Definitions, Epidemiology & Pathogenesis

Question	Answer
1. What constitutes a "Presumptive Pediatric Pulmonary TB" case under NTEP 2024?	Under NTEP guidelines, a child is classified as a Presumptive Pulmonary TB case if presenting with ANY of the following: 1) Persistent fever $>2\text{ weeks}$ without an obvious identifiable alternative cause; 2) Persistent, unremitting cough $>2\text{ weeks}$ not responding to a course of standard antibiotics; 3) Unexplained weight loss ($>5\%$ weight loss in 3 months or no weight gain over 3 months); 4) History of close contact with an active pulmonary TB patient within the last 24 months.
2. What is the Ghon Focus, Ghon Complex, and Ranke Complex?	Ghon Focus: The initial site of subpleural alveolar parenchymal infection by inhaled M. tuberculosis bacilli (usually middle or lower zones of the lung). Ghon Complex (Primary Complex): Ghon focus PLUS draining lymphangitis PLUS enlarged draining regional hilar/bronchopulmonary lymph nodes. Ranke Complex: The end-stage, healed, calcified Ghon complex visible on chest radiography as a calcified parenchymal nodule and calcified hilar lymph node.
3. Why is childhood pulmonary tuberculosis termed "Paucibacillary"?	Unlike adult post-primary reactivation TB which is characterized by extensive cavitary necrosis with high bacillary loads ($10^7-10^9$ bacilli/mL in cavity walls), primary pediatric TB is predominantly a disease of intrathoracic lymphadenopathy and contained parenchymal lesions. Bacillary replication is controlled by cell-mediated immunity with minimal tissue necrosis and rarely any cavitation ($<10^3-10^4$ bacilli). Hence, children produce very few bacilli in respiratory secretions and are rarely contagious.
4. What are the commonest radiological manifestations of primary pediatric TB on chest X-ray?	1) Intrathoracic Lymphadenopathy (Hallmark in $>70\%$): Unilateral hilar, paratracheal, or subcarinal lymph node enlargement; 2) Parenchymal Consolidation: Typically non-segmental or segmental, frequently involving the right upper or middle lobes; 3) Miliary Pattern: Diffuse, uniform, bilateral $1-2\text{ mm}$ millet-seed nodular opacities from hematogenous dissemination; 4) Atelectasis (Collapse/Consolidation): Right middle lobe syndrome due to extrinsic compression of the long, narrow bronchus by enlarged nodes; 5) Pleural Effusion: Typically in children $>5\text{ years}$.
5. VIVA TRAP: Can you rule out tuberculosis if the Mantoux test is 0 mm (completely negative)?	Examiner: "The Mantoux induration is 0 mm. Does this rule out TB?" Response: "No, sir/ma'am! A negative Mantoux test NEVER rules out tuberculosis. False-negative tuberculin tests (Anergy) occur in up to 30-40% of active pediatric TB cases, caused by: 1) Severe Acute Malnutrition (SAM); 2) Disseminated / Miliary TB and TBM; 3) Concurrent viral infections (measles, varicella, mumps, influenza); 4) Pediatric HIV co-infection; 5) Systemic corticosteroids or immunosuppressants; 6) Early incubation phase ($<6-8\text{ weeks}$ before cell-mediated immune conversion). Therefore, clinical and radiological findings override a negative Mantoux."

