Bites (Quiz 2) Flashcards Preview

SPRING16 N833 Adv Pedi > Bites (Quiz 2) > Flashcards

Flashcards in Bites (Quiz 2) Deck (75):

What are the most common animal bites?

  • 1.Dogs: 85-90% of all animal bites
  • 2.Cats: 5-10% of all animal bites
  • 3.Humans: 3rd most common of all bites


Are dog bites typically provoked?

  • >70% of dog bites: unprovoked & from dogs known to the victim
  • Most dog bites are preventable
  • Most deaths from bites are caused by dogs, particularly Rottweilers & Pit Bulls

  • Surprisingly, dog bites to infants that result in death occur most commonly when infant is sleeping


Prevention of bites includes:

training, proper control of dogs, & education


Characteristics of abrasions


  • Superficial damage to skin
  • Limited bleeding
  • Lower risk of infection

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Characteristics of crush injuries


  • Related to force of bite
    • Dogs can exert 200-450 psi of pressure when they bite
  • Open or closed wound
  • Can injure muscle, bone, tendon
  • Crush injuries usually contain devitalized tissue that should be debrided to help prevent infection

  • Compression lacerations
    • Irregular wound edges
  • Severe crush injuries:
    • Risk for rhabdomyolysis
    • Neurovascular injury
      • Assess distal to injury

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Characteristics of puncture wounds


  • Result of trauma from sharp, pointy object (cat tooth/nail)
  • Typically no excessive bleeding
  • May be deep penetration
  • Highest risk for infection
  • ***Often wounds do not look very bad, and are already infected when parent brings child in

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Characteristics of lacerations


  • Soft tissue tear
  • May be very deep
  • Often irregular edges
  • Surrounding abrasion and bruising
  • Bleeding may be heavy
  • Often contaminated with bacteria and debris
  • High risk for infection

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Characteristics of avulsion


  • Skin or soft tissue is partially or completely torn away
  • Most common on face: lips and ears
  •  Send to ED


Comparison: abrasion, laceration, avulsion, incision, puncture, amputation



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Important aspects of wound to document


  • Document precisely and take photo if possible
  • Note:
    • Type of wounds
    • Size (measure)
    • Depth
    • Foreign bodies
    • Devitalized tissue
  • Signs of Infection/Cellulitis:
    • Rubor, dolor, calor, tumor
    • Purulent discharge
    • Increasing area of redness
      • Can draw circle around red area w/ permanent marker


Common bacteria in dog and cat bites


Dog & cat bites are typically polymicrobial infections

Polymicrobes: aerobic and anaerobic bacteria mainly come from animal oral flora, but also from children’s skin and the environment

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Pasteurella multocida and Capnocytophaga canimorsus


  • •Pasteurella multocida: Can cause a rapid infx. More common in cats than dogs. Wounds that become infected < 24 hrs are often caused by P. multocida
  • •Capnocytophaga canimorsus has been found in the mouths of 24% of dogs and 17% of cats.


Who is at highest risk for dog bites?

  • Boys 5-9 yo
  • ~4 mil Americans are bitten/year


Where on the body are children usually bitten by dogs?

  • = 3x more likely than adults to get bitten
  • Younger children: head & neck

  • Adolescents: hand & extremities (upper ext)


Characteristics of dogs who bite

  • 75% unneutered male dogs
  • 50-75% of dogs are known
  • >50% are unprovoked


Common breeds that bite

Pit bull breeds, malamutes, chows, Rottweilers, huskies, German shepherds, wolf hybrids


Types of wounds from dog bites

  • Crush Injuries (Most dog bites will have some degree of crush injury)
  • Lacerations
  • Abrasions
  • Puncture
    • less common in dog bites than cat bites


Most common complication of dog bites + symptoms

  • Most common complication is 2ndry infection
    • 10-15% infection rate
    • Systemic s/s:
      • Fever, chills
    • Local s/s:
      • Local erythema, warmth, increasing pain, edema, exudate
  • Dog bites are considered contaminated and contain mixed organisms, need to cover for anaerbic and aerobic!

