A 32-year-old woman from Mumbai presents on day 5 of illness with fever, severe retroorbital pain, myalgia, and a maculopapular rash over the trunk and limbs. Her platelet count is 85,000/μL, haemoglobin 14 g/dL, and haematocrit 38%. Blood pressure is 110/72 mmHg. NS1 antigen is positive. What is the most appropriate clinical classification and immediate management?

Explanation

## Clinical Classification of Dengue **Key Point:** Dengue classification depends on the presence of warning signs and evidence of plasma leakage (haemoconcentration, pleural effusion, ascites) or severe bleeding, NOT platelet count alone. ### Case Analysis This patient has: - Fever on day 5 (critical phase) - Classic dengue symptoms (retroorbital pain, myalgia, rash) - Mild thrombocytopenia (85,000/μL) - **Normal haematocrit (38%)** — no evidence of haemoconcentration - **Stable vitals** (BP 110/72 mmHg) — no hypotension or shock - **No bleeding manifestations** mentioned - **Positive NS1** — confirms dengue ### Dengue Classification Criteria | Feature | Dengue Fever | DHF Grade I | DHF Grade II | DHF Grade III | DHF Grade IV | |---------|--------------|------------|-------------|--------------|-------------| | **Fever** | Yes | Yes | Yes | Yes | Yes | | **Bleeding** | Spontaneous: No | Positive tourniquet | Spontaneous bleeding | Spontaneous bleeding | Spontaneous bleeding | | **Platelets** | >100,000 or <100,000 | <100,000 | <100,000 | <100,000 | <100,000 | | **Haemoconcentration** | No | Yes (>20%) | Yes (>20%) | Yes (>20%) | Yes (>20%) | | **Shock** | No | No | No | Yes | Yes | **High-Yield:** Haematocrit rise (haemoconcentration) is the hallmark of plasma leakage in DHF, not thrombocytopenia alone. ### Why This Is Dengue Fever (Not DHF) 1. **No haemoconcentration** — haematocrit 38% is normal; DHF requires >20% rise 2. **No spontaneous bleeding** — only mild thrombocytopenia 3. **Stable haemodynamics** — no warning signs of shock 4. **Meets WHO 2009 dengue fever criteria** — fever + 2 of: headache, retroorbital pain, myalgia, rash, leucopenia ### Management **Clinical Pearl:** The critical phase (days 3–7) is when plasma leakage peaks. Daily monitoring of haematocrit, platelet count, and vital signs is essential to detect progression to DHF/DSS. **Immediate actions:** - Supportive care: oral rehydration, paracetamol (avoid NSAIDs — bleeding risk) - Daily haematocrit and platelet monitoring - Outpatient follow-up if reliable and accessible - Admit if warning signs develop: persistent vomiting, abdominal pain, lethargy, mucosal bleeding, rapid drop in platelets, rising haematocrit [cite:Harrison 21e Ch 197]