A 28-year-old man from Bangalore presents on day 7 of illness with high fever, petechial rash, bleeding gums, and haematocrit rise from 38% to 44%. Platelet count is 40,000/μL. He is haemodynamically stable with normal blood pressure. All of the following warrant urgent intervention in dengue haemorrhagic fever EXCEPT:

Explanation

## Dengue Haemorrhagic Fever: Severity Criteria and Intervention Triggers **Key Point:** While thrombocytopenia is a feature of dengue, platelet count alone does NOT mandate transfusion or urgent intervention unless accompanied by active bleeding, haemodynamic instability, or progressive haemoconcentration. ### WHO Dengue Severity Classification ```mermaid flowchart TD A[Dengue Fever]:::outcome --> B{Plasma leakage signs?}:::decision B -->|No| C[Dengue Fever]:::outcome B -->|Yes| D{Bleeding or shock?}:::decision D -->|Bleeding only| E[Dengue Haemorrhagic Fever]:::outcome D -->|Shock| F[Dengue Shock Syndrome]:::urgent E --> G{Platelet <100k + Hct rise?}:::decision G -->|Yes| H[DHF Grade I-II]:::outcome G -->|Severe| I[DHF Grade III-IV]:::urgent ``` ### Urgent Intervention Triggers in DHF | Trigger | Action | Rationale | |---------|--------|----------| | **Persistent vomiting** | IV fluid resuscitation, antiemetics | Prevents hypovolaemia and shock | | **Hct rise >20% despite IV fluids** | Increase fluid rate, consider colloids, monitor for shock | Indicates ongoing plasma leakage | | **SBP <90 mmHg + cool extremities** | Aggressive fluid resuscitation, vasopressors if needed | Dengue Shock Syndrome — life-threatening | | **Platelet <50k + active bleeding** | Platelet transfusion, correct coagulopathy | Only if spontaneous bleeding present | | **Platelet <50k alone (stable, no bleeding)** | Observation, avoid NSAIDs | Transfusion NOT indicated by count alone | **High-Yield:** Platelet count <50,000/μL WITHOUT active bleeding or haemodynamic instability does NOT require transfusion. Transfusion is reserved for: - Active spontaneous bleeding (GI bleed, intracranial bleed) - Platelet count <10,000/μL (risk of spontaneous bleeding) - Procedure-related bleeding **Clinical Pearl:** The focus in DHF management is on plasma leakage (haemoconcentration) and shock prevention, not platelet count. A stable patient with thrombocytopenia but no bleeding does not warrant urgent intervention. **Warning:** Unnecessary platelet transfusions increase risk of transfusion reactions, volume overload, and worsening of plasma leakage. Avoid transfusing based on count alone. [cite:Park 26e Ch 8]