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redback_spider [2020/02/22 10:20] (current)
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 +====== red back spider bites / Latrodectism ======
  
 +see also:
 +  *[[spider_bites]]
 +  *[[anaphylaxis]]
 +
 +=====introduction====
 +  *the red back spider (//(L hasselti)//​) belongs to the widow spider family (//​Latrodectus sp.//) and are a common cause of spider bite in Australia with 3,000-5,000 bites per annum which result in Latrodectism which is primarily due to neurotoxins such as alpha latrotoxin
 +  *most bites occur when people accidentally put their hand in the web and the spider feels threatened, or put on clothing containing a spider
 +
 +=====clinical features of Latrodectism=====
 +  *the most consistent and prominent symptom is pain at the bite site which generally increases over the 1st hour and may spread proximally up the limb
 +  *this may be associated with other local features such as sweating, local erythema, piloerection,​ and systemic features such as:
 +    *nausea, malaise
 +    *headache
 +    *abdominal pain
 +    *tachycardia
 +    *hypertension
 +    *diaphoresis elsewhere (eg. bilateral legs)
 +  *in some cases, there may also be:
 +    *paraesthesiae
 +    *fever
 +    *muscle spasms and even some patchy paralysis
 +    *[[priapism]]
 +  *it is rarely lethal (none since 1950 in Australia) although bites to babies may be a significant risk
 +  *effects generally last 1-4 days and nearly all resolve within 1 week
 +
 +
 +=====Mx in ED=====
 +  *unlike snake bites:
 +    *first aid principles of compression and immobilisation are NOT indicated and may increase the pain
 +    *there is generally NO need for blood tests nor IV cannulation,​ unless you also suspect snake bite
 +    *there are NO diagnostic tests - the diagnosis is clinical
 +    *antivenom may NOT be needed even in those with envenomation
 +    *consider using an ice pack locally
 +  *it is rare for victims to require any Rx other than analgesia (although these analgesic regimes tend to be poorly effective in these bites) such as:
 +    *[[paracetamol]]
 +    *[[NSAIDs]]
 +    *[[oxycodone]]
 +  *historically most victims were given im or iv red back antivenom, however, a recent study by Isbister et al suggests that the benefits of antivenom in reducing pain, systemic symptoms or sequelae in those over 8 years of age may not outweigh the 3-4% risk of allergic reaction (([[http://​dx.doi.org/​10.1016/​j.annemergmed.2014.06.006]]))
 +  *older children and adults generally do not need observation in hospital, nor anti-venom
 +  *it may be prudent to given anti-venom to younger children and consider admission for observation,​ particularly in the very young
redback_spider.txt ยท Last modified: 2020/02/22 10:20 (external edit)