Master TB for NEET PG 2026: India burden, primary vs post-primary pathogenesis, pulmonary and EPTB presentation, CBNAAT and culture, RNTCP/NTEP categories, ATT regimens, drug side effects (HIEP), MDR/XDR, and latent TB.
NEETPGAI EditorialPublished 2 Apr 202618 min read
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This content is for educational purposes for NEET PG exam preparation. It is not a substitute for professional medical advice, diagnosis, or treatment. Clinical information has been reviewed by qualified medical professionals.
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Diagnosis — CBNAAT / Xpert MTB/RIF is preferred initial test under NTEP (88% sensitivity + rifampicin resistance in 2 hours). Culture on LJ medium (6–8 weeks) remains gold standard.
Mantoux — 5 TU PPD, read induration at 48–72 hr. Cutoffs: >=5 mm (HIV, immunocompromised), >=10 mm (high-prevalence / HCW / child <4 yr), >=15 mm (low-risk adult). IGRA (QuantiFERON, T-SPOT) avoids BCG false positive.
Chest X-ray — Primary TB: Ghon complex, Simon focus (apical, reactivation source). Post-primary: apical cavity, fibronodular lesions. Miliary: 1–3 mm nodules throughout both lung fields
NTEP regimen (daily) — New: 2HRZE + 4HRE. Previously treated: same regimen + universal DST at baseline. Old Category II (SHRZE) phased out.
Drug side effects (HIEP) — Isoniazid: hepatitis, neuropathy (prevent with pyridoxine). Rifampicin: hepatitis, orange fluids, enzyme induction. Pyrazinamide: hepatitis, hyperuricemia. Ethambutol: optic neuritis
Latent TB — 3HP (isoniazid + rifapentine weekly × 12) preferred under NTEP. Screen all HIV patients and household contacts.
Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis complex — and in India, it is the highest-yield infectious disease topic for NEET PG. The student who masters ATT regimens, drug side effects (HIEP), and MDR-TB treatment has covered the foundation for 3–5 marks across medicine, pharmacology, and microbiology papers. Pair this guide with daily MCQ practice on the Medicine subject hub, cross-reference the high-yield medicine topics overview, and revise high-yield microbiology topics for the organism-level detail.
Epidemiology — India's burden and NTEP
India accounts for approximately 27% of the global TB burden — the highest of any country — with an estimated 2.8 million incident TB cases per year and 320,000 TB deaths annually (WHO Global TB Report 2024).
Key epidemiology numbers:
Incidence: ~199 cases per 100,000 population per year
HIV co-infection: ~3% of TB cases in India
Treatment success rate: 85% for new drug-sensitive TB (NTEP 2023)
MDR-TB burden: ~135,000 cases per year (~5% of total)
Histology hallmark: Caseating granuloma with Langhans giant cells, epithelioid histiocytes, lymphocytic cuff, central caseous necrosis. Acid-fast bacilli on Ziehl-Neelsen stain (red-pink rods on blue background).
Clinical presentation — pulmonary and extrapulmonary
Pulmonary TB accounts for 75–80% of cases in adults; extrapulmonary TB (EPTB) accounts for 20–25%, rising to 40–50% in HIV co-infection.
Pulmonary TB symptoms (classic tetrad):
Chronic cough >2 weeks (NTEP screening criterion)
Evening-rise (low-grade) fever with night sweats
Weight loss, anorexia
Hemoptysis (cavitary disease)
EPTB by site (high-yield):
Site
Clinical clues
Diagnosis
Lymph node (scrofula)
Most common EPTB. Cervical, matted, cold abscess, sinus. "Collar stud" abscess
FNAC: necrotising granulomas, AFB; CBNAAT
Pleural TB
Young adult, unilateral lymphocytic exudate, low glucose, high ADA (>40 U/L)
HIV-TB radiographic atypia: Early HIV (CD4 >300) looks like typical reactivation TB. Advanced HIV (CD4 <200) shows lower lobe infiltrates, minimal cavitation, mediastinal adenopathy, and up to 15% have normal chest X-ray despite active pulmonary TB.
