EMPYEMA

1. EMPYEMA Felicity Meikle, FRACS Waikato Cardiothoracic Unit

2. Pleura • Serous membrane • Pleural cavity is potential space between visceral and parietal pleura • Normally contains a small amount of fluid • Parietal pleura very sensitive to pain • Improves respiration and transmission of forces to lungs • Humans have separate pleural cavities

3. Pleural fluid • Serous fluid • Produced by parietal pleura • Reabsorbed by lymphatic system • Continuously produced and reabsorbed • Reabsorption rate will increase up to 40 times the normal rate before significant fluid is seen

4. Parapneumonic effusion • Bacterial pneumonia associated with pleural effusion (35-40% of hospitalized pneumonia) • Pneumococcal – 60% effusion rate • Uncomplicated – negative gram stain, no loculations, resolve spontaneously • Complicated (20%) – empyema or loculated effusions, require drainage • Low ph <7.2, high LDH >1000 suggests complicated effusion

5. Empyemathoracis • Purulent pleural effusion • Oldest surgical diseases • Hippocrates 400 BC • Predominantly parapneumonic • Pulmonary abscess, suppurative pneumonia Underlying conditions • Age • Alcoholism, IVDU • Chronic pulmonary disease, - TB, bronchiectasis • DM, RA • Immunosuppression - steroids, malignancy • Debilitation, malnutrition • Poor oral hygiene • GORD/aspiration

6. Other causes - trauma Penetrating injury • 1.6% incidence • Organic foreign bodies being carried into pleural space Haemothorax • Haemopneumothorax more likely to become infected • Secondary infection from chest tube – highlights importance of strict asepsis

7. Other causes - surgery • 2-4% risk after pulmonary resection Improved with: • Surgical technique • Patient selection

8. Other causes • Rupture of oesophagus • Infection from posterior region of the neck • Chest wall infections • Thoracic spine • Subphrenic infections – tend to be reactive • Haematogenous spread in immunocompromised patient

9. Bacteriology • Pre antibiotics era – pneumococci 64%, S. pneumoniae (Ehler 1941) • Greater lung destruction more abscess formation Recently – • No inoculate found in 80% • Streptococcus species 30% – S pneumoniae/pyogenes/milleri • Staph aureus ~34% - post op/trauma • Gram -ve – klebsiella, pseudomonas, haemophilus • Anaerobes 35% - bacteroides, peptostreptococcus • Complex inoculates – aspiration pneumonia

10. Stages • 3 stages over 3-6 week period • Stage 1: Exudative: 2-5 days - pleural membranes swell and discharge thin exudate, neutrophils present, no organisms • Increased capillary permeability • Stage 2: Fibrinopurulent: 5-10 days - heavy deposition of fibrin, pleural fluid turbid, loculations, no organisms • Bacterial infection • Stage 3: Organising: within 3-4 weeks over 2-3 weeks – thick viscous fluid, thick fibrous peel forms, lung becomes trapped

11. Diagnosis • Suspect empyema in patients with acute respiratory tract illness and pleural effusion • Persistent fever following AB therapy Symptoms • Dyspnoea - 82% • Fever - 81% • Cough - 70% • Pleuritic pain 67% • Tachypnoea, Tachycardiac • Malaise, anorexia, weight-loss • Signs – reduced chest wall movement, breath sounds and dullness

12. bloods • Leukocytosis • Left shift of neutrophils • CRP • Blood cultures • Sputum culture

13. Radiology • CXR – pleural effusion (pneumonia/lung abscess) • Lateral film – posterolateral collection “pregnant lady sign” – inverted D shape • Decubitus views to assess fluidity of collection • USS – differentiate between consolidated lung and fluid and guide drainage Uncomplicated – simple effusion Complicated – stranding, loculations Empyema – echogenic, septations

14. CT scan Gold standard • Visualisation of thickened and separated pleural surfaces • Compression of lung parenchyma • Pleural thickening

