Morning Report: 8/1/2013

Today’s Morning Report is presented by Dr. Bradby!

Human Bite Wounds

Overview

– 10-15% of human bite wounds become infected

– Most injuries occur in the hands

– Saliva contains as many as 100 million organisms per mL and up to 190 different species!

– HIV is unlikely to be transmitted through these bites

– Goals of therapy: minimize possible soft tissue deformity and prevent/treat infection

Pathophysiology

– 2 types: clenched fist injuries (closed fist strikes teeth of another individual) and occlusive bites (bite with sufficient force to violate the integrity of the skin)

– Commonly isolated bacteria: Eikenella corrodens, Staph, Strep, Corynebacterium

Staph aureus is isolated in up to 30% of infected human bite wounds w/ the highest complication rates
E. corrodens – slow growing gram negative bacillus – assoc with chronic infection and abscess formation
Commonly isolated anaerobes: Bacteriodes and Peptostreptococcus

– Must consider the potential for transmission of systemic infections – ex: Hep B – the antigen is detectable in the saliva of 75% of infected patients.

History/Physical

– Things you must ask:

Tetanus Immunization status
Time delay from injury to presentation
Underlying disease (diabetes, immunosuppressive disorders)
Mechanism of injury
Signs of infection: Pain, Fever, Erythema, Swelling, Discharge/Odor

– Document injuries well – assault cases might go to court

– Wound Characteristics: location, size, shape, type (puncture, laceration, avulsion, crush), depth of penetration, drainage, foreign body, loss of tissue, tenderness, involvement of other structures, NV status, lymphadenopathy

Treatment

– Tetanus

– Irrigate! Irrigate! Irrigate!

– Consider x-rays (fight bites, possible boxer’s fractures, etc)

– Closure: do not close hand wounds/puncture wounds/infected wounds more than 12 hours old (heal by secondary intention); head/neck wounds may be closed if less than 12 hours old for cosmesis.

All of these patients must get abx prophylaxis
Avoid layered closure
Goal: provide wound edge approximation, but still allow for drainage

– Consider consults as needed – ex. OMFS/ENT if wounds are to the face/ear

– Antibiotics for 3-5 days:

Augmentin or Unasyn
- Keflex does NOT cover Eikenella
Bactrim or a Quinolone (ex. Levofloxacin or Moxifloxacin) + Clindamycin – for the PCN allergic

– Consider: Hep B vaccine + HBIG, HIV prophylaxis, though they are low risk for transmission.

– Admission should be considered for those who are already showing signs of infection from the bite at presentation.

References:

Baddour, LM. Soft Tissue Infections in Human Bites. In: Uptodate, Baron, E (Ed), UpToDate, Waltham, MA, 2013.
Barrett, J. (2012, September 20). Human Bites. Emedicine. Retrieved July 15, 2013, from http://emedicine.medscape.com/article/218901-overview.