#TOXINology #cram #tables > [!Key Points] > Antidote:: antivenom See: [Cameron snakebite](x-devonthink-item://10DC3BB1-027C-40D6-BDB3-4AF0C6B160E6?page=896) [Bear snakebite](bear://x-callback-url/open-note?id=DDC6CB1A-2E43-484A-B0E2-21228425F01E-34582-0000858523D2BE65) | species | location | neurotoxicity | coagulopathy | cardiac effects | antivenom | | ------------------------- | --------------------- | -------------------------------- | ------------- | --------------------- | ---------------------- | | brown | everywhere but Tas | - | severe VICC | syncope/collapse | 2amps brown | | tiger | Tas and east coast | delayed paralysis | VICC | sometimes early death | 2ams tiger | | Black (mulga/red-bellied) | everywhere but tas | mild paralysis | anticoagulant | - | 1am CSL black or tiger | | Death Adder | not VIC or tas | symmetrical descending paralysis | - | - | 1 am death adder | | Taipan | north and Coober pedy | paralysis 1-2 hours | severe VICC | - | 1 am taipan | ![[Pasted image 20230701121314.png]] # Snakes ## Brown snake - sudden arrest from cardiac arrest - Vicc ## Tiger snake - vicc ## Red bellied black - anticoagulant coagulopqthy # Effects > [!tip]- General symptoms and signs to review for > history: > - witnessed bite vs suspicion > - ?multiple bites > - time since bite > - where > - first aid? > > symptoms: > - headache > - diaphoresis > - nausea/vomiting > - abdo pain > - diarrhoea > - blurred or double vision > - slurring speach > - muscle weakness or pain > - resp distress > - dark or red urine > - local pain at bite site > - LOC > - seizures > > exam: > - evidence of bite > - evidence of venom movement (eg swollen or tender draining lymph nodes > - neurotoxic paralysis (ptosis, ophthalmoplegia, diplopia, dysarthria, limb weakness, resp muscle weakness) > - coagulopathy (bleeding gumbs, venipuncture site, bite site) > - muscle damage (tenderness, pain on movement, red/dark urine indicating myoglobinuria) ## Coagulopathy, VICC > ==coagulopathy is a leading cause of death in human snake bite== > > clinical evidence: > **bleeding** from bite site, cannula, oral cavity, or occult sites (GI, urinary, intracranial) 2 types: - **procoagulants** (i.e. prothrombin activators): result in ==venom induced consumptive coagulopathy (VICC)== - defibrination or [[DIC]]-like picture from brown, tiger, and taipan snakes - activation of clotting pathway by prothrombin activator toxins and consumption of clotting factors (fibrinogen, factor V, and factor VIII) lead to a **consumptive coagulopathy** - ==coag studies:== - INR high or unrecordable - aPTT prolonged - fibrinogen level is **low** or undetectible - D-dimer very high - direct **anticoagulants** -- result in a a "pure" anti-coagulation picture (black snakes) - this is biochemical abnormality usualy without clinical consequences - aPTT si moderately abnormal (1.5-2.5 times above lab reference) - mild elevation of INR <1.3 - D-dimer and fibrinogen levels are normal **Thrombotic microangiopathy**: - always associated with VICC - microagniopathic haemolytic anameia (presence of fragmented red blood cells on blood film, thrombocytopenia, and rising Cr >120, which may lead to acute renal failure ### VICC severity grading | parameter| severe VICC| less severe VICC| | --- | ---| ---- | | fibrinogen| indetectable level| low but detectible <1.5 g/L | |INR| > 3.0 | <3.0 | | D-dimer | very high 100-1000x | high >10x cut off, more than 2.5 mg/L | ## Neurotoxicity - **pre-synaptic inhibitors** -- seen in tiger and taipan venom - inhibit the release of neurotransmitter → progressive neuromuscular paralysis - antivenom may prevent paralysis but cannot reverse neuronal damage that has already occured - damanged neurons may take weeks to recover - **post-synaptic inhibitors** -- seen in death adder venom - non-depolarizing competitive block at post-synaptic receptors (like rocuronium) > generally neurotox pattern shows cranial nerve involvement → paralysis of large limb muscles → paralysis of resp muscles > > ==descending flacid paralysis== > - eye muscle (*ptosis*, ophthalmoplegia, diplopia) -- to proprly test for ptosis, get pt to look upwards for a full minute > - followed by bulbar muscle paralysis (dysphagia, dysarthria) > - followed by limb paralysis > - followed by resp muscle paralysis ## Myotoxicity cause [[rhabdomyolysis]] which