Spiders and Stingers

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A clinical overview of four important Australian envenomings: Redback spider, Funnelweb spider, Box jellyfish and Irukandji Syndrome. The talk was given at the Bedside Critical Care 2012 conference in the Whitsunday Islands.

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  • This is a whirlwind update and reminder about some more of our venous brethren: spiders and marine beasties.
  • Given the time limitations, we’re going to focus on RBS, FWS and the stingers – Chironexfleckeri and the cnidarians causing Irukandji syndrome.
  • First up, right Redback envenoming, Lactrodectus.Other species found worldwide include the Black Widow and the Katipo in NZ.Redback spiders were probably introduced to Australia in the 1870s and today bites occur throughout the country. Bites are more likely in the warmer months and peak between January and April.Redback spiders live in dark or dry areas. Bites tend to occur when people are putting on shoes or when they are moving outdoor pot plants, furniture, or firewood. A favourite hiding place is under the seat in an outdoor “dunny” (toilet)…
  • Alpha- lactrotoxin is vertebrate-specific, but there are also lactroinseectotoxinsRedback spider bites are not initially painful.Intense local pain develops 5-10 minutes after the bite and is followed by sweating and piloerection within an hour. Puncture marks are not always evident and erythema, if present, is usually mild.Systemic envenoming occurs in a significant minority of patients. Pain typically radiates proximally from the bite site to become regional then general (e.g. pelvic, back, abdominal, chest or shoulder pain). Autonomic features include severe sweating which may be regional (e.g. both legs) or generalised, mild hypertension and tachycardia.Non‑specific features of envenoming include headache, nausea, vomiting and dysphoria.Untreated, systemic envenoming may follow a fluctuating course lasting 1-4 days. Rarely, patients may feel unwell for up to a week. Very rarely, untreated patients report on‑going local symptoms that last weeks or months.
  • The problem is when things don’t go by the book:The severity and generalized nature of the pain may mimic an acute abdomen, such as appendicitis, especially in children. In one case report a child with lactrodectism was initially suspected of having tetanus! Lactrodectism should also be suspected in cases of priapism.Spider may not be seen or witnessed – need a high index of suspicion in endemic areasThere is no diagnostic test – it is a clinical diagnosis!
  • Reassure the patient, apply an ice pack and give simple oral analgesia such as paracetamol.Do not apply a pressure immobilisation bandage (PIB).Refer to hospital if the patient has local symptoms refractory to simple analgesia, clinical features of systemic envenoming, or the diagnosis is in doubt.Redback spider envenoming is not life‑threatening and resuscitation is rarely required.
  • Give an initial two ampoules (2 × 500 units) IV or IM to all patients with systemic latrodectism or local symptoms unrelieved by simple analgesia.Give further doses of two ampoules every 2 hours until symptoms are relieved.
  • Redback spider envenoming can follow a fluctuating course over about 4 days, and rarely patients may be systemically unwell for up to a week. Given this natural history and anecdotal reports of effectiveness, antivenom should be considered up to 96 hours after the bite.
  • I tend to treat with a maximum of 4 ampoules of CSL Redback Spider antivenom, I might go to 6 ampoules if the patient has shown definite but incomplete improvement.“the difference between IV and IM routes of administration of widow spider antivenom is, at best, small and does not justify routinely choosing one route over the other.”BUT IV has low reaction rate (5% hypersensitivity, <1% severe and ~10% serum sickness), can be stopped, repeat does given, detectable in the blood soomer – cf. 3 hours for IM
  • The RAVE trial of IM versus IV was unimpressive – there are concerns that it may not be better than placebo. Hence RAVE2… (though there was a small suggestion of improvement at D2)
  • Big black spider with fangsOn the east coast from Tas, to SA, Vic, NSW and Far north QLDEnvenoming is usually from males on the lookout for females. Can occur in the house, in the garden, shoes + clothing, firewood, bike helmets, etc etc.Alpha- atracotoxins = sodium channel activators
  • Painful bite by big black spider with visible fang marksNo significant swelling or rednessA minority of bites lead to systemic envenoming usually within20 minutes, almost always within 2 hoursFeatures:Nonspecifc: headache, nausea and vomiting, abdo painAutonomic (PS and S): sweating, salivation, piloerection, lacrimationCardiovascular: slow or fast HR, HTN or hypotension, pulmonary edemaNeuromuscular: agitation, fasciculations, paralysis, spasms, paraesthesiaecoma
  • Apply PIB – proven to work on Monkeys by Sutherland… Delayed cases of FWS systemic toxicity occur on or after PIB removal. Incidently, FWS venom only appears to affect primates, not other mammals… lucky us! If no evidence of systemic envenoming then observe 4 hours. Some of these are bitten by FWS but not envenomed, others may be other BBS like mouse or trapdoor spiders.They need observation for min 12 hours post antivenom and are best monitored in an HDU setting.
