susiewabisabi's version from 2015-10-12 23:51

Approach to snake bites

Question Answer
Pre hospital managementpressure immobilisation bandage, transport to suitable hospital (all hrs lab, antivenom)
pressure immobilsationpressure bandage whole limb, immobilise limb, immobilise pt, do not remove until either no evidence of envenomation OR antivenom has been given
indications for PIBblue ringed octopus, all snakes, funnel web spider NB. not jellyfish
hospitla assessmenthistory, examination, investigations, if all normal remove PIB, reapply if pt suddenly deteriorates, otherwise observe and rpt exam and Ix at 1,6,12h; if abn at any time give antivenom.
Ixcoags, fibrinogen, Ddimer, FBC, CK, EUC, urine myoglobin
coags in VICCincr INR, undetectable fibrinogen, elevated d-dimer, elevated fibrin degradation products
thrombotic microangiographythrombocytopenia, raised LDH, fragmented RBCs, ARF
Hospital Mxresuscitation; determine if pt is envenomed by serial assessments; determine type of antivenom required and administer; adjuvant and supportive treatment

Australian snakes

Question Answer Column 3 Column 4 Column 5 Column 6
brownVICC alwaysneurotoxicity rarerhabdomyolysis norenal failure uncommoncardiac toxins; microangiopathic HA and thrombocytopenia; sudden collapse with systemic envenoming
tigerVICC alwayspresynaptic neurotoxicity slow onsetrhabdo may be severerenal failure may be secondary to rhabdomicroangiopathic HA and thrombocytopenia
death addersno viccpost synaptic neurotox (descending flaccid paralysis) slow onsetno rhabdono renal failurelocal bite painful
black (mulga, red belly black)no vicc but mild anticoagulant effect, incr APTT (mulga only)no neurotoxrhabdo may be severerenal failure sec to rhabdopainful bite, N and V, abdo pain, headache, myalgia; anosmia in RBB
taipanVICC alwayspresynaptic neurotox may be rapid onsetrhabdo may developrenal failure sec to rhabdomicroangiopathic HA and thrombocytopenia
sea snakesno VICCpresynaptic neurotox rapid onsetrhabdo may developrenal failure sec to rhabdo

Clinical syndromes of snake bites

Question Answer
elevated CKblack, sea snake (taipan, tiger)
painful bitesblack, death adders
VICCbrown, tiger, taipan
paralysisdeath adder, taipan (tiger)
collapsebrown most common (tiger, taipan)

Snake Antivenom

Question Answer
absolute Indicationscollapse, cardiac arrest, seizure; elevated INR; paralysis (ptosis, ophthalmoplegia early)
relative indicationsystemic symptoms, CK > 1000, incr APTT, leukocytosis
administrationone vial of monovalent diluted in 100-250ml NS over 15-30mins
which onebase on clinical features and knowledge of endemic snakes, Snake Venom Detection Kit only in light of these as inaccurate; give tiger antivenom + brown antivenom rather than polyvalent; give polyvalent rather than black, death adder and taipan
reactions to antivenomhypersensitivity 30%, anaphylaxis 3%, cease infusion, give adrenaline, recommence when symptoms controlled; Serum sickness - 30%, influenza- like symptoms, fever, myalgia, arthralgia and rash 4–14 days after Rx. Treated with prednisolone (25 mg daily for 5–7 days)

Box jellyfish

Question Answer
clinicalsevere pain, crosshatched welts, collapse or sudden death
IxECG (tachy, VEBs, bigeminy, BBB), FBC, EUC, Ck, Tn, cxr
RxCPR, icepack, vinegar, NO PIB; box jellyfish antivenom x6 iv push in arrest, x3 diluted in 100ml NS over 20m, x1 for pain; Mg 10mmol iv, morphine

Irukandji syndrome

Question Answer
clinicalsymptoms start after leaving the water. Agitation, dysphoria; diaphoresis, vomiting; severe HT, pulm oedema, CMO, cardiogenic shock. Minimal dermal signs of sting.
Rxvinegar, NO PIB; fentanyl, GTN infusion

Blue ringed octopus

Question Answer
clinicalminor bite, followed by rapidly progressive flaccid paralysis (early ptosis, ophthalmoplegia), general paralysis, resp failure
Rxapply PIB; intubation and ventilation if necessary

Red back spider

Question Answer
clinicalintense pain 5-10m after bite, sweating, piloerection; autonomic features ma y be regional or generalised; not life threatening
Rxice pack, simple analgesia, NO PIB, analgesia, antivenom

Funnel web spider

Question Answer
Hxpainful bite by big black spider with large fangs
clinicalrapid systemic envenoming, agitation, Autonomic (sweating, piloerection), CVS (HT, tachy, hypot, brady, APO); Neuro (fasciculations, paraesthesia, muscle spasm, coma
RxPIB, transfer to hospital, manage resp failure, BP, APO, cardiac arrest - undiluted antivenom at least 4 ampoules


Question Answer
clinicaldrowsiness, unsteady gait, ascending paralysis (DDx guillain barre). Death from respiratory paralysis.