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Q1: Diagnosis and acute presentation (2 min)
- Walk me through the laboratory diagnosis of HIV infection. What is the 4th-generation testing algorithm, and what do you do when the screening test is reactive?
- A patient presents with a mononucleosis-like illness 3 weeks after a high-risk exposure; the rapid antibody test is negative. What is the most likely diagnosis and how do you confirm it? (Acute HIV — HIV-1 RNA PCR; p24 antigen is positive; antibody may be negative.)
- State the window periods for: HIV RNA PCR (~day 10), p24 antigen (~day 16), 4th-generation Ag/Ab combo (~day 18), 3rd-generation antibody ELISA (~day 21 to 28), rapid oral-fluid antibody test (~day 28 to 90).
- Distinguish HIV-1 from HIV-2 (epidemiology, pathogenicity, drug susceptibility, diagnostic cross-reactivity).
Q2: Pathophysiology and classification (3 min)
- Describe the HIV replication cycle in six steps and name the drug class that targets each.
- How does HIV cause CD4+ T-cell depletion? (Direct cytopathic effect, syncytia, apoptosis, pyroptosis, CTL killing, impaired regeneration.)
- What is the latent reservoir, where does it live, and why does it preclude cure?
- Define AIDS (CDC 1993: CD4 under 200/uL, CD4% below 14, or AIDS-defining illness).
- Reproduce the CDC clinical classification (A/B/C) and the WHO clinical staging (1 to 4).
- List the AIDS-defining malignancies and at least five AIDS-defining infections.
Q3: Management — cART, prophylaxis, prevention (3 min)
- What is the first-line cART regimen globally and in India? (2 NRTIs + INSTI: TDF/FTC + DTG or BIC.)
- Which trial established ART for all regardless of CD4? (START, NEJM 2015.)
- Reproduce the CD4 ladder of opportunistic infection prophylaxis: co-trimoxazole at CD4 under 200 (PJP), with toxo coverage if IgG+ at under 100; azithromycin 1200 mg weekly at CD4 under 50 (MAC); TB preventive treatment for all without active TB.
- Define U=U and cite the supporting evidence. (HPTN 052, PARTNER/PARTNER 2.)
- Define PrEP (daily TDF/FTC; long-acting cabotegravir — HPTN 083/084) and PEP (TDF + FTC + DTG for 28 days within 72 hours).
- How do you monitor a patient on ART? (VL at 2 to 4 weeks, 3 months, then 6-monthly; CD4 6-monthly until stable above 300; switch if VL over 200 confirmed.)
Q4: Specific scenarios and complications (2 min)
- A patient starts ART for advanced HIV and 2 weeks later develops worsening fever, expanding cervical lymphadenopathy and a new chest infiltrate. What is the diagnosis and how do you manage it? (IRIS — continue ART, treat the underlying OI, corticosteroids for severe or organ-threatening IRIS.)
- A patient with HIV (CD4 80) and pulmonary TB starts RIPE. When do you start ART and what dose adjustment is needed? (SAPiT: within 2 weeks if CD4 under 50, within 8 weeks otherwise; double DTG to BD with rifampicin.)
- A patient with CD4 30 develops subacute headache, confusion and a raised opening pressure on LP. What is the most likely diagnosis, the CSF finding, and the treatment? (Cryptococcal meningitis — India ink positive, CrAg positive; amphotericin + flucytosine induction then fluconazole; manage raised ICP with therapeutic LPs; defer ART 4 to 6 weeks.)
- What counselling would you give a pregnant woman with HIV to prevent MTCT? (cART for all, vaginal delivery if VL undetectable at 36 weeks, C-section if VL over 1000, neonatal prophylaxis, MTCT under 1% with cART.)