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IM27.1-18 | Tuberculosis — PBL Case

CLINICAL SETTING

Ward 7 of a district government hospital in Surat, Gujarat. The medical intern, Dr Riya, has just seen a new admission: Mr Mohan Das, a 42-year-old power-loom operator from a workers' dormitory (a 30-person shared room) in the textile district. He was brought in by a co-worker after two days of high fever. On clerking, Mohan reports that he has had a cough for 6 weeks — productive, with yellow-green sputum — and has been treating himself with cough syrups from a local chemist. He has lost approximately 6 kg over the past 2 months and wakes up drenched in sweat at night. He has never been diagnosed with TB. His co-worker mentions that 'two other people in our room had TB last year — they took some tablets for a few months and got better.' Mohan has no known HIV status. He smokes 10 cigarettes per day and drinks alcohol on weekends. He has been taking paracetamol and a branded antibiotic from the chemist for the past 10 days without improvement. Dr Riya's resident, Dr Arjun, glances at the referral slip and says: 'Classic presumptive TB. Get a sputum — but which test do we order first?'

Trigger 1: First Assessment — What Tests, and in What Order?

Dr Riya examines Mohan. He is febrile (38.9°C), tachycardic (pulse 102/min), and thin (weight 48 kg). Respiratory rate is 22/min. Chest examination reveals dullness to percussion at the right upper zone with reduced breath sounds. Post-tussive crepitations are heard over the right upper lobe on auscultation after asking the patient to cough. Trachea is central. No cervical lymphadenopathy. No hepatosplenomegaly. BCG scar is present on the left arm. Dr Arjun hands Dr Riya the hospital investigation request form: 'Write the investigations in order of priority under current NTEP guidelines. And do NOT write sputum smear only — that is 2008, not 2024.' He adds: 'Also, before you order anything, what does this patient need to know about why we are doing these tests?'

DISCUSSION POINTS

  • Using the NTEP 2020 diagnostic algorithm, list the investigations you would order for Mohan in order of priority, starting with the mandatory first-line molecular test. Why is sputum smear alone no longer sufficient as the first test?
  • Describe the physical examination findings in Mohan's chest and explain the pathological basis for each sign in the context of right upper lobe TB with possible early cavitation.
  • What information should Dr Riya give Mohan before ordering the sputum test — including what the test involves, what it can detect, and why it is different from the 'old sputum test'?
Click to reveal Trigger 2: CBNAAT Result — An Unexpected Resistance Flag (discuss previous trigger first!)

Trigger 2: CBNAAT Result — An Unexpected Resistance Flag

The CBNAAT result returns 4 hours later: 'MTB detected; Rifampicin resistance: detected.' The sputum AFB smear result from the same specimen: '2+ AFB positive.' Dr Arjun looks at the CBNAAT printout and says: 'We cannot start the standard 2HRZE + 4HRE regimen. This changes everything.' He explains that Mohan must be treated as presumptive RR-TB (rifampicin-resistant TB) pending full drug sensitivity testing. Mohan overhears part of the conversation and asks: 'Doctor, is this a different kind of TB? Is it more dangerous? And how did I get a resistant type when I never took TB medicines before?' The dormitory manager phones the ward to ask whether Mohan's 29 dormitory co-workers need to be examined.

DISCUSSION POINTS

  • What does a CBNAAT result of 'RIF resistance detected' mean in terms of drug resistance classification (RR-TB vs MDR-TB), and what are the mandatory next steps under NTEP before starting a DR-TB regimen?
  • Mohan says he has never taken ATT before. What are the possible explanations for primary (transmitted) rifampicin resistance in a previously untreated patient? What programmatic and microbial factors in his dormitory setting increase this risk?
  • How should Dr Riya respond to Mohan's questions and to the dormitory manager's call? What is the correct contact investigation protocol for 29 close contacts of a smear-positive, RIF-resistant TB case under NTEP?
Click to reveal Trigger 3: Managing Comorbidities — Blood Sugar and HIV (discuss previous trigger first!)

Trigger 3: Managing Comorbidities — Blood Sugar and HIV

Dr Arjun orders routine blood tests. Results: random blood glucose 14.2 mmol/L (256 mg/dL); HbA1c 9.1%. HIV ELISA: reactive; HIV confirmatory Western blot: pending. CD4 count: 210 cells/mm3. Dr Arjun tells Dr Riya: 'We now have presumptive RR-TB, newly diagnosed type 2 diabetes, and likely HIV. These three conditions interact in ways that will determine how hard this case is to manage — and whether Mohan survives.' He asks her to think through the interactions before the next ward round. The resident also raises the question of antiretroviral therapy: 'If the CBNAAT shows RIF resistance, the usual rule of ATT first then ART within 2–8 weeks still applies — but the drug interaction calculus is different when rifampicin is not the backbone.'

