic effusion which mostly resolves with antibiotics
• however approx. 10% become infected and hence form a complicated parapneumonic effusion
• if a complicated parapneumonic effusion is untreated, an empyema may form

Question 24

What are 3 bacteria which commonly cause empyema following community acquired pneumonia?

Answer 24

1. Streptococcus milleri group
2. Streptococcus pneumoniae
3. Staphylococci

Question 25

Which type of bacteria commonly cause empyema following hospital acquired pneumonia?

Answer 25

staphylococci

Question 26

What are 5 risk factors for empyema development?

Answer 26

1. Pneumonia
2. Iatrogenic intervention in pleural space e.g. thoracic surgery, chest drain insertion, thoracenteesis
3. Immunocompromised
4. Diabetes mellitus
5. Risk factors for aspiration - stroke, NG/ET tube, drug addition, alcohol abuse

Question 27

What are 7 clinical features of empyema?

Answer 27

1. Presence of risk factors: immunocompromise, lung disease, iatrogenic interventions in pleural space
2. Recent pneumonia
3. Constitutional symptoms
4. Pyrexia and rigors
5. Dullness to percussion
6. Reduced breath sounds and reduced vocal resonance
7. Signs of sepsis: pyrexia, tachypnoea, tachycardia, hypotension

Question 28

What are 6 key investigations to perform in empyema?

Answer 28

1. Blood cultures (before abx if clinical state permits)
2. CRP
3. WCC
4. CXR
5. Thoracetesis - cytology and microbiology
6. Thoracic ultrasound

Question 29

What type of CXR is more sensitive for detecting an effusion and what has this been superseded by?

Answer 29

• lateral decubitus more sensitive than PA for detecting an effusion
• superseded by thoracic ultrasound

Question 30

What are 2 features of empyema on CXR?

Answer 30

1. Loculated effusion - pleurally based, D-shaped appearance (can be mistaken for lung mass)
2. may be associated pulmonary consolidation due to pneumonia

Question 31

What are 4 aspects of the management of empyema?

Answer 31

1. urgently insert a chest drain (urokinase?)
2. empirical IV antibiotics
3. intrapleural fibrinolytics
4. video-assisted thoracoscopic surgery (VATS) - second line management