A 28-year-old man from Mumbai is on day 6 of dengue fever with dengue haemorrhagic fever (DHF) grade II (platelet count 80,000/μL, haematocrit rise 20%, petechiae, no spontaneous bleeding). He requires fluid resuscitation and is haemodynamically unstable. Which is the drug of choice for managing shock in this patient?

Explanation

## Shock Management in Dengue Haemorrhagic Fever **Key Point:** Crystalloid fluid resuscitation (normal saline or Ringer's lactate) is the first-line and primary treatment for dengue shock syndrome (DSS); vasopressors are only adjunctive and used after fluid optimisation. ### Pathophysiology of Dengue Shock 1. **Plasma leakage** (days 3–7) → hypovolaemia 2. **Capillary permeability** increases due to viral cytokine release 3. **Shock is primarily hypovolaemic**, not cardiogenic or septic 4. **Fluid restoration** restores perfusion and reverses shock ### First-Line Treatment: Crystalloid Fluid Resuscitation **Fluid choice:** - **Normal saline (0.9%)** or **Ringer's lactate** — both acceptable - Avoid hypotonic fluids (D5W, 0.45% saline) — risk of cerebral oedema - Avoid colloids as first-line (higher cost, no mortality benefit, risk of renal failure) **Bolus protocol:** - **10–20 mL/kg IV rapid bolus** over 15–30 minutes - Reassess haemodynamics, urine output, vital signs - Repeat bolus if shock persists - Maintenance: 5–10 mL/kg/hr after stabilisation **Monitoring endpoints:** - SBP ≥90 mmHg, MAP ≥65 mmHg - Urine output ≥0.5 mL/kg/hr - Normalisation of lactate - Resolution of cool extremities ### Role of Vasopressors (Adjunctive Only) | Vasopressor | Indication | Timing | |-------------|-----------|--------| | Dopamine, Noradrenaline | Persistent shock despite adequate fluid | After fluid optimisation | | Dobutamine | Cardiogenic component (rare in dengue) | Not first-line | **High-Yield:** Dengue shock is **fluid-responsive**. The majority of DSS patients respond to crystalloid boluses alone. Vasopressors are reserved for refractory shock (rare, <5% of DSS cases). **Clinical Pearl:** Over-aggressive fluid administration risks dengue-associated acute kidney injury (AKI) and pulmonary oedema. The goal is to restore perfusion, not to maximise fluid input. Reassess after each bolus and titrate carefully. **Warning:** Colloids (albumin, dextran) are NOT first-line in dengue. They increase cost, do not improve mortality, and may worsen renal function. Reserve for refractory shock only. ### Algorithm for Dengue Shock Management ```mermaid flowchart TD A[Dengue Shock Syndrome]:::outcome --> B[Crystalloid bolus 10-20 mL/kg]:::action B --> C{Shock reversed?}:::decision C -->|Yes| D[Maintenance fluids + monitoring]:::action C -->|No| E[Repeat bolus + reassess]:::action E --> F{Persistent shock?}:::decision F -->|Yes| G[Add vasopressor: dopamine/noradrenaline]:::action F -->|No| D G --> H[ICU monitoring]:::outcome ``` [cite:Harrison 21e Ch 197; WHO Dengue Guidelines 2009]