History
The diagnosis of sea snake envenomation requires the establishment of the potential for exposure to a sea snake (eg, exposure to water in an area known to harbor sea snakes), identification of symptoms of envenomation, and demonstration of evidence of a bite (eg, multiple puncture wounds or reliable history of observed bite).
Symptoms are attributable to multiple organ systems, with neurological symptoms predominating. They may occur as early as 5 minutes or as late as 8 hours following the bite, but they usually occur within 2 hours. Initial symptoms include generalized aching, stiffness and tenderness of all muscle groups, as well as pain with passive muscle stretching. Trismus is also common. This is followed by progressive flaccid paralysis, starting with ptosis and paralysis of voluntary muscles. Paralysis of muscles responsible for swallowing and respiration can be fatal. Within 8 hours of envenomation, myoglobin, as a result of muscle breakdown, begins to rise in blood plasma; this eventually leads to myoglobinuria with resultant acute renal failure. [8] If muscle breakdown is severe, hyperkalemia may ensue, possibly leading to cardiac arrest.
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Euphoria
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Anxiety
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Malaise
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Drowsiness or mild confusion
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Headache
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Myalgias (typically worse with movement, usually beginning in the afflicted extremity, as well as the neck, within 30-60 min after envenomation)
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Arthralgias
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Ptosis
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Mydriasis with sluggish reaction to light
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Ophthalmoplegia, leading to diplopia
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Failing vision (usually a terminal symptom)
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Sialorrhea
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Trismus
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Facial paralysis
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Muscle paralysis (usually ascending, may be flaccid or spastic)
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Dyspnea
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Nausea, vomiting, abdominal pain, and cramping
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Change in urine color (dusky yellow to reddish brown)
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Oliguria
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Thirst
Physical Examination
Physical examination findings of sea snake envenomation may include the following:
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Fang marks (usually two or more small circular dots, which may be difficult to initially identify)
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Local tissue reaction (usually absent or minimal)
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Paralysis (typically ascending)
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Hyporeflexia (progressing to loss of reflexes)
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Hypersalivation
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Trismus
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Bulbar paralysis
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Ptosis
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External ophthalmoplegia
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Dysarthria and slurred speech
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Dysphagia
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Respiratory distress or respiratory failure
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Tachypnea
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Cyanosis
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Apnea
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Cardiac arrest (secondary to hyperkalemia)
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Fever (variable)
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Lymphadenopathy (involving the nodes responsible for draining the site of envenomation)
Complications
Complications of sea snake envenomation may include the following:
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Respiratory failure
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Cardiovascular collapse and shock
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Allergic reactions (eg, anaphylaxis), in response to sea snake envenomation or antivenom administration [9]
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Serum sickness following antivenom administration (usually between 5 d and 3 wk), characterized by urticaria, fever, lymphadenopathy, and arthritis
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Renal failure, most commonly due to necrosis in the distal tubules
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Hyperkalemia
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Dysrhythmias (secondary to hyperkalemia)
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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.