Paediatric Tuberculosis
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Direct answer
Paediatric tuberculosis is treated under the National TB Elimination Programme (NTEP) with daily fixed-dose combination therapy: two months of isoniazid, rifampicin, pyrazinamide and ethambutol (2HRZE), followed by four months of isoniazid, rifampicin and ethambutol (4HRE) for most new pulmonary cases. Tuberculous meningitis is the exception that examiners love — it runs for twelve months (2HRZE plus 10HRE) with adjunctive corticosteroids. Because children are paucibacillary, diagnosis rests on a careful exposure history, tuberculin testing, imaging and microbiology wherever a sample can be obtained, rather than on smear positivity.
What you must remember
- Mantoux test: 5 TU intradermal, read at 48–72 hours by induration; 10 mm or more is positive in Indian children, but accept 5 mm or more in HIV infection and severe malnutrition. A negative test never excludes TB.
- BCG vaccination does not invalidate Mantoux interpretation in an Indian child.
- Best samples in a young child: three consecutive early-morning gastric aspirates; induced sputum in older children. Cartridge-based NAAT (CBNAAT/Xpert MTB-RIF) can be run on gastric aspirate, sputum or stool.
- Chest X-ray hallmark: hilar/paratracheal lymphadenopathy with compression, not the adult cavitary picture; uncomplicated primary focus is often invisible.
- TB meningitis CSF: clear or xanthochromic fluid, 10–500 cells with lymphocytic predominance, protein markedly raised (often 100–500 mg/dL), glucose low. Basal enhancement on contrast CT and hydrocephalus support it.
- TBM is staged: I (meningeal), II (cranial nerve palsies, irritability, raised intracranial pressure), III (coma). Outcome depends almost entirely on stage at treatment onset.
- Steroids in TBM: prednisolone 1–2 mg/kg/day (or dexamethasone) for about four weeks, then tapered — reduces mortality and sequelae.
- Tuberculosis preventive therapy for infection without disease: daily isoniazid 10 mg/kg (maximum 300 mg) for six months for household contacts under five years and HIV-infected exposed children; shorter rifamycin-based regimens are used in older children per current NTEP guidance.
How to work through a suspected case
Take a five-year-old with fever for three weeks, night sweats, weight loss and a coughing grandfather in the household. Step one: confirm exposure and chronology — contact tracing is the single most useful diagnostic clue in paediatric TB. Step two: tuberculin test and chest radiograph together; a 14 mm induration with right hilar fullness in this context is disease until proven otherwise. Step three: hunt for the organism. Get an induced sputum or early-morning gastric aspirate for CBNAAT, which also delivers rifampicin susceptibility in hours.
If the child instead presents with a two-week history of irritability progressing to a squint and a bulging fontanelle, think TBM and move faster. Lumbar puncture, then contrast CT of the head looking for basal exudates and hydrocephalus. Start 2HRZE with the intention of continuing to twelve months, add steroids, and address raised intracranial pressure — CSF diversion may be needed for obstructive hydrocephalus. Review every contact under five for preventive therapy, and screen the whole family for the index case.
Where students slip
Two errors dominate viva answers on this topic. First, quoting sputum smear as the diagnostic standard — smears are usually negative in children because disease is paucibacillary, so writing "sputum positive" as a diagnostic requirement loses the mark. Second, giving the adult six-month regimen to a child with TBM; the twelve-month course with steroids is non-negotiable. A subtler trap is calling every positive Mantoux "disease": a positive tuberculin test indicates infection, and infection plus symptoms, signs or radiology makes disease. Candidates who say "start category empirically on a positive Mantoux alone" in an asymptomatic contact should have written preventive therapy instead — and they lose easy marks for not knowing that distinction.
Frequently asked questions
What Mantoux size is considered positive in an immunocompromised child?
An induration of 5 mm or more is taken as positive in HIV-infected children, severe malnutrition and recent household contacts; 10 mm remains the standard cut-off otherwise. Erythema is ignored; only induration is measured.
Which antitubercular regimen does NTEP recommend for a new case of paediatric pulmonary TB?
Daily FDCs of 2HRZE followed by 4HRE, dosed by weight band. Ethambutol is included in the intensive phase for children in the current programme, and doses are revised as weight crosses band boundaries.
How does the CSF differ between tuberculous and pyogenic meningitis?
TBM shows lymphocytic pleocytosis of 10–500 cells with very high protein and low glucose, often with a cobweb clot; pyogenic meningitis shows neutrophil predominance (usually above 1,000 cells), very high protein and profoundly low glucose with a turbid appearance.
When is isoniazid preventive therapy indicated?
For infection without active disease: asymptomatic children under five years with household exposure, HIV-infected child contacts, and children converting from a negative to positive tuberculin test — after active TB has been carefully excluded.
Why is corticosteroid therapy mandatory in tuberculous meningitis?
Steroids reduce mortality and residual neurological deficits by limiting basal exudate formation, arachnoiditis and vascular occlusion. Prednisolone 1–2 mg/kg/day for about four weeks with gradual taper is the conventional schedule.