It’s a dog eat man world out there

1. It’s a dog eat man world out there Management of Dog Bites

2. Case – part 1 • 57yo male with PMH of HTN, GERD, past Etoh abuse attacked by his neighbor’s Chow while walking down the street. Dog’s 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

3. 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

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

5. 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

6. 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

7. History • Review the circumstances of the bite • Was the bite provoked or unprovoked? • Is the dog available for observation? • Is the dog’s 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 patient’s tetanus vaccination status?

8. 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%)

9. 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

10. Prophylactic measures • Antibiotic prophylaxis • Tetanus immunization • Rabies prophylaxis

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

19. 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

20. 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

21. 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 I&D

22. 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

23. 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

24. 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

25. Case - part 3 • Patient admitted to Orthopedic Surgery for I&D 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