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Professional Answer
Bites in humans
Redback spider bites rarely cause significant morbidity, and deaths are even more rare. On Australian record only 14 deaths from redbacks have been recorded. A significant proportion of bites will not result in envenomation or any symptoms developing. It is believed that thousands of people are bitten each year across Australia, although only about 20% of bite victims require treatment. Children and the elderly or those with serious medical conditions are at much higher risk of severe side-effects and death resulting from a bite. No deaths have been reported since the introduction of antivenom in 1956.
The larger female spider is responsible for almost all cases of Redback spider bites in humans. The smaller male spider was thought to be unable to envenomate a human; however, male bites have occurred. The rarity of male bites is probably due to smaller size and proportionally smaller fangs rather than the male being incapable of biting or lacking venom of potency similar to the female's. Cases have shown that the male bite usually only produces short-lived, mild pain.
Most bites occur in the warmer months between December and April and in the afternoon or evening. As the female Redback is slow moving and rarely leaves its web, bites generally occur as a result of a person placing a hand or other body part too close to the web, such as reaching into dark holes or wall cavities. But bites can occur wherever the spider may gain access, such as when putting on shoes or dressing.
Symptoms
Bites from Redback spiders produce a syndrome known as latrodectism. The symptoms are similar to bites from other Latrodectus spiders. The syndrome is generally characterised by extreme pain and severe sweating. Initially the bite may be painful but sometimes only feels like a pin prick or mild burning sensation. Within an hour victims generally develop more severe local pain with local sweating and sometimes piloerection (goosebumps). Pain, swelling and redness spread proximally from the site. Systemic envenoming is heralded by swollen or tender regional lymph nodes; associated features include malaise, nausea, vomiting, abdominal or chest pain, generalised sweating, headache, fever, hypertension and tremor. Rare complications include seizure, coma, pulmonary edema, respiratory failure or localised skin infection. Severe pain can persist for over 24 hours after being bitten.
Treatment
Medical advice should be sought after being bitten by a Redback spider. Usually this requires observation in or near a medical facility for six hours from time of the bite. Treatment is based on the severity of the bite; patients with localised pain, swelling and redness usually do not require any specific treatment apart from applying ice and routine analgesics. In more severe bites the definitive treatment consists of administering Redback antivenom. Antivenom will usually give immediate relief to symptoms of systemic envenoming.
Antivenom is indicated in anyone suffering symptoms consistent with Latrodectus envenoming. Particular indications for using antivenom are:
Pain and swelling spreading proximally from site
Chest pain
Abdominal pain
Unusual sweating
Currently it is recommended that this antivenom be given intramuscularly rather than intravenously, although some have suggested that IM antivenom is not as effective as IV antivenom. Adverse reactions to Redback antivenom are rare and antivenom may be effective for up to 3 months after a bite. Doses are the same for both children and adults. |
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发表于 16-11-2008 23:23:40
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发表于 17-11-2008 21:15:29
还好它胆子小不具备攻击性，不然我就挂了。。。
