What are the practice guidelines for treating a snake bite?

Practice Guidelines for Snake Bite Management

Activate emergency services immediately and transport the victim to a medical facility as rapidly as possible, as antivenom—the only definitive treatment—is exclusively available in hospital settings. 1, 2

Immediate First Aid at the Scene

Critical Actions to Take

• Immobilize the bitten extremity and keep the victim at rest to minimize systemic venom absorption through the lymphatic system 1, 2
• Remove all rings, watches, and constricting items from the affected limb immediately to prevent ischemic injury as swelling develops 1, 2
• Minimize patient exertion during transport, as walking and movement increase subcutaneous absorption of venom 2
• Do not wash the bite wound, as residual venom at the site is needed for species identification in the hospital 3

Absolutely Contraindicated Interventions

The following practices are ineffective and potentially harmful—never perform these interventions: 1, 2

• No ice application: causes tissue injury without proven benefit 1
• No suction devices (with or without incision): ineffective for venom removal and causes additional tissue damage 1
• No electric shock therapy: completely ineffective and dangerous 1
• No tourniquets: worsen local tissue necrosis 1
• No pressure immobilization bandaging in North America: this technique, developed for Australian neurotoxic snakes, worsens tissue injury with the cytotoxic venoms predominant in North American pit vipers 1, 2

Note: The older recommendation of incision and suction if medical care is more than 30 minutes away 4 has been superseded by current guidelines that explicitly contraindicate this practice due to tissue injury risk 1, 2.

Hospital-Based Medical Management

Antivenom Therapy

• Antivenom is the cornerstone and only definitive treatment for venomous snakebites 1, 2
• Administer antivenom within 4 hours of the bite for maximum effectiveness 4
• Perform skin allergy testing before antivenom administration to predict hypersensitivity reactions 5
• Have epinephrine immediately available at the bedside for potential anaphylactic reactions to antivenom 2
• Be particularly vigilant for allergic reactions in patients receiving antivenom a second time, as they may develop IgE-mediated immediate hypersensitivity even if they tolerated the first dose 5

Species-Specific Considerations

Pit Vipers (Rattlesnakes, Copperheads, Cottonmouths) - 99% of US envenomations: 2, 4

• Produce cytotoxic effects: tissue injury, swelling, pain, ecchymosis, coagulopathy, hypotension, and bleeding 2
• Treat with CroFab antivenom 2
• Monitor for local tissue necrosis, which is the major clinical finding 4
• Patients with pain, swelling, ecchymoses, systemic symptoms, or abnormal laboratory findings within 30-60 minutes are candidates for antivenom 4

Coral Snakes (Southeast and Southwest US) - 1% of US envenomations: 2, 4

• Produce neurotoxic effects with minimal tissue injury 1, 2
• Clinical signs may be delayed 10-18 hours after the bite 6
• Progression includes altered mental status, generalized weakness, muscle fasciculations, then paralysis of limbs and respiratory muscles 6
• Once clinical signs manifest, they progress with alarming rapidity and are difficult to reverse 6
• Require specific monitoring for respiratory compromise and potential mechanical ventilation for 48-72 hours 6
• Administer M. fulvius antivenom as the only definitive treatment 6

Supportive Care

• Administer plasma expanders, pain medication, diazepam, tetanus toxoid, antiseptics, and antibiotics as indicated 4
• Hospitalize all suspected envenomations for minimum 48 hours for continuous monitoring, particularly for coral snake bites where symptom onset is delayed 6
• Provide mechanical ventilation support if respiratory paralysis develops 6

Epidemiology and Risk Context

• Approximately 8,000-10,000 snakebite injuries occur annually in the US, with an average of 6-15 deaths per year 2, 4
• Most bites occur during warmer months and involve the extremities 1
• Attempts to kill or handle snakes are dangerous and often result in finger bites—avoid this behavior 3

Critical Pitfalls to Avoid

• Never delay transport to attempt ineffective first aid measures 2
• Do not fail to remove constricting items, which leads to progressive ischemic injury 1
• Do not allow excessive victim movement, which accelerates venom absorption 1
• Do not use pressure immobilization techniques developed for neurotoxic Australian snakes on North American cytotoxic snake bites 1
• Do not assume coral snake bites are benign due to lack of immediate symptoms—they require prolonged observation 6