History
The spider usually is seen, and its bite is extremely painful for hours to days (the fangs are large and enter with considerable force). Early symptoms of systemic envenomation may occur rapidly, with a 28-minute median onset. A pressure-immobilization dressing can delay onset of symptoms.
The following are symptoms of a serious envenomation:
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Perioral tingling
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Lacrimation
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Salivation
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Abdominal pain
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Nausea
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Vomiting
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Diaphoresis
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Severe dyspnea
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Muscle fasciculations and spasms are common.
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Agitation and confusion can occur.
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Unconsciousness occurs in a minority of patients.
Physical Examination
Erythema, piloerection, diaphoresis, and muscle fasciculation may be seen at and around the bite site.
Generalized diaphoresis, lacrimation, and salivation may be noted.
Fasciculations and muscle spasms are frequent findings in severe envenomation; however, paralysis does not appear to occur.
A brief period of hypotension and tachycardia is followed by severe hypertension.
Cardiac arrhythmias and cardiac arrest may occur.
Severe pulmonary edema that is poorly responsive to loop diuretics occurs early and may be fatal.
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The Sydney funnel-web spider, Atrax robustus. Male (left) and female (right). Photograph courtesy of the Australian Venom Research Unit, Department of Pharmacology, University of Melbourne, Australia.
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Female funnel-web spider. Image courtesy of Glenn DuBois, CEO, http://www.termite.com/spider-identification.html.
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Male funnel-web spider. Image courtesy of Glenn DuBois, CEO, http://www.termite.com/spider-identification.html.
