Pleural Tuberculosis

Pleural tuberculosis represents the most common form of extrapulmonary TB in children, accounting for approximately 30% of all tuberculosis cases in endemic areas.

Key Epidemiological Points:

• Peak incidence: Children aged 5-15 years
• Higher prevalence in immunocompromised patients
• More common in developing countries
• Often associated with primary TB infection

Risk Factors:

• Recent TB contact
• HIV infection
• Malnutrition
• Overcrowded living conditions
• Immunosuppressive therapy
• Diabetes mellitus

Pathophysiology

Mechanism of Disease:

• Primary mechanisms:
  • Rupture of subpleural caseous focus
  • Direct hematogenous spread
  • Lymphatic spread
• Immunological response:
  • Delayed hypersensitivity reaction
  • Formation of immune complexes
  • Release of inflammatory mediators

Pleural Fluid Characteristics:

• Exudative effusion
• High protein content (>3.5 g/dL)
• High LDH levels
• Lymphocytic predominance
• Low glucose levels
• Acidic pH (<7.30)

Histopathological Changes:

• Granuloma formation
• Caseous necrosis
• Pleural thickening
• Fibrosis development

Clinical Presentation

Common Symptoms:

• Acute presentation:
  • Fever (80-90% cases)
  • Chest pain (70-80% cases)
  • Dry cough (50-70% cases)
  • Dyspnea (50% cases)
• Subacute/Chronic presentation:
  • Weight loss
  • Night sweats
  • Fatigue
  • Anorexia

Physical Examination Findings:

• Decreased chest movement
• Dull percussion note
• Decreased breath sounds
• Decreased vocal resonance
• Pleural rub (early stage)

Diagnosis

Initial Evaluation:

• Detailed history and physical examination
• TB contact screening
• Growth assessment
• Nutritional status evaluation

Imaging Studies:

• Chest X-ray:
  • Costophrenic angle obliteration
  • Unilateral pleural effusion (90%)
  • Associated parenchymal lesions
• Chest ultrasound:
  • Quantification of fluid
  • Detection of septations
  • Guide for thoracentesis
• Chest CT:
  • Small effusions
  • Complex collections
  • Associated lymphadenopathy

Laboratory Studies:

• Pleural fluid analysis:
  • Cell count and differential
  • Protein and LDH
  • Glucose and pH
  • ADA levels (>40 U/L suggestive)
  • Interferon-gamma levels
• Microbiological studies:
  • AFB smear (low yield)
  • TB culture
  • Gene Xpert MTB/RIF
• Pleural biopsy:
  • Closed needle biopsy
  • Thoracoscopic biopsy

Treatment

Anti-tubercular Therapy:

• Initial Phase (2 months):
  • Isoniazid (10 mg/kg/day)
  • Rifampicin (15 mg/kg/day)
  • Pyrazinamide (35 mg/kg/day)
  • Ethambutol (20 mg/kg/day)
• Continuation Phase (4 months):
  • Isoniazid
  • Rifampicin

Adjunctive Therapy:

• Corticosteroids:
  • Prednisolone 1-2 mg/kg/day
  • Duration: 4-8 weeks
  • Gradual tapering
• Therapeutic thoracentesis:
  • Large effusions
  • Respiratory distress
  • Slow resolution

Monitoring & Follow-up

Clinical Monitoring:

• Weekly for first month
• Monthly thereafter
• Assessment of:
  • Symptom resolution
  • Weight gain
  • Treatment adherence
  • Adverse effects

Laboratory Monitoring:

• Liver function tests
• Complete blood count
• Follow-up imaging
• Drug-induced side effects

Complications

Early Complications:

• Respiratory failure
• Fibrothorax
• Empyema
• Bronchopleural fistula

Late Complications:

• Pleural thickening
• Restrictive lung disease
• Chronic chest pain
• Calcification

Special Considerations

In HIV-infected Children:

• More severe presentation
• Higher risk of complications
• Need for longer treatment
• Drug interactions with ART

Prevention Strategies:

• Contact screening
• Prophylaxis for exposed children
• BCG vaccination
• Environmental controls

Prognosis Factors:

• Early diagnosis
• Treatment compliance
• Immune status
• Extent of disease