Coral snake poisoning

From Dog

Snake-bite envenomation by coral snakes are relatively common in dogs across the Americas and Asia.

The Coral snake is an Elapid snake with distinctively colored beginning with a black snout and an alternating pattern of black, yellow, and red. They have fixed front fangs and a poorly developed system for venom delivery, requiring a chewing action to inject the venom.

The severity of a coral snake bite is related to the volume of venom injected and the size of the victim. The length of the snake correlates positively with the snakes venom yield[2].

Coral snake venom is primarily neurotoxic with little local tissue reaction or pain at the bite site[3]. Secondary effects include haemotoxic, cardiovascular, myotoxic and secondary nephrotoxic effects. The net effect of the neurotoxins is a curare like syndrome due to prothrombin activating enzymes, lipases and peptidic neurotoxins[4].

Clinical symptoms may be delayed up to 18 hours, and include mental depression, generalized weakness and muscle fasciculations. Progression to paralysis of the limbs and respiratory muscles then follows.

Blood tests usually reveal marked hemolysis with severe anemia. Urinalysis frequently shows hemoglobinuria.

Diagnosis is based on evidence of coral snake presence in the area and observation of the dog being bitten.

A differential diagnosis would include botulism and other snake-bite poisoning.

The only definitive treatment for coral snake envenomation is the administration of antivenin (M. fulvius). First aid treatment involves immediate use of a compression bandage.

Once clinical signs of coral snake envenomation become manifest they progress with alarming rapidity and are difficult to reverse. If antivenin is not available or if its administration is delayed, supportive care includes respiratory support.

Assisted mechanical ventilation can be used but may have to be employed for up to 48 to 72 hours

References

  1. Jerzeedevil
  2. Peterson ME et al (2006) Snake bite: coral snakes. Clin Tech Small Anim Pract 21(4):183-186
  3. Vital Brazil O (1987) Coral snake venoms: mode of action and pathophysiology of experimental envenomation. Rev Inst Med Trop Sao Paulo 29(3):119-126
  4. Heller J et al (2007) Elapid snake envenomation in dogs in New South Wales: a review. Aust Vet J 85(11):469-479