Its a dog eat man world out there

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Its a dog eat man world out there

• Management of Dog Bites

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Case part 1

• 57yo male with PMH of HTN, GERD, past Etoh abuse
  attacked by his neighbors Chow while walking
  down the street. Dogs last rabies vaccination
  3/01 dog taken into custody.
• Seen is the ED wounds irrigated, rabies immune
  globulin and rabies vaccine 1 administered, and
  1 gm of IV Ancef given
  
• Given a Rx for Augmentin 875 mg po tid x 7 days,
  and discharged to home, with instructions on
  completing his postexposure rabies prophylaxis

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Epidemiology

• Dog/cat bites comprise 1 of all ED visits per
  year combined
  
• 1 in every 775 persons seek emergency care for
  dog bites per year
  
• 1 dog bite fatality 16,000 ED visits for dog
  bites
  
• 1 dog bite fatality 670 dog bite hospitalizations

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• Men women
• Children adults
• Highest risk group boys, ages 5-9
• Upper extremities lower extremities, trunk

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• Some breeds are bigger offenders than others
• German Shepherd, Pit Bull, mixed breed
• German shepherd mixed breeds bite most often
• Pit Bull breed is 1 in dog bite fatalities,
  usually secondary to exsanguination, due to
  severity and sheer number of bites
  

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Microbiology of dog bite wounds

• Normal canine mouth flora is complex
• S. aureus, streptococci, gram negative bacteria,
  anaerobes
  
• Pasturella species are the most common isolates
  from wound cultures
  
• P. canis is most common in dog bite cultures
• P. multocida found in 20-50 of dog bite cultures

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History

• Review the circumstances of the bite
• Was the bite provoked or unprovoked?
• Is the dog available for observation?
• Is the dogs vaccination status known?
• Did the bite occur domestically or abroad?
• When did the bite occur?
• Who is the owner?
• Does the patient have RA, DJD, or prosthetic
  joints?
  
• Is the patient immunocomprised by chronic steriod
  use, HIV or chemotherapy?
  
• Cirrhotic? Alcoholic?
• What is the patients tetanus vaccination
  status?
  

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Physical

• Number location of bites
• Hand, joint or bone involvement?
• Puncture vs. laceration vs. tear
• Signs of infection
• Pain and swelling are most common
• Purulent drainage (40)
• Lymphangitis (20)
• Regional adenopathy (10)

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Management of Uninfected Wounds

• Thorough washing with povidone-iodine soap
• Wound cultures generally not helpful
• Puncture wounds and small tears require swab
  cultures after irrigation
  
• Wound closure is controversial
• Puncture wounds and injuries to the hand should
  not be closed primarily
  
• Crush injuries, extensive debridement required
• delayed primary closure

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Prophylactic measures

• Antibiotic prophylaxis
• Tetanus immunization
• Rabies prophylaxis

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Antibiotic prophylaxis

• Controversial topic
• High risk scenarios in which antibiotic
  prophylaxis in universally recommended
  
• hand bites
• deep puncture wounds
• bite in a limb with existing lymphatic/venous
  insufficiency
  
• wounds that need surgical debridement
• wounds in older /or immunocomprised patients
• bites in or near a prosthetic joint

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• Cummings, P. Antibiotics to prevent infection in
  patients with dog bite wounds. Annals of
  Emergency Medicine. 1994.
  
• Meta-analysis of 8 randomized controlled trials
• Major outcome was wound infection
• Found a relative risk in the treated groups of
  0.56
  
• Found a Number Needed To Treat of 14

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• 1st anitbiotic dose should be administered IV
  ASAP
  
• 1st choice Unasyn, Timentin, Zosyn
• Clinda/Cipro if PCN allergic
• 3-5 days of oral therapy to follow
• 1st choice Augmentin
• Clinda/Cipro if PCN allergic

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Tetanus immunization

• There have been no studies examining the risk of
  tetanus infection after a dog bite
  
