Mambites ho pdem 2008

Mammalian Bite Wounds
NB: immunocomprimizing conditions assess types of wounds: abrasion, laceration, puncture, crush injury assess wound for direct tissue damage - skin, bone, tendon, neurovascular Xrays:
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when possibility of bony injury, FB (e.g. tooth) or infections (looking for gas in tissues) always get skull films in children with scalp bite wounds, +/- CT to r/o cranial perforation
Treatment:
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wound cleansing and copious irrigation should occur as soon as possible good irrigation pressure can be achieved with a 20cc syringe and an 18 - 20 gauge angiocath irrigate/debride puncture wounds when feasible, but avoid hydrodissection along tissue planes debridement is important in crush injuries to reduce infection and optimize repair culture wound only if signs of infection - notify lab source is bite wound give Tetanus +/- TIG when indicated – remember, most mammalian bites are tetanus prone (i.e. deep, old, crushed, contaminated, or infected) The most common complication of mammalian bites is infection.
To suture or not to suture? Prophylactic Antibiotics?
High Risk Criteria for Infection
Wound Factors
Patient Factors

Bite Wound Infection Rates
• always ask about immunocompromising conditions similar infections can result from cat scratches long slender teeth cause deep puncture wounds high because often delay in seeking treatment may also transmit Hep B, tuberculosis, or syphilis HIV transmission via bite is rare, but has been reported Microbiology
Bite wounds involve many different species of bacteria and are often polymicrobial Gram negatives and Anaerobic organisms are also common Pasteurella multocida
infections usually become clinically evident within 24 hours propensity to cause metastatic infections: septicemia, osteomyelitis, tenosynovitis, meningitis penicillin is drug of 1st choice - also sensitive to doxycycline, septra, 2nd generation cephalosporins, cipro and flouroquinolones not covered by cloxacillin, clindamycin, erythromycin, cephalexin, or aminoglycosides
Capnocytophaga canimorsus (DF-2)
part of normal flora in both dogs & cats can cause overwhelming sepsis with DIC - multisystem failure case fatality rate 25%; 80% of fatalities had predisposing conditions such as splenectomy NB: post-splenectomy patients with dog or cat bites must get prophylactic antibiotic therapy and Sensitive to: penicillin or amoxil, tetracycline, clindamycin, chloramphenicol, 2nd & 3rd gen
Eikenella corrodens
anaerobic gram-negative rod - special medium for culture covered well by penicillin, cipro, clavulin, septra not covered by erythromycin, cloxacillin, clindamycin or keflex Antibiotic Choices
For prophylaxis or treatment of established infections These recommendations are appropriate for dog, cat and human bites
1. Amoxacillin-Clavulanic acid (Clavulin)
2. 2nd generation Cephalosporin (e.g. Cefuroxime, Cefaclor, or cefoxitin iv)
3. Clindamycin AND Fluoroquinolone* or Doxycycline* or Septra
Do not use erythromycin, cloxacillin or keflex
Common animal sources:
Wild: foxes, skunks, bats, raccoons
Domesticated: cattle, cats, dogs, sheep, horses • rare in rodents (rats and squirrels), rabbits, birds, and reptiles travelers to areas where canine rabies is endemic are at significantly increased risk eg: Thailand, parts of India, Africa, Central and South America Rabies Treatment Notes
Significant exposure: bite, lick of mucous membrane or fresh wound, or other significant
exposure to saliva. Petting of an infected animal is not exposure. Consult with Public Health: now mandatory reporting in Ontario • If animal available for testing – animal observed x 14d by Public Health – if animal remains If animal not available – consult with Public Health re: risk – if any risk – administer post-exposure prophylaxis Bat exposure: new recommendations in Ontario as of August 2008 Postexposure prophylaxis (PEP) is recommended for a bat bite or scratch, or when direct contact with a bat has been observed and either of the following cannot be ruled out: • Saliva from a live bat entered an open wound or mucous membrane (PEP can be deferred if the bat is available for testing) Note: PEP is no longer recommended when a bat is found in the same room as a sleeping person, an unattended child or disabled person, due to the extremely low risk of infection. Prompt postexposure prophylaxis is indicated in cases of face, head or neck bites, corticosteroid use or other immunosuppressed state, victim bitten in high-risk area for dog or cat rabies.
Treatment - Postexposure Prophylaxis - most effective within 48 hours
Persons not previously immunized:
Passive immunization with RIG: 20 IU/kg, as much as possible infiltrated into and around the wound, remainder IM - concentration = 150 IU/cc, so often > 9 cc - NB: if there are extensive wounds, dilute the RIG in saline to make up an adequate volume for infiltration Active immunization with HDCV: 5 injections of 1 ml IM over 28 days - given on days 0, 3, 7, 14, and 28 - NB: always administer into deltoid Persons previously immunized: 2 doses of HDCV 1 ml IM (into deltoid) on days 0 and 3. RIG
Selected References
1. Morgan M. Hospital management of animal and human bites. J Hosp Inf 2005; 61:1-10. 2. DeSerres, G. et al. Bat rabies in the United States and Canada from 1950-2007: human cases with and without bat contact. Clinical Infectious Dis 2008; 46:1329-37. 3. Recommendations for Rabies Post-Exposure Prophylaxis with Respect to Bat Exposures. MOHLTC Ontario publication, 2008. Available at: http://www.health.gov.on.ca/english/providers/pub/disease/rabies.html

Source: http://files.cepdtoronto.ca/support_files/3432/0800TimRutledgeWordMamBites_HO_PDEM_2008.pdf