What is the appropriate emergency management for a patient who has been bitten by a snake?

Emergency Management of Snake Bite

Immediately activate emergency medical services and transport the patient to a hospital as quickly as possible, as antivenom—the only definitive treatment—is available exclusively in hospital settings. 1, 2

Immediate Field Actions (Do These)

Universal First Steps for All Snake Bites

• Call 911 or activate emergency medical services immediately for any venomous or possibly venomous snake bite, as transport by EMS allows delivery of supportive care en route. 1

• Remove all rings, watches, jewelry, and constricting objects from the bitten extremity immediately before progressive swelling develops, as edema can cause ischemic injury to digits and tissues. 1, 2

• Immobilize the bitten extremity and keep it at or below heart level to minimize venom absorption through the lymphatic system—this is reasonable if it does not delay access to emergency care. 1, 2

• Minimize all physical exertion by the victim during transport, as walking or activity for ≥10 minutes increases systemic absorption of venom based on radiotracer studies. 1, 2

Geographic and Venom-Type Specific Considerations

For North American pit viper bites (rattlesnakes, copperheads, cottonmouths):

• Do NOT apply pressure immobilization bandaging, as this may worsen local tissue injury by trapping cytotoxic venom at the bite site. 1, 2
• These snakes cause hemotoxic/cytotoxic envenomation with progressive local tissue necrosis, coagulopathy, and thrombocytopenia. 2, 3

For neurotoxic snake bites (coral snakes, sea snakes, exotic elapids):

• Apply pressure immobilization bandaging with 40-70 mm Hg pressure in the upper extremity or 55-70 mm Hg in the lower extremity around the entire length of the bitten limb to slow lymphatic dissemination of neurotoxic venom. 2, 4, 5
• The bandage should be snug enough that a finger can barely slip underneath. 2
• This technique is reasonable for neurotoxic envenomation as it slows venom absorption without worsening local tissue damage. 4

Contraindicated First Aid Measures (Do NOT Do These)

The following interventions are potentially harmful and should be avoided:

• Do NOT apply ice or cold therapy—this is of unproven benefit and may cause additional tissue injury from aggressive cryotherapy. 1, 2

• Do NOT use suction devices (with or without incision)—these are ineffective at venom removal, remove negligible amounts, and may aggravate the injury. 1, 2

• Do NOT apply tourniquets—systematic reviews show they are ineffective and worsen local tissue injury without preventing systemic envenomation. 1, 2

• Do NOT use electric shock therapy—this is completely ineffective and potentially harmful. 1, 2

• Do NOT incise the wound or perform excision—these methods cause additional tissue damage without benefit. 3

Critical Clinical Pitfalls to Avoid

Never Assume No Envenomation Based on Minimal Local Findings

• The absence of immediate pain or swelling does NOT rule out serious envenomation—this is particularly critical with neurotoxic bites (coral snakes, sea snakes), which cause life-threatening systemic toxicity despite minimal local findings. 2, 5

• Neurotoxic envenomation can result in progressive paralysis developing within minutes to hours, potentially delayed up to 13 hours after the bite. 2, 4

Do Not Delay Transport for Ineffective Field Interventions

• Time to antivenom is the most important prognostic factor—do not waste critical time attempting ineffective field treatments. 2, 5

Do Not Misapply Pressure Immobilization Techniques

• Never apply pressure immobilization techniques developed for neurotoxic snakes to North American pit viper bites, as this worsens cytotoxic tissue damage. 2
• Studies show that even medical personnel and lay rescuers have low rates of appropriate pressure immobilization bandage placement, even under ideal conditions. 1

Hospital-Based Definitive Treatment

Monitoring and Assessment

• Monitor respiratory rate, blood pressure, heart rate, renal function, fluid balance, and coagulation status continuously. 3

• For neurotoxic envenomation, hospitalize for a minimum of 48 hours with continuous monitoring, as neurotoxicity onset can be delayed up to 13 hours despite minimal local findings. 2, 4

• Watch for signs of neurotoxicity: muscle weakness, ptosis, difficulty swallowing, respiratory distress, or altered mental status. 5, 6

Antivenom Administration

• Antivenom is the only specific treatment and definitive therapy for snake envenomation—it is not available in first aid settings. 1, 3

• For North American pit viper envenomation, polyvalent antivenin (CroFab or ACP) should be administered based on the degree of envenomation (local vs. systemic signs). 4, 7, 8

• For neurotoxic envenomation, North American Coral Snake Antivenin should be administered to all patients with confirmed or suspected neurotoxic envenomation showing any signs of neurotoxicity. 4

• The general indication for antivenom administration is presence of progressive venom injury, defined as worsening local injury (swelling, ecchymosis), clinically important coagulation abnormality, or systemic effects (hypotension, altered mental status). 7, 8

Understanding Venom Types for Proper Management

Hemotoxic/cytotoxic venom (pit vipers):

• Causes progressive local tissue necrosis, coagulopathy, thrombocytopenia, and wounds that are red, warm, tender, and swollen. 1, 2
• Pressure immobilization is contraindicated. 2

Neurotoxic venom (coral snakes, sea snakes, elapids):

• Causes minimal local injury but progressive paralysis and respiratory failure through inhibition of acetylcholine release or blockage of acetylcholine receptors. 2, 6
• Pressure immobilization is beneficial. 2, 4