Bite Me

1
Bite Me

• Howard J. McGowan, Maj, USAF, MC

2
Objectives

• Discuss general wound care principles
• Determine high risk vs low risk bites as related
  to antibiotic prophylaxis
  
• Determine need for tetanus prophylaxis
• Determine need for rabies prophylaxis
• Review common biting animals to include dogs,
  cats, humans, snakes, spiders, and ticks
  

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General Wound Care

• Cleanse and debride wound
• Liberal application of ice or other cold packs
• Pressure to control bleeding
• Sterile dressing
• Hand and foot wounds require immobilization
• If wound high risk antibiotics should be started
• Consider need for tetanus/rabies

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High Risk Wounds

• Location
• Hand, wrist, foot
• Scalp or face in infants (risk of cranial
  perforation)
  
• Over a major joint (risk of perforation)
• Through and through bite of cheek

• Biting species
• Human (hand wound)
• Cat (hand and lower extremity wounds)
• Pig

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High Risk Wounds

• Patient factors
• Older than 50 years of age
• Asplenia
• Chronic alcoholic
• Altered immune status (chemotherapy, AIDS, immune
  defects)
  
• Diabetes
• Peripheral vascular insufficiency
• Chronic corticosteroid therapy
• Prosthetic or diseased cardiac valve
• Prosthetic or seriously diseased joint

• Type of wound
• Puncture (impossible to irrigate)
• Tissue crushing that cannot be debrided (typical
  of herbivore)
  
• Carnivore bite over vital structure (artery,
  nerve, joint)
  

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Low Risk Wounds

• Face, scalp, ears, mouth
• Self-bite of buccal mucosa (not through and
  through)
  
• Large clean lacerations that can be thoroughly
  cleansed
  
• Partial thickness lacerations and abrasions

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Antibiotics

• Antibiotic prophylaxis if high risk wound
• Amoxicillin/clavulanate or ampicillin/sulbactam
• Cefoxitin or carbapenem for mild pcn allergy
• Vibramycin, trimethoprim/sulfamethoxazole, or a
  fluoroquinolone plus clindamycin if severe pcn
  reaction
  

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To Close or Not

• Wound closure
• Puncture wounds, wounds that appear clinically
  infected, and wounds more than 24 hours old may
  have a better outcome with delayed primary
  closure
• May consider early primary closure if less than 8
  hours old or located on face
  

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Tetanus Prophylaxis

• CLEAN MINOR ALL OTHER
• WOUNDS WOUNDS
• HISTORY OF
• TETANUS
• PROPHYLAXIS Td TIG Td TIG
• Uncertain or Yes No Yes Yes
• 3 doses
• last dose within 5 yrs No No No No
• last dose 5-10 yrs No No Yes No
• last dose 10 yrs Yes No Yes No

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Rabies

• Widespread vaccination of dogs against rabies in
  US
  
• Still reported cases of rabies virus associated
  with dog bites
  
• Most common source of rabies now is wild animals,
  specifically raccoons, skunks, and bats
  

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Rabies
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Rabies

• Nonprovoked dog/cat bites should be considered
  higher risk
  
• Owner reliable?
• confirm animals vaccination status
• observe pet in owners home
• Vaccinaton status unknown or animal ill
• observation by veterinarian is appropriate
• May need to sacrifice animal
• If animal cannot be quarantined for 10 days, the
  bite victim should receive rabies prophylaxis
  within 48 hours

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Rabies

• Vaccination Status Treatment
  Regimen
  
• of bite victim
• Not vaccinated RIG 20
  IU/kg around wounds or IM in
  site distant from vaccine
  site
• Vaccine
  Daily on days 0,3,7,14,28
  
• Vaccinated RIG
  NO
  
• Vaccine
  Daily on days 0 and 3

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Dog Bites
15
Dog Bites

• 80-90 of mammalian bites inflicted by dogs
• Only species whose bites have been well studied
  in large numbers
  
• Most contributing factors related to owners
  level of responsibility

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Dog Bites

• Total annual US national cost of ED services for
  new dog bite-related injuries more than 102
  million
  
• 165 million when combined with physican service
  charges and postdischarge care
  

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Dog Bites

• Dogs under 1 year of age responsible for the
  highest incidence of bites
  
• Incidence of biting increases during warm summer
  months
  
• Most bites between 1-9PM
• Men bitten more often than women
• Pit bull breed of the Staffordshire terrier has
  been associated with the majority of dog bite
  related deaths in the United States
  
• Death usually from exsanguination

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Dog Bites

• Most wounds minor
• Adult dogs can bite with up to 450 pounds of
  force
  
• Enough to puncture light sheet metal
• A dogs bite can break human bones
• Characteristic pattern of lacerations and
  punctures
  
