Dengue and other arboviral infections: Viva

Branch 1: Recognising the time-critical problem

The candidate should immediately recognise that this is dengue entering its critical phase. The travel history to a dengue-endemic country, the positive NS1 antigen, the defervescence of the fever with new abdominal pain and vomiting, and the rising haematocrit with a falling platelet count together meet WHO 2009 criteria for dengue with warning signs, and the magnitude of the haematocrit rise (25 per cent above baseline) signals significant plasma leak. The single most important teaching point is that the child is most at risk now, as the fever falls, not at the fever peak. ^[2]

The candidate should state the first priorities: airway, breathing and circulation; a fingerprick glucose; intravenous access; and a panel of baseline bloods including full blood count, electrolytes, liver function, albumin, coagulation and lactate. The disposition is admission for WHO group B management, because the warning signs and the haematocrit rise place her at risk of progression to severe dengue. ^[1]