Transcript Bites and Stings - Emory University Department of Pediatrics

Terrestrial Bites and
Stings
Brian Costello, MD
Department of Pediatric
Emergency Medicine
June 24, 2010
Objectives
By the end of this lecture you should be able to:
 Describe the management and treatment for
• Reptile envenomations
• Arthropod envenomations
• Mammalian bites and common associated
infections
 Understand and perform initial management of
these injuries, such as
• Local wound care
• Venom specific antidotes
• Stinger and tick removal
2
Snakes
 US has 120 different
species of snakes
• Only 15% poisonous
 Two families:
• Crotalidae (pit
vipers) 99% of
snakebites
• Elapidae 1% of
snakebites
3
Identifying Poisonous Snakes
4
Crotalids
 Include Water Moccasin (aka Cottonmouth),
Rattlesnake, and Copperhead
 Venom is a combination of necrotizing, hemotoxic,
neurotoxic, nephrotoxic and cardiotoxic substances
• Mojave rattlesnake has a large fraction of neurotoxin
• Neurotoxin prevents depolarizing action of
acetylcholine (paralytic)
• Proteolytic enzyme acts like hyaluronidase causing
local tissue destruction, swelling
• Increased capillary leak – shock, respiratory failure
• Hemotoxic effects include hemolysis,
thrombocytopenia and fibrinogen proteolysis leading
to bleeding diathesis
5
Crotalids
 Small children are more susceptible to venom given
their size compared to adults causing more
systemic symptoms
 Bites on the head, neck or trunk hasten systemic
absorption
 Most bites are on the extremities
 Measure the distance between the two fang marks
to estimate snake size
• 8 mm = small snake
• 8-12 mm = medium snake
• >12 mm = large snake
 10-20% of rattlesnake strikes are “dry” (no venom)
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Crotalid Bites - Symptoms
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 5-10 min – Intense pain, erythema, and edema
 Perioral numbness with metallic taste
 N/V, chills, weakness, syncope, sweating
 Neuromuscular symptoms after a few hours:
• Diplopia, difficulty swallowing, lethargy,
progressive weakness
 Next 8 hours – Progressive edema at wound site
 Shock – usually 6-24 hrs (may be as soon as 1 hr)
 Vesicles and hemorrhagic blebs by 24 hours
 Edema may lead to compartment syndrome and
necrosis
 Secondary infection – gram-negative bacteria
Crotalid - Management
 Pre-Hospital
• ABCs
• Rest
• Take off jewelry and clothing from affected
extremity
• Immobilize extremity and keep below level of
heart
• Keep warm
• NPO
• Constriction band (experienced hands only)
• Incision and Suction kit if available (must use
within 5-10 minutes of bite)
• Rapid transport to medical facility
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Snake Bite Kits
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Crotalid - Management
 ED
• IV access, fluids, (central line & CVP?), morphine
• If snake is brought to ED, treat it with respect
 Many people bitten by “dead” snake
 Decapitated snakes bite reflexively for up to 1
hour
• Measure circumference of extremity at leading
point of edema and 10 cm proximal Q30min X 6
hours, then Q4 for 24 hours
• CBC with platelets, coags, type and cross, U/A
• If moderate or severe poisoning, then also get
BMP, fibrinogen and ABG
• Repeat labs Q4-6 hours
10
Crotalid Antivenin
 AVCP polyvalent antivenom
• Horse serum, highly antigenic – needs skin
testing prior to giving
• Don’t use it if you can get CroFAB
 CroFAB
• Sheep derived antibody with cleaved Fc portion
 Cleared from kidneys fast
• Less adverse reactions
 For maximal binding, use antivenom within 4 hours
of bite.
 Dosage NOT based on weight. Kids need more.