• Penetrating component causes most morbidity

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Dog Bites

• Median of 5 bacterial isolates identified per
  culture for dog bites
  
• Pasteurella species the most common pathogen
• P. canis
• Streptococcus, Staphylococcus, Moraxella,
  Corynebacterium, Neisseria

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Dog Bites

• Infection rate of non-bite lacerations 5-15
• Similar rate to that of the typical dog bite when
  managed properly with irrigation and debridement
  
• Dog bite wounds that are NOT high risk are
  probably no more infection prone than non-bite,
  accidental cutaneous lacerations

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Dog Bites

• Low risk bitesgeneral wound care principles
• High risk bitesantibiotic prophylaxis
• Amoxicillin/clavulanate or ampicillin/sulbactam
• Cefoxitin or carbapenem for mild pcn allergy
• Vibramycin, trimethoprim/sulfamethoxazole, or a
  fluoroquinolone plus clindamycin if severe pcn
  reaction

22
Cat Bites
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Cat Bites

• 5-10 of mammalian bites inflicted by cats
• Increasing problem in US as stray population has
  exploded to over 90 million
  
• Women more likely than men to be bitten
• 63 of bites on hand or finger

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Cat Bites

• Weaker biting force than dogs
• Sharp slender teeth
• Deep puncture wounds
• Notorious for high infection rate
• 15-80 become infected
• Pasteurella multocida and septica
• Typically two risk factors for infection
• Hand location
• Depth of puncture
• Most considered high risk and abx prophylaxis
  warranted

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Human Bites

• 2-3 of mammalian bites
• Most occur during fights
• At least 42 different species of bacteria in
  human saliva
  
• Bacteroides fragilis, Prevotella, Porphyromonas,
  Peptostreptococcus, Fusobacterium, Veillonella,
  Clostridium, Strep, Staph,Haemophilus, Eikenella
  

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Human Bites

• Transmission of actinomycosis, syphillis, herpes,
  hepatitis C, hepatitis B, and tuberculosis have
  been reported after a human bite
  
• Not thought to pose significant HIV risk as HIV
  usually not present in saliva
  
• Is thought to have been mode of transmission in
  at least two cases
  
• Slovenia man bitten while trying to control
  airway
  
• Lip bite to a male from a female prostitute

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Human Bites

• Infection rate of 17.7 compared with 5-15
  infection rate of non-bite lacerations
  
• Hand wounds particularly at risk of infection and
  considered high risk
  

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Human Bites

• Fight bite
• 60-80 occur in males
• Deep laceration that disrupts superficial and
  deep fasciae, extensor tendon and bursa, and
  joint capsule
  
• Once fingers extend skin and tendon retract and
  seal off contaminated wound

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Human Bites

• Any penetrating wound in vicinity of MCP joint
  should be considered a human fight bite until
  proven otherwise
  
• Need xrays and up to 70 have positive findings
• Need rapid and aggressive treatment

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Human Bites

• Fight bite
• Significant injuries should be explored and
  debrided in OR
  
• In field wounds should be thoroughly irrigated
  and left open
  
• Hand should be immobilized
• Abx should be started ASAP

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Human Bites

• Forensics
• Bite marks as well as any DNA that can be
  recovered can be used as evidence
  
• Photograph wound and consult forensic pathologist
  or dentist through local law enforcement agency

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Snake Bites

• 8,000 venomous snake bites/yr in US
• Most occur in April and October
• Venom from four families toxic to humans
• More common worldwide than in US

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Snake Bites

• In US 99 of snake bites are caused by pit
  vipers
  
• Rattlesnakes
• Copperheads
• Cottonmouths

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Snake Bites

• Coral snakes also a US snake

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Snake Bites

• Initial treatment
• Avoid excessive activity
• Immobilize bitten extremity in a functional
  position below the level of the heart
  
• Quickly transport patient to nearest hospital
• May consider wide flat constriction band proximal
  to bite
  
• Blocks only superficial venous and lymphatic
  flow
  
• Venom extractormay be beneficial if applied
  within 5 minutes of the bite and left in place
  for 30 minutes

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Snake Bites

• If possible try to identify snake from a safe
  distance
  
• Digitial photo
• Do not try to catch the snake
• Be wary of an apparently dead snake

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Snake Bite

• Venomous vs Non-venomous
• Venomous snakes
• Triangular shaped head
• Elliptical pupil
• Hollow retractable fangs
• Non-venomous snake
• Round head
• Round pupil
• No fangs
• Coral snakes
• Recognize banding pattern

