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Snake Envenomation, Sea: Treatment & Medication
Updated: Nov 6, 2008
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
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Treatment
Prehospital Care
The critical components of prehospital care for sea snake bites are initial stabilization with airway control, pressure immobilization of the bitten extremity, and prompt transport to a facility capable of providing advanced medical care (including antivenom administration).
- A brief attempt to visually identify the offending snake is warranted, but prolonged attempts to kill or capture the snake should be avoided. The bite reflex persists for up to an hour even after the snake is decapitated, making it possible for dead snakes to inflict a serious bite.
- If needed, institute supportive measures, including endotracheal intubation and mechanical ventilation, as clinically indicated.
- Apply pressure immobilization of the bitten extremity as quickly as possible because it may impede venom spread. Rapidly wrap the limb with a broad pressure bandage, starting at the wound site and extending as high up the extremity as possible. The bandage should be wrapped to venous occlusive pressure (approximately 70 mm Hg) in a manner similar to wrapping a sprained ankle. An extremity splint completes the immobilization.
Technique for application of pressure immobilization in field management of sea snake bites. See Image 2 for Figures 4-6. 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.
Technique for application of pressure immobilization in field management of sea snake bites. See Image 1 for Figures 1-3. 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.
- Avoid incision, ice, or other cooling measures.
- Suction is unlikely to be beneficial and only should be attempted if a mechanical suction device is immediately available.
Emergency Department Care
- Stabilization of airway, breathing, and circulation (ABCs)
- Intravenous access
- Cardiac monitoring and continuous pulse oximetry
- Tetanus prophylaxis
- Antivenom administration is indicated for any patient with signs of envenomation. The agent of choice is polyvalent sea snake antivenom (Commonwealth Serum Laboratories, Melbourne, Australia). Alternatively, tiger snake (Notechis scutatus) antivenom can be substituted because of the close relationship of tiger snake and sea snake venoms.
- Indications for antivenom use include shock, respiratory distress or failure, generalized myalgias, trismus, moderate-to-severe pain with passive movement of extremities, myoglobinuria, elevated creatine kinase level (>600 IU/l), altered level of consciousness, hyperkalemia, or leukocytosis.
- Administer antivenom as soon as possible. Benefits may be observed up to 36 hours after the bite.
- For early mild-to-moderate envenomation, use one ampule of antivenom (1000 U). Later or severe envenomation typically requires 3-10 ampules (3000-10,000 U) of antivenom, respectively.
- If antivenom is not available, consider dialysis. Sea snake neurotoxin is of low enough molecular weight to be dialyzable. Furthermore, dialysis may be life saving in cases of severe hyperkalemia.
- Aggressive hydration with diuresis can help promote renal myoglobin clearance. Urine alkalinization may be of some benefit in cases of myoglobinuria.
- In-patient admission for observation, especially if the patient is to receive antivenom as allergic/anaphylactic reactions are common.
Consultations
- Poison control centers, zoos, or experts in snake envenomation may help guide the management of sea snake envenomations and assist with the location of antivenom.
- In cases of serious envenomation, an internist or intensivist should be consulted for admission to the hospital or intensive care unit, respectively.
Medication
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
Antivenom conveys passive immunity to patients with sea snake bite.
Antivenin polyvalent sea snake
Can be obtained from Commonwealth Serum Laboratories, Melbourne, Australia. DOC for treatment of symptomatic sea snake envenomation. 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 IV.
IV 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.
Adult
Early and mild envenomations: Administer 1000 U
Late envenomations: Administer 3000-10,000 U
1000 U = 1 ampule
Pediatric
Administer as in adults
None reported
Documented hypersensitivity; may give in severe envenomation despite hypersensitivity
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Because of presence of horse serum, agents for emergency treatment of anaphylaxis should be available; in the event of a severe reaction, antivenom administration usually can be restarted at a slower rate with concurrent infusion of IV epinephrine and close patient monitoring
Antihistamines
These agents are used to treat minor allergic reactions and anaphylaxis.
Diphenhydramine (Benadryl)
May be used to pretreat patients with prior documentation of minor allergic reactions. Used as a prophylactic treatment and for treatment of allergic reactions to antivenom.
Adult
1 mg/kg IV; not to exceed 100 mg
Pediatric
1 mg/kg IV q6h
Potentiates effect of CNS depressants; because of alcohol content, do not give syrup dosage form to patients taking medications that can cause disulfiramlike reactions
Documented hypersensitivity; MAOIs
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
May exacerbate angle-closure glaucoma, hyperthyroidism, peptic ulcer, and urinary tract obstruction
Immunizations
Active immunity can prevent hypersensitivity reactions and neutralize toxoids.
Diphtheria-Tetanus Toxoid
Used to induce active immunity against tetanus in selected patients. The immunizing agents of choice for most adults and children >7 y are tetanus and diphtheria toxoids. 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.
