Today I had a 5 year old child presenting with a snake bite on the right foot 36 hours ago. He was booked in theatre for a fasciotomy.
On examination of the child, he had severe swelling of the leg up to the mid-thigh level. He was in severe pain. The leg felt very tense & His pulses were impalpable. I was able to detect a very faint arterial pulse with the use of a saturation probe (a monitoring device used to detect oxygen level in the blood). He had a tachycardia (fast heart rate) and a temperature – typical of the inflammatory response to the venom (known as SIRS)
The bite site itself was unremarkable – no bleeding or blistering. His blood results showed an abnormal clotting profile – his INR was 2.0 (double the normal) indicating that he has a coagulopathy. However, there was no bleeding from IV puncture sites, his gums, his nose or any other sites.
The snake was described as “black” but that was the sum total of the description. There was no parent present to give any further information. The patient had the clinical syndrome of progressive swelling plus coagulopathy. The possible culprit could be a puff adder, but the lack of local skin changes was against this. Snake bite is treated syndromically, however, so the identity is immaterial.
The surgeons wanted to do an immediate fasciotomy. I managed to convince them of an alternative management plan.
We induced anaesthesia in the child and secured his airway with an endotracheal tube. Then, I gave him a pre-treatment dose of intramuscular adrenalin (dosage based on the paper by Silva et al entitled “Low-Dose Adrenaline, Promethazine, and Hydrocortisone in the Prevention of Acute Adverse Reactions to Antivenom following Snakebite: A Randomised, Double-Blind, Placebo-Controlled Trial” www.plosmedicine.org May 2011 | Volume 8 | Issue 5)
We gave him some plasma to counteract the clotting abnormality. We then administered 5 vials of polyvalent antivenom over 30 minutes. During this time, there was no change in his heart rate, blood pressure or airway pressure (i.e. no bronchospasm) – he had no signs of allergy or anaphylaxis. We gave him co-treatment of hydrocortisone 10mcg/kg and promethazine 6.25mg.
We then measured his compartmental pressures directly via a needle attached to an electronic transducer. Unfortunately, the pressures inside his compartments were very high. The pressures inside his muscles exceeded his diastolic blood pressure. This was confirmation that he did indeed have a compartment syndrome. Had we waited for loss of the arterial pulsation (which would have been inevitable given the pressure), we would have missed the boat to salvage the limb.
We made a decision to proceed with the fasciotomy. This was very sad but I do not regret the decision.
The antivenom will still help with his pain and will prevent further swelling of the limb. It will also help to treat the coagulopathy.
I will keep you informed of his progress.