🦟 Chapter 46: Dengue and Dengue Shock Syndrome

Febrile Phase · Critical Phase (Plasma Leak) · Recovery Phase · Warning Signs · Haematocrit-Guided Resuscitation · PICU Management

🦟 Dengue: Flavivirus with Four Serotypes — Second Infection Increases Risk of Severe Disease

📋 Phases of Dengue Infection
• Febrile phase (2-7 days): high fever, positive tourniquet test
• Critical phase (24-48 hrs after defervescence): plasma leakage, rising HCT, warning signs
• Recovery phase: reabsorption of leaked fluid, diuresis, itching
⚠️ Warning Signs (WHO 2012)
• Abdominal pain/tenderness
• Persistent vomiting
• Clinical fluid accumulation (ascites, pleural effusion)
• Mucosal bleeding
• Lethargy/restlessness
• Liver enlargement >2 cm
• Rise in HCT with rapid drop in platelets
🩸 Severe Dengue
• Severe plasma leakage (shock, fluid accumulation with respiratory distress)
• Severe bleeding
• Severe organ impairment (AST/ALT >1000, CNS impairment, heart failure)
💧 Fluid Management (HCT-guided)
• Rising HCT + unstable → 10 mL/kg colloid bolus
• Rising HCT + stable → continue maintenance fluids
• Falling HCT + unstable → suspect occult bleed → PRBC transfusion
• Normal/decreasing HCT + stable → recovery phase, stop IV fluids
🩺 Dengue Shock Syndrome Features
• Shock occurs at defervescence (not during fever)
• Relative bradycardia (not tachycardia like septic shock)
• Narrow pulse pressure (20-30 mmHg)
• Haematocrit rises (haemoconcentration)
• Mentation preserved until late
⚠️ Differentiate from Septic Shock
Septic shock: fever at shock onset, tachycardia, wide pulse pressure, early altered sensorium. Dengue shock: afebrile at shock onset, relative bradycardia, narrow pulse pressure, preserved mentation.
📌 Key Laboratory Monitoring: Haematocrit q2-4h (most important), platelets, WBC, albumin, LFTs. Rising HCT = plasma leakage. Falling HCT with instability = bleeding. No role for prophylactic platelet transfusion.

🩺 Step-by-Step: Dengue Shock Syndrome Management

1
Recognition & triage
Identify warning signs: abdominal pain, persistent vomiting, bleeding, lethargy, hepatomegaly, rising HCT. Any warning sign requires hospitalisation. Hypotension or narrow pulse pressure (<20 mmHg) indicates severe shock → PICU admission.
2
Initial assessment & monitoring
Baseline HCT, platelets, LFTs. Insert urinary catheter for hourly UOP. Monitor vitals q1h, HCT q2-4h. CVP monitoring if available. Bedside ultrasound for pleural effusion/ascites.
3
Fluid resuscitation (HCT-guided)
• Compensated shock: crystalloid 5-10 mL/kg over 1 hour
• Hypotensive shock: colloid (5% albumin) 10-20 mL/kg rapid bolus
• Reassess after each bolus. Target: UOP >1 mL/kg/h, HCT decreasing, pulse pressure widening
4
Manage refractory shock
If HCT rising but no improvement → continue fluids. If HCT falling or normal with shock → suspect occult bleeding → transfuse PRBC. If shock persists despite normal HCT and adequate CVP → consider inotropes (dobutamine/milrinone).
5
Bleeding management
No prophylactic platelets. Transfuse platelets only for active bleeding or pre-procedure (target >50,000). PRBC for significant bleeding with falling HCT. FFP for coagulopathy with bleeding. Avoid IM injections, NSAIDs.
6
Recovery phase & de-resuscitation
Watch for diuresis and HCT normalisation → stop IV fluids. If fluid overload develops (respiratory distress, oedema), give furosemide 0.5-1 mg/kg. Avoid rapid fluid discontinuation.