What are the characteristics of coral snakes. How to distinguish venomous coral snakes from non-venomous look-alikes. What are the symptoms of a coral snake bite. How is a coral snake bite treated. What preventive measures can be taken to avoid coral snake bites.

Understanding Coral Snakes: Species and Identification

Coral snakes are members of the Elapidae family, which also includes cobras. These snakes are known for their distinctive pattern of colored rings that span their bodies. In the United States, there are three primary species of coral snakes:

• Eastern coral snake (Micrurus fulvius) – Found in Florida and the southeastern US
• Texas coral snake (Micrurus tener) – Found in Texas and northwestern Mexico
• Arizona or Sonoran coral snake (Micruroides euryxanthus) – Found in southeastern US, and Sonora, Mexico

A well-known rhyme helps distinguish venomous coral snakes from their non-venomous look-alikes: “Red touch yellow, kills a fellow; red touch black, venom lack.” However, it’s crucial to note that this rule doesn’t apply to non-native coral snake species, which may have different patterns.

How can you accurately identify a coral snake?

Coral snakes typically have a pattern of red, black, and yellow (or white) colored rings. The order of these rings is critical for identification. In venomous North American coral snakes, red bands touch yellow bands. Non-venomous mimics like king snakes, shovel-nosed snakes, and milk snakes have red bands touching black bands instead.

Coral Snake Behavior and Bite Incidence

By nature, coral snakes are reclusive creatures. They seldom bite unless provoked or threatened. This behavior contributes to the relatively low incidence of coral snake bites compared to other venomous snakes. In fact, coral snake bites represent only about 2% of snake bites reported to US Poison Centers annually.

Which coral snake species pose the greatest risk?

Of the three species found in the US, bites from the Eastern coral snake tend to be the most severe. Bites from the Arizona/Sonoran and Texas coral snakes are generally not associated with serious side effects or death. However, all coral snake bites should be treated as potentially dangerous and require immediate medical attention.

The Mechanics of a Coral Snake Bite

Coral snakes have small, fixed fangs, unlike the retractable fangs of pit vipers like rattlesnakes. When they bite, coral snakes tend to latch onto their prey and “chew” for a few seconds to deliver their venom effectively. This behavior can result in multiple puncture wounds.

Why are coral snake bites often difficult to identify?

Compared to other venomous snakes, coral snake bite marks can be easily missed. They often show no significant local tissue damage, obvious injury, or immediate pain. This lack of immediate symptoms can lead to delayed treatment, which can be dangerous given the potency of their venom.

Coral Snake Venom: Composition and Effects

The venom of the Eastern coral snake contains potent neurotoxins that can cause severe illness or death if left untreated. These neurotoxins block an important neurotransmitter called acetylcholine, which is crucial for muscle activation in the body.

What are the primary effects of coral snake venom?

The blockade of acetylcholine after envenomation can lead to weakness, paralysis, and even complete respiratory failure in severe cases. The effects of the venom are usually delayed, sometimes taking up to 13 hours to manifest. However, once symptoms develop, they can progress rapidly.

Symptoms of Coral Snake Envenomation

Coral snake bites can produce a range of symptoms, which may not appear immediately but can become severe once they develop. These symptoms can include:

• Nausea and vomiting
• Paresthesias (abnormal sensations)
• Slurred speech
• Double vision
• Ptosis (drooping eye)
• Muscle twitching
• Weakness
• Paralysis

What is the most significant risk associated with coral snake envenomation?

The major cause of death from coral snake envenomations is respiratory failure resulting from neuromuscular weakness. This underscores the importance of immediate medical attention and close monitoring following a suspected coral snake bite.

Treatment Approaches for Coral Snake Bites

Given the potentially serious outcomes after a coral snake bite, all individuals with a suspected envenomation should be seen in a hospital immediately and observed for at least 24 hours. The traditional treatment for coral snake envenomation has been antivenom therapy.

What is the primary antivenom used for coral snake bites?

The North American Coral Snake Antivenin, a horse-derived IgG antibody antivenom produced by Wyeth Pharmaceuticals (now a subsidiary of Pfizer, Inc.), has been the standard treatment. However, production of this antivenom ceased in 2006, creating challenges in treatment availability.

How is antivenom administered in coral snake bite cases?

If antivenom is available, the decision to administer it is made on a case-by-case basis after careful risk/benefit assessment. Antivenom administration is not without dangers, and its use must be weighed against potential adverse reactions.

What alternative treatments are available when antivenom is not accessible?