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Snake Bites

• Clinical effects of a snake bite
• Mild local reaction
• Severe life-threatening systemic reaction
• Depends on species of snake, size of snake,
  location of bite, volume on venom injected,
  age/size/health of victim
  
• Snake venom
• Hemotoxic
• Neurotoxic

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Snake Bites

• Hemotoxic symptoms
• Intense pain
• Edema
• Weakness
• Swelling
• Numbness/Tingling
• Rapid pulse
• Ecchymoses
• Muscle fasciculation
• Unusual metallic taste
• Vomiting
• Confusion
• Bleeding disorders

• Neurotoxic symptoms
• Minimal pain
• Ptosis
• Weakness
• Paresthesia/Numbness at bite
• Diplopia
• Dysphagia
• Sweating
• Salivation
• Diaphoresis
• Hyporeflexia
• Respiratory depression
• Paralysis

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Snake Bites

• Croatalinae subfamily
• Rattlesnakes, copperheads, cottonmouths
• Hemotoxic
• Local tissue destruction, coagulopathy,
  hypotension
  
• Mojave rattlesnake is only rattlesnake associated
  with significant neurotoxicity
  
• Elapidae familyIn US coral snakes
• Neurotoxic

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Snake Bites

• Evaluation/Treatment
• General wound care
• Exam
• Hypotension, tachycardia, oozing, blistering,
  LAD, local tissue damage, signs of bleeding
  
• For suspected coral snake or mojave rattlesnake
  need serial neurologic exams
  
• Laboratory evaluation
• CBC, PT, PTT, fibrinogen, FDPs ASAP and recheck
  in 12 hours
  
• Blood type and cross match, electrolytes,
  glucose, BUN, LFTs, Bilirubin, CK, Stool
  hemoccult
  
• EKG if over 50 or with heart dz
• ABGs if respiratory compromise

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Snake Bites

• Antibiotics
• Snake bites may result in inoculation of Gram
  negative anaerobic bacteria
  
• Local bacterial wound infections rare when abx
  not prescribed
  
• Use abx only for established infection or if
  first aid measures have involved an incision

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Snake Bites

• Degree of envenomation Presentation
  Treatment
  
• 0. None
  Puncture, abrasions, pain Wound
  care
  or
  tenderness at bite site
• I. Mild
  Pain, tenderness, edema
  Antivenom
  
• 
  perioral paresthesias
  
• II. Moderate
  Pain, tenderness, erythema
  Antivenom
  
• 
  beyond area adjacent to bite
  
• 
  systemic cx, coagulopathy
  
• III. Severe
  Intense pain/swelling of entire
  Antivenom
  
• 
  extremity, severe systemic sx
  
• 
  coagulopathy
  
• IV. Life-threatening
  Marked abnl signs/symptoms
  Antivenom
  
• severe coagulopathy

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Snake Bites
Antivenoms

• Polyvalent Crotalidae ovine immune Fab (FabAV)
• --Fab fragments from sheep Ig immunized with four
  snakes
  
• --western and eastern diamondbacks, mojave
  rattlesnake, cottonmouth
  
• --Effective for all NA rattlesnakes
• --Approved for copperheads as well
• --Safe and effective in children
• --Lower adverse events than ACP
• --indicated with any grade of envenomation
• --dosing 4-6 ampules repeated if no response in
  one hour

• Crotalidae polyvalent antivenom (ACP)
• --made from horse serum
• --produced from venom from 4 snakes
• --western/eastern diamondbacks, SA/Brazilian
  rattlesnake, SA pit viper
  
• --may be effective against other species as well
• --dosing based on severity of envenomation
• --serum sickness and anaphylactic reactions
  common
  

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Snake Bites

• Coral snake bites far less common in US
• Envenomation occurs following majority of bites
  and neurotoxicity can occur in the absence of
  obvious fang marks
  
• Symptoms onset immediate up to 12 hours later
• Horse serum based antivenom available and
  effective against Eastern and Texas coral snakes,
  but not others such as the Arizona coral snake
  
• Antivenin (Micrurus fulvius)

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Spider Bites

• Approx 3,000 species of spiders in NA and all are
  poisonous
  
• Most too small or have too little poison to
  bother humans
  
• Only a few species have powerful enough
  chelicerae to penetrate human skin

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Spider bites

• Most dangerous spiders to humans in NA
• Latrodectuswidow spiders
• Loxoscelesbrown spiders

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Spider Bites

• Can attribute a local or systemic reaction to a
  spider bite if
  
• Spider seen during biting
• Spider recovered, collected, sent for ID
• Other conditions such as vasculitis, infection,
  allergic reaction other than to the spider venom,
  vascular problems, and anxiety/panic must be
  ruled out

