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Cobra Envenomation Follow-up

  • Author: Robert L Norris, MD; Chief Editor: Joe Alcock, MD, MS  more...
 
Updated: Oct 27, 2015
 

Further Outpatient Care

Patients with necrosis need continued outpatient management of their wounds and should be warned about the signs and symptoms of infection. Continued outpatient physical therapy may be necessary.

Patients who received antivenom should be aware of the signs and symptoms of delayed serum sickness and should return if they develop.

Patients who have experienced acute ophthalmia following spitting cobra venom exposure should have outpatient ophthalmologic follow-up to monitor for complications such as uveitis or corneal ulceration.

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Further Inpatient Care

Admit all cobra snakebite patients to closely monitored settings, whether or not antivenom is given.

Observe asymptomatic patients for at least 24 hours. Delayed signs and symptoms may occur.

If signs or symptoms of envenomation progress after first administration of antivenom, a second dose of antivenom may be required. If two doses of antivenom are given and the victim still requires airway intubation and ventilatory support, further antivenom administration will be unhelpful.

Continue to administer epinephrine, antihistamines, and steroids to a patient experiencing an acute allergic reaction to antivenom until the patient is stable.

If necrosis occurs, initiate standard, conservative wound care (eg, cleansing, splinting, debridement as necessary). Secondary bacterial infections may occur and are usually caused by gram-negative bacilli, such as Proteus, Pseudomonas, and Enterobacter species. Initial antibiotics should cover gram-positive and gram-negative organisms. Culture results should determine use of further antibiotics. Occasionally, debridement, amputation, or grafting of tissue is required.

Warn patients who have received antivenom about the signs and symptoms of delayed serum sickness. If these signs or symptoms develop after discharge, evaluate the patient promptly for initiation of systemic steroids and diphenhydramine as outlined above.

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Transfer

People bitten by cobras should be cared for in a facility capable of intensive monitoring.

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Deterrence/Prevention

Professional snake keepers should use standard safety techniques (eg, locked cages, trap boxes, protective eyewear) when dealing with cobras and other species that spit venom.

Amateurs should refrain from keeping exotic venomous snakes in their collections. If they keep such snakes, they should know the specific species they keep, the appropriate antivenom type, and where it can be obtained in an emergency. Preferably, amateurs should maintain their own supply of appropriate antivenom, but this may be difficult (due to regulations related to importing foreign antivenoms into the country) and expensive.

Travelers in regions where cobras are indigenous should wear protective clothing (long pants and footwear), avoid areas where snakes seek cover, and know the location of the nearest source of medical care in case they are bitten.

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Complications

Complications of cobra envenomation may include the following:

  • Respiratory failure/arrest
  • Cardiovascular collapse
  • Prolonged neuromuscular weakness
  • Tissue necrosis
  • Antivenom-related complications - Nonallergic anaphylactic (anaphylactoid) reactions, delayed serum sickness
  • Venom-induced ophthalmia (spitting cobras)
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Prognosis

Many patients recover with no specific treatment.

The neurotoxic effects of cobra venom are completely reversible, though recovery may take up to 6 days.

Reports of death within 1 hour of cobra bite exist, but a timeframe of 2-6 hours is more typical of fatal cases.

With sound supportive care (eg, prevention of aspiration and respiratory support) and appropriate, prompt antivenom administration, anticipate recovery from cobra envenomation.

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Patient Education

Advise amateur herpetoculturists bitten by a venomous snake in their collection to not keep such animals. If they previously have received antivenom, their risk for an allergic reaction may be increased should antivenom use be required again in the future.

For excellent patient education resources, visit eMedicineHealth's First Aid and Injuries Center. Also, see eMedicineHealth's patient education article Snakebite.

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Contributor Information and Disclosures
Author

Robert L Norris, MD Professor, Department of Emergency Medicine, Stanford University Medical Center

Robert L Norris, MD is a member of the following medical societies: American College of Emergency Physicians, Society for Academic Emergency Medicine, International Society of Toxinology, American Medical Association, California Medical Association, Wilderness Medical Society

Disclosure: Nothing to disclose.

