Overview
Definition:
Tuberculosis (TB) in children is an infectious disease caused by Mycobacterium tuberculosis
Latent TB infection (LTBI) refers to infection without symptoms or radiological evidence of active disease, while active TB involves symptomatic illness and evidence of mycobacterial replication
Pediatric TB is a significant global health challenge, often reflecting recent transmission.
Epidemiology:
Globally, TB is a leading cause of death in children
Incidence varies by region, with higher rates in low- and middle-income countries and areas with high TB endemicity, including India
Children under 5 years are at higher risk of progression to active disease and severe forms of TB.
Clinical Significance:
Early diagnosis and appropriate management of both latent and active TB in children are crucial to prevent disease progression, dissemination, and long-term sequelae
Understanding the differences in presentation, diagnosis, and treatment between latent and active TB is paramount for pediatricians and residents preparing for examinations.
Clinical Presentation
Symptoms:
Latent TB: Asymptomatic
Active TB: Persistent cough (>2-3 weeks), fever (often low-grade, prolonged), weight loss/failure to thrive, night sweats, fatigue, irritability
Specific symptoms depend on site of involvement (e.g., lymphadenopathy, meningeal signs, abdominal distension, bone pain).
Signs:
Active TB: Growth faltering, pallor, lymphadenopathy (cervical, supraclavicular), crackles on chest auscultation, pleural effusion, hepatosplenomegaly
Neurological signs in TB meningitis
Abdominal tenderness in intestinal TB.
Diagnostic Criteria:
No single test confirms TB
Diagnosis relies on a combination of clinical suspicion, exposure history, tuberculin skin test (TST) or interferon-gamma release assay (IGRA), chest radiography, and microbiological confirmation (e.g., sputum smear microscopy, culture, nucleic acid amplification tests - NAAT)
Children with suspected disseminated TB require extensive workup.
Diagnostic Approach
History Taking:
Detailed history of contact with an infectious TB case (adult or child) is essential
Ask about duration and nature of symptoms, fever patterns, cough characteristics, weight changes, and BCG vaccination status
Assess for risk factors like malnutrition, immunosuppression (HIV, malignancy), and comorbidities.
Physical Examination:
Comprehensive physical exam focusing on general assessment (growth, nutritional status), vital signs, thorough lymph node examination, respiratory system (auscultation for crackles, decreased breath sounds), abdominal exam, and neurological assessment for meningeal signs or focal deficits.
Investigations:
TST/IGRA: Used to detect TB infection
a positive result indicates infection but not necessarily active disease
Chest X-ray (CXR): May show infiltrates, consolidation, pleural effusion, lymphadenopathy, or miliary pattern
Acid-fast bacilli (AFB) smear and culture: From sputum, gastric aspirates, urine, or other body fluids
culture is gold standard
GeneXpert MTB/RIF: Rapid molecular test for M
tuberculosis and rifampicin resistance
Other tests: Complete blood count (CBC), ESR/CRP, liver function tests (LFTs), HIV testing, ultrasound, CT scan depending on suspected site.
Differential Diagnosis:
For pulmonary TB: Pneumonia (bacterial, viral), bronchiolitis, asthma, foreign body aspiration
For extrapulmonary TB: Lymphadenopathy (reactive, other infections, malignancy), meningitis (bacterial, viral), osteomyelitis, inflammatory bowel disease, other granulomatous diseases.
Management
Initial Management:
Prompt initiation of anti-TB treatment once active TB is suspected or confirmed
Isolation of infectious cases if possible
Supportive care including nutritional support and management of comorbidities.
Medical Management:
Latent TB Infection (LTBI): Treatment aims to prevent progression to active TB
Standard regimen: Isoniazid (INH) 10 mg/kg/day (max 300 mg) for 6-9 months, or 15 mg/kg twice weekly (max 900 mg) for 9 months
Alternative: Rifampicin (RIF) for 4 months (10-20 mg/kg/day), or INH + RIF for 3 months (INH 15 mg/kg, RIF 15 mg/kg, daily or thrice weekly)
Active TB: Treatment duration is typically 6 months for drug-susceptible TB, divided into an intensive phase (2 months) and continuation phase (4 months)
Standard regimen (2HRZE/4HR): Intensive phase: Isoniazid (INH), Rifampicin (RIF), Pyrazinamide (PZA), Ethambutol (EMB)
Continuation phase: INH, RIF
Doses are weight-based and vary by age and drug
Drug-resistant TB requires specialized, longer regimens based on susceptibility testing.
Surgical Management:
Rarely indicated in children
May be considered for complications like large empyema, drug-resistant TB with localized disease, or abscess formation refractory to medical therapy.
Supportive Care:
Adequate nutrition and hydration are essential
Management of fever, cough, and other symptoms
Close monitoring for adherence to medication and adverse drug reactions
Psychological support for the child and family
Prompt management of complications.
Complications
Early Complications:
Dissemination of TB (miliary TB, TB meningitis), acute respiratory distress syndrome (ARDS), pleural effusion, pericardial effusion, intestinal obstruction, acute liver failure from drug toxicity
Immune Reconstitution Inflammatory Syndrome (IRIS) in HIV-coinfected children on ART.
Late Complications:
Fibronodular lung disease, bronchiectasis, pulmonary hypertension, neurological sequelae (e.g., hearing loss, cognitive impairment from TB meningitis), bone deformities, chronic pain, infertility.
Prevention Strategies:
Contact tracing and prompt treatment of infectious cases
BCG vaccination (offers partial protection against severe forms)
Preventive therapy for LTBI in high-risk children
Infection control measures in healthcare settings and communities.
Prognosis
Factors Affecting Prognosis:
Age at diagnosis (younger children have worse prognosis), extent and site of disease, nutritional status, presence of comorbidities (especially HIV), drug resistance, adherence to treatment, and promptness of diagnosis and initiation of therapy.
Outcomes:
With appropriate and timely treatment, most children with drug-susceptible TB have excellent outcomes
However, severe forms or drug-resistant TB can lead to significant morbidity and mortality
Long-term sequelae can impact quality of life.
Follow Up:
Regular follow-up is essential during and after treatment to monitor treatment response, adherence, drug toxicity, and nutritional status
Chest X-ray may be repeated
Long-term follow-up may be required for children with complicated disease or sequelae.
Key Points
Exam Focus:
Differentiate latent vs
active TB in children
Know standard treatment regimens (INH, RIPE) and durations for LTBI and active TB
Understand weight-based dosing for common anti-TB drugs
Recognize high-risk groups for progression
Recall common sites of extrapulmonary TB in children.
Clinical Pearls:
Always suspect TB in a child with prolonged cough, fever, or failure to thrive, especially with known contact
Gastric aspirates are preferred over induced sputum for AFB testing in young children
Monitor LFTs closely, especially with PZA
Do not forget HIV co-infection workup.
Common Mistakes:
Underestimating TB in infants and young children
Inadequate duration or dosage of anti-TB therapy
Failure to consider drug resistance
Not adequately investigating for extrapulmonary TB
Inappropriate use of TST/IGRA without clinical correlation.