In cases where antivenom is unavailable, management of the patient focuses on supportive care, which includes airway management with mechanical ventilation if necessary. Other treatment options, such as the anticholinesterase drug neostigmine, have shown potential benefits for certain coral snake bites. However, data on its efficacy is limited and inconsistent.

The Role of Poison Control Centers in Coral Snake Bite Management

Poison Control Centers play a crucial role in the management of coral snake bites. These centers can provide valuable guidance to healthcare providers and help locate sources of antivenom when needed.

How do Poison Control Centers assist in coral snake bite cases?

Healthcare providers often need to work with their regional Poison Control Center to locate a source of antivenom supply. Additionally, Poison Control Centers can provide expert advice on treatment strategies and help coordinate care between different medical facilities if necessary.

What should you do if you suspect a coral snake bite?

If you or someone you know has been bitten by a coral snake, it’s crucial to seek immediate medical attention. Call 911 or contact Poison Control at 1-800-222-1222. Alternatively, you can use the webPOISONCONTROL® online tool for guidance.

Prevention Strategies: Avoiding Coral Snake Encounters

While coral snakes are generally not aggressive, taking precautions to avoid encounters is essential, especially in areas where these snakes are known to inhabit. Here are some prevention tips:

• Be aware of your surroundings when in coral snake habitats
• Wear closed-toe shoes and long pants when walking in areas with potential snake activity
• Avoid reaching into brush or leaf litter without visual inspection
• Use a flashlight when walking in snake-prone areas at night
• Keep your yard free of debris and tall grass that might attract snakes
• Seal entry points to your home to prevent snakes from entering

What should you do if you encounter a coral snake?

If you come across a coral snake, the best course of action is to leave it alone and slowly back away. Do not attempt to handle or capture the snake, as this increases the risk of being bitten. Remember, coral snakes are generally non-aggressive and will only bite when threatened or handled.

By understanding coral snakes, their behavior, and the appropriate response to encounters and bites, we can better coexist with these fascinating creatures while minimizing the risk of dangerous interactions. Education and awareness are key to preventing coral snake bites and ensuring prompt, effective treatment when they do occur.

Ecological Importance of Coral Snakes

Despite the potential danger they pose to humans, coral snakes play a vital role in their ecosystems. These snakes are important predators that help maintain the balance of their habitats by controlling populations of small animals.

What do coral snakes eat?

Coral snakes primarily feed on other snakes, including smaller venomous species. They also consume lizards, particularly small skinks. This dietary preference helps regulate the populations of these animals in their ecosystems.

How do coral snakes contribute to biodiversity?

As both predator and prey, coral snakes are an integral part of the food web in their habitats. They serve as a food source for larger predators such as kingsnakes, which have evolved a resistance to coral snake venom. This intricate relationship contributes to the overall biodiversity of their ecosystems.

Research and Future Developments in Coral Snake Bite Treatment

The field of coral snake bite treatment is an area of ongoing research, with scientists and medical professionals working to improve both prevention and treatment strategies.

What new treatments are being developed for coral snake bites?

Researchers are exploring new antivenom formulations that may be more effective and have fewer side effects than traditional horse-derived antivenoms. Some studies are investigating the potential of using small molecule inhibitors to block the action of coral snake neurotoxins.

How might advances in molecular biology impact coral snake bite treatment?

Advances in proteomics and genomics are allowing researchers to better understand the composition of coral snake venoms. This knowledge could lead to the development of more targeted and effective treatments in the future.

Global Perspective: Coral Snakes Beyond North America

While this article has focused primarily on North American coral snakes, it’s important to note that these snakes are found in other parts of the world as well, particularly in South America and parts of Asia.

How do coral snakes in other parts of the world differ from North American species?

Coral snakes found in South America and Asia can have different color patterns and venom compositions compared to their North American counterparts. For example, some South American coral snakes have potent hemorrhagic toxins in addition to neurotoxins, which can cause different symptoms and require different treatment approaches.

What challenges exist in treating coral snake bites globally?

In many parts of the world where coral snakes are found, access to appropriate medical care and antivenom can be limited. This presents significant challenges in treating coral snake bites effectively, particularly in remote or under-resourced areas.

As we continue to learn more about coral snakes and improve our ability to prevent and treat their bites, it’s crucial to remember that these creatures are an important part of our natural world. By respecting their habitats and taking appropriate precautions, we can reduce the risk of dangerous encounters while appreciating the role these unique snakes play in our ecosystems.