can result in [[hyperkalemia]] in short term and renal failure due ot myoglobunuria in longer term - can be local or generalised - clinical features include: - myalgia - muscle tenderness - weakness - biochemical features: - elevated CK levels - CK usually nomral on admission, but rise over next 24-48 hrs (pleak from 1000 in mild cases to >100,000 in severe cases) - K may be >5 in severe cases - renal failure ## time course of systemic effects - usually over 2-3 hours, but great variation; can range from immediate sudden collapse to up to 12 hrs following fite average time course: - within first hour - headache - nausea and vomiting - collapse/transient hypotension - 1-3 hours - cranial nerve paralysis (fist evidence usually ptosis and diplopia, followed by dysarthria/dysphagia) - agitation/confusion - HTN/tachycardia - \>3 hours - paralysis of larger limb muscles - resp paralysis - cardio collapse - rhabdo - renal failure - coma # Treatment ## overview 1. pressure bandage 2. baseline bloods 1. if normal and no features of envenomation → remove pressure bandage → re-check bloods at 1 hour, if still normal, SSU and re-check at 6 hours, 12 hours 2. if abnormal or evidence of envenomation → antivenom 3. If patient remains w/o signs of envenomation and bloods normal at 12 hours, pt discharged in daylight > [!important] absolute indications for antivenom > sudden collapse > seizure > cardiac arrest > INR > 1.3 > clinical evidence of paralysis, ptosis and/or ophthalmoplegia > > relative indications: > - systemic symptoms > - leukocytosis CK >1000 > - elevated aPTT ## pressure immobilisation bandage - apply pressure bandage starting from teh bite site up the entire limb - immobilise the limb with a splint, keep patient calm and still - do not remove the pressure bandage until in facility equipped for snakebite management # Antivenom **Brown snake antivenom** - brown snake envenomation **tiger snake antivenom** - tiger snake, copper head, red-bellied black snake > *administration:* dilute ampule in 100 mL NaCl, infuse over 15-30 min # indications - Clinical evidence of systemic envenoming - Laboratory evidence of coagulopathy - CK >1000 ## allergy to antivenom - anaphylaxis incidence ~30% - Usually mild and manifests w/ erythema or urticaria. Severe cases have hypotension - stop infusion, then re-start at slower rate if small reaction - hypotension → fluid resus - hypotension + hypoxia, wheeze, or stridor → adrenaline 0.01 mg/kg to 0.5 mg ## serum sickness see also [[Rash#serum sickness]] - occurs in ~1/3 of pts given antivenom - flu-like sx: fever, myalgia, arthralgias, rash - generally develops 4-14 days after administration of antivenom - warn all patients about serum sickness who get antivenom - tx: Oral steroids (e.g. prednisolone 50 mg/day in adults or 1–2 mg/ kg/day in children for 5 days) ameliorate symptoms. # Treat coagulopathy antivenom ==give FFP in addition to antivenom if life threatening bleeding== # Related Questions ## snake bite - [x] 85Q: [Snake Bite](x-devonthink-item://834C484F-DDAA-4819-8DF0-84AE5E70DA1D?page=17) -- [Answer](x-devonthink-item://D46998FE-62E2-4A3A-860D-C32C94B86E42?page=7) ## snakebite - [ ] 86Q: [Snakebite](x-devonthink-item://CA0CC973-6102-4C33-AB59-A43A87724DF0?page=9) -- [Answer](x-devonthink-item://9F437E5A-02D4-43FC-B795-5386EDE954F3?page=7) - [ ] 87Q: [Snakebite](x-devonthink-item://EE0B8625-5F19-46CF-8208-56D79DC48BC5?page=11) -- [Answer](x-devonthink-item://6F751245-A36C-447A-8AE7-599AD5871C71?page=14) -- [prop](x-devonthink-item://308BBEF4-A83E-4972-8F63-9249898FC8E8?page=11) - [x] 88Q: [Snakebite](x-devonthink-item://40F10AFA-5F29-4EE4-B149-300627B498B0?page=3) -- [Answer](x-devonthink-item://2088AEED-9FCF-4CF0-B58D-E4279D4BCC76?page=22) - [x] 89Q: [Snakebite](x-devonthink-item://CA4D5561-277D-47A1-9EC2-E0DB4C59DCFD?page=10) -- [Answer](x-devonthink-item://2551B51B-0E7C-448E-9FB5-3B547E74974A?page=10) - [ ] 90Q: [Snakebite](x-devonthink-item://335900F2-D054-4D3D-983F-04A22741BF68?page=16) -- [Answer](x-devonthink-item://E3D816B5-653D-4DC6-A389-8C69022A6062?page=26) -- [prop](x-devonthink-item://42954006-1F26-4D23-93DB-6738A8FA6D94?page=16) - [ ] 91Q: [Snakebite in Pregnancy](x-devonthink-item://3F154834-B3DA-4ADD-8596-C57D6EC9C8A8?page=6) -- [Answer](x-devonthink-item://CF07FAA1-C055-4A43-BFEE-A0DA2DD95452?page=4)