Specialty Editor Board

John T VanDeVoort, PharmD Regional Director of Pharmacy, Sacred Heart and St Joseph's Hospitals

John T VanDeVoort, PharmD is a member of the following medical societies: American Society of Health-System Pharmacists

Disclosure: Nothing to disclose.

David Eitel, MD, MBA Associate Professor, Department of Emergency Medicine, York Hospital; Physician Advisor for Case Management, Wellspan Health System, York

David Eitel, MD, MBA is a member of the following medical societies: American College of Emergency Physicians, American Society of Pediatric Nephrology, Society for Academic Emergency Medicine, Society of Critical Care Medicine

Disclosure: Nothing to disclose.

Chief Editor

Joe Alcock, MD, MS Associate Professor, Department of Emergency Medicine, University of New Mexico Health Sciences Center

Joe Alcock, MD, MS is a member of the following medical societies: American Academy of Emergency Medicine

Disclosure: Nothing to disclose.

Additional Contributors

James Li, MD Former Assistant Professor, Division of Emergency Medicine, Harvard Medical School; Board of Directors, Remote Medicine

Disclosure: Nothing to disclose.

Acknowledgements

Special thanks to the family of Dr. Sherman A. Minton who died on June 15, 1999. Dr. Minton, a renowned herpetologist and toxinologist, was instrumental in co-authoring the first edition of this chapter.

References
  1. Minton SA. Bites by non-native venomous snakes in the United States. Wilderness Environ Med. 1996. 4:297-303.

  2. Reid HA. Bites by foreign venomous snakes in Britain. Br Med J. 1978 Jun 17. 1(6127):1598-1600. [Medline].

  3. Goldman DR, Seefeld AW. Ocular toxicity associated with indirect exposure to African spitting cobra venom. Wilderness Environ Med. 2010 Jun. 21(2):134-6. [Medline].

  4. Russell FE. Snake venom poisoning in the United States. Annu Rev Med. 1980. 31:247-59. [Medline].

  5. Tin-Myint, Rai-Mra, Maung-Chit, et al. Bites by the king cobra (Ophiophagus hannah) in Myanmar: successful treatment of severe neurotoxic envenoming. Q J Med. 1991 Sep. 80(293):751-62. [Medline].

  6. Looareesuwan S, Viravan C, Warrell DA. Factors contributing to fatal snake bite in the rural tropics: analysis of 46 cases in Thailand. Trans R Soc Trop Med Hyg. 1988. 82(6):930-4. [Medline].

  7. Reid HA, Thean PC, Martin WJ. Epidemiology of snake bite in north Malaya. Br Med J. 1963. 1:992-997.

  8. Viravan C, Looareesuwan S, Kosakarn W, et al. A national hospital-based survey of snakes responsible for bites in Thailand. Trans R Soc Trop Med Hyg. 1992 Jan-Feb. 86(1):100-6. [Medline].

  9. Sawai Y, Tseng CS. Snakebites on Taiwan. Snake. 1969. 1:9-18.

  10. Stahel E. Epidemiological aspects of snake bites on a Liberian rubber plantation. Acta Trop. 1980 Dec. 37(4):367-74. [Medline].

  11. Norris RL, Ngo J, Nolan K. Physicians and lay people are unable to apply pressure immobilization properly in a simulated snakebite scenario. Wilderness Environ Med. 2005. 16(1):16-21. [Medline].

  12. Ang LJ, Sanjay S, Sangtam T. Ophthalmia due to spitting cobra venom in an urban setting--a report of three cases. Middle East Afr J Ophthalmol. 2014 Jul-Sep. 21 (3):259-61. [Medline].

  13. Gold BS. Neostigmine for the treatment of neurotoxicity following envenomation by the Asiatic cobra. Ann Emerg Med. 1996 Jul. 28(1):87-9. [Medline].

