rastoni and Pelagia noctiluca, infrequently cause severe prolonged reactions and have rarely been reported to
lead to death, but are capable of causing dramatic immediate reactions. Sudden death in a child has followed
envenomation by Chiropsalmus quadrumanus in the Gulf of Mexico at Crystal Beach, Texas. Death was
attributed to acute arrhythmia after a catecholamine surge, followed by cardiogenic shock and pulmonary
edema.
Clinical aspects. The extreme example of envenomation occurs with the chirodropid Chironex ("The
Assassin's Hand") fleckeri (after Dr. Hugo Flecker). Death is attributed to hypotension, profound muscle
spasm, muscular and respiratory paralysis, and subsequent cardiac arrest. The overall mortality after box-
jellyfish stings may approach 15% to 20% in selected locales. Most commonly, bathers are stung, frequently
aboriginal children in shallow and remote coastal waters who do not recognize the small, semitransparent, and
submerged creature, which may approach as a member of a small armada. Most stings are minor; severe
reactions or death follows skin contact with tentacles longer than 6 or 7 m, although 10 cm of tentacle is
capable of delivering a lethal dose of venom. The sting is immediately excruciatingly painful, and the victim
usually struggles purposefully for only a minute or two before collapse. The toxic skin reaction may be
intense, with rapid formation of wheals, vesicles, and a darkened reddish brown or purple whiplike flare
pattern with stripes 8 to 10 mm in width. With major stings, skin blistering occurs within 6 hours, with
superficial necrosis in 12 to 18 hours. The skin defect(s) that result from a severe envenomation can be
profound. On occasion a pathognomonic "frosted" appearance with a transverse cross-hatched pattern may be
present. More severe reactions and increased mortality in women and small children have been attributed to
greater hairless body surface area and smaller body mass.
Treatment. In the case of a known or suspected box-jellyfish envenomation, the victim must be
assessed rapidly for adequacy of breathing and supported with an airway and artificial ventilation if necessary.
The victim should be moved as little as possible. It is essential to immediately and liberally flood the skin
surrounding any adherent tentacles with acetic acid 5% (vinegar) before any attempt is made to remove them;
this paralyzes the nematocysts and avoids worsening the envenomation. Significant pain relief should not be
expected from this maneuver. Although most nematocysts cannot penetrate the thickened skin of the human
palm, the rescuer should pay particular attention to his or her own skin protection. If acetic acid is not
available, aluminum sulfate surfactant (Stingose) may be used in substitution, although its efficacy has not
been well demonstrated for a Chironex envenomation. A number of experts recommend that isopropyl alcohol
not be used as a topical decontaminant for a box-jellyfish envenomation, based on in vitro observations of
inefficacy and nematocyst discharge after application of this detoxicant.
The pressure-immobilization bandaging technique can be used to prevent the absorption of Chironex
venom, and is applied after vinegar has been used to inactivate the nematocysts. Pressure-immobilization is
applied by taking a cloth or gauze pad of approximate dimensions 6 to 8 cm by 6 to 8 cm by 2 to 3 cm
(thickness) and placing it directly over the bite. The pad is then held firmly in place by a circumferential
bandage 15 to 18 cm wide applied at lymphatic-venous occlusive pressure (40 to 70 mmHg for the upper
extremity; 55 to 70 mmHg for the lower extremity).
If the pad is not available, the wrap is applied without it.
The arterial circulation should not be occluded, as determined by the detection of arterial pulsations and
proper capillary refill. One hypothesis holds that the pressure-immobilization technique devascularizes the
area immediately below the pad and prevents the distribution of venom into the general circulation. After the
wrap is applied, the limb should be splinted to prevent motion. The bandage should be released after the
victim has been brought to proper medical attention and the rescuer is prepared to provide systemic support. It
should be noted that pressure-immobilization is not uniformly recommended throughout Australia, as some
have questioned its efficacy and have noted the fact that large affected skin surfaces can not be effectively
bandaged.
In the absence of the ability to apply a pressure-immobilization bandage, a rescuer might apply a constriction
bandage proximal to the site of an extremity sting, to impede lymphatic and superficial venous return. Such a
bandage should be loosened for 90 seconds every 10 minutes and should be completely removed after 1 hour.
In no case should an arterial tourniquet be applied. Use of a proximal constriction band has not been proven to
be helpful.
Chironex antivenom should be administered intravenously as soon as possible. The intramuscular
route is less preferred. The antivenom is supplied in ampoules of 20,000 units by Commonwealth Serum