11
Crotalid - Management
 CroFAB
• Initial dose is 4-6 vials
• Repeat initial dose if there is progression of
symptoms
• Once there is no progression, then give either:
 2 vials Q6h for 3 doses OR
 2-6 vials if progression of symptoms recur
• Admit to PICU
• All patients must be reexamined in 2-5 days after
bite
• Watch for serum sickness up to 3 weeks out
12
Crotalid - Management
 Local wound care
 Tetanus prophylaxis
 NO ice to wound
 Watch for signs of compartment syndrome, call
surgery
 Superficial debridement needed in 3-6 days
• Local oxygen, aluminum acetate 1:20 solution,
triple dye
 Blood products for coagulopathy
 No prophylactic antibiotics (current thinking)
 Physical therapy in healing phase
13
Elapids
 Only 3 poisonous Elapids in
US:
• Eastern Coral Snake –
Found in Georgia
• Texas Coral Snake
• Arizona Coral Snake
• “Red on yellow, kill a
fellow; Red on black,
venom lack”
14
Elapids
 Coral snakes are relatively passive (10-15 bites/yr
in US)
 Share physical characteristics of non-venomous
snakes (round pupils, blunt head) but have fangs
 Uses a potent neurotoxin
 Local signs are minimal with little pain
 Several hours later, pt will develop malaise, N/V,
muscle fasiculations and weakness
 Neurologic signs include diplopia, difficulty talking
or swallowing, bulbar dysfunction, and generalized
weakness
 Risk of respiratory failure
15
Elapids - Management
 Tourniquets, incision & suction, etc. don’t work for
coral snakes
 If eastern or Texas coral snake is suspected, give
antivenin
• Horse serum derived, requires skin testing before
giving
• Dosage is 3-5 vials IV
• Repeat if signs of venom toxicity continue
• Antivenin not in production as of 2008
 No antivenin available for Arizona coral snake
 Admit to PICU
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Quiz: Name Georgia’s Venomous
Snakes…
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Georgia Venomous Snakes
 Georgia
 Carolina Pygmy Rattlesnake - Sistrurus miliarius miliarius









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Dusky Pygmy Rattlesnake - Sistrurus miliarius barbouri
Eastern Coral Snake - Micrurus fulvius
Eastern Cottonmouth - Agkistrodon piscivorus piscivorus
Eastern Diamondback Rattlesnake - Crotalus adamanteus
Florida Cottonmouth - Agkistrodon piscivorus conanti
Northern Copperhead - Agkistrodon contortrix mokasen
Southern Copperhead - Agkistrodon contortrix contortrix
Timber Rattlesnake - Crotalus horridus
Western Cottonmouth - Agkistrodon piscivorus leucostoma
Exotic Snakes
 Consult a medical herpetologist or poison control
(1-800-222-1222)
 Contact your local zoo
• Required by law to carry antivenin for the snakes
they have
 Report illegally possessed reptiles to the police
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Arthropods (“Bugs”)
 Largest phylum in the animal kingdom
 Terrestrial Invertebrates
• Centipedes/Millipedes
• Ticks
• Spiders
• Scorpions
 Insects
• Bees
• Hornets
• Yellow Jackets
• Wasps
• Fire Ants
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Scorpions
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 Very few are dangerous to humans in North
America
• Centruroides sculpturatus (“Arizona bark
scorpion”) -- southwestern U.S.
 Grasps prey by pincers and then stings with tail
 Nocturnal
• Crawl into sleeping bags and unoccupied
clothing
 Injects an excitatory neurotoxin affecting autonomic
and skeletal nervous systems -minimal local edema
• Pain, restlessness, hyperactivity, roving eye
movements, respiratory distress/failure
• Convulsions, drooling, hyperthermia,
HTN/tachycardia
Scorpions - Management
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 Cryotherapy (ice) at sting site and supportive care
 Antivenin if symptoms persist after supportive care
• Tachycardia
• Fever
• Severe hypertension
• Agitation
• Available from Antivenom Production Laboratory,
Arizona State University, Tempe, Az.