Coral Snake Bite Treatment | Poison Control

The Full Story

“Red touch yellow, kills a fellow; red touch black, venom lack.“ Of all the childhood rhymes we’ve grown up learning, this one might be high on the list of ones to remember if you live in coral snake country. If you aren’t familiar with this saying, it refers to distinguishing the venomous coral snake from its nonvenomous look-alikes (e.g., the king snake, shovel-nosed snake, and milk snake). It’s important to note that this general rule doesn’t apply to non-native coral snake species, which might have different patterns. Coral snakes are members of the Elapidae family, which includes cobras. Coral snakes usually have a pattern of red, black, yellow (or white) colored rings that span their bodies. For the purposes of this article, we’ll focus primarily on the three species found in the US, which are:

• Eastern coral snake (Micrurus fulvius) – Found in Florida and the southeastern US
• Texas coral snake (Micrurus tener) – Found in Texas and northwestern Mexico
• Arizona or Sonoran coral snake (Micruroides euryxanthus) – Found in southeastern US, and Sonora, Mexico)

By nature, coral snakes are reclusive and seldom bite unless they’re provoked or threatened. Compared to their pit viper counterparts (e.g., rattlesnakes), coral snake bites are uncommon and represent only about 2% of snake bites reported to US Poison Centers annually. Of the three species in the US, bites by the eastern coral snake tend to be the most severe, while those of the Arizona/Sonoran and Texas coral snakes aren’t generally associated with serious side effects or death. 

Coral snakes have small, fixed fangs, and when they bite they tend to latch onto their prey and “chew” for a few seconds in order to deliver their venom. Compared to other venomous snakes, their bite marks can be easily missed, often showing no significant local tissue damage, obvious injury, or pain. However, the venom of the Eastern coral snake contains very potent neurotoxins that can cause severe illness or death if left untreated. The neurotoxic venom blocks an important neurotransmitter called acetylcholine, which is important for the activation of muscles in the body. Blockade of acetylcholine after envenomation can lead to weakness and paralysis and even complete respiratory failure in severe cases. The effects of the venom are usually delayed (up to 13 hr) but progress rapidly once they develop. Symptoms of a coral snake envenomation can include nausea, vomiting, paresthesias (abnormal sensations), slurred speech, double vision, ptosis (drooping eye), muscle twitching, weakness, and paralysis. The major cause of death from coral snake envenomations is respiratory failure as a result of neuromuscular weakness.

Given the potentially serious outcomes after a coral snake bite, all people with a suspected envenomation should be seen in a hospital immediately and observed for at least 24 hours. The traditional treatment for coral snake envenomation has been a horse-derived IgG antibody antivenom produced by Wyeth Pharmaceuticals (now a subsidiary of Pfizer, Inc.) called the North American Coral Snake Antivenin. However, the manufacturer stopped production in 2006. The remaining available antivenom has passed the manufacturer-assigned expiration date of 2008, but FDA continues to provide information on expiration date extensions based evaluation of stability data. Because having a supply of the antivenom is uncommon in most hospitals, healthcare providers need to work with their regional Poison Control Center to locate a source of supply. If the antivenom is available, if and when to start is decided on a case-by-case basis after careful risk/benefit assessment as antivenom administration is not without dangers. If the antivenom is unavailable, management of the patient is focused on supportive care, which includes airway management with mechanical ventilation. There are other treatment options that have been shown to possibly provide benefit for certain coral snake bites, like the anticholinesterase drug neostigmine. However, data on its efficacy is limited and inconsistent. In all cases, discussion among the healthcare providers, Poison Control Centers, and toxicologists is key to providing optimal care for each patient.

If you or someone you know has been bitten by a coral snake, seek medical attention by calling 911 or Poison Control (1-800-222-1222), or use the webPOISONCONTROL^{® online tool for guidance.}

Kristina Yee, PharmD
Certified Specialist in Poison Information

Poisoned?

Call


1-800-222-1222


or

HELP ME online

Prevention Tips

• Coral snakes aren’t usually aggressive unless they feel threatened or are provoked. If you come across one, leave it alone!
• If someone has been bitten by a coral snake, seek medical evaluation immediately. Do NOT wrap the area in a tourniquet, cut the wound, or attempt to “suck the venom out.” None of these are helpful and can potentially make things worse.

This Really Happened

Case 1. A 9-year-old boy was bitten on the right index finger after a coral snake was thrown at him. He reported local and radiating pain at the bite site as well as abdominal pain. One hour after the incident, he was taken to a hospital and received 5 vials of antivenom. He was observed in the ICU and only developed mild local swelling. He was discharged after 3 days in the hospital.

