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Dengue — SCE Infectious Diseases MCQ

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ModerateTropical & Imported InfectionsDengueSCE Infectious Diseases

A 25-year-old backpacker returns from South-East Asia with 5 days of high fever, retro-orbital pain, myalgia, and a blanching macular rash. Platelet count is 65 × 10⁹/L. Haematocrit is 48%. Dengue NS1 antigen is positive. He is alert and haemodynamically stable. What is the most important monitoring parameter for detecting progression to severe dengue?

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Correct answer: E — Serial haematocrit measurement for haemoconcentration (rising haematocrit indicates plasma leak)

Dengue infection can progress to severe dengue (dengue haemorrhagic fever/dengue shock syndrome) characterised by plasma leakage, haemorrhage, and organ impairment. A rising haematocrit (>20% increase from baseline or absolute haematocrit >50%) indicates significant plasma leakage and is the key warning sign. The critical phase occurs around defervescence (days 3–7). Management is supportive with careful IV fluid resuscitation guided by haematocrit. There is no specific antiviral therapy. NSAIDs and Aspirin should be avoided due to bleeding risk.

Reference: WHO 2024 – Dengue guidelines; UKHSA 2023 – Dengue management