Crotalid snakebites can be graded by the severity of the clinical findings.
Crotalid snakes (pit vipers):
(1) genus Agkistrodon: cottonmouths and copperheads
(2) genus Crotalus: rattlesnakes
(3) genus Sistrurus: Massauga and pigmy rattlesnakes
Grade |
Envenomation |
Findings |
---|---|---|
0 |
none |
fang marks minimal pain |
I |
minimal |
fang marks pain 1-5 inches of edema and erythema in the first 12 hours no systemic symptoms |
II |
moderate |
fang marks pain 6-12 inches of edema and erythema in the first 12 hours systemic symptoms may be present bloody ooze at bite site possible |
III |
severe |
fang marks pain edema > 12 inches in first 12 hours systemic symptoms coagulation defects after pit viper bites rapid progression through grades I and II, with immediate systemic signs and symptoms |
IV |
very severe |
local reaction develops rapidly edema may involve ipsilateral trunk ecchymoses, necrosis, blebs and blisters may develop at tightly restrictive fascial planes tension may be sufficient to obstruct venous or even arterial blood flow |
Limitations:
• The number of categories is limited.
• Some patients cannot be categorized.
• The distinctions are somewhat subjective and imprecise.
Specialty: Toxicology, Emergency Medicine, Critical Care