10.22 Marine envenomations
==========================

agk's Library of Common Simple Emergencies

Presentation
------------

After swimming in the ocean and coming into 
contact with marine life, the patient may seek 
medical attention because of local pain or 
swelling or skin discoloration. Marine animal 
envenomations can be divided into two major 
categories: puncture wounds and focal rashes. 
Severe envenomations can be accompanied by 
systemic symptoms like vomiting, paralysis, 
seizures, respiratory distress and hypotension, 
but this review is limited to the more common 
local injuries.

- Puncture wounds:
    - A laceration of the leg with blue edges 
        suggests a stingray attack. There is 
        immediate, local, intense pain, edema 
        of soft tissue, and a variable amount 
        of bleeding. The pain peaks after 30 to 
        60 minutes, may radiate centrally, and 
        may last 48 hours.
    - A single ischemic puncture wound with a 
        red halo and rapid swelling suggests a 
        scorpionfish envenomation. The pain is 
        immediate, intense and radiating. 
        Untreated, the pain peaks 60 to 90 
        minutes after the sting, persists for 
        at least 6 to 12 hours, and sometimes 
        for days.
    - Multiple punctures in an erratic pattern 
        with or without purple discoloration or 
        retained fragments are typical of a sea 
        urchin sting. The venomous spines can 
        innflict immediate and intense burning 
        pain with severe muscle aching. The 
        area surrounding the puncture wounds 
        may be red and swollen.
- Focal rashes:
    - Contact with a bristleworm is followed by 
        an intense red, itchy rash.
    - Contact with feather hydroids and sea 
        anemones induce a mild reaction, 
        consisting of instantaneous burning, 
        itching and urticaria. The reaction may 
        be delayed and can include the 
        appearance of papules, hemorrhagic 
        vesicles or zoster-like reactions 4 to 
        12 hours after contact.
    - The sting of the fire coral induces 
        intense burning pain, with central 
        radiation and reactive regional 
        lymphadenopathy.
    - Most of the jellyfish with suspended 
        tentacles create "tentacle prints" or a 
        whip-like pattern of darkened reddish 
        brown, purple or frosted and 
        cross-hatched stripes in the precise 
        areas of skin contact. Vesiculation and 
        skin necrosis may follow.