  14. Watt G, Theakston RD, Hayes CG, et al. Positive response to edrophonium in patients with neurotoxic envenoming by cobras (Naja naja philippinensis). A placebo-controlled study. N Engl J Med. 1986 Dec 4. 315(23):1444-8. [Medline].

  15. Lim BL. Venomous land snakes of Malaysia. In: Chou LM, Gopalkrishnakone P, eds. Snakes of Medical Importance - Asia-Pacific Region. National of University of Singapore. 1990:387-417.

  16. Warrell DA. Clinical toxicology of snakebite in Africa and the Middle East and Asia. In: Clinical Toxicology of Animal Venoms and Poisons. CRC Press. 1995:433-594.

 
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Naja naja (Indian Cobra). Photo by Robert Norris, MD.
Naja atra (Chinese cobra). Photo by Sherman Minton, MD.
Naja kaouthia (Monocellate cobra). Photo by Sherman Minton, MD.
Naja nivea (Cape cobra). Photo by Sherman Minton, MD.
Necrosis from a cobra bite. Photo by Sherman Minton, MD.
Necrosis from a Naja atra (Chinese cobra) bite. This resulted in a severe deformity. The patient had few systemic signs or symptoms. Photo by Sherman Minton, MD.
Table of antivenom choices for cobra bites. As antivenom manufacturers come and go in the market, choices in this list may or may not be available. Consultation with regional poison control centers, which have access to the Antivenin Index, may help identify and locate an appropriate product for use.
Cobra antivenoms and their manufacturers (part 1). As antivenom manufacturers come and go in the market, choices in this list may or may not be available. Consultation with regional poison control centers, which have access to the Antivenin Index, may help identify and locate an appropriate product for use.
Cobra antivenoms and their manufacturers (part 2). As antivenom manufacturers come and go in the market, choices in this list may or may not be available. Consultation with regional poison control centers, which have access to the Antivenin Index, may help identify and locate an appropriate product for use.
The Australian pressure immobilization technique. This technique has been shown to be helpful in delaying systemic absorption of elapid venoms, but its use in cobra bites remains controversial. A broad pressure bandage is immediately wrapped, beginning distally (illustration 1 of 5), around as much of the extremity as possible (illustrations 2 and 3). No effort should be spent removing clothing prior to bandage application. The bandage is wrapped snugly, as for a severely sprained ligament. A splint (or sling when applied to the upper extremity) is then placed (illustrations 4 and 5), and the victim is carried from the scene. The victim should expend no effort in getting to definitive care. Pressure immobilization should remain in place until the victim has reached medical care. The doctor will decide when to remove the bandages. If venom has been injected, it will move into the bloodstream quickly once the bandages are removed. The doctor should leave the bandages and splint in position until appropriate antivenom is available. Used with permission from Commonwealth Serum Laboratories.
The Australian pressure immobilization technique, illustration 2 of 5. A broad pressure bandage is immediately wrapped, beginning distally (as shown above), around as much of the extremity as possible. No effort should be spent removing clothing prior to bandage application. The bandage is wrapped snugly, as for a severely sprained ligament. Used with permission from Commonwealth Serum Laboratories.
The Australian pressure immobilization technique, illustration 3 of 5. A broad pressure bandage is immediately wrapped, beginning distally (as shown above), around as much of the extremity as possible. No effort should be spent removing clothing prior to bandage application. The bandage is wrapped snugly, as for a severely sprained ligament. Used with permission from Commonwealth Serum Laboratories.
The Australian pressure immobilization technique, illustration 4 of 5. A splint (or sling when applied to the upper extremity) is then placed and the victim is carried from the scene. The victim should expend no effort in getting to definitive care. Pressure immobilization should remain in place until the victim has reached medical care. Used with permission from Commonwealth Serum Laboratories.
The Australian pressure immobilization technique, illustration 5 of 5. A splint (or sling when applied to the upper extremity) is then placed and the victim is carried from the scene. The victim should expend no effort in getting to definitive care. Pressure immobilization should remain in place until the victim has reached medical care. Used with permission from Commonwealth Serum Laboratories.
 
 
 
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