Dengue Hemorrhagic Fever (DHF)
Dengue is an arboviral infection transmitted by the Aedes aegypti mosquito. DHF is the severe, potentially fatal form characterized by plasma leakage and a hemorrhagic diathesis.
1. Diagnostic Criteria (WHO)
All four criteria must be present for a clinical diagnosis of DHF:
- Fever (acute onset, high grade, lasting 2–7 days).
- Hemorrhagic manifestations (positive tourniquet test, petechiae, purpura, or mucosal bleeding).
- Thrombocytopenia (platelet count ≤ 100,000/mm³).
- Plasma leakage (evidenced by rising hematocrit ≥ 20%, pleural effusion, or ascites).
2. Clinical Phases
| Phase | Key Characteristics |
|---|---|
| Febrile | High fever, flushing, headache, and myalgia. |
| Critical | Occurs at defervescence; plasma leakage and shock risk. |
| Recovery | Reabsorption of extravascular fluid; watch for fluid overload. |
3. Management Principles
- Fluids: Judicious use of Isotonic crystalloids (e.g., NS or Ringer’s Lactate). Over-hydration is a major risk, especially in the recovery phase.
- Monitoring: Strict input-output charts, hourly monitoring of vitals, and hematocrit levels.
- Avoid: Aspirin, NSAIDs, and unnecessary IM injections due to bleeding risks.
NEET PG Hint: Remember the “Warning Signs” of severe dengue: abdominal pain, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, liver enlargement, and a rapid drop in platelets with a concurrent rise in hematocrit. For high-yield clinical practice questions, visit mymedschool.org.