Felicity Meikle, FRACS Waikato Cardiothoracic Unit EMPYEMA Felicity Meikle, FRACS Waikato Cardiothoracic Unit

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

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

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

Empyema thoracis 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

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

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

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

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

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

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

bloods Leukocytosis Left shift of neutrophils CRP Blood cultures Sputum culture

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

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

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)

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

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

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

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

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

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)

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

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

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

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

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

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)

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

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

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

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

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

Alexander Thoracoplasty

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

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

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

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

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

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.