Spiders & their toxinsSpiders & their toxins

Joe Alcock MD MS

Emergency Medicine, NM VAMC

UNM Dept Emergency Medicine

Joe Alcock MD MS

Emergency Medicine, NM VAMC

UNM Dept Emergency Medicine

21 year old woman in Sydney21 year old woman in Sydney

Cleaning out swimming pool trap Feels a sharp pain in her right hand Develops nausea, paresthesias, sweats

Cleaning out swimming pool trap Feels a sharp pain in her right hand Develops nausea, paresthesias, sweats

Sydney Funnel Web SpiderSydney Funnel Web Spider

Funnel Web SpiderFunnel Web Spider

Australasian funnel-web spiders

Suborder Mygalomorphae - includes tarantulas

Family Hexathelidae Sydney f.w.s Atrax

robustus Chelicerae (fangs)

contain venom apparatus 2 genera in Australia:

Atrax, Hadronyche

Australasian funnel-web spiders

Suborder Mygalomorphae - includes tarantulas

Family Hexathelidae Sydney f.w.s Atrax

robustus Chelicerae (fangs)

contain venom apparatus 2 genera in Australia:

Atrax, Hadronyche

Range & habitatRange & habitat

Eastern coast of Australia

Fws also found in New Guinea & Solomon Islands

Spiders construct a funnel shaped web and wait for prey to fall in.

Funnels constructed near rocks, logs

Diet consists of insects and small vertebrates

Eastern coast of Australia

Fws also found in New Guinea & Solomon Islands

Spiders construct a funnel shaped web and wait for prey to fall in.

Funnels constructed near rocks, logs

Diet consists of insects and small vertebrates

Scope of problemScope of problem

77 severe envenomations between 1999 and 2003

Deaths only recorded from Atrax robustus

No deaths since introduction of antivenom

77 severe envenomations between 1999 and 2003

Deaths only recorded from Atrax robustus

No deaths since introduction of antivenom

ToxicityToxicity 77 severe cases 1999 - 2003 Male spiders cause most bites 10-25% bites produce toxicity Spiders measure 5 cm, fangs can penetrate

fingernails Delta-Atracotoxins Presynaptic neurotoxins - open sodium

channels - inducing action potentials Autonomic storm - endogenous Ach

norepinephrine & epinephrine.

77 severe cases 1999 - 2003 Male spiders cause most bites 10-25% bites produce toxicity Spiders measure 5 cm, fangs can penetrate

fingernails Delta-Atracotoxins Presynaptic neurotoxins - open sodium

channels - inducing action potentials Autonomic storm - endogenous Ach

norepinephrine & epinephrine.

EnvenomationEnvenomation

Painful Bite - acidic pH, large size of fangs Onset rapid - median 28 min, 2 cases after 2

hours (pressure dressing) Early symptoms: periorbital paresthesias,

facial muscle twitching, vomiting, diaphoresis, salivation, dyspnea

Agitation, confusion, coma, hypertension, metabolic acidosis, mydriasis, fasciculations

Increased ICP - death

Painful Bite - acidic pH, large size of fangs Onset rapid - median 28 min, 2 cases after 2

hours (pressure dressing) Early symptoms: periorbital paresthesias,

facial muscle twitching, vomiting, diaphoresis, salivation, dyspnea

Agitation, confusion, coma, hypertension, metabolic acidosis, mydriasis, fasciculations

Increased ICP - death

Funnel Web TreatmentFunnel Web Treatment

Pressure immobilization bandage Antivenom purified rabbit IgG Developed in 1981 in Melbourne Fast acting and effective Hospitalization rates have changed

from 14 days to 3 days on average with no deaths since its availability.

Pressure immobilization bandage Antivenom purified rabbit IgG Developed in 1981 in Melbourne Fast acting and effective Hospitalization rates have changed

from 14 days to 3 days on average with no deaths since its availability.

First AidFirst Aid

Keep victim calm and still if possible

Immobilize the bitten area and keep it lower than the heart. Remove rings.

Pressure dressing - NOT tourniquet

Get patient to definitive care - antivenin - Sooner the better!

Keep victim calm and still if possible

Immobilize the bitten area and keep it lower than the heart. Remove rings.

Pressure dressing - NOT tourniquet

Get patient to definitive care - antivenin - Sooner the better!

Other Australian Mygalomorph spidersOther Australian Mygalomorph spiders Mouse Spider - local pain, local

paresthesias Trap door spider - minor effects only

Mouse Spider - local pain, local paresthesias

Trap door spider - minor effects only

60 yo m collecting yard waste next to house60 yo m collecting yard waste next to house Feels a sharp bite on forearm Noticed a medium sized spider with

prominent abdomen Red spot on underside of abdomen Hourglass shaped Should he worry?