 Phenobarbital or other sedative/anticonvulsants for
persistent hyperactivity, convulsions or agitation
 Calcium gluconate 10% 0.1ml/kg for muscle
contractions (used but unproven)
Brown Recluse Spider (Loxosceles)
Loxosceles reclusa
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 Brown violin shaped
mark on dorsum of
cephalothorax
(“Fiddleback”)
 Usually outdoors, but
make indoor nests in
closets
 Shy and will only attack
when provoked
 Venom is cytotoxic
(hyaluronidase-like
factor)
Loxosceles Geographic Distribution
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Brown Recluse – Clinical Signs
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 2-8 hours
• Local reaction with mild-moderate pain
• Erythema, central blister or pustule
 24 hours
• Fever, chills, malaise weakness, N/V, rash with
petechiae, joint pain, DIC, hematuria, renal
failure, hemolysis, respiratory failure
• Subcutaneous discoloration that spreads over
 3-4 days
• Spreads to 10-15 cm
• Pustule drains leaving ulcerated crater that scars
 Scar formation is rare if no necrosis after 72 hrs
 Reaction varies according to amount of
envenomation
Brown Recluse Bite Mimics in Children
 Staph/strep (MRSA)
 Herpes simplex
 Herpes zoster
 E. multiforme
 Lyme disease
 Fungal infection
 P. gangrenosum
 Chemical burn
 Poison ivy/oak
 Other spider bite:
1.
2.
3.
4.
5.
6.
7.
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Golden orb weaver (North
America)
Running (or sac) spider
(U.S.)
Wolf spider (U.S.)
Black jumping spider
(Atlantic coast to Rocky
Mountains)
Hobo spider (Pacific
Northwest)
Fishing spider (U.S.—
lakes and streams)
Green lynx spider
(Southern U.S.)
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It’s NOT a brown recluse if…
 It's really BIG! The size of the body, not including legs, of a
recluse is smaller than a dime.
 It's really HAIRY! Brown recluses have only very fine hairs
that are invisible to the naked eye.
 It JUMPS! Jumping spiders live up to their name, and some
other spiders including wolf spiders occasionally jump, but
recluses don't.
 I found it in a WEB! Brown recluses don't spin a web to
catch prey; they spin silk retreats and egg cases, but don't
form a typical recognizable web.
 It has DISTINCT MARKINGS VISIBLE TO THE NAKED
EYE, such as stripes, diamonds, chevrons, spots, etc. that
are easily seen! The "violin" is very small and located on the
front half of the body. The violin is also indistinct in some,
especially young spiders. They're really pretty dull looking.
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http://department.monm.edu/biology/recluse-project/identify.htm
Quiz: Indentify 2 Brown Recluses…
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Brown Recluse - Management
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 Unless spider is brought for ID, definitive diagnosis
cannot be made
 Good local wound care
 If systemic symptoms, then CBC with platelets, U/A,
BUN, creatinine
• Vigorous supportive care in PICU as needed
 Surgical excision and (rarely) skin grafting after
necrosis is demarcated
 Steroids, heparin, and hyperbaric O2 don’t work
 No Dapsone for kids – methemoglobinemia
 No antivenom available
 Have wound rechecked daily for progression
Black Widow (Latrodectus)
Latrodectus mactans
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 Shiny black spider with brilliant
red hourglass marking on
abdomen
 Only the female bite is
dangerous
• Male spiders are ¼ the size of
females and bite cannot
penetrate human skin
 Females not aggressive unless
provoked or guarding egg sac
 Produces a neurotoxin—
stimulates myoneuronal
junctions, nerves, nerve endings
Black Widow – Clinical Signs
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 No local symptoms
 1-8 hours after bite
• Generalized pain and muscle rigidity
 Cramping pain to abdomen, flanks, thighs,
chest – “rigid abdomen”
• Chills, N/V
• HTN, Tachycardia
• Respiratory distress
• Urinary retention
• Priapism
• Death from cardiovascular collapse
 Mortality 50% in young children
Black Widow - Management
33
 Children < 40kg: Antivenin given as soon as bite