Case 2. A 15-year-old girl was bitten on her arm by an exotic coral snake. She was taken to a hospital and observed in the ICU. She was not treated with antivenom due to its unavailability. Her only reported symptoms were vomiting and swelling, and she was discharged after 3 days in the hospital.

Case 3. A 6-year-old boy was bitten while catching a coral snake. He developed anaphylaxis during antivenom administration. Nine hours after the bite he had drooling and difficulty swallowing and required mechanical ventilation for 8 days. He was discharged after 16 days in the hospital.

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For More Information

Expiration date extension for North American coral snake antivenin (Micurus fulvius) (equine origin) lot L67530 through January 32, 2020. Silver Spring (MD): US Food and Drug Administration; 2019 Feb 1 [cited 2020 Aug 31].

Sartore J. Eastern coral snake [photo].Washington: National Geographic Society [cited 2020 Aug 31].

References

Corbett B, Clark RF. North American snake envenomation. Emerg Med Clin North Am. 2017 May;35(2):339-54.

Expiration date extension for North American coral snake antivenin (Micurus fulvius) (equine origin) lot L67530 through January 32, 2020. Silver Spring (MD): US Food and Drug Administration; 2019 Feb 1 [cited 2020 Aug 31].

Hessel MM, Sauerberg N, McAninch SA. Coral snake toxicity. Treasure Island (FL): StatPearls Publishing; 2020 Apr 23 [cited 2020 Aug 31].

Hoffman, RS, Howland, MA, Lewin, NA, Nelson, LS, Goldfrank, LR, editors. Goldfrank’s toxicologic emergencies. 10th ed. New York: McGraw Hill; c2015. Chapter 122, Native (US) venomous snakes and lizards.

McAninch SA, Morrissey RP, Rosen P, Meyer TA, Hessel MM, Vohra MH. Snake Eyes: Coral Snake Neurotoxicity Associated With Ocular Absorption of Venom and Successful Treatment With Exotic Antivenom. J Emerg Med. 2019 May;56(5):519-522.

Pawar DK, Singh H. Elapid snake bite. Br J Anaesth. 1987 Mar;59(3):385-7. 

Peterson ME. Snake bite: coral snakes. Clin Tech Small Anim Pract. 2006 Nov;21(4):183-6. 

Sánchez EE, Lopez-Johnston JC, Rodríguez-Acosta A, Pérez JC. Neutralization of two North American coral snake venoms with United States and Mexican antivenoms. Toxicon. 2008 Feb;51(2):297-303.

Sasaki J, Khalil PA, Chegondi M, Brzezinski A, Meyer KG, et al. Coral snake bites and envenomation in children: a case series. Pediatr Emerg Care. 2014 Apr;30(4):262-5.

Wood A, Schauben J, Thundiyil J, Kunisaki T, Sollee D, et al. Review of eastern coral snake (Micrurus fulvius fulvius) exposures managed by the Florida Poison Information Center Network: 1998-2010. Clin Toxicol (Phila). 2013 Sep-Oct;51(8):783-8.

Poisoned?

Call


1-800-222-1222


or

HELP ME online

Prevention Tips

• Coral snakes aren’t usually aggressive unless they feel threatened or are provoked. If you come across one, leave it alone!
• If someone has been bitten by a coral snake, seek medical evaluation immediately. Do NOT wrap the area in a tourniquet, cut the wound, or attempt to “suck the venom out.” None of these are helpful and can potentially make things worse.

This Really Happened

Case 1. A 9-year-old boy was bitten on the right index finger after a coral snake was thrown at him. He reported local and radiating pain at the bite site as well as abdominal pain. One hour after the incident, he was taken to a hospital and received 5 vials of antivenom. He was observed in the ICU and only developed mild local swelling. He was discharged after 3 days in the hospital.

Case 2. A 15-year-old girl was bitten on her arm by an exotic coral snake. She was taken to a hospital and observed in the ICU. She was not treated with antivenom due to its unavailability. Her only reported symptoms were vomiting and swelling, and she was discharged after 3 days in the hospital.

Case 3. A 6-year-old boy was bitten while catching a coral snake. He developed anaphylaxis during antivenom administration. Nine hours after the bite he had drooling and difficulty swallowing and required mechanical ventilation for 8 days. He was discharged after 16 days in the hospital.

