Snakes, Spiders, and Creatures from the Sea
Adam Algren, MD
Medical Toxicology Fellow
Georgia Poison Center
Clinical Instructor
Emory University Dept. of Emergency Medicine
Objectives
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Review clinical manifestations of North American
snake envenomations
Review presentation and management of black
widow and brown recluse spider bites
Discuss the indications for the use of
antivenoms: CroFab and Lactrodectus
Discuss common marine envenomations
Snake Envenomations
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Crotalids
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Pit Vipers
Found in every state except Alaska, Hawaii, Maine
6000-8000 bites/yearly
5-10 deaths/yearly
Elapids
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Coral Snake
69 Bites reported in 2000
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64% Florida
NEJM 2002;347:350
Crotalids
Crotalids
Crotalids
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Crotalus
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Eastern Diamondback rattlesnake
Western Diamondback rattlesnake
Timber rattlesnake
Canebrake rattlesnake
Mojave rattlesnake
Prairie rattlesnake
Sidewinder rattlesnake
Sistrurus
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C. adamanteus
C. atrox
C. horridus horridus
C. horridus atricaudatus
C. scutulatus
C. viridis viridis
C. cerastes
S. milarius
S. catenatus spp.
Pigmy rattlesnake
Massasauga rattlesnake
Agkistrodon
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A. contortix
A. piscivorus
Copperheads
Cottonmouths
Eastern Diamondback Rattlesnake
Crotalus adamanteus
Crotalids
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Majority of victims are male
Majority of bites occur May-October
>50% victims of provoked bites are intoxicated
¾ bites occur to upper extremities
0-75% of snake’s venom is discharged
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Venom replenished within 1 month
5-20% of bites are “dry bites”
Crotalids
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Venom
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Components
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Metalloproteinases
Collagenases
Hyaluronidases
Proteases
Composition/potency
varies
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Snake
Species
Age
Season
NEJM 2002;347:351
Western Diamondback rattlesnake
Crotalus atrox
Crotalid Envenomations
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Pathophysiology
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Local Effects
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Most common
Metalloproteinases and other components damage vascular
endothelium and basement membranes
Edema, ecchymosis, blistering
Systemic Effects
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Coagulopathy
Hypotension
Crotalid Envenomations
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Pre-hospital Management
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Avoid exertion
Immobilize the extremity at or below level of heart
Rapid transport to nearest emergency dept.
Consider constriction band if there is going to be a
prolonged transport time
Extractor devices probably not helpful
Avoid tourniquet, cryotherapy, electric shock, excision,
and incision
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
McKinney. Ann Emerg Med. 2001;37:168-74.
Alberts. Ann Emerg Med. 2004;43:181-6.
Crotalid Envenomations
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History
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Circumstance of bite
Type of snake
Number of bites
Time since envenomation
First aid provided
Previous history of snake envenomation/antivenom
treatment
Sensitivity to horse/sheep sera
Be cautious with any snakes brought to the ED
Copperhead
Akistrodon contortix
Crotalid Envenomations
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Clinical Manifestations
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Local
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Fang marks
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Number of fang marks
helpful, but not definitive
Edema
Ecchymosis
Bullae
Crotalid Envenomations
Crotalid Envenomations
Crotalid Envenomations
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Clinical Manifestations
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Systemic
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Anaphylaxis
Nausea, vomiting, diaphoresis, metallic taste
Hypotension
Coagulopathy
Thrombocytopenia
Rhabdomyolysis
Neurologic Effects
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Mojave rattlesnake
NEJM 2002;347:351
Timber rattlesnake
Crotalus horridus horridus
Canebrake rattlesnake
Crotalus horridus atricaudatus
Mojave rattlesnake
Crotalus scutulatus
Crotalid Envenomations
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Treatment
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Remove any constriction band slowly
Tetanus
Prophylactic antibiotics unnecessary
Consult poison center
Determine antivenom supplies
Document neurovascular exam for extremity bites
Measure limb circumference every 15 minutes
Labs- CBC, chemistries, PT, PTT, Fibrinogen, CK
Cottonmouths
Agkistrodon piscivorus
Crotalid Envenomations
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Treatment
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Surgical treatment
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Routine surgical treatment not recommended
Measure compartment pressures if there is concern
Digit dermotomy
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Hall E. Ann Emerg Med. 2001;37:175-180.
Crotalid Envenomations
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Antivenom
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Wyeth polyvalent antivenom
CroFab
Indications:
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Rapid progression of local effects
Compartment syndrome
Coagulopathy, Thrombocytopenia
Neurologic Symptoms
Shock
Crotalid Envenomations
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CroFab
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FDA approved in 2000
Sheep derived Fab IgG
Less immunogenic
Eastern/Western Diamondback rattlesnake,
Mojave rattlesnake, Cottonmouth
Skin testing not required
0-14% incidence of immediate hypersensitivity
<5% incidence of serum sickness
Crotalid Envenomations
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Dart et al. Arch Intern Med. 2001;161:2030-6.
