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EMS/Nursing
80112/
30312
Snake, Spider, and
Insect Bites
Paul R. Lockman, BSN, PhD
Assistant Professor,
Pharmaceutical Sciences
TTUHSC School of Pharmacy
Amarillo, Texas
EMS/Nursing
80112/
30312
Objectives
1. Identify venomous
bites associated with
Crotalidae and
Micrurus snakes.
EMS/Nursing
80112/
30312
Objectives
2. Identify signs,
symptoms, and
treatment options for
envenomations.
EMS/Nursing
80112/
30312
Objectives
3. Recognize clinical
symptoms associated
with envenomations
from a brown recluse,
black widow, tarantula,
scorpion, and fire ant
bite.
Snakes
1. Be familiar with the various
types of Crotalidae snakes
that are present in our
region
2. Discuss the primary signs
and symptoms of Crotalidae
envenomation
Snakes
3. Develop a treatment plan,
for both stabilization and
treatment of Crotalidae
envenomations
Snakes
4. Be familiar with the various
types of Micrurus snakes
that are present in our
region
5. Discuss the primary signs
and symptoms of Micrurus
envenomation
Snakes
6. Develop a treatment plan,
for both stabilization and
treatment of Micrurus
envenomation
Snakebites
• Snakes in Texas
–155 species altogether
–15 species are venomous
(10-15% of snakes)
–deaths in Texas from
snakebites = 2-3/year
Snakebites
• Snakes in Texas
–compare to insect bites:
5-7/year
–compare to lightning
strikes: ~8/year
Snakebites
• Venomous snakes bite 70008000 people annually
–occurred while snake
handling = ~3000
–accidental = 4000-5000
Snakebites
• Venomous snakes bite 70008000 people annually
–85% of natural bites are
below the knee
Snakebites
• Epidemiology
–male > female by 9:1
–average age = 24
• Significant rates of
intoxication at time of bites
(28%)
General Principles
• Most bites aren’t lethal!!
• Be concerned about:
–very old
–very young
–very sick
–very pregnant
General Principles
• Anaphylaxis risk
• Good first aid/wound care
avoid: ice, shock, cowboy
treatment, and tourniquet
• Remain calm and seek
medical attention
Good vs. Bad ???
Pit Vipers: Crotalidae
• Crotalus: true rattlers
Crotalidae
• Sistrurus
–massasauga
–pygmy rattler
Crotalidae
• Agkistrodon: Copperhead
Crotalidae
• Agkistrodon: Cottonmouth
Crotalidae
• Usually rattle before biting
but not always
• Rattles can fall off with
trauma, so may not be
present
• Rattle done to give warning;
may be startled
Crotalidae
• Accounts for average of 5.5
deaths/year in US
• 50% of all bites occur in 1828-year-old group; young
males most common
Venom
• Modified saliva: digests the
tissue in the affected area
–90% water
–5-15 enzymes
–3-12 proteins
Venom
• Potency and effects vary by
species and individual snake:
~25% of bites are “dry”
Symptoms
• Local symptoms
–skin necrosis
–tissue sloughing
Symptoms
• Histotoxic
–hyaluronidase
–collagenase
–metalloproteinase
• Edema: stimulation of the
inflammatory cascade
Crotalidae
• Hematologic mediators
–main one is fibrinolysis
–defibrination, without DIC
(disseminated intravascular
coagulation)
Crotalidae
• Hematologic mediators
–thrombocytopenia
(unknown mechanism)
–uncommonly may cause
generalized bleeding
Crotalidae
–labs: abnormal for up to a
week; reports of relapse
•elevated fibrin split
products
•elevated PT (prothrombin
time)
•low fibrinogen
Crotalidae
–DIC is uncommon – if it
occurs it is the primary
reason for mortality
Crotalidae
• Local mediators
–VMPs (venom
metalloproteinases):
cleave/activate TNF (tumor
necrosis factor) alpha,…
Crotalidae
• Local mediators
–…which then cleaves
endogenous
metalloproteinases =
amplification
Crotalidae
• Local mediators