NTEP treatment regimens
NTEP treatment is weight-band-based daily fixed-dose combinations (FDCs), administered under supervision or via 99DOTS / MERM adherence monitoring.
Regimens (2021 update — daily, weight-banded):
Category
Population
Intensive phase (IP)
Continuation phase (CP)
Duration
New
Never treated OR <1 month of prior ATT
2 months HRZE
4 months HRE
6 months
Previously treated
Relapse, treatment after failure, treatment after loss to follow-up
2 months HRZE + universal DST at baseline
Regimen tailored to DST
6–9 months
H = isoniazid (5 mg/kg), R = rifampicin (10 mg/kg), Z = pyrazinamide (25 mg/kg), E = ethambutol (15 mg/kg) in daily regimen.
Key NTEP policy changes (post-2018):
Universal DST at baseline — CBNAAT done on every presumptive TB case
Old Category II (8-month SHRZE) phased out — any previously-treated case now gets DST-guided therapy
Daily regimen replaced thrice-weekly DOTS in 2017 (2H3R3Z3E3 no longer used)
Pediatric FDCs with dispersible tablets since 2019
Nikshay Poshan Yojana ₹500/month nutritional DBT
Active case finding among vulnerable populations (migrant workers, urban slums, tribal areas)
Pretomanid: hepatitis; approved only as part of BPaL/BPaLM
Latent TB infection
Latent TB infection (LTBI) is the presence of M. tuberculosis immune sensitisation without clinical or radiographic active disease — and treating LTBI prevents future reactivation in 60–90% of patients.
Diagnosis of LTBI (all 3 required):
Positive Mantoux or IGRA
No symptoms of active TB
Normal chest X-ray (or only fibrotic lesions without activity)
Who to screen for LTBI (NTEP 2021):
Household contacts of smear-positive / CBNAAT-positive TB cases
All HIV-positive individuals
Patients starting anti-TNF biologics or other immunosuppressants
Single dose at birth (along with OPV-0, Hepatitis B birth dose)
Live attenuated Mycobacterium bovis
Protects against disseminated TB and TBM in children (~80% efficacy)
Poor protection against adult pulmonary TB
Contraindicated in symptomatic HIV and severe immunodeficiency
Sources and references
World Health Organization — Global Tuberculosis Report 2024 — authoritative source for incidence, mortality, and MDR burden by country.
Central TB Division, Ministry of Health & Family Welfare, Government of India — NTEP Technical and Operational Guidelines for TB Control (2021 edition) and 2022 updates for MDR/XDR regimens.
Harrison's Principles of Internal Medicine, 21st Edition (Loscalzo et al., 2022) — Chapter on Tuberculosis.
WHO Consolidated Guidelines on Tuberculosis — Module 4: Treatment (2022 update) — BPaL, BPaLM regimen evidence.
Nahid P et al. Treatment of Drug-Susceptible Tuberculosis: ATS/CDC/IDSA Clinical Practice Guidelines. Clinical Infectious Diseases 2016; 63:e147-e195.
API Textbook of Medicine, 11th Edition (Munjal et al., 2019) — Indian clinical perspective on TB.
Frequently asked questions
How many TB questions appear in NEET PG?
Tuberculosis contributes 3-5 direct questions per NEET PG paper across medicine, pharmacology, microbiology, and community medicine. ATT regimen by category, drug side effects (HIEP mnemonic), CBNAAT interpretation, and MDR-TB treatment are the most tested subtopics based on 2019-2025 pattern analysis.
What is India's TB burden?
India accounts for approximately 27 percent of the global TB burden — the highest of any country — with an estimated 2.8 million incident cases per year (WHO Global TB Report 2024). The government has adopted a National Strategic Plan target of TB elimination by 2025, five years ahead of the global SDG target of 2030. NTEP (formerly RNTCP) is the delivery vehicle.
What is the difference between primary and post-primary TB?
