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IRIS — RACP Adult Medicine MCQ

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ModerateInfectious DiseasesIRISRACP Adult Medicine

A 50-year-old man with HIV and a CD4 count of 50 cells/µL is commenced on antiretroviral therapy. Two weeks later, he develops high fever, worsening lymphadenopathy, and new pulmonary infiltrates. His viral load has decreased from 500,000 to 5,000 copies/mL. What is the most likely explanation?

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Correct answer: E — New opportunistic infection

IRIS occurs when reconstituting immune cells mount an inflammatory response against pre-existing (often subclinical) infections, typically within the first 2–12 weeks of ART initiation. The paradoxical worsening of symptoms despite falling viral load and rising CD4 count is characteristic. Common IRIS-associated infections include TB, MAC, cryptococcus, and CMV. Management involves continuing ART, treating the underlying infection, and using corticosteroids for severe IRIS.

Reference: ASHM – 2024 – HIV Management Guidelines; eTG – 2025 – Antibiotic Guidelines