• Nevertheless, dog bites are considered tetanus
  prone wounds
  
• Td booster should be given if the patient has not
  had a booster immunization within 5 years and has
  completed the primary immunization
  
• If tetanus status is unknown or primary
  immunization was not completed, tetanus toxoid
  and tetanus immune globulin should be given

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Rabies

• Background
• Universally fatal
• 50,000 rabies deaths/year
• only 36 cases of rabies in the US 1980-2000
• 12 cases were exposures to dog bites abroad
• 21 cases were exposures to bats
• Postexposure prophylaxis (PEP) costs 1500 per
  person for the HRIG and vaccines alone
  
• 40,000 people in the US receive PEP/year

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• Moran et al., Appropriateness of rabies
  postexposure prophylaxis treatment for animal
  exposures. Emergency ID Net Study Group. JAMA,
  2000.
• Prospective study of university-affiliated, urban
  EDs
  
• Found that PEP was given inappropriately in
  approximately 40 of cases

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Rabies prophylaxis

• Animal control must be notified of ALL bites
• A healthy dog should be observed for 10 days
• if dog becomes ill, veterinary evaluation is
  required
  
• should the dog be euthanized for rabies testing?
• An ill dog should be euthanized for testing
• If the dog is not available for observation, it
  should be considered rabid

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• Administration of Rabies prophylaxis
• Day 0
• 20 IU/kg of human rabies immune globulin
• infiltrated directly in and around the wound
• that which cannot be directly infiltrated should
  be given IM with a clean syringe
  
• Dose 1 of 5 rabies vaccines
• given IM in the deltoid muscle
• Days 3, 7, 14, 28
• doses 2-5 rabies vaccines IM in the deltoid muscle

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• Check titers in immunocompromised patients
• check 2-4 weeks after the completion of the PEP
• should failure to respond occur, contact the CDC
• Safe in pregnancy
• Antimalarial agents decrease Ab response to the
  vaccine
  
• If PEP was not completed or non-standard
  biologics used
  
• Check an Ab titer
• Readminister PEP if titer inadequate

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Case - part 2

• Patient returns to ED on Days 2 and 3
• gets wounds checked, dressings changed, and
  rabies vaccine 2/5
  
• Lost to follow-up until 6/17/02
• presents to ED with fever, chills and obvious
  infection of the puncture wound on the dorsum of
  his L foot
  
• Patient reports not taking his Augmentin

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Management of Infected Wounds

• Wound and drainage cultures
• Photos for law enforcement
• Copious irrigation
• Xray to evaluate for underlying bone
  fragmentation or foreign material
  
• Consultation with a surgeon for possible ID

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Antibiotics for infected wounds

• 1st choice
• Parenteral - Unasyn, Timentin, Zosyn
• Oral Augmentin
• Patients with non-life threatening PCN allergy
• Cefuroxime
• Patients with life threatening PCN allergy
• Clindamycin and Cipro

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• Infection that develops within 24-48 hrs of bite,
  strongly suggests P. multocida
  
• ABx choice must include coverage for this
  bacterium
  
• Treatment length is 10 days
• longer if there is septic arthritis or
  osteomyelitis
  
• Close follow-up
• Daily office visits until infection clearing

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When to hospitalize

• No firm recommendations, but situations that lean
  towards inpatient treatment are
  
• signs/symptoms of sepsis
• rapidly developing/advancing cellulitis
• heavy suspicion of vascular, neurologic,
  musculoskeletal involvement
  
• failure of oral therapy
• questions about patient competence /or compliance

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Case - part 3

• Patient admitted to Orthopedic Surgery for ID
  and IV Unasyn
  
• Tetanus booster not documented in database, so Td
  booster given during admission
  
• Rabies vaccine 3/5 administered in ED on DOA
• Received 4 days of IV Unasyn
• discharged with Rx for 7 days of Augmentin
• Rabies vaccines 4 5 scheduled to be given in ED
  on 6/24 and 7/7/02
  
• Patient did not show up for vaccine on 6/24/02