Coral Snake Toxicity – StatPearls

Continuing Education Activity

Coral snakes are members of the Elapidae family, and 40 to 50 species exist in the Americas. In the United States, three types predominate: Micrurus fulvius (eastern coral snake, located in Florida and the southeast US) and Micrurus tener (Texas coral snake, located in Texas and Northwestern Mexico), and Micruroides euryxanthus (Sonoran coral snake, located in the Southeastern US and the state of Sonora, Mexico) inhabit the US. Coral snakes in North America (north of Mexico City) are recognized by their circumferential bands (non-circumferential shape is found on the non-venomous shovel-nosed snake) of red, yellow, and black. This activity reviews coral snake toxicity, its presentation, and highlights the role of the interprofessional team in its management.

Objectives:

• Describe the pathophysiology of coral snake toxicity.

• Describe the presentation of a patient with coral snake toxicity.

• Summarize the treatment options for coral snake toxicity.

• Review the importance of improving care coordination among interprofessional team members to improve outcomes for patients affected by coral snake toxicity.

Access free multiple choice questions on this topic.

Introduction

Coral snakes are members of the Elapidae family, and 40 to 50 species exist in the Americas. In the United States, three types predominate: Micrurus fulvius (eastern coral snake, located in Florida and the southeast US) and Micrurus tener (Texas coral snake, located in Texas and Northwestern Mexico), and Micruroides euryxanthus (Sonoran coral snake, located in the Southeastern US and the state of Sonora, Mexico) inhabit the US.  [1] Coral snakes in North America (north of Mexico City) are recognized by their circumferential bands (non-circumferential shape is found on the non-venomous shovel-nosed snake) of red, yellow, and black (figure 1). In North American snakes only, the color sequence may distinguish the venomous coral snake from non-venomous snakes, such as the king snake, whose pattern is “red on black,” and is demonstrated by the mnemonic “red on yellow, kills a fellow; red on black, venom lack.” Coral snake envenomations are relatively uncommon compared to their pit viper counterparts. However, coral snake venom is very potent and may result in a delayed onset of significant neurotoxicity and respiratory failure. [2]

Etiology

The venom of M. fulvius and M. tener is a highly potent neurotoxin. M. euryxanthus envenomation is not known to cause significant symptoms in humans, although this species does boast a protective sonic warning capability called a “microfart” (caused by air expulsion from its cloaca). The incidence of significant coral snake envenomation is less than that of pit viper bites for several reasons. Unlike pit vipers, coral snakes are more elusive and will often retreat from any signs of danger rather than confront any potential threats. Hence, coral snake bites commonly occur after intentional handling of the snake by humans or from harassment by curious animals. 

Epidemiology

Only 25 to 50 of the approximately 9000 total snake bites in the US are due to coral snakes. Micrurus fulvius and Micrurus tener account for all clinically significant coral snake bites reported in the US. Only one death due to coral snake envenomation has been reported in North America in the recent past. [3]

Pathophysiology

Unlike pit vipers, whose venom causes local tissue necrosis and coagulopathy, coral snake venom gains systemic access through the lymphatic veins to cause neurotoxicity and respiratory muscle weakness using competitive inhibition of the nicotinic acetylcholine receptors at the neuromuscular junction.  [4]

Toxicokinetics

Both pre-synaptic and post-synaptic inhibition (by alpha neurotoxins) have been documented. Additionally, phospholipase A2 may cause myotoxicity and rhabdomyolysis. [5]

History and Physical

When a victim presents with a reported coral snake bite or mucous membrane exposure to its venom, it is important to determine when the bite occurred as neurotoxic effects and respiratory insufficiency may be delayed up to 13 hours. [6] If possible, the identity of the snake should be verified through photographic images. Initial presenting symptoms may include mild pain at the bite site (no puncture marks may be present), nausea, vomiting, dizziness, and abdominal pain. Neurotoxicity may present with progressive motor deficits including cranial nerve deficits, such as ptosis, dysarthria, and dysphagia as well as descending muscle weakness. Importantly, patients should be closely monitored for signs of respiratory muscle weakness with pulmonary insufficiency; this is the most life-threatening complication of coral snake envenomation.

Evaluation

Evaluation of coral snake envenomation victims should focus on assessment of the development of neurologic deficits and respiratory compromise. [7] Serial pulmonary function testing is helpful to predict respiratory insufficiency. Respiratory compromise is suggested by an FVC (forced vital capacity) less than 50% predicted, MIP (maximal inspiratory pressure) less negative than -30 cmh3O, or an MEP (maximal expiratory pressure) below 40 cmh30. Additionally, declines in mental status, bedside capnography (ETC02), and blood gas measurements may be used to monitor for hypercarbia or respiratory acidosis that may indicate impending respiratory failure. Rhabdomyolysis may occur in M. fulvius envenomation and should be evaluated as clinical scenario warrants. Unlike pit viper envenomation victims, significant bite area tissue necrosis and coagulopathies are uncommon in coral snake envenomation.