Feels a sharp bite on forearm Noticed a medium sized spider with

prominent abdomen Red spot on underside of abdomen Hourglass shaped Should he worry?

LatrodectusLatrodectus

HistoryHistory

Slight initial pain: pinch or pinprick

In 1 hour, systemic symptoms begin and may last for a few days.

Muscle cramping - local and large muscle groups - abdomen, back, thighs.

Nausea and vomiting Headache Anxiety

Slight initial pain: pinch or pinprick

In 1 hour, systemic symptoms begin and may last for a few days.

Muscle cramping - local and large muscle groups - abdomen, back, thighs.

Nausea and vomiting Headache Anxiety

PhysicalPhysical

Abnormal vital signs, Hypertension, Tachycardia

Diaphoresis: local or remote from site of envenomation

Tiny fang marks may be visible Bite appearance: small circle of

redness, swelling around immediate bite site. May have blanching with red border

Abnormal vital signs, Hypertension, Tachycardia

Diaphoresis: local or remote from site of envenomation

Tiny fang marks may be visible Bite appearance: small circle of

redness, swelling around immediate bite site. May have blanching with red border

Bite after 1 hourBite after 1 hour

Physical Exam - continuedPhysical Exam - continued

Abdominal rigidity - acute abdomen.

Neurotoxic effects, weakness, fasciculations, and ptosis

Latrodectus facies, with facial muscle spasm of, edematous eyelids, & lacrimation. Mimics an allergic reaction.

Abdominal rigidity - acute abdomen.

Neurotoxic effects, weakness, fasciculations, and ptosis

Latrodectus facies, with facial muscle spasm of, edematous eyelids, & lacrimation. Mimics an allergic reaction.

Grading BitesGrading Bites

Grade 1 - Mild envenomation, Localized pain at bitesite, Normal vitals

Grade 2 - Moderate envenomation: Muscle pain in the bitten arm or legMuscle pain may extend to abdomen if bitten on leg, or to the chest with bite on arm.Local diaphoresis of envenomation site or involved extremityNormal vital signs

Grade 1 - Mild envenomation, Localized pain at bitesite, Normal vitals

Grade 2 - Moderate envenomation: Muscle pain in the bitten arm or legMuscle pain may extend to abdomen if bitten on leg, or to the chest with bite on arm.Local diaphoresis of envenomation site or involved extremityNormal vital signs

Grade 3 LatrodectismGrade 3 Latrodectism

Severe envenomationGeneralized muscular pain in the back, abdomen, and chestDiaphoresis remote from envenomation siteAbnormal vital signs (blood pressure >140/90 mm Hg, pulse >100)Nausea and vomiting Headache

Severe envenomationGeneralized muscular pain in the back, abdomen, and chestDiaphoresis remote from envenomation siteAbnormal vital signs (blood pressure >140/90 mm Hg, pulse >100)Nausea and vomiting Headache

AntiveninAntivenin

Antivenin Latrodectus mactans - horse serum (Merck product)

Consider for patients with grade 2 or grade 3 envenomations in whom narcotics do not control pain and are low risk for allergic reactions

Rec for certain patient groups, such as children and elderly persons

skin testing for possible allergic reaction to the antivenom.

Antivenin Latrodectus mactans - horse serum (Merck product)

Consider for patients with grade 2 or grade 3 envenomations in whom narcotics do not control pain and are low risk for allergic reactions

Rec for certain patient groups, such as children and elderly persons

skin testing for possible allergic reaction to the antivenom.

Antivenin PrecautionsAntivenin Precautions

Mortality from widow spider envenomation is extremely rare, and some argue against administration of antivenom when treatment may be more dangerous than the injury

some recommend routine premedication with antihistamines (H1 and H2 blockers)

black widow spider envenomation is associated with abruptio placentae and fetal demise; benefits of antivenom administration in pregnancy must be weighed against risks

Mortality from widow spider envenomation is extremely rare, and some argue against administration of antivenom when treatment may be more dangerous than the injury

some recommend routine premedication with antihistamines (H1 and H2 blockers)

black widow spider envenomation is associated with abruptio placentae and fetal demise; benefits of antivenom administration in pregnancy must be weighed against risks

The dreaded brown recluseThe dreaded brown recluse Necrotic skin ulceration Spiders get a bad rap - blamed for

every little skin infection, folliculitis

Necrotic skin ulceration Spiders get a bad rap - blamed for

every little skin infection, folliculitis