Viparidae

Venom can cause local tissue injury, systemic vascular damage, hemolysis, fibrinolysis, and neuromuscular dysfunction

• 25% are dry bites

• Swelling may progress over minutes to hours

• Compartment syndrome is rare

• Labs: platelet count, hemoglobin, fibrinogen, fibrin degradation products, D-dimer, pt, ptt

• Management: admit to burn, wound care, elevation and immobilization of extremity, tetanus

• Antivenom: Crotalidae Polyvalent Immune Fab (Crofab) vs. Crotalidae equine immune F(ab’)2

  • Indicated if systemic symptoms, hematological abnormalities, rapidly progressing symptoms and edema

  • Anaphylaxis common with Crofab

  • Anavip is a F(ab’)2 fragment with two venom binding sites, compared to a CroFab which is a single Fab fragment with one venom binding site

  • The F(ab’)2 confers a longer elimination half-life, and therefore is proposed to require less re-dosing than the single Fab antivenom