  • Pasteurella multocida & Staphylococcus aureus are the most common aerobic organisms, present in 20-30% of infected dog bite wounds


Laws regarding reporting bites

  • Laws vary state by state
  • Know the laws where you practice!!
  • In every state, must report suspected cases of rabies
    • Rabies: suspected animals should be sent for testing. Local or state health dept. can give info on submitting specimens
    • Examples of state laws:
      • •In MA: Healthcare providers must report any bite by a domestic animal to the Animal Inspector in < 24 hrs
      • •In CT: Victim of a dog bite must report the attack.
    • Ellis & Ellis, 2014, American Family Physician


Psychological After-Effects of a Dog Bite

  • High prevalence of PTSD (25% of pedi pts after DB)
  • Common behaviors in children:
    • More fearful of dogs
    • Avoid dogs/things/places that remind child of the bite
    • Increased anxiety
    • Sleep disturbance
    • Tantrums, aggression
    • Decreased school performance
  • These behaviors may not appear until months after the bite
  • APRNs can help: Educate parents on the symptoms to look out for. Evaluate at f/u. Make referrals to mental health services as needed


Epidemiology / prevalence of cat bites?

  • ~400,000/year in US
  • Most common in middle age women
  • 89% of cat bites are provoked


Common locations of cat bites

Majority (2/3) involve upper extremities and scratches may be on face


Types of cat wounds

  • Puncture wounds, abrasions, lacerations
  • Caused by cats’ long, sharp teeth & claws


Common pathogens in cat bites


75% contain Pasteurella multocida

Can cause rapid infection in humans

Wounds that become infected < 24 hours of the bite are often caused by Pasteurella



Complications of cat bites

  • 2x risk of infection than dog bites (30-50%)
  • More likely to become infected than dog bites
  • Progress rapidly (12-24 hours after the bite)
  • Deep puncture wounds can lead to osteomyelitis, tenosynovitis, septic arthritis
  • Cat scratch fever
  • *Bacteria can be inoculated deep into tissue or closed spaces such as joint capsules, which can lead to septic arthritis and osteomyelitis (contiguous or penetrating pathogenesis)


Treatment of cat bites

  • Most cat bites are prophylaxed with antibiotics!
  • Beta-lactams most effective
  • Rabies prophylaxis is the same as for dog bites


Prevalence of human bites

  • 3rd leading cause bite wounds treated in the ED
  • Often result of 1 person striking another in the mouth w/ a clenched fist 


Cause of human bites

  • Aggressive behavior
    • often in setting of ETOH use (cause of most clenched-fist injuries)
  • Accidents during sporting events
  • Aggressive play of children in daycare
  • Rough sexual play or sexual assault
  • Child abuse
  • Self-inflicted wounds


Common pathogens in human bites

  • Similar to cat/dog, no Pasteurellae or C. canimorsus
  • Anaerobes Eikenella corroden
  • Viridans streptococci
  • Streptococcus pyogenes, S. aureus
  • Hepatitis B & C; HIV; HSV
  • Similar in that they are polymicrobial infections with aerobic & anaerobic microbes

  • Potential for transmitting blood borne pathogens


Most common location for human bites

  • >50% occur in upper extremities
  • “Love nips” to the face, breasts or genital region
  • Most victims of human bites have >1 bite, so thoroughly inspect the patient’s skin


Main types of human bites

Occlusion bites and clenched fist injuries

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Characteristics of occlusion bites

  • Elliptical or ovoid
  • Patterns of ecchymosis, abrasions, or lacerations
  • Rarely penetrate deep into tissue
  • 70% abrasions
  • Lower risk of infection (~10%)

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At what ages / places is biting in children most common?

  • Most common in toddlers
  • Subsides by 3.5 yo
  • Typically occurs at daycare


What to suspect if bite on child is >3cm?

adult bite / abuse


MGMT of biting in children

  • Educate parents on normality of biting in pre-verbal children for variety of reasons: frustration, coping, attention, overtired, overwhelmed, teething, oral stimulation
  • What to do?  Basic behavior management
    •  - When it happens, stop the behavior
    •  - Immediately tell the child it is not okay, biting hurts
    •  - Time out may be appropriate
    •  - Distraction & move on. No harsh punishments.
  • Many resources for parents to cope with a biting child.


