causes only a small amount of discomfort, described as a minor ache, slight stinging, or a pulsating sensation.
Occasionally the site is initially numb, followed in 5 to 10 minutes by discomfort that may spread to involve
the entire limb, persisting for up to 6 hours. Local urticarial reactions occur variably, and profuse bleeding at
the site is attributed to a local anticoagulant effect or may rarely be a harbinger of coagulation abnormalities.
Within 30 minutes, considerable erythema, swelling, tenderness, heat, and pruritus develop. By far the most
common local tissue reaction is absence of symptoms, a small spot of blood, or a tiny blanched area. More
serious symptoms are related predominantly to the neurotoxic properties of the venom. Within 10 to 15
minutes of the bite, the patient notices oral and facial numbness, rapidly followed by systemic progression.
Voluntary and involuntary muscles are involved, and the illness may rapidly progress to total flaccid paralysis
and respiratory failure. Other symptoms include perioral and intraoral anesthesia (classically, numbness of the
lips and tongue), diplopia, blurred vision, aphonia, dysphagia, ataxia, myoclonus, weakness, a sense of
detachment, nausea, vomiting, peripheral neuropathy, flaccid muscular paralysis, and respiratory failure,
which may lead to death. Ataxia of cerebellar configuration may occur after an envenomation that does not
progress to frank paralysis. The victim may collapse from weakness and remain awake, so long as
oxygenation can be maintained. When breathing is disturbed, respiratory assistance may allow the victim to
remain mentally alert, although paralyzed. Cardiac arrest is probably a complication of the anoxic episode.
Although tetrodotoxin is a potent vascular smooth muscle depressant, it does not appear to often produce
significant hypotension in humans. However, hypotensive crisis has been mentioned in the literature as a
complicating factor.
Treatment. First aid at the scene might include the pressure-immobilization technique described in the
section on treatment of box-jellyfish envenomation, although this is as yet unproven for management of
octopus bites. A monoclonal rabbit serum antibody IgG has been effective against tetrodotoxin injected
into
mice. This raises the possibility of the practical use of passive immunotherapy in the event of tetrodotoxin
poisoning.
Treatment is based on the symptoms and is supportive. Prompt mechanical respiratory assistance has by far
the greatest influence on the outcome. Respiratory demise should be anticipated early, and the rescuer should
be prepared to provide artificial ventilation, including endotracheal intubation and the application of a
mechanical ventilator. The duration of intense clinical venom effect is 4 to 10 hours, after which the victim
who has not suffered an episode of significant hypoxia shows rapid signs of improvement. If no period of
hypoxia occurs, mentation may remain normal. Complete recovery may require 2 to 4 days. Residua are
uncommon and related to anoxia rather than venom effects.
Management of the bite wound is controversial. Some clinicians recommend wide circular excision of
the bite wound down to the deep fascia, with primary closure or an immediate full-thickness free skin graft,
while others advocate observation and a nonsurgical approach. Because the local tissue reaction is not a
significant cause of morbidity, excision is recommended presumably to remove any sequestered venom.
Kinetic studies of radiolabeled venom absorption are necessary to track the movement of octopus bite-
introduced tetrodotoxin. As previously mentioned, there is no antivenom. Granuloma annulare of the hand
developing over a 2-week period after an octopus (presumed to be Octopus vulgaris of the Florida Gulf Coast)
bite of the hand has been reported. On biopsy, histologic sections demonstrated superficial and deep dermal
foci of altered dermis surrounded by histiocytes, lymphocytes, and fibroblasts. Intralesional triamcinolone
acetonide injections were temporarily successful in treating the primary lesion.
Prevention. All octopuses, particularly those less than 20 cm in length (including Octopus joubini of
the Caribbean), should be handled with gloves. Divers need to be familiar with the lethal creatures in their
domain. Giving an octopus a ride on the back, shoulder, or arm is not recommended.
Stingrays
The stingrays are the most commonly incriminated group of fishes involved in human envenomations.
There are 22 species of stingrays found in U.S. coastal waters, 14 in the Atlantic and 8 in the Pacific. The
family Dasyatidae includes most of the species that cause human envenomation. Skates are harmless. It is
likely that at least 2000 stingray injuries take place each year in the United States. On the west coast of the
United States, the round stingray (Urolophus halleri) is a frequent stinger; along the southeastern coast, it is
the southern stingray (Dasyatis americana). Most attacks occur during the summer and autumn months, as
