Dengue with warning signs — DTM&H MCQ

Correct answer: D — Dengue with warning signs

The correct answer is D, dengue with warning signs. The classic pattern of high fever for several days followed by defervescence with new abdominal pain and persistent vomiting, alongside marked thrombocytopenia (42 x 10^9/L) and a rising haematocrit (38% to 48%, a rise of over 20%), is the hallmark of the critical phase of dengue, when increased capillary permeability causes plasma leakage. Persistent vomiting and abdominal pain are recognised warning signs, and haemoconcentration with a concurrent fall in platelets reflects plasma leakage into the extravascular space rather than bleeding, which is exactly the pathophysiology of dengue at defervescence. Sri Lanka is a highly dengue-endemic country, making this the epidemiologically most likely diagnosis. This combination does not yet meet criteria for severe dengue (no shock, severe bleeding or organ impairment), so it is classified as dengue with warning signs, requiring hospital admission and close monitoring of fluid status. Why the other options are wrong: E. Acute hepatitis E: causes jaundice, malaise and deranged liver enzymes over days to weeks, not an acute abdominal pain and vomiting syndrome with thrombocytopenia and haemoconcentration at defervescence. A. Enteric fever: causes a stepwise fever pattern over one to two weeks with relative bradycardia, and the fever typically persists rather than settling before abdominal symptoms and haemoconcentration develop. C. Zika virus infection: usually causes a mild illness with rash, conjunctivitis and arthralgia, and does not cause significant thrombocytopenia or plasma leakage with rising haematocrit. B. Uncomplicated chikungunya: dominated by severe, often disabling polyarthralgia, without the marked thrombocytopenia or haemoconcentration seen here, and by definition excludes warning sign features. Key point: defervescence with abdominal pain, persistent vomiting, falling platelets and a rising haematocrit signals dengue entering the critical plasma-leakage phase and mandates admission as dengue with warning signs.

Reference: WHO, Dengue: Guidelines for Diagnosis, Treatment, Prevention and Control (2009), Chapter 3: Warning signs and classification of dengue severity, https://www.who.int/publications/i/item/9789241547871