–myotoxin A
•necrosis of skeletal
muscle
•may cause distant
rhabdomyolysis
Crotalidae
• Local mediators
–pain and edema
•rapid edema indicative of
severe envenomation
•bullae formation/blebs not
uncommon
General Treatment
• Do nothing that delays
getting to ED (emergency
department)
General Treatment
• Basic and advanced life
support
• Mark border of advancing
edema with pen every 15
minutes
General Treatment
• No benefit with negative
pressure venom extraction
device
General Treatment
• Fang marks not
recommended
• Mouth suction
contraindicated
General Treatment
• Constriction and pressure
immobilization: may help
impede spread of venom
• Tourniquets not
recommended
• Keep in neutral position
General Treatment
• Do not give antivenom in
field secondary to
anaphylaxis risk
General Treatment
•Do not try and find snake
–may result in more bites
–may delay ED arrival
Crotalidae Bite Severity
• Grading based on clinical
presentation
• Dry bite
–puncture wound only
–no systemic effect
–normal labs
Crotalidae Bite Severity
• Mild
–local effects at bite site
only
–no systemic effects
–normal labs
Crotalidae Bite Severity
• Moderate
–local effects beyond
immediate bite area
–vomiting, metallic taste,
fasciculation
Crotalidae Bite Severity
• Moderate
–platelets <90,000,
fibrinogen <90-100 mg/dl
–PT >14 seconds
–CPK (creatine
phosphokinase) >500-1,000
U/L
Crotalidae Bite Severity
• Severe
–rapid involvement of entire
area near bite
–compartment syndrome
–systemic shock
–severe bleeding
Crotalidae Bite Severity
• Severe
–renal failure
–respiratory difficulty
–altered mental status
–platelets <20,000
–rhabdomyolysis
Polyvalent Antivenin
• Derived from horse serum
immunized with venom from
various species
Polyvalent Antivenin
• Used for moderate to severe
symptoms
–test dose for anaphylaxis –
skin testing
Polyvalent Antivenin
• Used for moderate to severe
symptoms
–start with 10 vials (average
10-15 for moderate bite) –
can go up to 25-30 vials
Polyvalent Antivenin
Polyvalent Antivenin
• Used for moderate to severe
symptoms
–~80% develop serum
sickness
Severity
Score
• 0-3 minimal
severity
• 4-7 moderate
severity
• 8-20 severe
Serum Sickness
Serum Sickness
• Fever
• Redness of joints
• Skin rash
• Itching
• Swollen glands
• Malaise
• Anorexia
Serum Sickness
• Patient has to be hospitalized
to treat
®
Crofab
• Sheep-derived antivenin
–venom-specific Fab
fragment of
immunoglobulin G (IgG)
–binds and neutralizes
venom toxins
®
Crofab
• Because the antibodies are
raised in sheep there is
minimal to no serum
sickness
• Start with 4-6 vials
®
Crofab
• Administer 4-6 more vials
every hour until
coagulopathies and edema
have been controlled
• After initial control, provide 2
vials every 6 hours for 18
hours
®
Crofab
Compartment Syndrome
• Increased pressure within the
fixed compartment of the
limb muscle fascia
Compartment Syndrome
• Symptoms
–skin is taught, warm,
blanched
–distal to the swelling may
have numbness, loss of
blood supply
Compartment Syndrome
• Diagnosis: made by
percutaneous insertion of
needle with measurement of
internal pressure
Compartment Syndrome
• Treatment
–surgical release
–fasciotomy
Compartment Syndrome
• With antivenin, may have
some disfigurement, rare
functional impairment, and
even rarer loss of a limb
Fasciotomy
Mexican Milk Snake
Mexican Milk Snake
• Red touches yellow: kill a
fellow
• Red touches black: a friend
of Jack
Coral Snake
Coral Snake
• Micrurus sp.
• Moderate to severe
neurologic symptoms usually
seen with envenomation
• Systemic effects may be
delayed >12 hours
• May require antivenin!!