15. Pleural fluid • Clear – uncomplicated • Turbid – complicated • Purulent - established empyema Increased leukocyte activity and increased acid production within pleural space leads to reduced pH and increased LDH • pH<7.2, LDH >1000u/l, glucose <3.4mmol/L, WCC >50000cells/uL • Effusions with high pH can be managed with antibiotics and repeat thoracocentesis (Sahn 1989) • If pH low then effusion requires drainage with chest tube or surgery (VATS)

16. Empyema complications • Lung fibrosis • Contraction of chest wall • Empyema necessitans • Bronchopleural fistula • Sepsis • Distant abscess formation • Osteomyelitis • Mediastinitis • Pyopericardium • Trans-diaphragmatic drainage • Death 5-20% – elderly, comorbidities

17. Management Acute empyema (stage 1 and 2) • Antibiotics and fluid drainage • Repeat thoracocentesis if toxicity is well controlled • Controversial – only useful if implemented early enough • May develop multiloculated collections that are difficult to drain • VATS drainage may improve survival and shorten hospital stay (Ferguson1990) • Uniloculation of space • Washout of space • Better drain placement

18. ACCP Guidelines • Uncomplicated effusion: <10mm on CXR • Antibiotics • Uncomplicated effusion: >10mm, pH>7.2, gluc>3.4 • Antibiotics • Thoracocentesis or Intercostal drain insertion if large symptomatic effusion • Complicated effusion: large/loculated effusion pH<7.2, gluc<3.4 • Antibiotics • Thoracocentesis/drainage • Intrapleural fibrinolysis • Early surgical intervention • Empyema: pus • Antibiotics • Drainage/fibrinolysis • Surgical decortication

19. Antibiotic therapy • Guided by local antibiotic resistance patterns and policies • Common causative organisms • CAP/HAP/VAP • Severity of illness • CAP • Penicillin, co-amoxiclav, clindamycin • Cephalosporins • Metronidazole • HAP • Consider MRSA • Ideally should be continued for 2-4 weeks

20. Methods of drainage Tube thoracostomy (28-36fr) • beware of the retracted diaphragm • can revert to open system by cutting tube Pigtail catheter • Often block • Less useful when fluid thick • 70-90% success rate when used early

21. VATS • Shown to have reasonable success rate (18/18) in early empyema (Wakabayashi 1991) Benefits • Direct vision • Break down all loculations and evacuate pus • Remove fibrinous membranes • Irrigate pleural cavity • Lung re-expansion • Direct drains appropriately • Mortality 0-3% in larger studies with success rate 80-97% in stages 2-3 (Luh 2005, Wurnig 2006, Solaini 2007)

23. Streptokinase? • Fibrinolytic • Used since 1949 • Initial problems with bleeding and allergy Davies 1997 • RCT streptokinase vs saline flushes for 3 days • 24 patients • Increased fluid drainage, greater radiographic improvement Wait 1997 • Compared VATS and fibrinolytic therapy • VATS improved efficacy, shorter hospital stay and lower cost

24. MIST (management of intrapleural sepsis trial) 2005, 2011 I 454 patients streptokinase 250000u BD for 3 days vs placebo – no benefit • Primary end point: Death&surgery = 31% SK vs 27% placebo p0.43 • Increased serious adverse events 7% vs 3% p0.08 • No increased risk of bleeding during surgery II double blind/ double dummy 193 patients DNase 5mg, t-PA 10mg BD for 3 days • Primary end point reduction in effusion size – tPA/DNase better than placebo or with tPA or DNase alone • Referral for surgery lower in tPA/DNase group than placebo. 4%vs 16% p0.03 • Reduced hospital stay in tPA/DNase group than placebo 11.8 vs 17days p0.006 • Mortality rates similar 4%(placebo)/8%(t-PA&DNase)/8%(t-PA)/13%(DNase) p0.46 • Pleural thickening increases risk of failure of fibrinolytic therapy

25. Other care • Treatment of underlying respiratory disease • Nutrition • Chest physio • Promote lung re-expansion • Prevent chest wall collapse

