Platelet Transfusion in Dengue: When to Transfuse
Prophylactic platelet transfusion should NOT be given routinely in dengue patients based solely on low platelet counts, as it does not prevent bleeding and may cause harm. 1
Key Principle: Dengue is a Platelet Destruction Disorder
Dengue causes thrombocytopenia through platelet destruction, not decreased production. Prophylactic transfusion is relatively contraindicated in platelet destruction disorders like dengue. 2 This fundamental pathophysiology explains why transfusion strategies effective in chemotherapy-induced thrombocytopenia do not apply to dengue.
Evidence Against Prophylactic Transfusion
The highest quality evidence comes from a multicenter randomized controlled trial that definitively showed:
- Prophylactic platelet transfusion in dengue patients with platelets ≤20,000/μL without bleeding did NOT reduce clinical bleeding (21% in transfusion group vs 26% in control group, p=0.16) 1
- Transfusion was associated with significantly more adverse events (13 events vs 2 events, p=0.0064), including anaphylaxis, transfusion-related acute lung injury, and fluid overload 1
- Patients who received prophylactic transfusion actually had slower platelet recovery (taking 1 day longer to reach 50,000/μL) and longer hospitalizations 3
- In patients with poor platelet recovery, prophylactic transfusion increased bleeding risk (OR 2.34,95% CI 1.18-4.63) 4
When Platelet Transfusion IS Indicated in Dengue
Active Significant Bleeding
Maintain platelet count ≥50,000/μL (50 × 10⁹/L) in patients with active significant bleeding. 5 This is the primary indication for transfusion in dengue.
Invasive Procedures
- For major surgery or high-risk invasive procedures: maintain platelets ≥50,000/μL 5
- For lumbar puncture: transfuse if platelets <50,000/μL 5
- For central venous catheter placement: transfuse if platelets <20,000/μL 5
Severe Thrombocytopenia with Risk Factors
Consider transfusion only in patients with platelets <20,000/μL AND concomitant coagulopathy (not thrombocytopenia alone) 5
Practical Transfusion Approach
When transfusion is indicated:
- Give 4-8 platelet concentrates or one apheresis pack initially 5
- Always obtain post-transfusion platelet count to confirm adequate increment 5
- Expect suboptimal increments due to ongoing platelet destruction 3
Common Pitfalls to Avoid
Do not transfuse based on arbitrary platelet thresholds alone (e.g., <10,000/μL or <20,000/μL) without bleeding or planned procedures 1, 3
Do not assume transfusion will prevent bleeding progression - the RCT showed no benefit even at very low counts 1
Recognize that transfusion may paradoxically worsen outcomes through adverse events, delayed platelet recovery, and potentially increased bleeding in poor responders 4, 1, 3
Avoid extrapolating guidelines from chemotherapy-induced thrombocytopenia (where 10,000/μL prophylactic threshold is appropriate) 6 to dengue, as the pathophysiology is fundamentally different 2
Observational Data Supporting Restrictive Strategy
A prospective observational study using restrictive transfusion criteria (only for severe bleeding, invasive procedures, emergency surgery, or platelets <5,000/μL with risk factors) in 350 dengue patients found this approach was feasible and safe, with only 9 of 165 thrombocytopenic patients requiring transfusion 7. This real-world experience supports the RCT findings.