Neurotoxicity
Neurotoxicity manifests in different ways, depending on the animal responsible for envenomation. For instance:
- Some snake venoms show actions which initially involve the cranial nerves, thence causing a descending paralysis over time.
- Funnelweb spider envenomations are characterised by a condition labelled "sympathetic overdrive", which may include localised sweating, piloerection and fasciculation, excessive salivation and lachrymation, tachycardia and hypertension.
- Paralysis tick venom causes an ascending paralysis, with the lower limbs involved before the trunk.
- Blue-ringed octopus venom typically acts initially on the VIIth cranial nerve.
In cases where antivenom is available, its use is the surest way to resolve neurotoxicity. In other cases it is appropraiate to treat the condition symptomatically, for instance, mechanical ventilation where diaphragmatic involvement is evident.
Last updated: July 2005
