Physical Examination
Abnormal heart rate and hypotension can result from autonomic dysfunction. Respiratory distress may lead to respiratory failure due to muscular paralysis.
Patient may present with altered mental status, ptosis (often the earliest sign of systemic toxicity), mydriasis, and/or generalized weakness or paralysis. Bulbar muscular dysfunction may result in slurred speech and drooling.
With venom into the eye, acute inflammation is present with ocular congestion, edema of the conjunctiva and cornea, and a whitish discharge. Slip-lamp or fluorescein tests may show corneal erosions.
Around the bite site, soft tissue edema with surrounding blistering may be noted. Necrosis may result, usually appearing within 48 hours of the bite.
Complications
Complications of cobra envenomation may include the following:
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Respiratory failure/arrest
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Cardiovascular collapse
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Prolonged neuromuscular weakness
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Tissue necrosis, potentially resulting in limb loss / amputation
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Venom-induced ophthalmia (spitting cobras)
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Anaphylaxis, non-allergic anaphylactoid reaction, delayed serum sickness (if and after antivenom administration)
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Naja naja (Indian Cobra). Photo by Robert Norris, MD.
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Naja atra (Chinese cobra). Photo by Sherman Minton, MD.
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Naja kaouthia (Monocellate cobra). Photo by Sherman Minton, MD.
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Naja nivea (Cape cobra). Photo by Sherman Minton, MD.
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Necrosis from a cobra bite. Photo by Sherman Minton, MD.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.