Characteristics of clenched fist injuries

  • “Fight Bite” Injury
  • Adolescents and adults
  • Dominant fist
  • 3rd/4th MCPs
  • >50% of all human bites
  • Higher risk of infection

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mgmt of clenched fist injuries

Refer to ED


Risk to bat bites

  • May be asymptomatic but…Bats are #1 cause of rabies in human in the US
  • Nearly all bat exposure is prophylaxed but controversial
  • Mortalities are typically related to failure to seek medical treatment after exposure


Prevalence of rabies infection :

  • 92% of reported rabies cases are contracted through wild animals
    • Raccoons, bats, skunks are the most common carriers (32.4%, 27.2%, 24.7%)
    • Raccoons are the most common rabid animal in the NE


Initial bite mgmt

Pts should clean wound with warm water and soap, apply compression for active bleeding, and cover with a dry gauze dressing (or equivalent). All human/animal bites (that puncture skin) should be seen by a PCP.

“Primary care clinicians must be able to assess and manage animal and human bites, initiate antibiotic therapy if indicated, and refer patients for surgery or rabies prophylaxis when appropriate. Prompt assessment and treatment can prevent most bite wound complications” (Bower, 2011, 36-38.)


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Important HPI after a bite


  • Is pt awake and alert?
  • Illicit PMH, medications, allergies, vaccine status (how many tetanus, last tetanus, Tdap? Hep B? Rabies, RIG?)
  • Ask about animal/person that bit the patient
  • For dogs: Was it a known dog? Rabies status know? Provoked?
  • If hand bite (was it open or closed/fist?)
  • Duration of time since bite
  • Patients presenting >8 hours following the bite are at greater risk of infection
  • Cleaning / tx of bite so far?
  • For human bites: clenched fist or open hand bite? What is vaccine status of biter (HIV/other virus)


Important ROS after a bite?


  • General
  • Is pt stable? Distressed?
  • Fever, chills, malaise
  • Skin
  • Size &  location of laceration/abrasion/puncture
  • Color, temp
  • Erythema, edema
  • Extent of bleeding
  • MS
  • ROM, MS
  • Neuro
  • Sensation, parasthesias


Bite wounds: what to look for on exam


  • Type/extent of wound
  • Extent of bleeding
  • Signs of infection:
  • Erythema, edema, purulent drainage, lymphangitis,pain
  • Sensation
  • ROM
  • Bone/joint involvement
  • Tendon rupture (extrinsic and intrinsic flexor at palmar aspect, extensor at dorsal aspect): evaluate joint's full extension & flexion - refer
  • Neurovascular bundles: need repair
  • Measure and photograph the wound/s as necessary


Bite wound mgmt: wound cleaning


  • Minor abrasions & puncture wounds --> wash with soap and water
  • Lacs--> irrigate with sterile water, NS, LR’s, or dilute povidone-iodine solution
  • Use 20-mL+ syringe to generate adequate pressure (7o psi)
  • 20-gauge catheter can be connected to increase pressure
  • Debride devitalized tissue to decrease potential for infection


What solution to clean with if suspect rabid animal


Iodine/betadine if animal may be rabid

however, saline seems to be comparable

  “Povidone iodine is a broad spectrum antimicrobial solution effective against a variety of pathogens including Staphylococcus aureus. However,  similar wound infection rates have been reported in adult and pediatric populations with saline irrigation versus 1% povidone-iodine” (Gabriel et al.,   2011)


When to obtain imaging with bites / what type of imagine


  • Radiographs if puncture wound is near a joint/bone, foreign body suspected, ALL clenched fist injuries
  • Plain film of hand, wrist, scaphoid series, forearm


When to get tetanus shot /tetanus immune globulin in setting of bite


  • No clear history of at least three tetanus vaccinations who have a wound that is anything other than clean and minor NEED tetanus immune globulin (TIG) in addition to vaccine (CDC, 2016)

