Sunday 11 November 2018

Spider bites and other creepy crawlers

#KYJ-  Spider bite.
In the last great act of defiance look at where this spider decided to sit.  We hear a lot about creepy crawleys in our area. Spiders, scorpions, ants, wasps and centipedes (and that is just my yard).
Recent east coast wet weather has produced a minefield of critters that can cause harm.

This KYJ is dedicated to terrestrial arthropod bites. 
These fall into two categories.  Insects (6 legged bugs) and arachnids like Scorpians, centipede and spiders.

With the exception of the infamous Funnel web spider, all critters listed above are treated the same. 
Wash the bite with soap and water, apply an ice pack for 10-20 minutes.
Rest the patient.
Paracetamol or ibuprofen for pain.

Funnel web spiders are potentially lethal. They can cause respiratory failure and are managed as snake bites using pressure immobilisation bandaging and antivenin.

Only male Sydney Funnel Web Spiders and Redback Spiders have caused human deaths, but none have occurred since antivenoms
were made available in 1981.
The Australian funnel-web spiders are among the deadliest spiders in the world, but while they can kill us, their venom has little effect on cats n dogs.  There are many species of funnel-web spiders in Australia but only males of the species is deadly. Despite an average of 40 bites per year from funnel webs, only 13 deaths have been recorded, and none for over 35 years.
Other large hairy spiders like Mouse spiders may have venom that is as toxic as that of some funnel-webs, and while people are bitten from time to time, no-one has been recorded as having died from the effects of a mouse spider bite. Antivenoms are available for both funnel-web and Redback Spider bites.
Red Back bites occasionally get antivenin, but this is a controversy.  In 2012 an Australian study concluded that there was little point, other than a mild, hit n miss analgesic effect.  Considering the fact that no one has died from Red Back spider bites for well over 60 years, many clinicians consider a wait n watch. That said, there is fierce debate among toxicologists (http://mobile.abc.net.au/news/2013-11-22/doctors-warned-to-keep-using-redback-anti-venom/5109838)
Typically spider bites cause an neurotoxic and cytotoxic responses.  
Neurotoxic symptoms include muscle rigidity, stiffness, myalgia and at its worst, weakness and paralysis (eg funnel web).
Cytotoxic effects cause local skin irritation and blistering.  A white hypo perfused area directly onthe bite, with a wide area of redness (inflammation) around the pale bite centre is common. Sweating around the bite site is a function of the neurotoxic effects. 
Some international spider bites (brown recluse) have been associated with necrosis and muscle breakdown but we don't see this in Australian spiders despite the mythical notion of the white tail spider.  It's now widely accepted that any infection post spider bite was not due to venom it was due to soil bacteria introduced at the time of the puncture.
First aid for spider bites remains rest, ice packs, analgesia and give it a good clean.  If the patient has not had a recent tetanus shot then this should be attended to.
Scorpions and centipede in Australia are not deadly. That said and anaphylactic reaction to any bite or sting is a life-threatening emergency.  Like spider bites scorpions and centipede bites I treated using basic first aid.
Whilst this post is focused on spider bites, is important to recognise that wasps and ants stings are also treated with ice packs although much success has been gained from rubbing the freshly cut surface of an onion straight onto a wasp or ant sting.
Personally I have had tremendous success with an onion. Instant pain relief. 



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