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Although a large proportion of the morbidity and mortality from
bites and stings occurs in the pediatric age group, there are surprisingly
few studies dealing with their diagnosis and treatment in children.
As with other injuries, the immediate care of a child suspected
of having suffered from an animal bite or sting should start with
a rapid evaluation of vital signs, followed by a more detailed assessment
of the local signs, including the size and appearance of fang or
sting marks, pain, swelling, and color of surrounding skin. Any
further investigation of the source of the injury should not result in
overlooking the administration of tetanus prophylaxis when appropriate,
or in delaying symptomatic treatment of pain and itching. Frequently,
a period of observation is necessary to define the seriousness of
the injury, particularly when it is not clear whether the causing
animal is venomous.
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A large number of venomous marine animals cause mild, debilitating,
or even fatal envenomation. These are seen most frequently in tropical
or temperate waters of North America and the Indo-Pacific region.
Because of the marked increase in recreational water sports, especially diving,
exposure to marine-animal envenomation has become more frequent.
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Phylum Coelenterata (Cnidaria)
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Members of this group are divided into three large classes: the
Hydrozoa (hydras, Portuguese man-of-war), Scyphozoa (true jellyfish),
and Anthozoa (soft corals, stone corals, and anemones). All of these
animals are present in temperate, subtropical, and tropical environments.
All members of the phylum have specialized organelles called nematocysts (ie, cnidae)
that are used for entrapping and poisoning prey. When the tentacles
touch a victim, the nematocysts discharge toxin on or through barbed
threads. The discharging of the nematocysts is not fully understood;
the process may be protein or cation mediated. The severity of envenomation
is related to the toxicity of the specie’s venom, number
of nematocysts discharged, general condition of the victim, and
whether prior sensitization exists. Mild to severe local and/or
systemic reactions may ensue. Stings from sessile species are, in
general, not as severe as stings from free-floating forms. Paralysis
and central nervous system (CNS) dysfunction appear to be caused
by specific toxic peptides contained in the venom. Burning pain
and urticaria are secondary to the presence of serotonin, histamine, and
histamine-releasing agents.
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The hydrozoans include the feathered hydroid (Pennaria
tiarelia) and the Portuguese man-of-war (Physalia
physalis). The mild sting of the feathered hydroid occurs
with handling and may be treated with local care. The Portuguese
man-of-war is commonly considered a jellyfish, but in reality, it
is a hydrozoan colony. The tentacles hang from the float and may
reach a length of more than 75 feet. Each tentacle contains about 750,000
nematocysts. Because of the length and transparency of the tentacles
in the water, swimmers are often stung without seeing the animal. Nematocysts
may discharge even when the animal is dead and on the beach. The
toxin injected is one ...