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Characteristics, signs and symptoms of tetanus

  • Gram + bacterium C. tetaniàtoxin
  • Soil, dust, manure
  • Wounds (punc & contaminated)/crush injury
  • No person-person spread
  • 3–21 days (avg 10) incubation
  • S/S: muscle spasm, pain, HA, “lock-jaw,” seizure, --> BP/HR/temp, hydrosis
    • PE, PNA, ARD


Algorithm for tetanus prophylaxis in routine wound mgmt


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Protocols for post-exposure prophylaxis for Hep B


If human bite, HBIG w/in 24h!

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Viral prophylaxis for human bites


  • HBIG series should be administered within 24 hours!Other viral prophylaxis: HIV PEP is generally not recommended for human bites, given the extremely low risk for transmission.


Rabies Post Exposure Prophylaxis


  • PEP w/ or w/o RIG tx should be considered when:
  • Direct contact between human & bat: unless knows no bite or mm exposure
  • Category II & III contact
  • Child is bitten by unknown dog
  • Vaccine status unknown
  • Animal can’t be found for testing & 10 day obs
  • If can be observed until r/o rabies, may d/c tx
  • Rabid animal bite:
  • Prophylaxis!
  • Prophylaxis must be given within 48 hrs* Ideally 24 hours


What are the categories of exposure to suspect rabid animal?


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How can rabies be diagnosed?

  • Rabies: Virus-specific immunofluorescent staining of skin specimens, isolation of virus from saliva, or detection of anti-rabies abs in serum or CSF can be used for dx.
  • Serum antibody titers alone are not sufficient, as they may not test positive until late in the course of illness, if at all.


What is given if previous rabies prophylaxis

* two intramuscular doses of a cell-derived vaccine separated by three days are sufficient

*Pts who have received RIG before do not receive again



Details on rabies vaccine: doses, site of admin

  • IM doses of 1 ml or 0.5 ml given as 4-5 five doses over 4 weeks
  • One dose administered on day 0, 3, 7, 14 & 30
  • Always in deltoid or AL thigh in young children, never in gluteus!
  • 3 types of rabies vaccine are currently available in the United States: human diploid cell vaccine (HDCV), rabies vaccine adsorbed (RVA) and purified chick embryo cell vaccine (PCEC). Equivalent efficacy and safety.
  • The first dose of vaccine should be inoculated at the same time as the immunoglobulin, but in a different part of the body.


RIG: doses and sites of admin

  • Inject into wound & IM into surrounding area
  • Single dose of 20 IU/kg for human anti-rabies immunoglobulin OR
  • 40 IU/kg for heterologous (equine) immunoglobulin
  • 21 hr half life


Rabies PEP schedule (chart)

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Rabies: algorithm for whether or not to use PEP


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Rabies: pathophysiology

  • negative-stranded RNA virus of the rhabdovirus family that affects the CNS (primarily neurons) and is nearly always fatal
  • Neuroinvasiveness and ensuing symptoms are the major defining characteristic of classic RV infection
  • The exact MOA by which RV causes a fatal neurological disease is not fully understood
  • Drastic inhibition of protein synthesis required to maintain neuronal function is thought to be the most significant underlying factor


Presentation of Rabies 

  • S/s can present months after bites
  • Prodrome:
    • S/S: low-grade fever, chills, malaise, myalgias, weakness, fatigue, anorexia, sore throat, N/V, HA, occasionally photophobia
    • Duration: Last days-1 week
  • Clinical Rabies:
    • Encephalitic (80%)
      • Fever, hydrophobia (33-50%), pharyngeal spasms, face/neck contraction, autonomic instability, hyperactivity leading to paralysis, coma & death
      • Patients usually die as a result of respiratory and vascular collapse
    • Paralytic (<20%)
      • Patients present with an ascending paralysis, similar to GBS
      • Loss of DTR, + fasciculations
      • Hydrophobia rare


