Model Answer
0 min readIntroduction
Dengue fever, a mosquito-borne viral infection, is a significant public health concern in tropical and subtropical regions. While most cases are self-limiting, severe Dengue can lead to plasma leakage, thrombocytopenia, and coagulopathy, necessitating blood component therapy. The goal of transfusion in Dengue is not merely to correct counts but to address the underlying pathophysiology and prevent life-threatening complications. Judicious use of blood components is crucial, as indiscriminate transfusion can worsen outcomes. This answer will detail the indications for different blood components in the treatment of Dengue fever, adhering to current clinical practices.
Indications for Blood Component Therapy in Dengue Fever
Dengue fever’s pathophysiology often involves increased vascular permeability leading to plasma leakage, thrombocytopenia due to bone marrow suppression and increased platelet destruction, and in severe cases, disseminated intravascular coagulation (DIC). Blood component therapy aims to address these issues.
1. Platelet Transfusion
- Indications: Platelet transfusions are indicated in Dengue patients with active bleeding (e.g., epistaxis, gastrointestinal bleeding, menorrhagia) and a platelet count <20,000/µL. Transfusion may also be considered for counts between 20,000-50,000/µL if the patient has significant comorbidities (e.g., pregnancy, post-surgical status) or is anticipating an invasive procedure.
- Target Platelet Count: The goal is not necessarily to normalize the platelet count, but to achieve a temporary increase sufficient to control bleeding.
- Caution: Repeated platelet transfusions can lead to alloimmunization and refractoriness.
2. Fresh Frozen Plasma (FFP)
- Indications: FFP is indicated in Dengue patients with evidence of coagulopathy, such as prolonged prothrombin time (PT) and activated partial thromboplastin time (aPTT), especially when associated with bleeding. It provides coagulation factors that are deficient in severe Dengue.
- DIC Management: FFP is a crucial component of managing DIC associated with severe Dengue, alongside platelet transfusions and addressing the underlying cause.
- Dosage: Typically, 10-15 mL/kg is administered.
3. Packed Red Blood Cells (PRBC)
- Indications: PRBC transfusions are indicated for symptomatic anemia (e.g., fatigue, dizziness, shortness of breath) with a hemoglobin level <7 g/dL. Hemoglobin levels between 7-10 g/dL may warrant transfusion in patients with underlying cardiovascular disease or ongoing bleeding.
- Hypovolemia: PRBCs can help restore blood volume in patients with significant plasma leakage and hypovolemic shock, although crystalloids are the first-line treatment.
- Caution: Transfusion-related acute lung injury (TRALI) is a potential complication.
4. Cryoprecipitate
- Indications: Cryoprecipitate, rich in fibrinogen, factor VIII, von Willebrand factor, and factor XIII, is rarely required in Dengue. It may be considered in cases of severe fibrinogen deficiency (<100 mg/dL) associated with significant bleeding, particularly in DIC.
- Dosage: Typically, 1 unit per 5-10 kg body weight.
| Blood Component | Indications in Dengue | Typical Dosage |
|---|---|---|
| Platelets | Bleeding with <20,000/µL; 20,000-50,000/µL with comorbidities | 1 unit/5-10 kg body weight |
| FFP | Coagulopathy (prolonged PT/aPTT) with bleeding; DIC | 10-15 mL/kg |
| PRBC | Symptomatic anemia (<7 g/dL); Hypovolemia | 1 unit (approx. 300-450 mL) |
| Cryoprecipitate | Severe fibrinogen deficiency (<100 mg/dL) with bleeding | 1 unit/5-10 kg body weight |
It is important to note that transfusion decisions should be individualized, considering the patient’s clinical condition, laboratory parameters, and response to therapy. Monitoring for transfusion-related complications is essential.
Conclusion
In conclusion, blood component therapy plays a vital role in managing severe Dengue fever, particularly in cases with bleeding and coagulopathy. Platelets, FFP, and PRBC are the most commonly used components, with cryoprecipitate reserved for specific situations. Judicious and targeted transfusion, guided by clinical assessment and laboratory parameters, is crucial to optimize patient outcomes and minimize potential complications. Continuous monitoring and reassessment are essential throughout the course of treatment.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.