Snake eyes: Characterization of topical ocular exposures from rattlesnakes in Arizona

• Published in: Toxicon (Oxford) Vol. 244; p. 107775
• Main Authors: Maciulewicz, Thom S., Cardwell, Michael D., Brandecker, Kevin, Massey, Daniel J., Shirazi, Farshad Mazda
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-06-2024
• Subjects: Musk; Ocular; Rattlesnake; Spitting; Spray; Venom; Rattlesnake; Spray; Ocular; Musk; Venom; Spitting
• ISSN: 0041-0101; 1879-3150
• DOI: 10.1016/j.toxicon.2024.107775

Patients occasionally present with reports of ocular exposure to fluids from rattlesnakes, claiming or suspecting the substance to be venom. This study set out to evaluate and characterize reported cases of suspected venom-induced ophthalmia in humans. A retrospective review of rattlesnake exposures reported to the Arizona Poison and Drug Information Center over a 24-year period was conducted for ocular exposures. Recorded information included patient demographics, clinical course, laboratory results, and treatments. Documentation regarding interactions between patients and snakes was reviewed by Arizona Poison and Drug Information Center herpetologists to evaluate what substance was expelled from the snake resulting in ocular exposure. Our review of rattlesnake encounters found a total of 26 ocular exposure cases. Patient demographics were largely intentional interactions and involved the male sex. Symptoms ranged from asymptomatic to minor effects with 46.2% managed from home and treated with fluid irrigation. A review of cases by herpetologists concluded the exposure patients commonly experienced was to snake musk. Kinematics of venom expulsion by rattlesnakes conclude the venom gland must be compressed, fangs erected to ≥60o, and fang sheath compressed against the roof of the mouth for venom expulsion. Evidence suggests the chance of venom “spitting” by rattlesnakes is close to zero. Rattlesnakes are documented to forcefully expel airborne malodorous “musk” defensively. An important distinction to remember is musk has a foul odor and is usually colorless, while venom is comparatively odorless and yellow. Rattlesnake venom-induced ophthalmia is a rare event as venom expulsion requires the kinematics of feeding or defensive bites. If the rattlesnake is not in the process of biting or otherwise contacting some other object with its mouth, it is more biologically plausible patients are being exposed to snake musk as a deterrent. Whether it's venom or musk, topical exposure to the eyes should prompt immediate irrigation.
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•Rattlesnakes do not “spit” venom as documented in some cobras.•Rattlesnakes may spray venom into the air in the process of biting something, such as striking a screened cage vent.•Rattlesnakes frequently spray malodorous musk a meter or more at antagonists.•Musk has a prominent foul odor while venom is virtually odorless.•Whether it's rattlesnake venom or musk, non-penetrating topical exposure to the eyes should prompt immediate irrigation.