Rattlesnakes are pit vipers whose venom damages tissue around the bite and can disturb blood clotting and blood pressure. Some bites are dry with no venom, yet every bite needs hospital evaluation because swelling and bleeding problems can worsen over hours.
Key symptoms
- Fang marks with burning pain at the bite
- Swelling and bruising that spread up the limb
- Nausea, sweating and a metallic or rubbery taste
- Tingling around the mouth or muscle twitching
- Dizziness or fainting in severe bites
What you find on exam
- Mark the edge of swelling and the time every 15 to 30 minutes
- Vital signs; look for low blood pressure
- Bleeding from the gums, IV sites or the bite
- Circulation, sensation and movement of the limb
- Airway swelling if the bite is on the face or neck
Tests
- Blood count with platelets
- PT/INR, fibrinogen and D-dimer
- Repeat labs and swelling checks over time
- Creatine kinase and kidney function in severe cases
Treatment basics
- Keep the patient calm, remove rings and watches, keep the limb still at heart level
- No tourniquet, cutting, suction, ice or electric shock
- Rapid transport to a hospital with antivenom
- Crotalidae antivenom (Fab or F(ab')2) for spreading swelling, abnormal labs or systemic signs
- Pain control with an opioid such as fentanyl; avoid NSAIDs; update tetanus
Red flags
- Swelling spreading quickly toward the trunk
- Low blood pressure, fainting or vomiting
- Bleeding from the gums, in the urine or at IV sites
Practice it in Making Synapses
Making Synapses cases
Related guides
Sources: NASEMSO National Model EMS Clinical Guidelines; NREMT psychomotor skill sheets (EMT and Paramedic); National EMS Education Standards (2021). Written by Making Synapses. Making Synapses is not affiliated with these organizations.