What to do:
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- Puncture wounds:
    - To relieve pain and perhaps attenuate 
        some of the thermolabile protein 
        components of the venom, soak the wound 
        in hot (not scalding) water 
        (approximately 45 degrees C or 113 
        degrees F) for 30 to 90 minutes or 
        longer is required for pain control.
    - During hot water treatment, infiltrate 
        into or around the wound with 0.5% 
        bupivacaine or 1% or 2% lidocaine 
        without epinephrine to provide further 
        pain control. When necessary, add 
        narcotic analgesics.
    - Irrigate the wound as soon as possible 
        with normal saline or dilute 1% 
        povidone-iodine solution (add 10% 
        Betadine to 0.9% NaCl in a 1:10 ratio) 
        and remove visible pieces of spine or 
        debris.
    - Obtain x rays if there might be any 
        radio-opaque fragments like sea urchin 
        spines retained.
    - When anesthesia is complete and pain has 
        been controlled, then thoroughly 
        explore, debride and irrigate open 
        wounds. Remove fragile sea urchin 
        spines using the technique for 
        [superficial sliver](cse1106.html).
    - Suture lacerations loosely or, better, 
        pack open for delayed primary closure.
    - Ensure current [tetanus prophylaxis].
    - Prescribe prophylactic antibiotics except 
        for minor abrasions, superficial 
        punctures and superficial lacerations. 
        Ciprofloxacin 500 mg bid x 3-5 days for 
        adults or trimethoprim-sulfamethoxazole 
        are most appropriate for coverage of 
        pathogenic marine microbes. The genus 
        Vibrio is particularly common in the 
        ocean and poses a serious risk for 
        immunosuppressed patients. Injuries 
        with potential for serious infection 
        include large lacerations, deep punc- 
        ture wounds (particularly near joints) 
        and retained foreign material. Reco- 
        mended initial parenteral antibiotics 
        include cefoperazone, cefotaxime, 
        ceftazidime, chloramphenicol, 
        gentamycin and tobramycin.
    - For infected wounds obtain both aerobic 
        and anaerobic cultures, and alert the 
        clinical microbiology laboratory that 
        standard antimicrobial susceptibiliy 
        testing media may need to be supp- 
        lemented with NaCl to permit growth of 
        marine bacteria. Institute the above 
        antibiotics except for minor wound 
        infections with the classic appearance 
        of erysipelas, which can be treated 
        with erythromycin or cephalexin. 
        Prescribe antibiotics for 7-14 days.
    - Follow up all wounds in 1-2 days with 
        periodic revisits until healing is 
        complete.
- Focal rashes:
    - For fire coral, jellyfish, hydroid or sea 
        anemone stings, decontaminate the area 
        with a liberal soaking of 5% acetic 
        acid (vinegar). The leading alternative 
        is 40-70% isopropyl (rubbing) alcohol. 
        Apply continuously for 30 minutes or 
        until the pain disappears.
    - After decontamination, remove any visible 
        large tentacles with forceps or 
        doubly-gloved hands. Remove small 
        particles by applying shaving foam or 
        some equivalent and gently shaving the 
        area with a safety razor, dull knife or 
        plastic card, then clean with an 
        antibacterial soap and flush with water 
        or saline solution.
    - Treat any generalized allergic reactions 
        with antihistamines, corticosteroids 
        and epinephrine.
    - When irritation from sponges, bristle 
        worms or other marine creatures cause 
        erythematous or urticarial eruptions, 
        it usually means tiny spicules and 
        spinules are embedded in the skin. Dry 
        the skin and apply the sticky side of a 
        piece of adhesive tape to the affected 
        area and peel the tape back to remove 
        these particles.
    - Residual inflamation can be treated with 
        topical corticosteroids like Aristocort 
        A 0.1% or 0.5% cream or Topicort 
        emollient cream or ointment 0.25% 
        (dispense 15 grams and apply tid-qid). 
        A topical steroid in combination with a 
        topical anesthetic can be additionally 
        soothing (eg Pramosone cream, lotion or 
        ointment 2.5% or Zone-a-cream 1% 
        tid-qid).
    - Check wounds for infection in two and 
        seven days.

What not to do:
---------------

- Do not use fresh water to decontaminate 
    jellyfish stings. It may cause microscopic 
    cysts to swell and rupture and trigger 
    additional stinging.
- Do not use topical or systemic cortico- 
    steroids for puncture wounds unless there 
    is an allergic reaction.
- Do not constrict limbs tightly.

Discussion
----------

Any wound acquired in the marine environment 
can become infected, and this is particularly 
likely if the wound is large, a puncture, or 
contaminated with bottom sediment or organic 
matter.

Stingray victims are generally innocent beach 
walkers who step on the back of the ray, which 
reflexively strikes upward with its tail, 
inflicting a penetrating wound along the upper 
foot, ankle, or lower leg. The anatomical 
structure of the stingray's back causes a deep, 
jagged, painful wound that may contain 
fragments of barb located proximal to the tail.

Scorpionfish, lionfish and stonefish stings 
occur in divers and fishermen, and sometimes 
keepers of marine aquariums or those involved 
in illegal tropical fish trade. Catfish stings 
are common when the fish are handled or kicked. 
Certain catfish species produce a venom in 
glands at the base of the dorsal spine, but 
most do not, and catfish venom causes only mild 
local pain, redness and swelling. Of more 
concern is the wound caused by the spine and 
the likelihood of infection.

Sea urchin victims are stung when the step on, 
handle, or brush up against these sessile 
creatures. The sea urchin secretes a toxin on 
the surface of its spines, which is transferred 
into the wound when they penetrate the skin. 
The brittle spines also tend to break off and 
remain in the wound.

References:
-----------

- Auerback PS: Marine env envenomation. *N Eng 
    J Med* 1991;325:486-493.

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