Empyema

Key points

Introduction

These guidelines may not be appropriate for neonates, the immunocompromised child or a child with chronic lung disease (e.g. cystic fibrosis, bronchiectasis, neonatal chronic lung disease). See also complications section of the pneumonia guideline.

• Empyema refers to the presence of pus within the pleural space, most often in association with an underlying pneumonia.

• Compared with community acquired pneumonia, empyema is associated with higher morbidity, longer hospitalisation, longer duration of antibiotic therapy and often requires invasive intervention.

• New Zealand has a comparatively high incidence of empyema at 5.6 per 100,000, with Māori and Pasifika children disproportionally affected. Clinicians should have a high level of suspicion for empyema amongst Māori and Pacific children with pneumonia.

Children with empyema will have a clearly nominated care team throughout their admission according to the Starship Responsibility of Care Guideline.

Admitting team

• Most children will be admitted under General Paediatrics.

• Respiratory consultation is appropriate in children:-

  • with known or suspected relevant underlying lung disease (e.g. Bronchiectasis)

  • relevant significant co-morbidity (e.g. primary immunodeficiency)

  • who don't make anticipated clinical progress.

  • Referral may also be appropriate in those with particularly severe empyema/pneumonia

Surgical team

Cases requiring surgical intervention will be referred to Paediatric Surgery via the on-call paediatric surgical registrar. At the point they are accepted for surgery, their care will be transferred to the surgical service (usually Ward 24b) until the last drain is removed, at which time they will be passed back to the appropriate medical team. While the patient is under the surgical service, the medical team(s) will continue to provide medical input if required.

Patients referred from out of region

The service that patients are referred to, from other hospitals will depend on their clinical setting - if the request is for surgical intervention then the referral may be directly to the surgical team who will involve a medical team as appropriate. Often care will shift directly back to the out of region medical team once drains have been removed.

Algorithm

Clinical features

• Children with empyema present in a similar fashion to those with pneumonia but may be more unwell than expected and/or prefer to lie on the affected side. Pleuritic chest pain is seen more frequently in adults.

• Pleural effusion is suggested on examination by unilaterally decreased breath sounds and chest expansion, dullness to percussion and scoliosis. It may evolve after treatment for pneumonia has commenced and should be suspected in any child with persistent fever or failure to improve.

• Non-purulent parapneumonic effusions (PPE) may represent the first stage of a developing empyema but can also be present without progression to empyema. PPE are an important differential diagnosis and require less active management. They can be differentiated based on clinical severity, imaging or microscopy of fluid.

Risk factors are as for pneumonia (see Pneumonia Guideline).

Children suspected of parapneumonic effusion or those with pneumonia who have persistent (>48hr) fever on IV antibiotics should have a chest x-ray.

Children with apparent non-infective pleural effusions (eg malignancy) require different investigations / management and should be discussed with the respiratory service

Causative organisms

Investigations

• Standard baseline investigations should include FBC and electrolytes (risk of SIADH, possibility of haemolytic uraemic syndrome complicating severe pneumococcal disease).

• Coagulation should be checked and corrected prior to surgical interventions

• Blood culture

Radiology

In discussion with clinical team’s SMO and radiologist, chest ultrasound may be appropriate.

Routine thoracocentesis (pleural taps) and bronchoscopy are not recommended for empyema. Computer tomography (CT) is also not routine but may be appropriate in certain circumstances, after discussion with radiologist.

Subsequent investigations

• Pleural fluid (if drained): microscopy, culture & sensitivities, and Streptoccocus pneumoniae antigen test (consider PCR if culture/antigen negative)

• Cytology and other cultures i.e. (mycobacterial culture) in selected cases

Management

• Intravenous antibiotics

• Supportive care

Further management will depend on the size of effusion, response to antibiotics and degree of respiratory compromise.

Antibiotics

• Cover for less common or multi-resistant organisms (including MRSA) should be considered depending on the child's history and subsequent clinical progress Early consultation with Infectious Diseases service is advised

• Additional empiric MRSA antibiotic (clindamycin or vancomycin) for severe pneumonia/empyema may be considered in the child who is very unwell (eg requiring PICU admission) or has positive blood cultures indicating Staphylococcus species (pending sensitivity)

• For antibiotics in severe sepsis or suspected concurrent meningitis (particularly infants) please see relevant guidelines.

Consider inserting a PICC line early in treatment if a long course is expected.

Culture or antigen/PCR detection from sterile sites can enable antibiotics to be rationalised to target specific organisms. e.g. Penicillin/ amoxicillin for S. pneumoniae, Flucloxacillin for susceptible S. aureus.