Primary TB occurs on first exposure, usually in children, and features the Ghon focus (subpleural granuloma in lower part of upper lobe or upper part of lower lobe) plus hilar lymphadenopathy — together the Ghon complex (Ranke complex when calcified). Post-primary (reactivation) TB occurs in adults, typically in apical posterior segments of upper lobes due to high oxygen tension, and cavitates.
What is CBNAAT and when is it preferred over sputum smear?
CBNAAT (Cartridge-Based Nucleic Acid Amplification Test) uses the Xpert MTB/RIF platform to detect Mycobacterium tuberculosis DNA and rifampicin resistance in 2 hours. It has higher sensitivity than smear (88 percent vs 60 percent) and detects rifampicin resistance directly. Under NTEP, CBNAAT is now the preferred initial diagnostic test for all presumptive TB cases (Universal DST policy).
What are the NTEP categories and ATT regimens?
Under NTEP (daily regimen, 2021 update), there are two categories. New cases receive 2 months of HRZE intensive phase plus 4 months of HRE continuation phase (2HRZE + 4HRE). Previously treated cases (relapse, failure, loss to follow-up) now receive the same regimen with universal drug sensitivity testing at baseline — the old Category II (SHRZE 8-month regimen) has been phased out.
What are the side effects of first-line ATT (HIEP mnemonic)?
The HIEP mnemonic captures first-line ATT toxicity. H (isoniazid): hepatitis, peripheral neuropathy — prevented by pyridoxine 10 mg daily. R (rifampicin): hepatitis, red-orange body fluids, flu-like syndrome, enzyme induction. Z (pyrazinamide): hepatitis, hyperuricemia with gout, arthralgia. E (ethambutol): retrobulbar optic neuritis — dose 15 mg/kg in daily regimen to minimize.
How do you diagnose TB meningitis?
TB meningitis diagnosis requires a high index of suspicion. CSF shows elevated protein (often greater than 100 mg/dL), low glucose (less than 40 mg/dL or CSF/serum ratio less than 0.5), lymphocytic pleocytosis (100-500 cells), and sometimes a cobweb clot. CBNAAT on CSF is the preferred confirmatory test (sensitivity 70-80 percent). Treatment is 12 months of ATT with adjunctive dexamethasone.
What defines MDR-TB and XDR-TB?
MDR-TB is resistance to at least isoniazid AND rifampicin. Pre-XDR-TB is MDR-TB plus resistance to any fluoroquinolone. XDR-TB (WHO 2021 revised definition) is MDR-TB plus resistance to any fluoroquinolone AND at least one additional Group A drug (bedaquiline or linezolid). MDR-TB treatment now uses all-oral shorter regimens — 6-month BPaL (bedaquiline, pretomanid, linezolid) or BPaLM (+ moxifloxacin).
How is latent TB treated?
Latent TB infection (positive Mantoux or IGRA with no clinical or radiological evidence of active TB) is treated to prevent reactivation. Preferred regimen under NTEP is 3HP (isoniazid 900 mg plus rifapentine 900 mg weekly for 12 doses, given under supervision). Alternative regimens include 6-9 months of daily isoniazid or 3-4 months of daily rifampicin. Screen all household contacts of TB patients and HIV-positive individuals.
What is the Mantoux test cutoff?
Mantoux test is tuberculin skin testing with 5 TU of PPD read at 48-72 hours by measuring induration (not erythema). Cutoffs are: greater than or equal to 5 mm in HIV, immunocompromised, recent contacts, or fibrotic lesions on chest X-ray; greater than or equal to 10 mm in high-prevalence populations, healthcare workers, and children under 4 years; greater than or equal to 15 mm in low-risk adults. BCG vaccination can cause false positives up to 15 mm.
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This content is for educational purposes for NEET PG exam preparation. It is not a substitute for professional medical advice, diagnosis, or treatment. Clinical information has been reviewed by qualified medical professionals.
Written by: NEETPGAI Editorial Team
Reviewed by: Pending SME Review
Last reviewed: April 2026
This article is reviewed by qualified medical professionals for clinical accuracy and exam relevance. For corrections or updates, contact the editorial team.