26. Chronic empyema • Delay in diagnosis • Improper drainage • Inadequate antibiotic therapy • Continued reinfection • Foreign body • Tb • Fungal infection

27. Simple treatment • Eloesser flap • Window thoracostomy and rib resection • Minor procedure (under GA) • Debilitated patients • Small spaces • BPF with fixed space • Long recovery period

28. Space sterilisation Drain space Claggett procedure • Irrigation with antiseptics and/or antibiotic solution (Modified) • Useful in post pneumonectomy empyema (if no bronchopleural fistula) • Irrigate window thoracostomy (Classic)

29. Space filling procedures • Ideally fill space with lung • Decortication “is seldom required because most patients with parapneumonic effusions are treated before this stage” • Removal of constricting peel over lung • Empyemectomy – removal of visceral and parietal pleura with contents of empyema intact – not generally necessary

30. Decortication • Timing controversial • 3 months – maximal functional respiratory recovery • Early – less bloody, not as adherent to lung • Performed before fibrosis extends into lung tissue – less chance of lung injury • May need to remove lung tissue at same time

31. Other options? Pleural plombage • 1930-1950 • Air • Olive oil • Mineral oil • Parafin wax • Rubber sheets/balls • Lucite balls (PMMA) • Glass balls used initially • Complications – infection, haemorrhage, fistulisation • Therefore not an option for pleural infection

32. Muscle transposition • Obliterating the space with viable tissue • Reinforcement of stump (bronchopleural fistula) • Type of muscle flap taken depends on size and shape and location of cavity • Lat dorsi/serratus/pectoralis/intercostal • Omentum • Take care to preserve blood supply, bulk and innervation

33. Thoracoplasty • Rib resection to collapse infected space 1st described in 1879 (Estlander) • Alexander redefined this to a posterior extramusculoperiosteal approach • Used for Tb predominantly • Felt to be mutilating • Some usefulness in post resectional empyema

34. Alexander Thoracoplasty

35. Surgical considerations • Infection must be treated • Drain • Tube/Open window thoracostomy • Extent of thoracoplasty • Apical – extrapleural lysis to allow apex to collapse • Disarticulate posterior rib ends • Resection of scapula tip if entrapment occurs • Used in conjunction with muscle flap/omental transfer • Thoracopleuroplasty (Andrews thoracoplasty) • Useful for post pneumonectomy empyema

36. Post pneumonectomy empyema • Uncommon • Life threatening • Treatment depends on timing and extent of BPF • Degree of pleural contamination • General condition of the patient • Control infection • (Close fistula) • Sterilise closed pleural space

37. Bronchopleural fistula 4.5-20% following pneumonectomy 0.5% following lobectomy Etiology • Endobronchial Tb, contamination of pleural space during procedure • Devascularisation of bronchus • Right sided resection • Previous radiotherapy • Long bronchial stump • Concomitant illness – DM, steroids, cirrhosis • Infection • Residual tumour at bronchus • Post pneumonectomy ventilation

38. Symptoms • Coughing up serosanguinous fluid or pus • Fever • Malaise • General unwellness (“flu like illness”) • CXR – new air fluid level, sudden disappearance of pleural effusion or mediastinal shift

39. Emergency management of Post pneumonectomy BPF • Prevent soiling of remaining lung • Nurse with resected side down, • Selectively intubate remaining lung • Bronchoscopy • Closure of fistula/buttress stump • If infected drain space • Open/closed

40. Conclusion • Complicated pneumonia is common. • Mortality continues to improve as techniques for dealing with empyema and antibiotic therapy improves 50% -> 5-20% • Ongoing battle with physicians who don’t want to traumatise patients with large bore drains and so inappropriately rely on pigtail drainage • Appropriate timing of surgery is key to optimal outcome and avoidance of complications or disfiguring surgery. (Argumentative!) • May be a place for fibrinolysis in comorbid/inoperable patients • Thoracoplasty reserved for end of the line treatment for patients who can tolerate this procedure • Beware the post Pneumonectomy Empyema – can be subtle.