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Spider Bites

• Black Widow Bite (Latrodectus species)
• Latrodectism
• Caused by alpha-latrotoxinneurotoxiccauses
  massive presynaptic release of most
  neurotransmitters including acetylcholine,
  norepi, dopamine, and glutamate
• Severe muscle spasm, nausea, vomiting, deaths in
  less than 1 of patients
  
• Local wound care, analgesia, bzd
• Initial labs to include cbc, ua, ck, ldh
• Latrodectus antivenom for severe regional or
  systemic toxicity and for patients with
  uncontrolled HTN, seizures, or respiratory arrest

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Spider Bites

• Brown Recluse Bite (Loxosceles reclusa)
• Necrotic arachnidism
• Sphingomyelinase D
• Immediate wound care
• Debridement of necrotic tissue, culture directed
  abx, delayed excision of eschars with split
  thickness skin grafting as needed
  
• With proper care necrotic wounds heal over 8
  weeks with a 10-15 incidence of major scarring

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Tick Bites

• Nearly painless bites. May not be notice until
  after it is attached
  
• Important to remove ASAP after it is discovered
• Need to also remove tick completely
• Risk of Lyme dz tranmission increases
  significantly after 24 hours of attachment and is
  even higher after more than 48 hours
  

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Tick Bites

• Removing a Tick
• Manual extraction
• Blunt tipped angled forceps to grasp tick as
  close to skin as possible
  
• Use perpendicular traction to remove
• Do not twist

• Do NOT Do
• Use sharp instruments
• Crush or puncture the ticks body
• Apply substances
• Use heat
• Twist or jerk
• Handle with bare hands

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Tick Bites
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Tick Bites

• Tick-borne Diseases
• LymeBorrelia burgdorferi
• Ixodes scapularis tickDeer tick
• Symptoms 7-10 days after tick bite
• Early localized formStage 1
• Erythema migrans and flu like illness
• Early disseminatedStage 2
• AV block, carditis, fatigue, meningitis, Bells
  palsy
  
• Late chronicStage 3
• Arthritis, encephalopathy

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Tick Bites

• Lyme Dz
• If erythema migrans present make dx and begin tx,
  otherwise determine pretest probability

AFP 7/15/2005
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Tick Bites

• Tick-borne Diseases
• EhrlichiosisEhrlichia
• Ixodes tick
• Human monocytic and Human granulocytic
• 7-10 day incubation period
• Fever, headache, myalgias, chills
• Leukopenia, thrombocytopenia, and elevated liver
  transaminases
  
• Dx base in HP and common lab findings
• Doxycycline is drug of choice

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Tick Bites

• Tick-borne Diseases
• Rocky Mountain Spotted FeverRickettsia
• Hard-bodied ticksAmerican dog tick/wood tick
• 7 day incubation period
• Fever, headache, myalgia, malaise, vomiting
• Rash within first week
• Depressed WBC, thrombocytopenia, elevated liver
  transaminases, hyponatremia
  
• Encephalitis, pulmonary edema, ARDS, cardiac
  dysrhythmias, coagulopathies, GI bleeding, skin
  necrosis.
  
• Death in 8-15 days if left untreated
• Mortality 25 if untreated and 5 if treated

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Tick Bites

• Rocky Mountain Spotted Fever
• Diagnose by HP
• Treat with tetracycline and chloramphenicol

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Tick Bites

• Tick-borne diseases
• TularemiaFrancisella tularensis
• 3-5 day incubation
• Fever, chills, headache, malaise, anorexia,
  fatigue, cough, myalgies, chest discomfort,
  vomiting, sore throat, abdominal pain, diarrhea
  
• In addition one of six classic patterns of
  disease
  

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Tick Bites

• Tularemia
• Ulceroglandular patternmost common
• Enlarged, tender, localized LAD-cervical/occipital
  
  
• Painful skin ulcer
• Glandular pattern
• Similar, but without ulcer
• Oculoglandular
• 90 unilateral
• Photophobia, lacrimation, lid edema,
  conjunctivitis, scleral injection, conjunctival
  ulcers
  
• Pharyngeal
• Severe sore throat, exudative pharyngitis
• Typhoidal
• Watery diarrhea
• Pneumonic
• Acute respiratory illness

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Tick Bites

• Tularemia
• HP to diagnose
• Streptomycin unless meningits is present
• Gent, tetracycline, chloramphenicol,
  fluroquinolones

63
Summary

• Discussed general wound care principles
• Reviewed high risk vs low risk bites as related
  to antibiotic prophylaxis
  
• Reviewed need for tetanus prophylaxis
• Reviewed need for rabies prophylaxis
• Reviewed common biting animals to include dogs,
  cats, humans, snakes, spiders, and ticks
  

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• ?QUESTIONS?