Cytotoxic and neurotoxic snakebite

T63.0 + (X20.99)

MEDICINE TREATMENT

Polyvalent antivenom

Used in some cytotoxic and neurotoxic envenomations, only when indicated

Obtainable from South African Vaccine Producers (tel: (011) 386-6063/2/78 or afterhours 0716809897 or 0828842971). See package insert for full details.

Note:

  • In most cases patients do not need and should not be given antivenom.

LoEIII [3]

  • Adverse reactions to antivenom are common and may be severe. Pre-medication with adrenaline (epinephrine) may reduce the risk of severe adverse reactions to polyvalent snake antivenom.
  • The dose of antivenom is the same for adults and children.
  • Monitor for any deterioration in respiratory function as patients may need ventilation whether or not polyvalent antivenom has been given.
  • Antivenom should be given as soon as possible, however administration may be considered even as late as 48-72 hours after the bite, if there is continued clinical deterioration indicating ongoing venom activity.

LoEIII [4]

Indications for polyvalent antivenom:

  • Signs of neurotoxicity.
  • Positively identified puff adder, Gaboon adder, Mozambique spitting cobra or rinkhals bites AND evidence of progressive severe cytotoxicity.
  • Unidentified snakebites and evidence of progressive severe cytotoxic envenomation i.e.:
    • swelling of whole hand or foot within 1 hour
    • swelling to the knee or elbow in less than 6 hours
    • swelling of the whole limb in less than 12 hours
    • swelling progression >2.5 cm per hour
    • a threatened airway due to swelling
    • evidence of complication e.g. compartment syndrome

Systemic evidence of severe cytotoxicity includes:

  • shock
  • haematological abnormalities: INR >1.5, Hb <8 g/dL, thrombocytopaenia (<100 x 109/L) or leucocytosis (>10 x 109/ L)
  • arrhythmias (rare)

LoEIII [5]

Note: Polyvalent antivenom is ineffective against the venom of:

  • night adders, berg adders and other smaller adders,
  • boomslang, and
  • vine/twig snakes.

Caution

Never administer antivenom without being prepared to manage

acute anaphylaxis.

Administration and polyvalent antivenom dose:

  • Pre-treat with adrenaline (epinephrine), SC, 0.25 mL of 1:1000 solution.

(Contraindicated in patients with IHD, stroke, uncontrolled hypertension

and tachyarrhythmia).

LoEI [6]

  • Polyvalent snake antivenom, slow IV infusion.

LoEIII [7]

LoEIII [8]