Author: Ciaran Eugene McKenna / Editor: John P Sloan / Reviewer: Jolene Rosario / Codes: EnvC8, PhC4, SLO3 / Published: 05/10/2020

A 36-year-old female, with a previous history of asthma, is brought to the Emergency Department (ED) at 1840hrs on a Saturday afternoon.

She was enjoying a walk through scenic woodlands in North West England (approximately 20km from a large zoo with a reptile enclosure) when she saw a snake on the pathway and stooped to take a photograph with her mobile phone. She subsequently was bitten on her right hand. The patient attended a local community hospital, but rapidly deteriorated. The paramedics found her to be pale, sweaty, wheezy, dizzy and light-headed with a BP of 82/46. The patient then had a syncopal episode. She was treated for anaphylaxis with IM adrenaline 0.5mg, nebulised B-agonists, IV steroids and a 500ml bolus of 0.9% Sodium Chloride (NaCl) IV. She vomited several times during transfer.

On arrival to the ED the patient has mild lip swelling, but no overt airway compromise, respiratory distress or stridor. Respiratory rate is 20/min with slight wheeze, SpO2 98% on room air. Pulse 110/min BP 110/64. Two puncture wounds to the dorsal aspect of her right hand are noted, and the hand itself is slightly swollen.

A further 1000mls of 0.9% NaCl is given as a bolus along with IV chlorpheniramine 10mg. Despite this, her blood pressure has dropped to 74/42. Another dose of 0.5mg IM adrenaline is given along with a further 1000mls of IV 0.9% NaCl. Her BP has improved to 106/48 but has needed 4000mls of crystalloid in total, along with another dose of IM adrenaline to maintain a systolic BP >90mmHg. Her tetanus status is unclear, so a tetanus booster is administered.

An initial ABG has revealed a metabolic acidosis.

  • pH 7.29
  • pCO2 4.5 kPa
  • pO2 10.3 kPa
  • HCO3 17.6 mmol/L
  • Base Excess -10.3 mmol/L
  • SpO2 96%
  • FiO2 21%

ECG has demonstrated sinus rhythm with widespread flattening of T-waves, but no acute ST changes or conduction abnormalities.

The mobile phone picture is shown to a staff nurse in the ED, whose husband is a research scientist at a local university’s Tropical Medicine Venom Department. The reptile has been identified as a European Viper (Vipera berus) more commonly known as an Adder in the UK.

Following consultation with the National Posions and Information Service, antivenom administration is advised. None is immediately available in the local ED and it has to be sourced regionally.

Fortunately, the staff nurse’s husband has access to Antivenom in his research facility and this is delivered to the ED, prior to arrival of the NHS regional supply, and is administered to the patient.

The patient is admitted on a monitored bed under the care of the acute physicians with plastic surgery review. Her bites do not require surgical intervention other than elevation and analgesia, and antibiotics.

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