Empyema
Key points
Definition: Presence of purulent fluid in the pleural space
• Remains a significant clinical challenge
• Considerable morbidity and mortality.
• Early diagnosis and management favours outcome
Sources of infection
Lungs: Pneumonia, CPAM, tumour
Nearby tissues: mediastinitis, spinal infections, osteomyelitis of the ribs
Haematogenous
Direct introduction: Trauma, surgery
Other sources of effusion:
Lungs - Pneumonia,
Abdomen - Pancreatitis, appendicitis
Oesophagus - OA/TOF dilatation, oesophageal tear
External - Surgical site, stab wound
Surgical Causes of Empyema
• Blunt traumatic lung contusion and haemothorax
• Penetrating chest injury
• Post thoracotomy
• Oesophageal rupture (Foreign body, caustic ingestion, oesophageal atresia repair, balloon dilatation)
• Congenital lung lesions CPAM
• Pancreatitis, Appendicitis, Subdiaphragmatic abscess
• Carcinoma
Empyema most commonly secondary to parapneumonic effusion (PPE)
Stages:
1. Pre collection - inflammation of pleura
2. Exudative - 1-2 weeks - clear fluid
3. Fibrinopurulent 2-6 weeks
4. Organising 6 weeks - thick peel
Not strict timings or order of progression
Bacterial invasion into the pleura space triggers release of transforming growth factor B and platelet derived growth factor. Draws Fibroblasts into the pleural space causing deposition of collagen rich fibrin- onto the visceral pleura, parietal pleura and causes septations.
Streptococcus Pneumoniae most common organism
Anatomical Effects of empyema fibrin deposition
Lungs and fissures: Lung trapping
Chest wall: Restriction of chest wall movement
Pleural Cavity: Septations and loculations
History and Examination
As pneumonia + scoliosis + rib crowding
May have ileus
Investigations
Chest X ray is difficult to distinguish between empyema and lung consolidation
Ultrasound is a better modality to differentiate between them
Contrast CT - when underlying tumour/condition/bronchopleural fistula is suspected
Small studies showed CT had no benefit over USS
Reasons for requesting Contrast CT:
To determine the underlying lung condition
To determine significant bronchopleural fistula
To rule out lung abscess
To rule out underlying tumour
Light criteria for pleural fluid
Exudate:
Fluid/Serum protein ratio >0.5
Fluid/Serum LDH ratio >0.6
Fluid LDH >2/3 upper limit of normal serum LDH
Porcel and Light classification
Complex effusion (class 4-5)
pH <7, glucose <40, culture positive
pH <7.1 highly prognostic for surgical intervention and severity
A malignant effusion will generally have elevated LDH, low pH, low glucose
Atypical or abnormal WBCs - however, cytology in most pleural effusions for malignancy is negative, and the yield is very low
Management
British thoracic society guidelines 2022:
Initial therapy should be insertion of a chest drain (<14Fr as larger sizes increase pain and have no benefit)
Tissue plasminogen activator plus DNAse is the fibrinolytic therapy of choice
In paediatric practice, a PICC line is usually inserted at the same time as the chest drain
6 doses of Urokinase are usually given as intra-pleural fibrinolytic therapy (similar efficacy to tPA and DNAse)
If the patient is not responding adequately to treatment - a CT should be performed and consideration of video-assisted thoracoscopy (VATS) debridement and drainage
If the empyema has been present for several weeks and there is thick pus and peel, then a thoracotomy can be considered
Lung necrosis should be treated with caution as iatrogenic injury can lead to severe haemorrhage
Principles of empyema surgery
To break down all the loculations and evacuate the pus (to remove source of infection)
To Remove fibrous tissue from lung surfaces AND fissures (lung expansion)
To Remove fibrous tissue from inner chest wall (chest wall expansion)
For broncho-pleural fistula:
Serratus Anterior Flap
Latissimus dorsi flap
Intercostal muscle flap
Pericardial flap
After surgery, usually two chest drains
Anterior at the Apex to drain the Air
Back (posterior) at the Base to drain fluid
Possible indications for suction:
Prolonged air leak
Prolonged unexpanded lungs in chronic empyema
After surgery helps both pleura to come together
Acute complications
Sepsis
Septic shock
Respiratory failure
Cardiovascular complications
Broncho-pleural fistula
Empyema necessitans
Chronic complications
Recalcitrant empyema
Recurrent empyema
Pleural fibrosis
Chest wall fibrosis
Page edited by Prof. Ashok Daya Ram MBBS, FRCS, FRCPS, FEBPS, FRCS (Paed Surgery), Consultant Paediatric and Neonatal Surgeon, Norfolk and Norwich University Hospital, Norwich, UK. March 2025
Page edited by Mrs Charnjit Seehra BSc March 2025
References
Iguina MM, Danckers M. Thoracic Empyema. [Updated 2023 Jul 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK544279/
Light RW, Macgregor MI, Luchsinger PC, Ball WC Jr. Pleural effusions: the diagnostic separation of transudates and exudates. Ann Intern Med1972;77:507-13
Rodríguez Suárez P, Freixinet Gilart J, Hernández Pérez JM, Hussein Serhal M, López Artalejo A. Treatment of complicated parapneumonic pleural effusion and pleural parapneumonic empyema. Med Sci Monit. 2012 Jul;18(7):CR443-9. doi: 10.12659/msm.883212. PMID: 22739734; PMCID: PMC3560768.
Roberts ME, Rahman NM, Maskell NA On behalf of the BTS Pleural Guideline Development Group, et al
British Thoracic Society Guideline for pleural disease
Thorax 2023;78:s1-s42