Review of scorpion envenomation

August 12, 2014, 12:17 am

Asian forest scorpion

Asian forest scorpion

★★★☆☆

Scorpion Envenomation. Isbister GK, Bawaskar HS. N Engl J Med 2014 Jul 31;371:457-463.

Reference

“O! full of scorpions is my mind, dear wife!”
Macbeth

With over 1700 species of scorpions found all over the world, this brief review article is much too short and unfocused to provide more than a superficial overview of its topic.

The authors point out that most scorpion stings cause, at most, minor toxicity with pain and other local effects only. Most serious envenomations are associated with the Buthidae family, which include the genus Centruroidesseveral of which are found in North America and commonly cause neuromuscular excitation.

Major toxicity is associated with α-toxins, which inhibit deactivation of voltage-gated sodium channels causing sympathetic and parasympathetic autonomic excitation, as well as the release of catecholamines epinephrine and norepinephrine. This can result in:

  • hypertension
  • myocardial injury
  • cardiogenic shock
  • impaired left ventricular function
  • hypotension
  • cardiac conduction abnormalities
  • pulmonary edema

Features of the sympathomimetic or cholinergic toxidromes can be prominent.

Use of antivenom in cases of scorpion stings is controversial, and this article really doesn’t provide much enlightenment regarding the pros and cons. The authors do note that although antivenom would seem to be more useful in cases of clinically severe envenomation, by the time clinical severity is apparent it may be rather late in the game — although antivenom can bind toxins and prevent progression, it does not reverse established injury. (A list of scorpion antivenoms available worldwide, as well as a summary of the effects of envenomation, can be found here.)

This fascinating video, featuring Dr. Leslie Boyer from the University of Arizona, makes the case for use of antivenom in stings by the Arizona bark scorpion (Centruroides sculpturatus). It also provides an unforgettable illustration of neuromuscular toxicity:

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