DISCUSSION POINTS

  • Describe the bidirectional interactions between HIV and TB: how does HIV modify the clinical presentation, diagnostic yield (Mantoux, smear, CBNAAT), and treatment outcomes of TB in Mohan's case?
  • Type 2 diabetes with HbA1c 9.1% in a TB patient: what are the specific mechanisms by which hyperglycaemia impairs anti-TB immunity, and how does this affect treatment planning (glycaemic targets, drug interactions, monitoring)?
  • If Mohan is confirmed HIV-positive and is starting DR-TB treatment (which will include bedaquiline and linezolid), what are the key drug interaction and toxicity considerations when introducing ART, and when should ART be initiated relative to DR-TB treatment?
Click to reveal Trigger 4: Discussing the Diagnosis with the Patient and Family (discuss previous trigger first!)

Trigger 4: Discussing the Diagnosis with the Patient and Family

Mohan's wife, Sunita, has travelled from their village and arrives at the ward. She is 6 months pregnant. She has no cough or fever. She has not been screened for TB. Mohan breaks down: 'If I have drug-resistant TB and I am HIV-positive, what will happen to my wife? What will happen to the baby?' Dr Riya must now have two conversations simultaneously: (1) a medical conversation with Dr Arjun about screening Sunita for both TB and HIV in pregnancy; and (2) a counselling conversation with Mohan and Sunita about the diagnosis, treatment, and prognosis — in a language and manner that does not cause panic but is honest about the seriousness and treatability of both conditions. Dr Arjun asks Dr Riya to draft the counselling talking points before the conversation.

DISCUSSION POINTS

  • What is the correct clinical approach to Sunita — a 6-months-pregnant woman who is a household contact of a smear-positive, RIF-resistant TB case? What tests should be ordered, and what are the NTEP-recommended actions if her CBNAAT is positive? If her HIV test is positive?
  • Draft the key talking points for the counselling conversation with Mohan and Sunita — covering: (a) what RR-TB and HIV mean in plain language; (b) whether TB and HIV are treatable; (c) what treatment involves (duration, adherence); (d) risks to the baby; (e) infectivity precautions. Avoid stigmatising language.
  • Under what Indian legal and ethical framework is the treating team obligated to notify Mohan's RR-TB status to public health authorities, and what is Mohan's right to confidentiality in the context of contact investigation of his dormitory co-workers?

Group Task Assignments

  • Construct the complete NTEP notification and DR-TB management pathway for Mohan from the moment RIF resistance is detected on CBNAAT to initiation of the DR-TB regimen — naming each step, the responsible healthcare worker, and the timeline.
  • Develop a contact investigation plan for the 29 dormitory co-workers of a smear-positive RR-TB index case, specifying which investigations are done, in what order, and what action follows each possible result.
  • Design a one-page patient information sheet in simple English (or Hindi) explaining DR-TB to a patient with low health literacy — what the disease is, why the medicines are different, how long treatment lasts, and what side effects to report.
  • Debate the proposition: 'India can achieve TB elimination by 2025 despite the rising burden of drug-resistant TB.' What would need to change at the programme level, and what is the current rate of MDR-TB case detection nationally?

Learning Issues

Research these questions and bring your findings to the discussion.

  1. [IM27.4] What are the mechanisms of primary (transmitted) and acquired drug resistance in M. tuberculosis, and what programmatic factors in India's high-burden settings drive the emergence and spread of RR-TB and MDR-TB?
  2. [IM27.9] What is the NTEP diagnostic algorithm for presumptive TB in 2020, and why does it mandate CBNAAT as the first-line test rather than sputum smear microscopy?
  3. [IM27.3] How do HIV and type 2 diabetes independently and synergistically modify the clinical presentation, diagnostic sensitivity, and treatment outcomes of TB, and what monitoring adjustments are required for the HIV-DM-TB triple burden?
  4. [IM27.14] What are the current NTEP regimens for drug-sensitive TB (2HRZE + 4HRE) and drug-resistant TB (including BPaL for pre-XDR/XDR-TB), and what are the key monitoring requirements and adverse effects for each?
  5. [IM27.18] How should a physician communicate a diagnosis of drug-resistant TB and HIV co-infection to a patient and their pregnant partner in a way that is honest, empathetic, and free of stigmatising language?