Treatment / Management

General treatment measures include ensuring a safe scene (remove from snake exposure), local wound care (although wounds are typically minimal), minimization of movement (relative immobilization in a functional position), avoiding activities that increase heart rate, and promoting patient (and family) relaxation (to decrease systemic propagation of venom). Tetanus prophylaxis is also considered standard in the treatment of snakebites. Pressure immobilization bandages [8] may be placed over the bite site with just enough force to allow arterial and venous flow but decrease lymphatic flow, potentially decreasing the systemic absorption of coral snake venom through lymphatics. [9] Tourniquets, venom extraction (either by incision and oral suction, manually or by a mechanical device), and cryotherapy are not recommended. If possible, avoid medications that may cause muscle weakness or decreased respiratory function, as these may inhibit the ability to assess for neurotoxic effects due to envenomation.

Due to the possibility of the delayed onset of life-threatening respiratory compromise, all patients with suspected coral snake envenomation warrant close observation for at least 24 hours at an appropriate level of care for close respiratory monitoring and frequent serial neurologic exams. Patients who demonstrate respiratory insufficiency warrant advanced airway management and treatment with coral snake antivenom and/or other pharmacologic measures, such as anticholinesterases (discussed below). Airway compromise may develop rapidly, so advanced airway medications and equipment should be prepared early and readily available. 

The North American Coral Snake Antivenin (NACSA) is a horse-derived IgG antibody used for both M. fulvius and M. tener envenomation in both adults and children. Its use has not been reported in patients who are pregnant. The administration of coral snake antivenom is recommended at the first sign of neurologic deficit or respiratory insufficiency, as some data suggest decreased need for intubation or decreased duration of muscle paralysis and intubation. On the other hand, other data suggest no differences in intubation rates when NACSA is given prophylactically before symptom onset. So, should practitioners administer NACSA empirically to patients without neurologic deficits or respiratory compromise? This is a controversial decision, but given the additional risk of immediate and delayed hypersensitivity reactions (discussed below) and mixed clinical evidence results regarding prophylactic antivenom benefit, it is reasonable to procure antivenom early but withhold administration until the development of the first neurologic symptoms.  In any case, the best course of action is to contact the Poison Control Center or a toxicologist for treatment guidance. Currently, there is a limited supply of the NACSA, as production ceased in 2006. The known remaining vials of this antivenom have passed the manufacturer’s expiration date (2008), but the FDA extended the expiration date through January 31, 2019, for NACSA Lot L67530.[10] If treatment with antivenom is indicated, contact the Poison Control Center (1-800-222-1222) or a toxicologist for the acquisition of the antivenom and further recommendations. Also, the FDA Office of Vaccines, Blood, and Biologics (301-827-3524) may be contacted for information regarding the risks and benefits of administering expired antivenom. Moreover, it is recommended to contact Poison Control early to assist with the location and mobilization of NACSA, as significant time and mobilization resources may be required to procure it. [11] Once the decision is made to administer NACSA, the patient undergoes a test dose of the included horse serum for reactions, and after that, the recommended initial dose of NACSA is three to five vials by slow intravenous push for both adults and pediatrics. Of note, a potential new coral snake antivenom, an equine-based F(ab’), is currently in clinical trials in the US. Other antivenoms useful for coral snakes may be available (such as Coralmyn, manufactured in Mexico) and recommended by Poison Control. [12]

As discussed earlier, NACSA is an equine-based IgG serum, and there is a risk of both immediate and delayed hypersensitivity reactions. [13] When giving NACSA, clinicians should watch for signs of hives, itching, shortness of breath, hypotension, or angioedema as evidence of an allergic reaction. If patients demonstrate signs of an immediate hypersensitivity reaction, infusion of the antivenom should be stopped immediately, and doses of epinephrine IM (0.3 mg if greater than 30kg, 0.15mg if less than 30 kg of the 1:1000 concentration), antihistamine, corticosteroids, and albuterol nebulizers should be given as needed based on clinical symptoms.

If the patient develops neurotoxicity or respiratory compromise and coral snake antivenom is not available, another pharmacologic treatment option is a trial dose of an anticholinesterase, such as neostigmine. Neostigmine acts by restoring neuromuscular transmission by increasing concentrations of acetylcholine in the neuromuscular junction when weakness is due to the post-synaptic blockade. Pretreatment with atropine or glycopyrrolate should be considered to prevent potential excessive cholinergic effects of neostigmine. Again, poison control and toxicologist consultation are recommended to guide treatment. 

