Page 67 - 2023 SMOG Digital

Environmental

Global Spider and Scorpion Envenomation (Continued)

Scorpions:
Scorpions envenomate humans by stinging them with the telson on their tail. Around 20 species
of medically important (meaning potentially lethal to humans) scorpions are known, and all but
one of these (Hemiscorpius lepturus) are members of the Buthidae family. Buthidae family
contains the large genera Ananteris, Centruroides, Compsobuthus, and Tityus. Centruroides are
the only clinically significant venomous scorpion indigenous to the United States (i.e., Bark
Scorpions). The majority of medically significant envenomations occur in the Middle East,
tropics (e.g., Southwest Asia, India, Central and South America), and North Africa.
Scorpion venoms are complex and can include phospholipase, acetylcholinesterase,
hyaluronidase, serotonin, and neurotoxins. Scorpion venom increases neuronal release by
blocking inactivation of the sodium channel, resulting in an increase in the amplitude and
duration of neuron action potential. The overall result is excess stimulation of the central
nervous system, the neuromuscular system, the sympathetic nervous system, and the
parasympathetic nervous system.
The components of scorpion venom are species specific and generally fall into the categories of
neurotoxic and cardiotoxic; however, this terminology is misleading since the cardiotoxic effects
are secondary to an excess release of catecholamines stimulated by the nervous system. The
venom of the unique species, Hemicorpius lepturus, found in Iraq and Iran is predominately
cytotoxic, similar to the brown recluse spider.
Antivenom is available for some species; data regarding the benefits and risks of many of these
antivenoms are significantly limited. In patients with moderate to severe symptoms refractory
to analgesics and benzodiazepines, antivenom, if available, may be indicated. Due to the high
risk of immediate or delayed allergic reactions to these antivenoms administration should be
done at a controlled clinical location and pre-hospital treatment should be focused on
supportive care. Intravenous histamine antagonists (i.e. diphenhydramine), steroids, and
epinephrine should be immediately available at the patient’s bedside prior to antivenom ENVIRONMENTAL
administration. The Joint Trauma System Clinical Practice Guideline: Global Spider and Scorpion
Envenomation Management (CPG ID: 84) contains a list of antivenoms available by country.
(https://jts.amedd.army.mil/assets/docs/cpgs/Global_Spider_and_Scorpion_Envenomation_Ma
nagement_09_Feb_2021_ID84.pdf)

Prehospital/En Route Care Treatment Goals for Spider and Scorpion Bites and Stings:
Some moderate to severe cases of envonomations will require medical evacuation to a
treatment facility with the capability to administer antivenom. En Route Care consists primarily
of supportive care and pain management. En route care providers should be prepared to
counter cholernergic, adrenergic, sympathetic and parasympathetic effects. Aggressive use of
benzodiazepines as indicated for agitation, neuromuscular stimulation, tachycardia, and
hypertension. Secure the airway and initiate mechanical ventilation if indicated. Anaphylaxis is
the most concerning initial effect. See specific treatment guidelines for Widow Spiders,
Funnel-Web Spiders and Scorpions for additional guidance.

67