USMLE Prep - Medical Reference Library

Snakebite Pit Viper - First Aid and Antivenom

System: Wilderness Medicine • Reviewed: Aug 31, 2025 • Step 1Step 2Step 3

Synopsis:

Keep patient calm, immobilize the limb at heart level, avoid incision or suction, and transport for assessment and antivenom when indicated; monitor for coagulopathy and compartment syndrome.

Key Points

  • Stabilize ABCs; begin targeted evaluation without delaying life-saving therapy.
  • Use system-specific risk tools to guide testing and disposition.
  • Order high-yield tests first; escalate imaging when indicated.
  • Start evidence-based initial therapy and reassess frequently.

Algorithm

  1. Primary survey and vitals; IV access and monitors.
  2. Focused history/physical; identify red flags and likely etiologies.
  3. Order system-appropriate labs and imaging (see Investigations).
  4. Initiate guideline-based empiric therapy (see Pharmacology).
  5. Reassess response; arrange consultation and definitive management.

Clinical Synopsis & Reasoning

For Snakebite Pit Viper First Aid Antivenom, frame the differential by acuity and pathophysiology, then align diagnostics to the leading hypotheses. Prioritize stabilization while obtaining high‑yield studies such as CBC (Baseline hematology), BMP (Electrolytes/renal). Incorporate bedside imaging and targeted labs to define severity and identify complications; synthesize results with clinical trajectory to refine the working diagnosis and disposition needs.


Treatment Strategy & Disposition

Initiate disease‑directed therapy alongside supportive care, titrating to objective response. Pharmacologic options commonly include Analgesia/Antipyretics. Use validated frameworks (e.g., Do Not Do) to guide escalation and site of care. Address precipitating factors, de‑escalate empiric therapies with data, and arrange follow‑up for monitoring and risk‑factor modification; admit patients with instability, high risk of deterioration, or needs for close monitoring.


Epidemiology / Risk Factors

  • Risk factors vary by condition and patient profile

Investigations

TestRole / RationaleTypical FindingsNotes
CBCBaseline hematologyAbnormal counts
BMPElectrolytes/renalDerangements

Do Not Do

ActionReason
Incision or suctionTissue damage, ineffective
Tourniquet or iceWorsens injury
Alcohol or caffeineIncreases absorption risk

Pharmacology

MedicationMechanismOnsetRole in TherapyLimitations
Lidocaine (local infiltration)Na⁺ channel blockadeMinutesLocal anesthesia for repairLAST (rare)
Amoxicillin/clavulanate (selected)β-lactam/β-lactamase inhibitorDaysHeavily contaminated or bite woundsGI upset
Tetanus prophylaxisVaccine/IG per statusHoursAs indicatedLocal rxn

Prognosis / Complications

  • Prognosis depends on severity, comorbidities, and timeliness of care

Patient Education / Counseling

  • Explain red flags and when to seek emergent care.
  • Reinforce medication adherence and follow-up plan.

Notes

Pressure immobilization bandage is for certain neurotoxic elapids and not for pit vipers in North America.


References

  1. CDC snakebite treatment overview — Link
  2. Wilderness Medical Society venomous bites guideline — Link