Laboratory Studies
Obtain arterial blood gas (ABG) measurements if the patient's respiratory status is questionable.
Myoglobinuria may be found on urinalysis, typically 3-6 hours following envenomation. The urine may test positive for protein and occult blood 1 hour before myoglobin is detected.
Creatine kinase (CK) level may be elevated secondary to muscle damage.
Serum glutamic-oxaloacetic transaminase (SGOT) level may be elevated secondary to muscle damage.
Electrolyte levels may reveal hyperkalemia from myonecrosis.
Assess blood urea nitrogen (BUN) and creatine levels to monitor renal function.
Obtain a CBC count. A leukocytosis higher than 20,000 cells/µL suggests significant envenomation.
Imaging Studies
The following imaging studies may be useful:
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Chest radiography: This is useful to exclude other causes of respiratory distress and is mandatory in patients requiring intubation and mechanical ventilation.
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Soft tissue and bone films of the bitten extremity: Radiographs may reveal embedded fangs and/or underlying osseous injury.
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Bedside ultrasonography: As ultrasonography is becoming a more useful adjunct to physical examination in the emergency department, bedside imaging may facilitate identifying retained fangs at the site of venomous inoculation.
Other Tests
An electrocardiogram (ECG) is useful to look for signs of hyperkalemia, including peaked T waves, a widened QRS complex, or ventricular arrhythmias.
Before antivenom administration, if time permits, skin testing to assess for allergy to horse serum is indicated, but it is not mandatory if the patient is unstable. The results of skin testing are not completely reliable. Intradermal injection of 0.02-0.03 mL of a 1:10 dilution of normal horse serum is the most commonly described technique; however, the test is more accurate if a 1:10 dilution of actual reconstituted antivenom is used. Skin test results are positive if a wheal develops in 5-30 minutes.
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Technique for application of pressure immobilization in field management of sea snake bites. Figure 1, Apply a broad-pressure bandage over the bite site as soon as possible. Do not take off jeans because the movement of doing so assists venom to enter the bloodstream. Keep the bitten leg still. Figure 2, The bandage should be as tight as would be applied to a sprained ankle. Figure 3, Extend the bandage as high as possible.
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Technique for application of pressure immobilization in field management of sea snake bites. Figure 4, Apply a splint to the leg. Figure 5, Bind the splint firmly to as much of the leg as possible. If the bandages and splint are applied correctly, they will be comfortable and may be left on for several hours. They should not be taken off until the patient 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 he or she has assembled appropriate antivenom and drugs that may need to be used when the dressings and splint are removed. Figure 6, For bites on a hand or forearm, bind to the elbow with bandages, use a splint to the elbow, and use a sling.
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Yellow-belly pelagic sea snake. Illustration by David Kirshner.