Differential Diagnosis

• Anaphylaxis

• Septic shock

• Serum sickness

• Wasp stings

• Wound care

• Wound infections

Pearls and Other Issues

• Coral snake venom acts by inhibiting acetylcholine receptors at the neuromuscular junction to cause neurotoxic motor weakness.

• Life-threatening complications of coral snake bites are related to respiratory muscle weakness and the need for ventilatory support.

• Although significant envenomation is uncommon due to the coral snake’s less-aggressive behavior and difficult mechanism of delivery, the potential of life-threatening respiratory insufficiency delay of up to 13 hours warrants very close observation after a reported exposure.

• While limited in supply and difficult to obtain and transport, coral snake antivenom should be given to all patients bitten by coral snakes regardless of symptoms.

• Hypersensitivity reactions to equine-based coral snake antivenom are common, and infusion should be stopped immediately if patients develop adverse reactions.

Enhancing Healthcare Team Outcomes

The management of coral snake bites is with an interprofessional team that consists of an emergency department physician, poison control, internist, intensivist, toxicologist, and ICU nurses. These patients need admission and close monitoring as life-threatening complications of coral snake bites are related to respiratory muscle weakness and the need for ventilatory support. Although significant envenomation is uncommon due to the coral snake’s less-aggressive behavior and difficult mechanism of delivery, the potential of life-threatening respiratory insufficiency delay of up to 13 hours warrants very close observation after a reported exposure. While limited in supply and difficult to obtain and transport, coral snake antivenom should be given to all patients bitten by coral snakes regardless of symptoms. The outcomes in patients treated with antivenom are excellent but if there is a delay in treatment, then fatalities are known to occur. [3][14][Level 5]

Review Questions

• Access free multiple choice questions on this topic.

• Comment on this article.

Figure

Coral Snake. Contributed by The CDC / Edward J. Wozniak D.V.M., Ph.D.

References

1.

Yang DC, Dobson J, Cochran C, Dashevsky D, Arbuckle K, Benard M, Boyer L, Alagón A, Hendrikx I, Hodgson WC, Fry BG. The Bold and the Beautiful: a Neurotoxicity Comparison of New World Coral Snakes in the Micruroides and Micrurus Genera and Relative Neutralization by Antivenom. Neurotox Res. 2017 Oct;32(3):487-495. [PubMed: 28674788]

2.

Vergara I, Castillo EY, Romero-Piña ME, Torres-Viquez I, Paniagua D, Boyer LV, Alagón A, Medina LA. Biodistribution and Lymphatic Tracking of the Main Neurotoxin of Micrurus fulvius Venom by Molecular Imaging. Toxins (Basel). 2016 Mar 26;8(4):85. [PMC free article: PMC4848612] [PubMed: 27023607]

3.

Norris RL, Pfalzgraf RR, Laing G. Death following coral snake bite in the United States–first documented case (with ELISA confirmation of envenomation) in over 40 years. Toxicon. 2009 May;53(6):693-7. [PubMed: 19673084]

4.

Vergara I, Pedraza-Escalona M, Paniagua D, Restano-Cassulini R, Zamudio F, Batista CV, Possani LD, Alagón A. Eastern coral snake Micrurus fulvius venom toxicity in mice is mainly determined by neurotoxic phospholipases A2. J Proteomics. 2014 Jun 13;105:295-306. [PubMed: 24613619]

5.

Arce-Bejarano R, Lomonte B, Gutiérrez JM. Intravascular hemolysis induced by the venom of the Eastern coral snake, Micrurus fulvius, in a mouse model: identification of directly hemolytic phospholipases A2. Toxicon. 2014 Nov;90:26-35. [PubMed: 25088177]

6.

Corbett B, Clark RF. North American Snake Envenomation. Emerg Med Clin North Am. 2017 May;35(2):339-354. [PubMed: 28411931]

7.

Strauch MA, Souza GJ, Pereira JN, Ramos TDS, Cesar MO, Tomaz MA, Monteiro-Machado M, Patrão-Neto FC, Melo PA. True or false coral snake: is it worth the risk? A Micrurus corallinus case report. J Venom Anim Toxins Incl Trop Dis. 2018;24:10. [PMC free article: PMC5894131] [PubMed: 29651298]

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Disclosure: Matthew Hessel declares no relevant financial relationships with ineligible companies.

Disclosure: Scott McAninch declares no relevant financial relationships with ineligible companies.

Coral Snake’s Unique Poison: How It Works

Blue Coral Snake can kill not only frogs and rodents, but also other venomous snakes. For these purposes, evolution has provided him with a unique toxin that turns the last hours of the victim’s life into a living hell.