Coral Snake Bite
• Neurotoxic, neuromuscular
dysfunction
• Little enzymatic activity, low
necrotic potential
• Little venom delivered per
bite
Coral Snake Bite
• Primitive delivery system
–small mouth
–pair of small, fixed hollow
fangs on anterior mouth
Coral Snake Bite
• Primitive delivery system
–venom released via
chewing motion – must bite
and temporarily hold and
“chew” to get venom out
Coral Snake Bite
• Respiratory distress
–pharyngeal spasm
–hypersalivation
–cyanosis
–trismus
Coral Snake Bite
• Cardiovascular collapse
–hypotension
–tachycardia
• Onset: symptoms may be
delayed up to 12 hours
Coral Snake Bite
• Bite site: paucity of
complaints
–little pain
–no necrosis
–paresthesias
–swelling usually mild
Coral Snake Bite
• Neurotoxic
–altered mental status can
occur
–diplopia, ptosis
–generalized weakness
–muscle fasciculations
Coral Snake
Coral Snake
• No advantage for giving
antivenom for other snake
species
Coral Snake
®
• Wyeth Antivenin (Micrurus
fulvius)
–dose: 3-6 vials IV
(intravenously) over 1-2
hours
Coral Snake
®
• Wyeth Antivenin (Micrurus
fulvius)
–if necessary, give extra 3-5
vials over 1-2 hours
–rarely need >10 vials
Coral Snake
®
• Wyeth Antivenin (Micrurus
fulvius)
–must be started early –
before any symptoms
develop, as soon as they
arrive at the ED
Crawlers
1. Be able to recognize the
clinical symptoms
associated with an
envenomation from a brown
recluse, black widow,
tarantula, scorpion, and fire
ant
Crawlers
2. Define a basic treatment
plan for individuals who are
bitten by the insects listed
in the first objective
Crawlers
3. Recognize the clinical
symptoms associated with
insect bite-associated
allergic reaction – be able
to define a treatment plan
for the individual
undergoing anaphylaxis
Brown Recluse
Characteristic fiddle pattern
Brown Recluse
• Loxosceles sp.
• Venom
–digestive enzymes
–sphingomyelinase D
Brown Recluse
• Proper wound care
–+/- debridement
–no prophylactic antibiotics
• No antidote – ??? early
dapsone
Brown Recluse
Symptoms
• Necrotic lesion
• Fever
• Rash
• Arthralgias
Brown Recluse
Symptoms
Brown Recluse
Symptoms
Black Widow
Characteristic hourglass pattern
Black Widow
• Latrodectus sp.
• Neurotoxic venom
–increased calcium influx
–increased acetylcholine
Black Widow
• Local pain
• Abdominal cramping
• Diaphoresis
• Nausea, vomiting, diarrhea
Black Widow
• Treatment
–wound care
–muscle relaxers
–opiate analgesics
–antivenin (rarely used)
Tarantula
• There is little toxicity
associated with North
American tarantulas
Tarantula
Hymenoptera
Hymenoptera
• Apidae: honey bees
• Bombidae: bumble bees
• Vespidae: wasps, hornets,
yellow jackets
• Formicoidea: ants
Hymenoptera
• Symptoms
–local pain, itching, and
swelling
–multiple stings or stings to
the face  risks
Hymenoptera
• Symptoms
–vomiting, cyanosis,
hypotension, syncope,
dyspnea
–anaphylaxis risk
Hymenoptera
• Treatment
–wound care
–remove stinger?
–analgesics
–antihistamines
Scorpion
Scorpion
• Very painful sting
• Typically supportive care is
all that is needed
• If numbness or paresthesias
persist for >48 hours need
medical evaluation
Fire ants
EMS/Nursing
80112/
30312
Snake, Spider, and
Insect Bites
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04/01/2012
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80112
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30312
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Nursing
30312
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Requirements of successful course completion:
•Complete the program via video presentation, PowerPoint
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•Complete the course evaluation.
•Complete the posttest with a score of 80% or greater.
•Complete the time utilized in course completion including
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Nursing
30312
Conflicts of Interest:
Paul R. Lockman, BSN, PhD has disclosed that no financial interests,
arrangements or affiliations with organization/s that could be perceived as a
real or apparent conflict of interest in employment, leadership positions,
research funding, paid consultants or member of an advisory board or
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30312
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Off-label Use:
Paul R. Lockman, BSN, PhD has disclosed that no products with off-label or
unapproved uses are discussed within this activity.
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30312
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