Snake bite: envenoming, antivenom and supportive care

Manage now— do this, in order

• Resuscitate first — A, B, C before vials. Keep the patient still, splint the bitten limb at approximately heart level, do not let them walk; remove rings, bangles and tight clothing before swelling makes them tourniquets; clean the wound with soap and running water and cover with a dry dressing.
• Release any tourniquet or constricting band only when prepared: monitoring attached, IV access established, oxygen running and resuscitation drugs drawn up — release may cause a sudden rush of venom with cardiorespiratory collapse.
• Airway and oxygen: intubate early and electively for face or neck bites, bulbar weakness, drooling or inability to swallow saliva; give high-flow oxygen for neurotoxic signs, shock or bleeding.Doctor / NurseNot available at your setup — Endotracheal intubation kit.
• Access and fluids: two large-bore IV lines in unaffected extremities — minimise venepunctures, avoid non-compressible sites; isotonic crystalloid 20–40 mL/kg IV as reassessed boluses (children 10–20 mL/kg); add noradrenaline if shock persists after fluids and antivenom.Doctor / Nurse
• Give antivenom for a clear indication: shock or arrhythmia; respiratory compromise; rapidly increasing swelling or swelling over half the limb; spontaneous systemic bleeding; incoagulable 20WBCT or abnormal INR; ptosis or any developing paralysis (treat at the first sign, not at breathlessness); black urine; developing renal failure; intractable vomiting. Consult the package insert for dose — children need the same dose as adults.Doctor / Nurse
• Route and rate: IV only — dilute in 0.9% sodium chloride (typically 250 mL for an adult) and infuse over about one hour, starting at 25–50 mL/h for the first 10 minutes. Never perform a skin or test dose; draw up adrenaline and have airway equipment ready before starting, and observe continuously during and for at least an hour after.Doctor / Nurse
• Acute reaction — stop the infusion: adrenaline 1:1000 IM anterolateral thigh 0.5 mg adult (repeat after 5 min if no response; child 0.01 mg/kg, max 0.5 mg); chlorphenamine 10 mg or diphenhydramine 50 mg slow IV (child diphenhydramine 1 mg/kg, max 50 mg); hydrocortisone 100 mg IV (child 2 mg/kg, max 100 mg); oxygen, legs up, crystalloid bolus (child 20 mL/kg). Once controlled, restart at 5–10 mL/h — the envenoming will kill, a treated reaction will not.Doctor / Nurse
• Redose sensibly: effective antivenom halts progression and reverses coagulopathy within about 6 hours — repeat if life-threatening bleeding, shock or paralysis persists a few hours after the first infusion, or blood is still incoagulable at 6 hours. Once paralysis is established and intubation is needed, more antivenom is unlikely to help — ventilate until recovery (days to weeks).Doctor / NurseNot available at your setup — Mechanical ventilator.
• Never do: cut, suck, cryotherapy, electric shock, snake stones or tourniquets; no aspirin or NSAIDs (they aggravate bleeding); no IM tetanus toxoid until coagulopathy is reversed; no blood products before adequate antivenom; no rushed fasciotomy (needed in under 1% — pressures above 30–40 mmHg mean more antivenom, not a knife). For pain: paracetamol 1 g 6-hourly max 4 g/24 h (child 15 mg/kg 6-hourly, max 60 mg/kg/24 h); morphine 2.5–5 mg IV titrated, reduced doses if neurotoxic features.