Terrestrial Bites and Stings

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Terrestrial Bites and Stings

• Brian Costello, MD
• Department of Pediatric Emergency Medicine
• June 24, 2010

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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

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Snakes

• US has 120 different species of snakes
• Only 15 poisonous
• Two families
• Crotalidae (pit vipers) 99 of snakebites
• Elapidae 1 of snakebites

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Identifying Poisonous Snakes
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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

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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
• gt12 mm large snake
• 10-20 of rattlesnake strikes are dry (no venom)

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Crotalid Bites - Symptoms

• 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

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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

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Crotalid Antivenin

• AVCP polyvalent antivenom
• Horse serum, highly antigenic needs skin
  testing prior to giving
• Dont 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.

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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

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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 120 solution,
  triple dye
• Blood products for coagulopathy
• No prophylactic antibiotics (current thinking)
• Physical therapy in healing phase

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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

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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

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Elapids - Management

• Tourniquets, incision suction, etc. dont 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 Georgias Venomous Snakes
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Georgia Venomous Snakes

• Georgia
• Carolina Pygmy Rattlesnake - Sistrurus miliarius
  miliarius
• 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

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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

• 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

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Scorpions - Management

• 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)

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Brown Recluse Spider (Loxosceles)

• 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 reclusa
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Loxosceles Geographic Distribution
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Brown Recluse Clinical Signs

• 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

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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
• 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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Its 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.
• http//department.monm.edu/biology/recluse-project
  /identify.htm

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Quiz Indentify 2 Brown Recluses
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Brown Recluse - Management

• 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 dont work
• No Dapsone for kids methemoglobinemia
• No antivenom available
• Have wound rechecked daily for progression

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Black Widow (Latrodectus)

• 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 neurotoxinstimulates myoneuronal
  junctions, nerves, nerve endings

Latrodectus mactans
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Black Widow Clinical Signs

• 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

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Black Widow - Management

• Children lt 40kg Antivenin given as soon as bite
  confirmed
• Dose 2.5ml (one vial)
• Children gt40kg not as urgent to give
  immediately indicated in age lt16, 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

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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

• 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

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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

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Bees, Hornets, Yellow Jackets, Wasps

• Bees have a barbed stinger next to a venom sac
  which can remain in the victims skin
• Bees die after the stinger is dislodged
• The stinger must be removed if seen dont
  delay, move venom is released with time
• Scraping works best, dont 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 11000 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 110,000
• IV Hydrocortisone 2mg/kg Q6h
• Admit to PICU

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Insects - Management

• 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

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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

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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

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Fire Ants - Treatment

• Symptomatic care
• Ice
• Cleansing
• Antihistamines for itching
• Steroids, antibiotics and antihistamines dont
  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

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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

• 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

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Human Bites

• Typically involve the hand when punching someone
  in the mouth
• Wound overlies the MCP joint, consider Boxers
  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 povidone-iodine
  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

• 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

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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?