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We are accustomed to the fact that in the wild snakes usually feed on rodents and other small and harmless animals. However, the beautiful and deadly blue coral snake preys on fast and venomous snakes. Such a prey must not only be caught up, but also immobilized, and for this purpose the reptile uses a special poison that turns the last seconds of the prey’s life into real torture.

Do not self-medicate! In our articles, we collect the latest scientific data and the opinions of authoritative health experts. But remember: only a doctor can diagnose and prescribe treatment.

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Unique Snake Venom

A bright color in nature often symbolizes the creature’s danger, and just a glance at this snake immediately tells the enemy who he is dealing with. Found in southeastern Asia, blue coral snakes, or as scientists call them, two-banded ferruginous snakes (Calliophis bivirgatus), are distinguished by a bright red, neon-lit head and blue patterns throughout – it is not for nothing that they are included in the genus “Decorated Asps”. In an article published in the journal Toxins, researchers from the University of Queensland in Australia describe the unique properties of snake venom, which, when released into the bloodstream, provides the victim with an extensive shock to the entire physiological system.

What happens to the victim after being bitten

Almost immediately after being bitten, the victim goes into a catatonic state. The poison causes the entire nervous network of the body to chaotically strain the muscles, as a result of which the victim beats in spasmodic convulsions. Paralyzed and helpless, she eventually becomes the prey of a predator. Although this sounds very ominous, evolution had its own reasons for this: coral asps prey on other poisonous snakes, which have exceptional reaction, flexibility and an impressive arsenal of self-defense. A special venom is produced and stored in the gland, which makes up a full quarter of the snake’s total body.

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Why scientists are interested in the toxin

Scientists have already seen similar toxins in nature, but they have never been found in snakes, let alone other vertebrate species. Such poisons are characteristic primarily of scorpions and spiders. Conus, a predatory gastropod, injects a similar toxin into the fish, which instantly paralyzes them with spasmodically tensed muscles, similar to tetanus. The venom of the two-striped glandular snake has the same effect, and scientists say it is a good example of convergent evolution (the case when the same trait appears in several species of living creatures independently of each other). Researchers refer to its effect as spasmodic paralysis, while the venoms of other snakes cause peripheral paralysis. Interaction with poison blocks the ability of nerves to “turn off” sodium channels, which results in continuous signal transmission and, as a result, constant tension in muscle fibers.

Ironically, the dreaded toxin can be used for medical purposes. Currently, experts are developing drugs based on it that will act as an analgesic.

PALITOXIN AND CORAL POISONING | Mürgistusteabekeskus

Palitoxin is a toxin found in coral that can also be found in tropical fish, sea anemones and crabs in the Caribbean, Indian and Pacific Oceans and off the coast of Africa. However, the main sources of this toxin are corals of the family Palythoa and mostly soft corals ( Palythoa spp., Zoanthus spp. ) and dinoflagellates ( Ostreopsis spp. ).

The toxin can also be found in corals grown in home marine aquaria. Palitoxin is an activator of sodium-potassium channels in the body and is a potent vasoconstrictor.

The toxin is also absorbed through damaged skin and mucous membranes during coral handling. Poisoning can also occur when the toxin is inhaled if the corals have been cooked, crushed, or otherwise processed. It can also happen when cleaning the aquarium, especially during coral blooms. In no case should such corals be brushed. Coral poisoning can happen not only to people, but also to pets.

Symptoms of coral poisoning usually begin within 30-60 minutes of first contact, rarely within 2 hours. However, serious poisoning requiring immediate attention can occur even within 15 minutes of first exposure to the toxin. All people exposed to palytoxin should be monitored in a hospital, and full recovery may take longer.

The most common symptoms are cough, metallic taste in the mouth, dry mouth, gastrointestinal irritation, headache, dizziness and tingling in the hands. In more severe cases, palpitations, low blood pressure, slow heart rate, cyanosis, and muscle cramps are added.

There is no laboratory method for determining the content of palytoxin. The diagnosis of human poisoning is usually based on the information collected (the person knows they have eaten fish that may contain palytoxin, or cleaned a marine aquarium containing palytoxin-producing corals) but on a description of the health complaints that have occurred. There is no antidote for treatment, but treatment is supportive and symptomatic.

As a first aid for poisoning when cleaning the aquarium, leave the room as soon as possible and ventilate it thoroughly before returning. To date, there is no single well-proven method for cleaning surfaces, but a mildly acidic cleaner is often used.