ALGORITHM FOR DISTRIBUTIVE SHOCK
Distributive shock occurs due to abnormal vasodilation and maldistribution of blood flow, leading to inadequate tissue perfusion despite normal or increased cardiac output. The most common causes are sepsis, anaphylaxis, and neurogenic shock.
Key Goals of Treatment:
Restore adequate perfusion and prevent organ failure. Correct vasodilation with fluids and vasopressors. Identify and treat the underlying cause (e.g., infection, anaphylaxis, spinal cord injury).
RECOGNITION: SIGNS OF DISTRIBUTIVE SHOCK
Early (Compensated) Signs:
- Tachycardia (earliest and most sensitive sign).
- Bounding pulses, widened pulse pressure (low diastolic BP).
- Warm extremities, flushed skin (in early sepsis or anaphylaxis).
- Altered mental status (irritability, confusion).
Late (Decompensated) Signs:
- Cold extremities (shock progression to hypoperfusion).
- Weak pulses, delayed capillary refill.
- Hypotension (late sign, ominous in children!).
- Lethargy, unresponsiveness.
Key Differentiator:
- Warm extremities + Bounding pulses = Early Distributive Shock.
- Cold extremities + Weak pulses = Late (decompensated) Shock.
MANAGEMENT ALGORITHM FOR DISTRIBUTIVE SHOCK
Step 1: Administer High-Flow Oxygen
100% oxygen via non-rebreather mask to optimize oxygen delivery. If respiratory distress worsens, consider intubation and mechanical ventilation.
Step 2: Establish Vascular Access and Give IV Fluids
Establish IV or IO access immediately. Fluid Resuscitation:
- 20 mL/kg isotonic crystalloid (NS or LR) over 5-10 minutes.
- Repeat boluses up to 60 mL/kg as needed, reassessing after each bolus. Monitor for Fluid Response:
- Improved pulses, capillary refill, urine output >1 mL/kg/hr.
- If persistent hypotension → Move to Step 3 (Vasopressors).
If fluid overload occurs (crackles, hepatomegaly), STOP fluids and initiate vasopressors.
Step 3: Initiate Vasopressors if Fluid Resuscitation Fails
If hypotension persists after 60 mL/kg of fluids, vasopressors are required.
| Condition | First-Line Vasopressor | Additional Therapy |
|---|---|---|
| Septic Shock | Norepinephrine (preferred), Dopamine | Epinephrine (if cold shock) |
| Anaphylactic Shock | Epinephrine IM (first-line), then IV infusion if needed | Antihistamines, corticosteroids |
| Neurogenic Shock | Norepinephrine, Dopamine | Atropine (if bradycardia present) |
Cold Septic Shock (poor perfusion, delayed cap refill)? → Use Epinephrine. Warm Septic Shock (bounding pulses, hypotension)? → Use Norepinephrine.
Step 4: Identify and Treat the Underlying Cause
A. Septic Shock Management
Start Broad-Spectrum Antibiotics ASAP (within 1 hour!)
- Neonates: Ampicillin + Gentamicin/Cefotaxime.
- Infants/Children: Vancomycin + Ceftriaxone/Cefotaxime. Consider Hydrocortisone for Refractory Shock.
B. Anaphylactic Shock Management
First-line treatment = IM Epinephrine (0.01 mg/kg, max 0.3 mg/dose)
- Repeat every 5-15 min as needed. Adjunct Medications:
- Diphenhydramine (H1 blocker) + Ranitidine (H2 blocker) → Reduce histamine effects.
- Methylprednisolone (1-2 mg/kg IV) → Prevent delayed reaction. Albuterol Nebulization if bronchospasm is present. Fluid Resuscitation (if hypotensive). IV Epinephrine infusion if IM dosing is insufficient.
C. Neurogenic Shock Management
Maintain Spinal Precautions (C-collar, immobilization). Vasopressors (Norepinephrine or Dopamine) to support BP. Atropine if bradycardia is present.
QUICK REFERENCE: PEDIATRIC DISTRIBUTIVE SHOCK MANAGEMENT
| Step | Action | Key Considerations |
|---|---|---|
| 1 | Oxygen | 100% via non-rebreather, consider ventilation if needed |
| 2 | IV/IO Access | IV first, IO if IV fails within 60-90 sec |
| 3 | Fluids: 20 mL/kg NS/LR | Repeat up to 60 mL/kg, reassess after each bolus |
| 4 | Vasopressors | Norepinephrine (sepsis), Epinephrine (anaphylaxis), Dopamine (neurogenic shock) |
| 5 | Identify & Treat Cause | Antibiotics (sepsis), Epinephrine IM (anaphylaxis), Spinal precautions (neurogenic) |
WHEN TO ESCALATE BEYOND FLUIDS?
If shock persists despite 60 mL/kg of fluids:
Condition Next Steps
Septic Shock Start Norepinephrine or Epinephrine, give antibiotics
Anaphylaxis IV Epinephrine infusion, steroids, antihistamines
Neurogenic Shock Vasopressors + Atropine if bradycardic
If worsening respiratory distress (stridor, wheezing, edema), intubate immediately.
SIGNS OF IMPROVEMENT AFTER TREATMENT
Heart rate normalizes. Strong, central pulses return. Warm extremities (septic shock resolution). Urine output >1 mL/kg/hr. Mental status improves (alert, responsive).
If these signs are absent, escalate to advanced shock management.
SUMMARY: WHY EARLY DISTRIBUTIVE SHOCK MANAGEMENT MATTERS
Early fluid resuscitation prevents decompensation. Vasopressors must be started early if fluids fail. Treating the underlying cause (sepsis, anaphylaxis, neurogenic injury) is key. Monitor for signs of improvement and escalate treatment as needed.
Takeaway: Pediatric distributive shock progresses rapidly—early recognition, fluid resuscitation, and targeted interventions are critical to survival.