North American Scorpion Envenomations

Abstract

The Arizona bark scorpion, Centruroides sculpturatus, is the only scorpion endemic to the United States that produces a systemic envenomation in humans. Most stings do not result in serious symptoms however, and children are much more likely than adults to experience life-threatening effects. Serious envenomations are classified as Grade III and Grade IV. Findings include neuromuscular hyperactivity, with myoclonic muscle movements, fasciculations, thrashing and twisting of the torso, and restless agitation. Cranial nerve findings also occur and include opsoclonus, with dysconjugate and roving eye movements, as well as tongue fasciculations, hypersalivation, incoordination of pharyngeal muscles, and stridor. Local tissue findings at the sting site do not occur. Severe bark scorpion envenomation may be managed with supportive care and airway interventions as needed. Deaths occur from respiratory failure and hypoxia. An anti-Centruroides antivenom is available for treatment of serious bark scorpion stings. The antivenom reverses clinical toxicity within about an hour of administration. With or without antivenom treatment, most patients have full recovery from the envenomation in about 24 h.