  • If envenomed then get ready to rock and roll!ABCS, etc addressing life threats:Respiratory failure due to neuromuscular effects or secretionsLow or high BPAPOComaGive supportive care, consider atropine for secretions but give antivenom stat!
  • Only 13 deaths ever reported, maybe up to 5 severe bites a year – no deaths since antivenom. Appears to be very effective anecdotally and in case series - will never be subjected to an RCT because of this. Give 2 amps (125 units each) IV in 100 mL NS over 20 minutes, prepare for anaphylaxis. Repeat in 2 hrs is the WA PIC advice, ISbister has said afterIf crashing give 4 amps of the bat – can give as IV push in an arrest. Rabbit Ig Fab fragments – comes freeze-dried, reconstitute in 6.3 mL Seems to be a good antivenom with anaphylaxis and serum sickness occurring in less than 1-2% of cases.
  • Photo by fir002
  • It turns out the marine world is a rich source of venomous and poisonous creatures – what’s on land pales in comparison…jellyfish-like creatures that sting (Cubozoans and Hydrozoans – true jellyfish are the Scyphozoans)Chironexfleckeriis a cubozoan with a deserved reputation of being the most lethal venomous animal in the world. There have been about 70 deaths in Australia alone and related species (other chirodropids, or multi-tentacled box jellyfish) probably account for much greater mortality figures worldwide. Each organism has 60 tentacles, each up to 2 or meters in length, and each packed with up to 1500 cigar-shaped nematocysts per mm2!!!
  • Chironex, and related multi-tentacled box jellyfish, are found in Australia’ s tropical waters and throughout the tropics. The global impact if these beasts is surely underestimated.
  • The stinging elements are nematoscysts – essentialy venom-laden mini-harpoons coiled up in a cigar shaped capsule.Firing is triggered by contact with prey or stray, with venom injected subcutaneously or even directly into the blood stream.
  • near cross-hatched weltsAdherent tentaclesIn Northern Australia, stings usually occur when wading in water <1m deep. Deaths typically occur in remote locations, usually children, who are less protected due to delicate skin and less body hair. Stinger suits and stinger nets are useful preventative measures where available.>2m lengths are stings are associate with death.
  • Stings result in immediate severe pain, the characteristic cross-hatched markings are pathognomonic. Systemic envenoming occurs with extensive stings – cardiovascular collapse can occur within minutes, presumably due to toxin-mediated disruption of sodium and calcium channel flux. Other problems in survivors include delayed type hypersensitivity and the potential for permanent scarring.DTH can be treated with prednisolone.
  • Copious application of vinegar and the removal of adherent tentacles, together with basic life support are the mainstays of first aid. Most stings require only simple analgesia and ice packs.It may be that, as for blue bottles, 15 min treatment with hot water may be more effective than ice packs, but the jury is still out.The effectiveness of CSL Box Jellyfish antivenom is unproven, its use in humans is based on anecdotal experience and case series.We know that it does work in animal models – if it is mixed with the venom before the victim is exposed!It may be that the venom is so fast acting that antivenom is clinically ineffective – the damage is already done. Doses given, preferably IV rather than IM, are: 6 ampoules (or whatever is available) for cardiac arrest, 3 ampoules for the haemodynamically unstable patient (repeat if required), and 1 ampoule for pain refractory to opioids.
  • Irukandji syndrome is a hypercatecholaminergic syndrome resulting from jellyfish envenoming. Named after a North QLd indigenous people, it ws attributed to a small carydeid (4 tentacledcubozoan jellyfish) carukiabarnesiHowever it is occurs throughout tropical australia, and perhaps even further south and a number of jellyfish species have been implicated.
  • A causative organism was identified with the discovery of the tiny carybdeid (4-tentacled box jellyfish) Carukiabarnesiby the intrepid Jack Barnes in 1963. Barnes demonstrating the causative role of this thumbnail-sized organism by stinging himself, his 9 year-old son and a local surf life-saver… All three were subsequently admitted to Cairns Base Hospital!
  • This is a pic from the NT series taken by Bart Currie – demonstrating skin markings caused by nematocysts on the bell of the jellyfish.
  • Irukandji syndrome is a hypercatecholaminergic syndrome resulting from jellyfish envenoming. Classically the syndrome involves a mild initial sting with delayed onset of systemic symptoms after about 20 minutes. Symptoms include nausea and vomiting, as well as severe and often cyclical pain (affecting many parts of the body, including the abdomen, back, chest and limbs) and even priapism. Cardiovascular manifestations include severe hypertension and its complications, cardiomyopathy (with raised troponins) and acute pulmonary edema.
