What is the appropriate diagnosis and treatment approach for a child with pleural effusion?

Diagnosis and Management of Pleural Effusion in Children

All children with pleural effusion should be admitted to hospital, and ultrasound must be used to confirm the presence of pleural fluid collection, followed by early active drainage if the effusion is enlarging or compromising respiratory function, as antibiotics alone result in prolonged illness and hospital stay. 1

Clinical Recognition

Presentation

• Children typically present with classic pneumonia symptoms (cough, dyspnea, fever, malaise, loss of appetite) but appear more unwell than expected, often with pleuritic chest pain 1
• Lower lobe infections may present with abdominal pain 1
• Critical decision point: If a child remains pyrexial or unwell 48 hours after admission for pneumonia, parapneumonic effusion/empyema must be excluded 1, 2

Physical Examination Findings

• Unilateral decreased chest expansion, dullness to percussion, and reduced or absent breath sounds 1
• Oxygen saturation below 92% indicates severe disease 1
• Assess hydration status, height, weight, presence of scoliosis, and underlying disorders 1

Diagnostic Algorithm

Initial Imaging

• Obtain posteroanterior (PA) or anteroposterior (AP) chest radiograph—there is no role for routine lateral radiograph 1, 3, 2
• Look for obliteration of costophrenic angle (earliest sign) and meniscus sign ascending the lateral chest wall 1
• Common pitfall: In supine younger children, effusion may appear as homogeneous opacity over the entire lung field without classic pleural-based shadows 1, 3

Mandatory Ultrasound Confirmation

• Ultrasound must be used to confirm the presence of pleural fluid collection—this is non-negotiable 1, 4, 2
• Ultrasound differentiates free from loculated fluid, estimates effusion size, and determines echogenicity 1
• Can be performed at bedside with no sedation or radiation 1
• Ultrasound should be used to guide thoracocentesis or drain placement 1, 4, 2

CT Scanning

• Chest CT scans should not be performed routinely 1, 2
• Radiation exposure ranges from 20-400 chest radiograph equivalents 1
• Ultrasound is superior for visualizing fibrinous septations 1

Laboratory Investigations

Blood Studies

• Blood cultures (including anaerobic bottle) in all patients 1, 4, 2
• Full blood count (anemia, white count with differential, platelet count) 1
• Electrolytes (to detect inappropriate ADH syndrome) 1
• Serum albumin (often low) 1
• Antistreptolysin O titre (ASOT) 1
• Sputum culture when available 1, 4

Pleural Fluid Analysis

• Pleural fluid must be sent for microbiological analysis including Gram stain and bacterial culture 1, 4, 2
• Send for differential cell count 1, 4, 2
• Tuberculosis and malignancy must be excluded in the presence of pleural lymphocytosis 1, 4, 2
• Biochemical analysis is unnecessary in uncomplicated parapneumonic effusions/empyema 1
• If effusion may not be infectious, consider small volume diagnostic tap for cytology, avoiding general anesthesia when possible 1, 2

Bronchoscopy

• There is no indication for flexible bronchoscopy—it is not routinely recommended 1

Treatment Approach

Antibiotic Therapy

• All cases should be treated with intravenous antibiotics and must include cover for Streptococcus pneumoniae 1, 4, 2
• Broader spectrum coverage required for hospital-acquired infections and those secondary to surgery, trauma, and aspiration 1, 4, 2
• Where possible, antibiotic choice should be guided by microbiology results 1, 4, 2
• Oral antibiotics should be given at discharge for 1-4 weeks, but longer if residual disease present 1, 2

Decision for Drainage

• Effusions which are enlarging and/or compromising respiratory function should not be managed by antibiotics alone 1, 4, 2
• Give consideration to early active treatment as conservative treatment results in prolonged duration of illness and hospital stay 1, 4, 2
• Small effusions may resolve with antibiotics alone 4
• Moderate to large effusions often benefit from drainage due to respiratory compromise 4

Drainage Procedures

• If a child has significant pleural infection, a drain should be inserted at the outset—repeated taps are not recommended 1, 2
• Chest drains should be inserted by adequately trained personnel with suitable assistant and trained nurse available 1
• Ultrasound guidance is mandatory for thoracocentesis or drain placement 1, 4, 2
• Routine platelet count and clotting studies only recommended in patients with known risk factors 1
• Correct any coagulopathy or platelet defect before drain insertion when possible 1

Specialist Involvement

• A respiratory paediatrician should be involved early in the care of all patients requiring chest tube drainage for pleural infection 1

Prognosis

• In the majority of children (60-83%), resolution occurs by 3 months; over 90% by 6 months; and all by 18 months 1

Critical Pitfalls to Avoid

• Do not delay ultrasound confirmation—clinical examination alone is insufficient 2
• Do not wait beyond 48 hours to reassess if child remains unwell—this mandates investigation for complicated effusion 1, 2
• Do not perform repeated thoracentesis—insert a drain at the outset for significant pleural infection 1, 2
• Do not order routine CT scans—ultrasound is superior and avoids radiation 1, 2