Model Answer
0 min readIntroduction
Tuberculosis (TB) remains a significant global health problem, particularly in developing countries like India. Pediatric TB presents unique challenges due to its paucibacillary nature, atypical presentations, and difficulty in obtaining confirmatory microbiological evidence. A two-year-old child presenting with prolonged fever, cough, weight loss, lymphadenopathy, and a positive Mantoux test strongly suggests the possibility of TB, even in the absence of a visible BCG scar. The BCG scar absence doesn’t rule out TB, as it can be absent in some individuals due to various factors including immune compromise or improper administration. This case necessitates a thorough evaluation and prompt initiation of appropriate treatment.
Diagnosis
Based on the clinical presentation – prolonged fever (two months), cough, weight loss, cervical lymphadenopathy, and a positive Mantoux test (15mm induration) – the most likely diagnosis is extrapulmonary tuberculosis, specifically tuberculous lymphadenitis. The absence of a BCG scar raises suspicion for early exposure or immune deficiency. While other possibilities like lymphoma, cat scratch disease, or other infections need consideration, TB is the primary concern given the epidemiological context.
Diagnostic Workup
A comprehensive diagnostic workup is crucial to confirm the diagnosis and rule out other possibilities:
- Complete Blood Count (CBC): To assess for anemia, leukocytosis, or thrombocytopenia.
- Erythrocyte Sedimentation Rate (ESR) & C-Reactive Protein (CRP): Elevated levels suggest inflammation.
- Chest X-ray: To rule out primary complex or miliary TB.
- Lymph Node Aspiration Cytology (FNAC): This is the most important diagnostic test. Samples should be sent for:
- Smear microscopy for Acid-Fast Bacilli (AFB): Though often negative in pediatric cases.
- Culture for Mycobacterium tuberculosis: Gold standard, but takes time (6-8 weeks).
- PCR for Mycobacterium tuberculosis: Rapid and more sensitive than smear microscopy.
- Gastric Aspirate (3 early morning samples): For AFB smear, culture, and PCR, especially if pulmonary involvement is suspected or FNAC is inconclusive.
- Tuberculin Skin Test (TST) / Interferon-Gamma Release Assay (IGRA): The positive Mantoux test (15mm) supports the diagnosis, but doesn’t confirm it. IGRA can be considered, but TST is more readily available.
- HIV testing: To rule out HIV co-infection, which increases susceptibility to TB and alters treatment strategies.
- Consider Bone Marrow Biopsy: If there is systemic involvement or diagnostic uncertainty.
Management
Management should be initiated promptly, even before definitive confirmation, based on clinical suspicion and a strong index of suspicion. The Revised National Tuberculosis Control Programme (RNTCP) guidelines should be followed.
Pharmacological Management
- Anti-Tuberculosis Treatment (ATT): The standard regimen for pediatric TB is a 6-month course. The initial intensive phase (2 months) consists of:
- Isoniazid (INH): 10-15 mg/kg/day
- Rifampicin (RIF): 15-20 mg/kg/day
- Pyrazinamide (PZA): 20-30 mg/kg/day (contraindicated in infants <2 months)
- Ethambutol (EMB): 15-20 mg/kg/day (to be discontinued once drug susceptibility testing is available)
- Continuation Phase (4 months): INH and RIF are continued.
- Directly Observed Treatment, Short-course (DOTS): Essential to ensure adherence.
Supportive Management
- Nutritional Support: Address weight loss with a high-calorie, protein-rich diet. Consider nutritional supplements if needed.
- Symptomatic Relief: Manage fever with paracetamol. Provide adequate hydration.
- Monitoring: Regular monitoring of weight, growth, and clinical response to treatment.
- Family Screening: Screen household contacts for TB and offer preventive therapy if indicated.
Specific Considerations
- Drug Susceptibility Testing (DST): Crucial to identify drug-resistant strains.
- Miliary TB: If miliary TB is suspected (based on chest X-ray), a longer duration of treatment may be required.
- Tuberculous Meningitis: If there are neurological signs, lumbar puncture should be performed to rule out tuberculous meningitis.
Conclusion
This 2-year-old child presents a strong clinical suspicion for extrapulmonary TB, specifically tuberculous lymphadenitis. A thorough diagnostic workup, including FNAC of the lymph node, is essential for confirmation. Prompt initiation of a 6-month ATT regimen under DOTS, along with supportive care and family screening, is crucial for successful treatment and prevention of further transmission. Regular monitoring for treatment response and potential complications is paramount. The absence of a BCG scar should prompt further investigation into potential immune compromise.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.