A 7-year-old boy from Chennai presents with fever, myalgia, and headache for 4 days. On examination, he has a maculopapular rash on the trunk and limbs, sparing palms and soles. His platelet count is 85,000/μL, haemoglobin 13.5 g/dL, and haematocrit 38%. Liver function tests show ALT 120 U/L and AST 180 U/L. NS1 antigen is positive. Which of the following is the most appropriate management at this stage?

Explanation

## Clinical Assessment This child presents with **dengue fever** (febrile phase) confirmed by NS1 antigen positivity, with clinical features of fever, myalgia, headache, and characteristic rash. The laboratory findings (mild thrombocytopenia, elevated transaminases, normal haemoglobin/haematocrit) indicate uncomplicated dengue fever without plasma leakage. ## Management Principles in Dengue Fever **Key Point:** The cornerstone of dengue management is **supportive care** — hydration, monitoring, and early recognition of warning signs. Platelet transfusion is reserved for counts <20,000/μL or <50,000/μL with active bleeding, not for asymptomatic thrombocytopenia. ### Why Admission and Observation? 1. **Monitoring for progression** — dengue can evolve from febrile phase (days 1–5) to critical phase (days 5–7) with plasma leakage, thrombocytopenia, and shock. 2. **Fluid management** — careful isotonic crystalloid administration to maintain perfusion without precipitating pulmonary oedema. 3. **Serial platelet/haematocrit monitoring** — rising haematocrit (>20% increase from baseline) signals plasma leakage; falling platelet count with rising haematocrit is a warning sign. **Clinical Pearl:** In dengue, the **critical phase** (day 5–7 of illness) is when dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS) develop. This child is still in the febrile phase and requires close observation. ### Platelet Transfusion Criteria | Scenario | Action | |----------|--------| | Platelet count 50–100,000/μL, asymptomatic | Observe, no transfusion | | Platelet count 20–50,000/μL, asymptomatic | Observe, transfuse if bleeding or invasive procedure | | Platelet count <20,000/μL | Transfuse regardless | | Any count + active bleeding | Transfuse | **High-Yield:** Prophylactic platelet transfusion in dengue increases risk of fluid overload and does NOT prevent spontaneous bleeding in uncomplicated dengue. ## Why Other Options Are Incorrect - **Dexamethasone and FFP:** Corticosteroids have no role in uncomplicated dengue and may worsen outcomes. FFP is not indicated without coagulopathy or active bleeding. - **Discharge:** This child requires admission for monitoring during the critical phase window (days 5–7). - **Antibiotics:** NS1 positivity confirms viral aetiology; bacterial superinfection is not the primary concern at this stage.