Medication Summary
The mainstay of medical therapy for sea snake venom poisoning is antivenom. If time permits, a skin test for sensitivity to horse serum may be performed before antivenom administration. The purpose of skin testing is to try to predict possible anaphylaxis, rather than determine whether antivenom should be used. Omit skin testing if the patient clearly needs antivenom because skin testing reliability is low. Closely monitor the patient during antivenom administration and begin aggressive treatment if any evidence of allergic reaction is observed.
Antivenom
Class Summary
Antivenom conveys passive immunity to patients with sea snake bite.
Antivenin polyvalent sea snake
This can be obtained from Commonwealth Serum Laboratories, Melbourne, Australia. It is the drug of choice for the treatment of symptomatic sea snake envenomation. It is a hyperimmune horse globulin prepared against the venoms of Enhydrina schistosa and N scutatus and is efficacious in the treatment of all sea snake envenomations.
An alternative to polyvalent sea snake antivenom is monovalent sea snake antivenom (Haffkine Institute, Bombay, India), prepared against the venom of E schistosa, which is effective against most sea snake venoms. Finally, tiger snake (N scutatus) antivenom (Commonwealth Serum Laboratories, Melbourne, Australia) displays substantial activity against sea snake venoms because of a close relationship between tiger snake and sea snake venoms.
Early or mild envenomation can be treated with 1 ampule, while late and/or severe envenomations should be treated with 3-10 ampules. Snake antivenom only is administered intravenously.
The intravenous infusion should be started at a slow rate, which may be increased if no evidence of significant allergic reaction exists. Most authorities recommend premedication with diphenhydramine.
Antihistamines
Class Summary
These agents are used to treat minor allergic reactions and anaphylaxis.
Diphenhydramine (Benadryl)
Diphenhydramine may be used to pretreat patients with prior documentation of minor allergic reactions. It is used as a prophylactic treatment and for the treatment of allergic reactions to antivenom.
Immunizations
Class Summary
Active immunity can prevent hypersensitivity reactions and neutralize toxoids.
Diphtheria & tetanus toxoids (Decavac, DT, Td)
This is used to induce active immunity against tetanus in selected patients. The immunizing agents of choice for most adults and children older than 7 years are tetanus and diphtheria toxoids. It is necessary to administer booster doses to maintain tetanus immunity throughout life.
Pregnant patients should receive only tetanus toxoid, not a diphtheria antigen–containing product.
In children and adults, may administer into the deltoid or midlateral thigh muscles. In infants, the preferred site of administration is the mid thigh laterally.
The tetanus immunization status should be updated for any patient bitten by a sea snake. The precise formulation used is dependent on the patient's age and prior immunization status.
Cardiovascular agents
Class Summary
These agents are useful for treatment or prophylaxis of acute allergic reactions and for support of blood pressure in patients with shock.
Epinephrine (Epi-Pen, Adrenaline)
Epinephrine is the drug of choice for the treatment of anaphylactoid reactions and should be considered as pretreatment before giving antivenom. It has alpha-agonist effects that include increased peripheral vascular resistance, reversed peripheral vasodilatation, systemic hypotension, and vascular permeability. Its beta-agonist effects include bronchodilatation, chronotropic cardiac activity, and positive inotropic effects.
Corticosteroids
Class Summary
Anti-inflammatory agents are useful in the management of acute and delayed allergic reactions to sea snake envenomation or antivenom administration.
Methylprednisolone (Solu-Medrol, Depo-Medrol)
Steroids ameliorate delayed effects of anaphylactoid reactions and may limit biphasic anaphylaxis. In severe cases of serum sickness, parenteral steroids may be beneficial to reduce inflammatory effects of this immune-complex mediated disease.
Prednisone (Deltasone, Orasone, Meticorten)
Prednisone decreases inflammation by suppressing the migration of polymorphonuclear leukocytes and reversing increased capillary permeability.
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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.