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31 patients
6 or 12 vials CroFab initially
16 patients PRN, 15 scheduled
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8 patients in PRN group required additional CroFab
0 patients in scheduled group
All patients had significant improvement in snakebite
severity scores
6 allergic reactions
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4 urticaria, 1 urticaria/cough, 1 urticaria/dyspnea/wheezing
Patient with Indication for
CroFab(TM) Administration
Establish Initial Control of Envenomation
By Administering 4 - 6 Vials of CroFab(TM)
Initial Control Achieved?
Yes
No
Administer Additional 4 - 6 Vials of CroFab(TM)
Infuse Additional 2 Vials Doses
at 6, 12, and 18 hours After Initial Control
Initial Control Achieved?
Crotalid Envenomations
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CroFab for Copperhead envenomations
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32 cases
25 (78%) were moderate severity
7 had mild laboratory abnormalities
23 (72%) achieved control with 4 vials
4 cases progressed following CroFab
No allergic reactions
1 mild case serum sickness
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Lavonas et al. Ann Emerg Med. 2004;43:200-6.
Crotalid Envenomations
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Safety and Efficacy of CroFab for Pediatric
Envenomations
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24 patients
Mean age 7.3 (range 1.9-13)
All had local swelling
14 (58%) PT >13sec
3 (12.5%) platelets <150,000
2 (8.3%) fibrinogen <150 mg/dl
Mean number of CroFab vials used 12.3 (4-24)
5 patients progressive thrombocytopenia
? 1 allergic reaction
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Pizon et al. Acad. Emerg Med. 2007;14:373-6.
Crotalid Envenomations
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Recurrence- Local or systemic
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Possible explanations
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Pharmacokinetic/pharmacodynamic mismatch of
venom/antivenom
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Late onset of venom effects
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CroFab elimination ½ life 15-20 hours
Prolonged absorption of venom from wound
Dissociation of venom/antivenom complex
Development of host anti-antivenom response
Crotalid Envenomations
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Post-marketing study of CroFab for rattlesnakes
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28 patients (3 children)
16/28 achieved local control with 4-6 vials
20/28 elevated PT, 6/28 thrombocytopenia, 12/28
hypofibrinogenemia
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6/21 had systemic recurrence
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Control achieved in all, 67-80% required >10 vials
No significant bleeding
No anaphylactic reactions
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Ruha et al. Ann Emerg Med. 2002;39:609-615
Ann Emerg Med 2001;37:2
Ann Emerg Med 2001;37:2
Crotalid Envenomation
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Disposition
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Observe for 6-8 hours if asymptomatic
May discharge if asymptomatic with normal labs
Admit all suspected Mojave rattlesnake
envenomations for 24 hours
Admit for significant local effects or if labs abnormal
Which snake is poisonous?
King snake
Lampropeltis getulus
Coral Snake
Micrurus fulvius
“Red on yellow, kill a fellow”
“Red on black, venom lack”
Coral Snake Envenomations
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Uncommon
Florida, Georgia
Eastern, Texas, Sonoran
Small, ~40 inches full grown, small teeth
25% of bites are “dry bites”
Venom
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Components not well understood
Zinc dependent acetylcholinesterase
Coral Snake Envenomations
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Clinical Presentation
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1/3 have mild local swelling
Mild systemic symptoms
May develop localized pain or fasciculations
Neurologic symptoms
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Normal mental status
CN palsies, weakness/paralysis, respiratory failure
Avg. delay to symptom onset is ~ 2 hours
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May be delayed up to 13 hours
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Kitchens et al. JAMA. 1987;258:1615-8.
Coral Snake Envenomations
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Treatment
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Supportive Care
Aggressive airway management, monitor NIF
Consult poison center, determine antivenom supplies
Consider Neostigmine
Early antivenom administration even if asymptomatic
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Equine derived
3-5 vials initially, redose additional 5 vials in symptomatic pts
Reconstitution 15-30 minutes
Immediate hypersenitivity- 6/17 urticaria, 1/39 anaphylaxis
Serum sickness- 4/39 patients
Coral Snake Envenomations
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Disposition
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Admit all suspected Coral snake bites for at least
24 hours
Black Widow Envenomations
Black Widow Envenomations
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Latrodectus mactans
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~2500 bites/year
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300-400 severe
Prefer dry, dark environments
Only females envenomate
No deaths in US in past 20 years
α-lactrotoxin
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Stimulates release of acetylcholine and
catecholamines
Black Widow Envenomations
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Non-specific symptoms can make diagnosis difficult
Bite is not always felt
Pain within 10-60 min, but may be delayed
75% will only have local symptoms
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Pain, diaphoresis, piloerection
Systemic symptoms may develop over several hours
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Generalized pain, abdominal pain, priapism, diaphoresis,
tachycardia, hypertension, headache, vomiting, tremor
Symptoms peak within 12-24 hours
Typically resolves over 24-72 hours
Black Widow Envenomations
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Treatment
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Opiates, benzodiazepines
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No evidence to support calcium
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115/163 patients had resolution of pain
23/24 no improvement
Antivenom
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Severe/refractory pain, severe hypertension, threatened
abortion
Equine IgG
58 patients received 1 vial; all had pain resolution <2 hrs
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4 urticaria, 1 analphylaxis death
 Clark et al. Ann Emerg Med. 1992;21:782-7.