Adult
Primary immunization: Administer 0.5 mL IM, give 2 injections 4-8 wk apart and a third dose 6-12 mo after the second injection.
Booster dose: Administer 0.5 mL q10y
Pediatric
Administer as in adults
Patients receiving immunosuppressants, including corticosteroids or radiation therapy, may remain susceptible despite immunization because of poor immune response; cimetidine may enhance or augment delayed-hypersensitivity responses to skin-test antigens; avoid concurrent use of medication with systemic chloramphenicol because it may impair amnestic response to tetanus toxoid; concurrent use of tetanus immune globulin may delay development of active immunity by several days (nevertheless, interaction is clinically insignificant and does not preclude its concurrent use)
Documented hypersensitivity; a history of any type of neurological symptoms or signs following administration of this product; FDA recommends that elective tetanus immunization be deferred during any outbreak of poliomyelitis because tetanus toxoid injections are an important cause of provocative poliomyelitis
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Do not use to treat actual tetanus infections or for immediate prophylaxis of unimmunized individuals (use tetanus antitoxin instead, preferably human tetanus immune globulin); diminished antibody response to active immunization may be observed in patients receiving immunosuppressive therapy; better to defer primary diphtheria immunization until immunosuppressive therapy discontinued; routine immunization of symptomatic and asymptomatic persons with HIV infection is recommended
Cardiovascular agents
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)
DOC for the treatment of anaphylactoid reactions and should be considered as pretreatment before giving antivenom. Has alpha-agonist effects that include increased peripheral vascular resistance, reversed peripheral vasodilatation, systemic hypotension, and vascular permeability. Beta-agonist effects include bronchodilatation, chronotropic cardiac activity, and positive inotropic effects.
Adult
Initial dose of epinephrine is 0.01 mL/kg IM/SC of 1:1000 solution; not to exceed 0.5 mL of 1:1000 solution (0.5 mg)
Fraction of total dose (0.1-0.2 mL) at site of antigenic exposure, if accessible
Severe anaphylaxis (laryngeal edema, respiratory failure, shock): 10 mL of 1:100,000 dilution of aqueous epinephrine IV over 10 min
If no improvement observed, establish a continuous infusion starting at 1 mcg/min of 4-mcg/mL concentration; increase to 4 mcg/min prn
Pediatric
0.1 mcg/kg/min SC q15min for 2 doses, then q4h with increments of 0.1 mcg/kg/min prn; not to exceed 1.5 µg/kg/min
Increases toxicity of beta- and alpha-blocking agents and that of halogenated inhalational anesthetics
Documented hypersensitivity; cardiac arrhythmias or angle-closure glaucoma; local anesthesia in areas such as fingers or toes because vasoconstriction may produce sloughing of tissue; do not use during labor (may delay second stage of labor)
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in elderly persons, prostatic hypertrophy, hypertension, cardiovascular disease, diabetes mellitus, hyperthyroidism, and cerebrovascular insufficiency; rapid IV infusions may cause death from cerebrovascular hemorrhage or cardiac arrhythmias
Corticosteroids
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.
Adult
10-125 mg IV q6-8h
Pediatric
1-2 mg/kg IV q6-8h
Coadministration with digoxin may increase digitalis toxicity secondary to hypokalemia; estrogens may increase levels of methylprednisolone; phenobarbital, phenytoin, and rifampin may decrease levels of methylprednisolone (adjust dose); monitor patients for hypokalemia when taking medication concurrently with diuretics
Documented hypersensitivity; viral, fungal, or tubercular skin infections
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Hyperglycemia, edema, osteonecrosis, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, growth suppression, myopathy, and infections are possible complications of glucocorticoid use
Prednisone (Deltasone, Orasone, Meticorten)
Decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability.
Adult
1-2 mg/kg qd or divided bid until symptoms resolved, followed by a 1-wk taper
Pediatric
Administer as in adults
Coadministration with estrogens may decrease clearance; concurrent use with digoxin may cause digitalis toxicity secondary to hypokalemia; phenobarbital, phenytoin, and rifampin may increase metabolism of glucocorticoids (consider increasing maintenance dose); monitor for hypokalemia with coadministration of diuretics
Documented hypersensitivity; viral, fungal, or tubercular infections
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Abrupt discontinuation of glucocorticoids may cause adrenal crisis; hyperglycemia, edema, osteonecrosis, myopathy, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, myasthenia gravis, growth suppression, and infections may occur with glucocorticoid use
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References
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Further Reading
Keywords
sea snake envenomation, sea snake bite, sea snakes, snake bite, Hydrophiidae, Pelamis platurus, P platurus, Enhydrina schistosa, E schistosa, sea snake venom, neurotoxins, myotoxins, snake envenomations, sea snake neurotoxin, sea snake wound
