Coral Snake Envenomation Clinical Presentation
- Author: Robert L Norris, MD; Chief Editor: Rick Kulkarni, MD more...
History
The vast majority of patients bitten by coral snakes report that a brightly colored snake bit them.
North of Mexico City, including the United States, the color pattern of the snake can be helpful in differentiating a coral snake from a harmless mimic (eg, nonvenomous milk snake). In this region, all coral snakes have a red, yellow, black, yellow, red banding pattern (red and yellow touching, see the image below); most harmless mimics have a red, black, yellow, black, red pattern (red and yellow separated by black). The mnemonic "Red on yellow, kill a fellow; red on black, venom lack," may be helpful in this region. South of Mexico City, the banding patterns are much less helpful, and bicolor (red and black) species are also present.
Snake envenomations, coral. Comparison of the harmless Lampropeltis triangulum annulata(Mexican milksnake) (top) with Micrurus tener(Texas coral snake) (bottom). Photo by Charles Alfaro. History may include the following:
- Onset of symptoms may be delayed up to 10-12 hours but may then be rapidly progressive.
- Paucity of local complaints
- Local paresthesias (may be painful)
- Soft tissue swelling (usually mild)
- Alteration of mental status
- Complaints related to cranial nerve dysfunction (eg, diplopia, ptosis, difficulty swallowing)
Physical
Physical findings of snake bite may include the following:
Impending respiratory failure
- Respiratory distress
- Pharyngeal spasm
- Hypersalivation
- Cyanosis
- Trismus
Neurologic dysfunction
- Altered mental status
- Ptosis
- Generalized weakness
- Muscle fasciculations
Cardiovascular collapse
- Hypotension
- Tachycardia
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