IV-Oral switch

Children may be switched to oral antibiotics when they have:

• had any drains removed,

• been afebrile for ≥*48 hours, AND

• are making good clinical progress ('well' looking, off oxygen, mild work of breathing).

* NOTE: International guidelines recommend switching to oral antibiotics when afebrile for 24 hours. The more conservative recommendation above reflects the generally higher complexity/severity encountered at Starship. 24 hours afebrile may be more appropriate in less severe cases.

Oral antibiotic choice

• Review the organism identified and any sensitivities, (eg. amoxicillin as oral step-down for confirmed S. pneumoniae or cephalexin/flucloxacillin syrup tablets for confirmed S. aureus).

• In the absence of a confirmed pathogen, oral options include amoxicillin-clavulanic acid syrup/tablets or cefalexin syrup/tablets.

Duration

Oral therapy should be continued to complete total therapy (IV/oral) of 2-6 weeks depending on the severity of disease, length of stay in hospital, complications and causative organism.

Pleural drainage

Antibiotic and supportive therapy is often all that is required for small parapneumonic effusions and where children are making good clinical progress. In more severe cases, drainage of the pleural cavity hastens recovery and may reduce long term complication (lung entrapment). The decision to intervene will be based on the child's condition, any co-morbidities and their initial response to therapy.

Indications for intervention include:

• Large effusion / empyema with significant respiratory impairment (respiratory distress, hypoxia, etc) and / or

• Persistent fevers after 48hr IV antibiotics
  
  Where further intervention is indicated, referral should be made to the on-call paediatric surgical team who, having accepted the patient, will take over as nominated care team until completion of the intervention (i.e. last drain removed).

Recommended pleural drainage options include:

• Chest drain without fibrinolytics (urokinase)

• Chest drain with fibrinolytics (urokinase)

• Video-assisted Thorascopic Surgery (VATS)

• Open thoracotomy
  
  Choice of intervention is case by case depending on the child, complexity of empyema, and availability of appropriate surgical support. Most cases will be treated with either a chest drain & fibrinolytics or with VATS. Where empyema fluid is non-echogenic non-loculated (ultrasound findings) and thin (gross sample) a simple drain alone may be appropriate. Open thoracotomy / decortication may be necessary in advanced or long-standing cases. Chest drains may be inserted by either percutaneous (Seldinger pigtail catheters) or open technique - Seldinger pigtail drains are preferred. When using fibrinolytics, small bore (8-12Fr) drains are recommended (more comfortable and fibrinolytic prevents blockage).

Drain management

Drain set-up

• All chest drains require a unidirectional drainage system. At Starship this will generally be an Atrium system; http://www.atriummed.com/en/chest_drainage/default.asp

• The drain should be clamped for 1 hour once 10 ml/kg are initially removed (reduce risk of re-expansion pulmonary oedema).

• A chest x-ray should be obtained following drain insertion to ensure appropriate drain placement.

• Drains should be placed on 10 cmH₂0 controlled suction.

• See Chest Drains in Children guideline

Drain maintenance

• For urokinase installation see below.

• An accurate record of the drain's status must be kept including where it is static, swinging or bubbling and how much fluid is draining (usually an hourly record with tallies each morning).

• Bubbling drains should never be clamped (or removed) and any clamped drain should be immediately unclamped if the patient develops breathlessness or signs of worsening respiration.

• If a drain suddenly stops swinging or draining fluid the medical staff should be notified as it may be obstructed. The patient may need to be re-positioned, the drain unkinked or the drain flushed (10-20ml 0.9% saline) to return it to patency. Once patency and position has been checked, non-functioning drains (neither swinging nor draining fluid) should be removed. Depending on the clinical setting the drain may need to be replaced. Discuss this with the child's primary clinician before removal.

Drain Removal

• If two drains are placed at surgery, one should be removed the following day.

• The last drain should be removed when less than 2ml/kg/day of fluid is draining (regardless of effusion size or clinical status). NB: A bubbling drain should not be removed.

• See Chest Drain Removal Protocol below and Chest Drains in Children guideline.

• Clamping of drains prior to removal is not routinely recommended.

• A chest x-ray is not routinely required after chest drain removal. A post-removal chest X-ray may be performed if there is any clinical concern. . A small pneumothorax on post-removal chest x-ray is not uncommon and will usually spontaneously reabsorb.

Urokinase

See below for urokinase installation protocol.