When NOT to suture


  • Controversial
  • High risk of infection
  • Cat bites, human bites
  • Bites to hand, crush injuries
  •  Presentation >12 hours from injury
  • Clinically appearing infected wounds
  • Puncture wounds*
  • Bites from a rabid animal
  • All may have better outcomes w/delayed primary closure (3-5 days) or healing by secondary intention (Presutti, 2001)


When to suture


  • Clinically uninfected facial wounds
  • Wounds <12 hours old
  • Several recent RTCs have found:
  • Primary closure of dog bites after thorough cleansing  have similar infection rate (6.3-8.3%) to non-suturing counterparts & overall ED suturing infection rate
  • Healing time of sutured groups was shorter
  • Cosmetic appearance of sutured groups was better
  • *<8 hrs and face/neck lacerations had lower rate of infection overall
  •  Recommend primary closure
  • Some providers will only close wounds that are <8 hrs old & wounds located on the face


When to start antibiotics after a bite?

  • All moderate or severe bites
  • All human and cat bites
  • Crush injuries
  • Puncture wounds (especially if penetration of bone, tendon sheath, or joint)
  • Deep or surgically closed facial bites
  • Hand, foot, genital area bites
  • Wounds with signs of infection
  • Immunocompromised or asplenic pts


When to Consider prophylactic antibiotics after a bite



If there’s a delay > 12 hrs in seeking care


With proper cleaning, Do NOT give prophylactic antibiotics for:


  • Mild/non-infected dog bites
  • Non-penetrating human and cat bites
  • Abrasions

limited data on wounds that don't appear infected


Which antibiotics should be used for bites?


  • 1st line: Augmentin (“dogmentin”)
    • Also Moxifloxacin & other combinations of extended-spectrum PCNS with beta-lactamase inhibitors
  • Patients > 8 yo allergic to PCN >> clindamycin + Doxycycline 
  • Patients < 8 yo allergic to PCN >> clindamycin + Bactrim
    • OR clindamycin + extended spectrum cephalosporin (cefotaxime or ceftriaxone)
  • For MRSA: Doxycycline (>9 yo) or Bactrim + Clindamycin


Length of antibiotic treatment:



  • For prophylaxis, 3-5 day course if bite is fresh (<12 hrs)
  • If signs of infection are present,  7-10 day course is usually sufficient for SSTI


When to culture bite wounds


  • If wound appears infected or has not responded to abx: obtain aerobic & anaerobic cultures, observe for a minimum of 7 to 10 days (to allow for slow-growing pathogens)
  • Not necessary for fresh wounds without signs of infection 


When to obtain labs after a bite wound

Blood culture if fever or systemic toxicity is noted


When to splint after a bite wound

If extremity is injured or broken


What % of dog bite wounds become infected?



When to refer bite wounds

  • Surgery consult/involvement may be necessary for:
    • facial wounds
    • deep wounds
    • wounds requiring significant debridement and or closure
  • Orthopedic consultation should be considered for:
    • wounds that directly involve joints or other bony structures


When to hospitalize for bite wounds

  • Systemic signs of infection (fever or chills) requiring IV abx
  • Severe or rapidly spreading cellulitis or cellulitis encompassing >1 joint
  • Immunocompromised patient
  • Wounds requiring surgery


Parent and child education: avoiding dog bites

  • An older dog should not be introduced into a household w/ children because of unpredictable behavior
  • Remain calm when threatened by a dog. Direct eye contact should be avoided, stand still (“like a tree”) with feet together, fists folded under the neck, arms against chest.
  • If knocked to the ground by a dog, lay face down, still, with legs together and fists behind neck w/forearms covering ears
  • Never leave baby or child alone with dog
  • Wait to get a dog until your children are > 4 yo
  • Socialize & train your dog as a puppy
  • Keep your dog healthy & vaccinated
  • Teach children to be careful around pets
  • Teach children not to approach strange dogs and to ask permission before petting
  • If a bite does occur, seek immediate medical attention
  • Report the dog bite to local authorities according to state law
  • Inform parents of possible behavioral changes to look for in themselves & their child