  • Following first aid treatment with vinegar, the mainstays of management are supportive care including analgesia (usually opioids such as IV fentanyl) and antiemetics (e.g. IV promethazine). IV glyceryl trinitrate may be a useful option for uncontrolled hypertension and acute pulmonary edema.IV magnesium is commonly used for refractory pain and hypertension, until recently evidence of effectiveness is limited to anecdotal experience and small case series lacking methodological rigour.In the past month a small RCT was published from investigators in Cairns that failed to find any benefit for magnesium. It remains possible that selected patients could benefit, or that different doses might be beneficial.
  • Spiders and Stingers

    1. 1. Spiders and Stingers A Talk by Chris NicksonPhoto by Stefan
    2. 2. BRO
    3. 3. Master of camouflageStonefish Stone
    4. 4. The ItineraryRedback Spiders Box jellyfishFunnelweb Spiders Irukandji syndrome
    5. 5. Redback SpiderPhoto by Eliztyrell Lactrodectus hasselti
    6. 6. LactrodectismLocal pain over 10 minSweating & piloerection over 1hPain becomes generalisedNonspecific systemic featuresAutonomic featuresUsually lasts <1-4 days
    7. 7. Photo by WockyBeware Atypical Presentations
    8. 8. ManagementPrehospital – Icepack, paracetamol – no PIBResuscitation (rare)Medications – analgesia – antiemetics – antivenom
    9. 9. RedbackAntivenomWhen? IV or IM? Photo by Fir002
    10. 10. Antivenom IndicationsSevere, refractory local pain Systemic envenoming
    11. 11. Antivenom Adminstration2 ampoules (2 x 500 units) IV or IM +/- Repeat in 2 hours
    12. 12. Is RedbackAntivenomEffective? Photo by Localoptimum
    13. 13. Funnelweb SpiderAtrax sppHadronyche spp Photo by squil
    14. 14. Clinical FeaturesPainful biteSystemic features in minority20 minutes to 2 hour onsetNonspecific featuresSpecific features – Autonomic – Cardiovascular – Neuromuscular
    15. 15. ManagementPrehospital – PIBResuscitationSupportive careMedications – +/- Atropine – AntivenomObserve 4 hours Struan Sutherland
    16. 16. Life threats Respiratory failure Acute Pulmonary Oedema Hypertension or shockPhoto by Mitch_Donavan Coma
    17. 17. Funnelweb Antivenom Photo by squil
    18. 18. Funnelweb Antivenom 2+2 Photo by squil
    19. 19. Whitetail Spider Lampona sppPhoto by fir002
    20. 20. NecroticArachnidism MYTH
    21. 21. Box JellyfishChironex fleckeri
    22. 22. Box jellyfish worldwide Fenner PJ, Williamson JA. Worldwide deaths and severe envenomation from jellyfish stings. Med J Aust. 1996 Dec 2- 16;165(11-12):658-61.
    23. 23. Photo from ABC News
    24. 24. Clinical featuresStinger season (Nov-April)Linear cross-hatched weltsAdherent tentaclesSevere pain (8h)Collapse andcardiovascular effectsScarringDelayed hypersensitivity
    25. 25. ManagementPrehospital Wound care – Analgesia Antivenom – Vinegar – Arrest: 6 amps – No PIB – Unstable: 3 ampsResuscitation – Refractory pain: 1 – Hypotension amp – Dysrhythmias Delayed type – Cardiac arrest hypersensitivityAnalgesia – Steroid cream – Ice (hot water?)
    26. 26. Irukandji SyndromeCarukia barnesi & others Photo by Lifeinthefastlane.com
    27. 27. “The first Carybdeid was applied to an adult (J.B.), and to a boy, aged nine years (N.B.). A robust young life-saver (C.R.) volunteered to test the second specimen, of similar size to the first.”Barnes, J. H. (1964). “Cause and Effect in Irukandji Stingings.” Med J Aust 1: 897-. http://lifeinthefastlane.com/2009/03/jack-barnes-and-the-irukandji-enigma/
    28. 28. Nickson CP, Waugh EB, Jacups SP, Currie BJ. Irukandji syndrome case series fromAustralias Tropical Northern Territory. Ann Emerg Med. 2009 Sep;54(3):395-403. Photo by Bart Currie
    29. 29. Clinical featuresMild sting…Progressive severe painCatecholamine excesssyndromeCardiovascular complications – Shock, acute pulmonary oedema, cardiomyopathy, intracranial hemorrhage
    30. 30. ManagementPrehospital – Vinegar, no PIBResuscitationMedications – Fentanyl – Promethazine – GTN – magnesium
    31. 31. THE ENDhttp://lifeinthefastlane.com/ education/toxicology/

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