What is the immediate management for a patient with a snake bite and hypertensive urgency?

Immediate Management of Snake Bite with Hypertensive Urgency

For a patient with snake bite and hypertensive urgency, immediate management should include activating emergency services, immobilizing the bitten extremity, removing constricting objects, and administering antivenom along with careful blood pressure control using IV labetalol or nicardipine.

Initial Snake Bite Management

• Activate emergency services immediately for any person bitten by a venomous or possibly venomous snake 1
• Rest and immobilize the bitten extremity to reduce systemic absorption of venom 1
• Remove rings and other constricting objects from the bitten extremity to prevent damage from swelling 1
• Transport the victim to a medical facility as quickly as possible, as definitive treatment (antivenom) is only available in healthcare settings 1

Harmful Practices to Avoid

• Do NOT apply ice to a snakebite wound as it has unproven benefits and may cause tissue injury 1
• Do NOT use suction devices (with or without incision) as they are ineffective for venom removal 1
• Do NOT apply tourniquets as they can worsen local tissue injury 1
• Do NOT use pressure immobilization bandaging in North America, as it may worsen tissue injury with cytotoxic venoms 1

Antivenom Administration

• Administer Anti-Snake Venom (ASV) as the cornerstone of treatment for venomous snakebites 2
• The recommended initial dose is 10 vials administered intravenously after appropriate testing for hypersensitivity 2
• Hospitals should have at least 12 vials of Anti-Snake Venom available for most pit viper envenomations in North America 2
• Have epinephrine readily available for treatment of potential anaphylactic reactions to antivenom 2

Management of Hypertensive Urgency

• For patients with hypertensive urgency (severe hypertension without evidence of acute organ damage), careful BP reduction is needed 3

• IV labetalol is recommended as first-line therapy for severe hypertension in the setting of snake bite 3, 4

  • Initial dose: 0.25 mg/kg IV, with additional doses of 0.5 mg/kg at 15-minute intervals as needed 4
  • Maximum cumulative dose: 3.25 mg/kg 4
  • Monitor for maximal effect within 5 minutes of administration 4

• Nicardipine is an alternative option for blood pressure control 3, 5

  • Administer by slow continuous infusion at a concentration of 0.1 mg/mL 5
  • Initial rate: 5 mg/hr, with increases of 2.5 mg/hr every 15 minutes up to a maximum of 15 mg/hr 5
  • For more rapid blood pressure reduction, titrate every 5 minutes 5

Blood Pressure Targets

• Reduce mean arterial BP by no more than 25% within the first hour 3
• Then, if stable, aim for BP of 160/100-110 mmHg within the next 2-6 hours 3
• Avoid excessive falls in pressure that may precipitate renal, cerebral, or coronary ischemia 3

Special Considerations

• Snake venom can cause autonomic dysfunction leading to severe hypertension that may respond to antivenom administration 6
• Some elapid snake envenomations (like krait bites) can cause severe hypertension requiring intravenous vasodilators 6
• Monitor for potential complications including:
  • Coagulopathy, which may occur with certain snake venoms 7
  • Renal dysfunction, which can be exacerbated by both snake venom and hypertension 7
  • Neurological symptoms, particularly with elapid envenomation 8

Monitoring and Follow-up

• Perform comprehensive work-up to look for hematologic, neurologic, renal, and cardiovascular abnormalities 7
• Monitor vital signs, including blood pressure, continuously during initial management 3
• Assess for signs of progressive envenomation (worsening swelling, ecchymosis, coagulopathy, or systemic effects) 9
• Continue blood pressure monitoring after initial control, as recurrence of hypertension may occur 4

Pitfalls to Avoid

• Delaying transport to a medical facility to attempt ineffective first aid measures 1
• Using short-acting nifedipine, which is no longer considered acceptable in the initial treatment of hypertensive emergencies or urgencies 3
• Failing to monitor for potential recurrence of venom effects, even after initial antivenom administration 9
• Overlooking the possibility that hypertension may be directly related to the snake venom's effect on autonomic function 6