Urokinase contraindications

• ongoing air leak

• active pleural bleeding

• known urokinase hypersensitivity

• age < 6 months (relative contraindication)

• recent major surgery including open thoracotomy (relative contraindication)
  Urokinase is not routinely given post VATS procedure but may be considered.

Discharge and follow up

Discharge criteria are:

• minimal respiratory distress

• eating, drinking and mobilising freely

• SpO2 consistently >92%

• afebrile for >48 hours AND

• last drain removed >24 hours ago

Radiological resolution is not required (or anticipated) prior to discharge.
Prior to discharge address healthy housing, social work review etc.

Follow up:

• Outpatient review with CXR at 6 weeks

• If clinical of radiological abnormalities persist, further follow up will be required.

Immune evaluation

• In severe pneumococcal pneumonia or associated pneumococcal bacteraemia see Invasive pneumococcal disease and investigation of immune deficiency guideline and complete investigations.

• For empyema as part of multifocal staphylococcal sepsis discuss with immunology regarding other investigations such as neutrophil function tests.

Immunisations

• Ensure all routine vaccinations are up to date and check eligibility for influenza and extended pneumococcal program.

Treatment failure and complications

• Persistent fever may be an indication of incorrect antibiotic, poor antibiotic penetration or simply severe inflammation. Lung necrosis or abscess may also lead to ongoing fever. In many cases, persevering with intravenous antibiotics may be the best course, especially if fever or inflammatory markers appear to be settling. Consider further imaging including chest x-ray and potentially CT scan if progress is not as expected. Persistent lobar collapse may be a sign of foreign body and bronchoscopy should be considered.

• Secondary scoliosis is common and usually transient. No specific treatment or investigation is necessary but resolution should be confirmed.

• Hypoalbuminaemia and/or thrombocystosis are common and require no specific therapy.

• See also the Complications section of the Pneumonia guideline

Urokinase instillation protocol

See contraindications above.

Urokinase is instilled twice daily (between 8am and midnight) for three days (6 doses total) by a medical officer. This is generally well tolerated though sometimes discomfort is experienced during instillation and pleural fluid may be transiently blood stained. Intrapleural bupivacaine (0.25% 0.5-1.0ml/kg) can be added if the child finds it uncomfortable. Urokinase may burn so take care not to get it on the skin and wash away with copious water if this occurs.

Required equipment

• Syringe with Urokinase with small bore needle

• Alcohol wipes

• Two chest drain clamps

Procedure

1. Note baseline observations

2. Explain what you are doing to patient / family as appropriate

3. Check that the drain is in good condition and properly sited within pleural cavity.

4. Position patient supine.

5. Instillation can be uncomfortable - a small morphine dose or bupivacaine (see above) in the urokinase may be helpful.

6. Place clamps about 10cm apart on the soft silicon drain tubing as close to the drain proper as possible.

7. Clean tubing between drains with alcohol wipe

8. Insert syringe needle obliquely between through the tube drains

9. Remove the clamp between the syringe and chest wall

10. Slowly instil urokinase over 5 minutes

11. Replace clamp and leave for 4 hours.

12. Encourage the child to mobilise

13. Instruct nursing staff to remove clamps after 4 hours and return drain to suction (10 cmH₂0) OR if the child develops sudden respiratory distress.

Chest drain removal protocol

See also Chest Drains in Children guideline.

In brief:

1. Explain the procedure.

2. Ensure adequate analgesia is given. Local anaesthetic cream applied to the adjacent skin 3 hours before removal is as effective as intravenous morphine.

3. A medical officer (or nurse on 23b / PICU) will remove the drain with nursing assistance

   1. Position child as appropriate to provide good access to the drain

   2. Stop suction and clamp drain

   3. Instruct child (where possible) to take a deep breath in and push or blow out slowly (Valsalva) during the drain removal. If this isn't possible, ideally the drain is removed during expiration.

   4. While one person cuts the anchoring suture and pulls the drain out (brisk smooth motion), the second person presses (seals) the wound edges together, or a single person can withdraw the drain with one hand whilst sealing the edges with the other.

   5. If there is a closing suture pulls and knots this (not so tight as to pucker the edges).

   6. Apply steristrips as necessary to seal the wound

   7. Apply an occlusive transparent sterile dressing

4. Ensure the child is comfortable and positioned for good chest expansion.

5. Ensure a chest x-ray is arranged and reviewed following removal.

6. Nursing staff will assess respiratory status immediately following drain removal, hourly for four hours and four hourly thereafter.