confirmed
• Dose: 2.5ml (one vial)
 Children >40kg: not as urgent to give immediately;
indicated in age <16, respiratory difficulty,
significant hypertension
 Morphine or Demerol
 Calcium gluconate 10% solution 0.1ml/kg IV over 5
minutes for muscle cramps
• Recent series showed effective in only 4% of
cases
• Valium can be used, but is short lived with
variable effects; Robaxin is ineffective
 Admit to PICU
Other Spiders
 Tarantulas
• Do not bite unless provoked
• Venom is mild and not a problem
 Wolf Spider and Jumping spider
• Mild venom only causes local reaction
 Treatment is good local wound care
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Centipede/Millipede
 Centipedes
• Bites with jaws that act like stinging pincers
• Extremely painful
• Toxin is innocuous – local reaction only
 Millipedes - harmless
 Treatment
• Local anesthetic at wound site
• Local wound care
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Ticks
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 Transmit many other infectious diseases:
• Spirochetes – Lyme Disease, relapsing fever
• Viruses – Colorado tick fever
• Rickettsiae – Rocky Mountain spotted fever
• Bacteria – tularemia, ehrlichiosis, babesiosis
• Protozoa
 Tick paralysis – wood tick, dog tick, deer tick
• Tick releases neurotoxin producing cerebellar
dysfunction and ASCENDING Weakness
• Latent period for 4-7 days
• Restlessness, irritability, ascending flaccid
paralysis, respiratory paralysis, death
Tick Paralysis - Management
 Diligently search for the tick
 Remove using blunt forceps held close to skin
 Do not squeeze – can release infective agents
 Admit to hospital for ascending paralysis, PICU if
worried about respiration
37
Bees, Hornets, Yellow Jackets, &
Wasps
 Bees have a barbed stinger next
to a venom sac which can remain
in the victim’s skin
 Bees die after the stinger is
dislodged
 The stinger must be removed if
seen – don’t delay, move venom
is released with time
• Scraping works best, don’t pull
or squeeze
 Wasps, Yellow Jackets, and
Hornets can sting multiple times
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Insects
 Venoms contain protein antigens which elicit an IgE
antibody response
 Major problem is allergic reactions and anaphylaxis
• Group I – local response
• Group II – Mild systemic reactions
 Generalized itching and urticaria
• Group III – Severe systemic reactions
 Wheezing, angioneurotic edema, N/V
• Group IV – Life threatening reactions
 Laryngoedema, hypotension, shock
 Occurs in 0.5-5% of the population from insects
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Insect - Management
 Group I – cold compresses
 Group II – Benadryl 4-5 mg/kg/day divided QID
 Group III
• Epinephrine 1:1000 0.01 ml SQ (max 0.3ml)
(IM?)
• Benadryl PO
• H2 blockers
• Steroids (?)
• Admit to hospital for 23 hr obs
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Insects - Management
 Group IV – may need intubation
• All of the above, plus
• Wheezing refractory to epinephrine may need
aminophylline
 6mg/kg bolus over 20 minutes, then
 1.1 mg/kg/hr infusion
• Hypotension
 Fluid bolus
 IV epinephrine 1:10,000
 IV Hydrocortisone 2mg/kg Q6h
• Admit to PICU
41
Insects - Management
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 Group III or IV reactions need referral to an allergist
for hyposensitization
 After obs, D/C home with EpiPen Jr.
• Spring loaded autoinjectors self-administered in
the thigh
• Always write for the twin pack
 Contains practice syringe and 2 loaded
syringes
• Parents should give this in the field AND seek
further care
 Avoid wearing bright colored clothing, perfumes
 Wear long sleeved garments, gloves when
gardening and hats
 Medical alert bracelets or necklaces
Fire Ants
 Wingless member of
Hymenoptera
 Bites with jaws and pivots
head to give multiple stings
 Venom is an alkaloid with
direct effect on mast cell
membranes
Solenopsis richteri
and Solenopsis invicta
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Red Imported Fire Ant (RIFA)
 Arrived in 1930s from
South America via port
of Mobile, Ala.