Specimen Collection, CBNAAT & Diagnostics

Question	Answer
1. How do you collect respiratory specimens for microbiological testing in an infant or young child who cannot expectorate?	Three validated modalities: 1) Early Morning Gastric Aspirate (GA): Performed on 2-3 consecutive mornings after 4-6 hours overnight fasting using an 8-10 Fr nasogastric tube before the child mobilizes, aspirating swallowed respiratory secretions; 2) Induced Sputum (IS): Pre-medicate with inhaled salbutamol, nebulize $3-5\%$ hypertonic saline for 15 minutes, followed by chest percussion and oral/nasopharyngeal suctioning; 3) Bronchoalveolar Lavage (BAL): Performed via flexible fiberoptic bronchoscopy when non-invasive methods are negative and high clinical suspicion remains.
2. What is CBNAAT (GeneXpert MTB/RIF Ultra) and why is it upfront mandatory under NTEP?	CBNAAT (Cartridge-Based Nucleic Acid Amplification Test) is an automated, real-time nested PCR assay that targets the rpoB gene of M. tuberculosis. It achieves two simultaneous objectives in $<2\text{ hours}$: 1) Confirms the presence of M. tuberculosis DNA with high sensitivity ($>75-80\%$ in pediatric gastric/sputum samples); and 2) Detects mutations conferring Rifampicin Resistance (RR) (a reliable surrogate marker for Multi-Drug Resistant TB [MDR-TB]). NTEP mandates upfront CBNAAT on at least one specimen for all presumptive pediatric cases.
3. How is the Tuberculin Skin Test (Mantoux) administered and measured?	Inject 2 TU (0.1 mL) of PPD RT-23 with Tween-80 intradermally into the volar aspect of the upper third of the left forearm using a 26/27-gauge needle, raising a discrete $6-10\text{ mm}$ pale wheal. Read the test at 48 to 72 hours. Measure the maximum transverse diameter of palpable INDURATION (firm thickening), NOT the surrounding erythema, using the ballpoint pen or caliper technique.
4. What are the diagnostic cutoffs for a positive Mantoux test in children?	1) Induration $\ge 10\text{ mm}$: Positive in immunocompetent, well-nourished children, regardless of prior BCG vaccination status. 2) Induration $\ge 5\text{ mm}$: Positive in high-risk immunocompromised children: HIV-infected children, children with Severe Acute Malnutrition (SAM), children on systemic steroids/immunosuppressants, or children with abnormal CXR consistent with TB.
5. VIVA TRAP: What is the clinical utility of Interferon Gamma Release Assays (IGRA / QuantiFERON-TB Gold) in active pediatric TB?	Examiner: "Can I rely on a positive QuantiFERON-TB Gold to start Anti-Tubercular Therapy in a child?" Response: "No, sir/ma'am! IGRAs (and Mantoux tests) are markers of infection (immune sensitization to mycobacterial antigens), NOT active disease. An IGRA cannot distinguish between Latent TB Infection (LTBI) and active tubercular disease. Furthermore, serological antibody detection kits are legally banned in India by the Government of India due to rampant false results. Active disease must be diagnosed on clinical, radiological, and molecular (CBNAAT/culture) grounds."

Treatment Regimens & NTEP Guidelines

Question	Answer
1. What is the standard NTEP 2024 treatment regimen for new drug-susceptible pediatric pulmonary tuberculosis?	Regimen: 2HRZE + 4HRE (Total 6 Months daily therapy): - Intensive Phase (IP - 2 Months): 4 drugs — Isoniazid (H), Rifampicin (R), Pyrazinamide (Z), and Ethambutol (E) daily. - Continuation Phase (CP - 4 Months): 3 drugs — Isoniazid (H), Rifampicin (R), and Ethambutol (E) daily. (Note: Ethambutol is now continued throughout the continuation phase to prevent emergence of drug resistance in the community).
2. What are the recommended daily doses of first-line anti-tubercular drugs in children?	1) Isoniazid (H): $10\text{ mg/kg/day}$ (range 7–15 mg/kg, max 300 mg); 2) Rifampicin (R): $15\text{ mg/kg/day}$ (range 10–20 mg/kg, max 600 mg); 3) Pyrazinamide (Z): $30-35\text{ mg/kg/day}$ (range 30–40 mg/kg, max 2000 mg); 4) Ethambutol (E): $20\text{ mg/kg/day}$ (range 15–25 mg/kg, max 1200 mg).
3. What are the pediatric dispersible Fixed-Dose Combination (FDC) formulations used under NTEP?	1) 3-FDC (Dispersible): Isoniazid $50\text{ mg}$ + Rifampicin $75\text{ mg}$ + Pyrazinamide $150\text{ mg}$ (used in IP); 2) 2-FDC (Dispersible): Isoniazid $50\text{ mg}$ + Rifampicin $75\text{ mg}$ (used in CP); 3) Ethambutol (Dispersible): $100\text{ mg}$ tablets (added to both IP and CP). Dosed strictly by weight bands (4–7 kg, 8–11 kg, 12–15 kg, 16–24 kg, 25–29 kg).
4. What are the indications for systemic corticosteroids (Prednisolone) in pediatric tuberculosis?	Corticosteroids (oral Prednisolone $1-2\text{ mg/kg/day}$ for 4-6 weeks with tapering over 2-4 weeks) are indicated in: 1) Tubercular Meningitis (TBM): Reduces mortality and neurological sequelae; 2) Tubercular Pericarditis with effusion / constriction; 3) Miliary TB with severe hypoxemia / ARDS; 4) Endobronchial TB / Tracheobronchial lymphadenopathy causing critical luminal airway obstruction and atelectasis; 5) Severe paradoxical Jarisch-Herxheimer / IRIS reactions.
5. What is TB Preventive Therapy (TPT) and what are the current NTEP protocols?	TPT aims to prevent progression of latent TB infection into active disease. Indications: 1) All household child contacts $<5\text{ years}$ of a pulmonary TB patient, once active TB is ruled out; 2) HIV-infected children $\ge 12\text{ months}$; 3) Children receiving prolonged immunosuppressive therapy/biologicals. Regimens: 6H (Daily oral Isoniazid $10\text{ mg/kg/day}$ for 6 months), OR 3HR (Daily Isoniazid + Rifampicin for 3 months), supplemented with Pyridoxine.