Black Widow Envenomations
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Disposition
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Discharge if symptoms improve
May discharge if antivenom given
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Observe for 2 hours after completion of infusion
Brown Recluse Envenomations
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Loxosceles reclusa
April-October
? more bites at night
Prefers warm, dry environment
Venom
Sphingomyelinase D,
hyaluronidase, phosphohydrolases
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Brown Recluse Envenomations
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Most bites have a benign course
May progress over several hours
Pain, induration, ecchymosis
May develop serous/bloody blisters
Gravitational
Necrosis at 2-4 days, heals over 6-8 weeks
Brown Recluse Envenomations
Brown Recluse Envenomations
Brown Recluse Envenomations
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Bacterial Infections
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Bee Sting
Skin cancer
Drug reactions
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Orf, Anthrax, Leishmaniosis
Coumadin, TEN, SJS
Ecthyma gangrenosum
Erythema migrans
Erythema nodosum
Erythema multiforme
Emboli, septic
Fire ants
Frostbite
Mites
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Necrotizing fascitis
Polyarteritis nodosa
Purpura fulminans
Pyoderma gangrenosum
Scrofula
Sporotrichosis
Systemic gonorrhea
Scleroderma
Tick bites
Ulcers
Viral infections
Vasculitis
Brown Recluse Envenomations
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Systemic loxoscelism
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Not proportional to dermal findings
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4/111 patients
6/546 pediatric series
? More common in children
Develops within 72-96 hours
Fever, nausea, myalgias, arthralgias, headache
Jaundice, coagulopathy, hemolysis, renal failure
Mortality from hemolysis, DIC
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Wright et al. Ann Emerg Med. 1997;30:28-32.
Elbahlwan et al. Pediatr Emerg Care. 2005;21:177-180.
Brown Recluse Envenomations
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Treatment
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Wound care
Prophylactic antibiotics unnecessary
Labs
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CBC, chemistries, LDH, retic count, PT, PTT, fibrinogen, UA,
plasma free hemoglobin, type & screen
Avoid dapsone/early surgical treatment
? Early HBO
Steroids for hemolysis
Brown Recluse Envenomations
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Disposition
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Admit for systemic complications
Children
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Consider daily out-patient labs for 96 hours
Marine Envenomations
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Jellyfish
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Box Jellyfish
Portuguese man-of-war
Stingrays
Scorpaenidae
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Lionfish
Box Jellyfish
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Chironex fleckeri
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15 tentacles up to 7 meters in length
Found along northern coast of Australia
Responsible for >60 deaths in past century
Box Jellyfish
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Millions of nematocysts/jellyfish tentacle
Venom
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Cardiotoxic/myotoxic
Increases intracellular Na/Ca
Most stings are minor
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Death possible within minutes
with severe envenomations
Box jellyfish
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Clinical Manifestations
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Immediate pain
Skin wheals/vesicles
Delayed hypersensitivity reaction common
Hypotension/cardiac arrest
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O’Reilly. Med J Aust. 2001;175:652-5.
Box jellyfish
Portuguese man-of-war
Portuguese man-of-war
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Physalia sp.
Responsible for thousands of stings in US
Found along Atlantic/Gulf coasts
Tentacles may be up to 30 meters
Most envenomations minor, deaths rare
Immediate pain/skin reaction
Jellyfish Treatment
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Supportive care
Irrigate with 5% acetic acid
Remove tentacles
Wound care
Pain meds
Consider prophylactic antibiotics
Monitor for delayed reactions
Stingrays
Stingrays
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Tropical/temperate environments
Shallow waters
Non-aggressive
1-4 spines
17 deaths reported worldwide
Venom
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Phosphodiesterases, serotonin,
5’-nucleotidase
Immediate pain lasting 6-48 hr
Vomiting, dizziness, weakness,
syncope, cramps, arrhythmias, hypotension
Stingrays
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Immediate cold water irrigation
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Then warm water (40-42°) immersion
Pain meds
Wound management
Consider prophylactic antibiotics
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Cook et al. J Emerg Med. 2006;30:345-7.
Lionfish
Lionfish
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Pterois sp.
Atlantic, Pacific, Caribbean
Popular aquarium fish
12 or 13 dorsal spines with
venom glands
Venom poorly characterized
Severe pain lasting 6-12 hours
Systemic effects rare
Lionfish
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Warm water (45°) immersion for 30-90 min
Pain meds
Wound care
Consider prophylactic antibiotics
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Vetrano et al. J Emerg Med. 2002;23:379-382.
Questions?