 Build mounds in sunny,
open areas (e.g., lawns
and parks)
 Aggressively attack
anyone who disrupts
their mound
44
Fire Ants – Clinical Presentation
 Immediate – wheal and
flare
 4 hrs – vesicle
 8-10 hours – vesicle
becomes umbilicated
pustule
 24 hrs – vesicle
surrounded by painful
erythematous area that
lasts 3-10 days
45
Fire Ants - Treatment
 Symptomatic care
• Ice
• Cleansing
• Antihistamines for itching
• Steroids, antibiotics and antihistamines don’t
have an effect on the lesions
 Occasional systemic reactions (hives, anaphylaxis)
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Mammalian Bites
 Dog bites account for 80-90% of all mammal bites
 Cats 5-10%
 Rodents 2-3%
 Humans 2-3%
 Other wild or domestic animals make up the rest
47
Mammal Bites
 Dogs generate strong forces and cause local crush
injuries
 Only 5-10% of bites become infected because
wound is easily cared for and not very deep
 Cat bites cause deep puncture wounds with 50%
infection rate
• May penetrate fascial compartments, tendons,
vessels and bones
 Most common bacteria: Staphylococcus &
Pasturella species
 Human bites are Strep viridans or Staph aureus
 Also many anaerobes are mixed in: Bacteroides,
Peptostreptococcus, Eikenella corrodens
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Dog Bites
 Usually attack head and neck in most victims
 Cause lacerations of lips, nose and cheek
 May penetrate the skull and cause depressed skull
fracture
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Cat Bites
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 Usually attack upper extremities
 Pasturella infections are very aggressive
• Symptoms begin at 12-24 hours with erythema,
significant edema and intense pain
 Cats also scratch, especially the face
 Consider corneal abrasions
 Bartonella henselae
• Papule at site of scratch with later regional
lymphadenopathy
• Self limited, resolves in 2-3 months
• May have unusual manifestations:
encephalopathy, hepatitis, atypical pneumonia
Human Bites
 Typically involve the hand when punching someone
in the mouth
• Wound overlies the MCP joint, consider Boxer’s
fracture
• Mild swelling in 1-2 days to site
• If there is pain with active or passive finger
motion, then consider tendonitis or deep
compartment infection
• Also consider Hepatitis B and syphilis being
spread by bites
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Rodent Bites and Other Mammals
 Rat-bite fever (rare)
 Pet owners and lab workers
• 2 forms:
 Haverhill fever (Streptobacillus moniliformis)
 Sodoku (spirullum minus)
• 1-3 week incubation period
• Chills, fever, malaise, rash, headache
• Both forms responsive to IV penicillin
 Rabbits – tularemia
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Mammal Bites - Treatment
 Meticulous and prompt wound care
• Scrubbing with soft sponge and 1% povidoneiodine solution
 Stronger solutions retard wound healing
• Pressure irrigation
 Facial wounds require primary closure for cosmesis
 Hand wounds should have delayed primary closure
or heal by secondary intention due to infection rate
• Place a few deep sutures to bring wound
together
• Skin sutures placed in 3-5 days
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Mammal Bites - Treatment
54
 Antibiotic prophylaxis
• No perfect drug, but Augmentin is close
• If allergic, then a combination of clindamycin
PLUS a 2nd or 3rd gen cephalosporin OR Bactrim
• First dose should be given in the ED
 Infected bites require aggressive drainage and
debridement
• Obtain aerobic and anaerobic deep would
cultures
• Leading edge would culture for cellulitis
• Admit for IV antibiotics
 Tetanus prophylaxis
Rabies
 Rabies virus
• Virus transmitted through scratches, abrasions
and animal saliva contact with mucous
membranes
• Causes an progressive, irreversible
encephalopathy traveling up peripheral nerves to
the brain
 Anxiety, insomnia, confusion, agitation,
hypersalivation, hydrophobia
• Unprovoked attacks
• Wild carnivorous animals, BATS
• Rodents, squirrels and rabbits are considered
no-risk
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Rabies
 If the animal can be observed, then prophylaxis can
be delayed
 If the animal shows signs of rabid behavior, then
start the patient on prophylaxis immediately
• Animal will be sacrificed and brain biopsy will be
done to look for rabies
 Prophylaxis is with passive antibody (RIG) and
vaccine HDCV
• RIG is given once, half IM and the other half
infiltrated around bite
• HDVC is given 1.0 ml IM on days 0,3,7,14
(Reduced 4-dose vaccine schedule as of 2010)
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Questions?
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