Initial Priorities
1. Airway, breathing, circulation, and rapid antivenom administration are the critical priorities during stabilization and treatment of a snakebite casualty.
2. DO NOT apply constricting bandages or tourniquets as these may worsen local tissue injury and increase the risk of permanent disability.64–66
If a tourniquet is already in place, do not remove it until you are ready to treat and resuscitate the patient as a rapid decompensation can occur.67,68 When removing a tourniquet do so sequentially (loosen for several seconds - tighten - observe - repeat) over 20 - 30 mins; if symptoms develop at any time administer antivenom and wait at least 30 minutes before resuming tourniquet release. Ideally, this should not be done until antivenom is available but prolonged evacuation times without antivenom may necessitate the risk of earlier removal to prevent limb death. Refer to the Joint Trauma System Tactical Combat Casualty Care (TCCC) Guidelines for tourniquet conversion in these settings.
3. If and when conditions allow, minimize patient activity and loosely immobilize bitten limb to reduce movement without constricting tissues.
4. Evaluate for specific signs and symptoms of snake envenomation. See Table 1 and refer to specific criteria for initial antivenom treatment and repeat doses for additional information.
Focused Assessment and Examination
Perform a physical examination and history focused on identifying signs and symptoms of neurotoxic, hemotoxic, and cytotoxic envenomation syndromes.
1. Determine how long ago the bite occurred. Circle the site of the bite wound and write the specific time that it occurred with a permanent marker on the patient
2. Do not rely on fang marks to assess the possibility of a bite or envenomation. Snakebites can leave punctures, multiple lacerations, or even no obvious fang marks whatsoever.
3. Rapid examination for signs of pain, swelling, or tissue destruction (cytotoxic syndrome). Separately mark the leading edge of both pain (dashed line) and edema (solid line) with a permanent marker and record time of observation next to each line
4. Rapid examination for signs of local or systemic bleeding (hemotoxic syndrome)
5. Rapid examination for signs of neuromuscular weakness (neurotoxic syndrome)
Ask the patient to take a deep breath and count as high as possible in their normal speaking voice without taking another breath. Demonstrate the test to the patient, then have them repeat it and record the highest number reached.
- SBC correlates closely with spirometry.
- Normal SBC is approximately 50 and SBC < 20 is associated with the need for mechanical ventilation.
- Signs and symptoms of descending flaccid paralysis: Ptosis, diplopia, neck flexor muscle weakness, bulbar weakness, etc.1,54,73
- Signs and symptoms of parasympathetic / cholinergic crisis: SLUDGE mnemonic - Salivation, Lacrimation, Urination, Defecation, GI distress, Emesis
Unstable Patients
Sudden Collapse Syndrome Treatment Protocol
Patient presents within 30 minutes of the bite with rapid onset shock ± angioedema, altered mental status, systemic bleeding, and diarrhea.1
See Sudden Collapse Syndrome section for more information.
Lab Tests
Advanced laboratory tests include:
Simple coagulation test for austere environments: Use the Whole Blood Clotting Test (WBCT) as described in Appendix A to diagnose and monitor coagulopathy if advanced labs not available
Transport Factors
1. If the patient is being medically evacuated from the field or between roles of care, confirm that the receiving facility has an adequate supply of the appropriate regionally specific antivenoms listed in this CPG to ensure treatment coverage against local species of concern.
NOTE: Evacuation is not an alternative to antivenom administration. A patient whose snakebite warrants evacuation will require antivenom. The earlier it is given the greater the chance of full recovery without permanent disability. DO NOT delay administration of antivenom in the field to a patient with an envenomation.
2. If clinical evidence of envenomation is present and treatment is occurring in a hospital setting, always admit to a bed with continuous vital sign monitoring if available. If no initial clinical evidence of envenomation, admit for 24 hours for observation. If treating in the field, continuously monitor patient trends for signs of progression, improvement, or deterioration.
3. Symptoms should be expected within 24 hours; if the patient is completely asymptomatic after 24 hours then they most likely received a dry bite and can be discharged. See Discharge Criteria.