WORKUP	Section 5 of 10
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Lab Studies:

• Routine laboratory studies: These are generally not indicated because the injured population is usually young and healthy. Diagnosis of infection is clinical.

• Wound culture: Microbiology of human bite wounds is fairly consistent, yet an untreated infected bite generally is cultured if purulence is present.

Imaging Studies:

• Radiography

• In closed-fist injuries, an underlying metacarpal head fracture is possible. This may dictate inpatient treatment.

• Infected bites of the hand of some duration may have evidence of osteomyelitis on plain radiographs.

• If history indicates that a tooth was broken during the incident, a radiograph may be indicated to examine for a foreign body.

Procedures:

• Wound care

	TREATMENT	Section 6 of 10
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Prehospital Care:

• Recovery of avulsed tissue parts (eg, ear, finger) is an important consideration for prehospital providers. Otherwise, human bite wound management generally is uncomplicated and involves temporary dressing and transport.

• Avulsed parts should be wrapped in sterile gauze dressing that is soaked with normal saline and placed in a plastic bag that is, in turn, placed in a container of ice water.

Emergency Department Care: Most infections resulting from bites are present at the first ED visit. A patient who presents early with a noninfected bite requires individual evaluation to decide on treatment. Treatments for specific injuries include the following:

• Infected closed-fist injuries: Because of the deep nature of these infections and relatively poor vascular supply to the tendons and other connective tissue, admitting patients for intravenous (IV) antibiotic therapy is best. Surgical drainage also may be necessary.

• Noninfected closed-fist injuries

  • An underlying fracture dictates inpatient treatment under certain circumstances. After appropriate anesthesia, explore wound for joint space violation or tendon injury. Involvement of the joint space indicates admission. Consider patients with tendon injuries, which usually are present, for admission. Proper wound assessment includes using a tourniquet and extending the wound as needed to improve visualization.

  • Provide outpatient treatment of these wounds (careful wound cleansing, antibiotic coverage, bulky dressing or splint, elevation) only in consultation with hand or orthopedic service. Early, mandatory follow-up care is essential.

• Chomping injuries: As with closed-fist injuries, generally admit a patient with an infected wound for IV antibiotics. Treat noninfected wounds that appear to violate the tendon apparatus in the same manner as noninfected closed-fist injuries.

• Puncture wounds

  • These most commonly are encountered about the head. Such wounds are difficult to clean adequately unless extended to allow for effective irrigation. In the absence of infection, such wounds are best left open and closed secondarily, if cosmetically necessary.

  • Use of antibiotics is debatable, as no large studies have examined this type of wound. Because of the high infection rate in these wounds, a course of outpatient antibiotics with close follow-up care usually is prescribed.

• Bites to the ear or nose

  • When associated with tissue loss, these wounds require consultation with plastic surgery or ear, nose, and throat (ENT) service. Seeking consult for a bite that violates cartilage in these areas also is prudent because of poor blood supply to cartilage and difficulties in treating chondritis.

  • No placebo-controlled studies have examined these types of wounds, but common practice includes the use of prophylactic antibiotics.

• Superficial bites: Where no significant penetration of the overlying skin is evident, human bites can be managed adequately with only local cleansing and tetanus immunization. These wounds clinically appear as a mixture of abrasions and contusions.

• Other bite wounds

  • Handle occasional deeper bite wounds to other areas similarly to other contaminated wounds. Delay suturing such wounds unless adequate cleansing is possible.

  • As with animal bites, the hand is considered a high-risk area. Other factors to consider in deciding treatment include cosmetic significance, local blood supply, time delay to treatment, and host factors.

  • Bite wounds to well-vascularized areas such as the face that can be cleansed adequately usually may be sutured primarily. When in doubt, delaying closure is best.

  • Use of antibiotics in these types of wounds does not decrease subsequent infection rates.

  • Studies examining infection rates of sutured bite wounds are limited. Chen et al reported that 1 of 12 (8.3%) human bite wounds sutured at the discretion of the treating physician became infected.

• HIV transmission has been noted only rarely after a human bite. Exposure to saliva alone is not considered a risk factor for HIV (or hepatitis) transmission. Transmission requires HIV-infected blood mixed in the saliva of the biter and a skin break on the victim. The reverse consideration also is important in that blood drawn from an HIV-infected victim would come in contact with the mucous membranes of the biter. A 2005 Centers for Disease Control and Prevention recommendation states that postexposure prophylaxis with a 28-day course of highly active antiretroviral therapy (HAART) should be used in either of these 2 scenarios.

Consultations:

• In general, consult hand and/or orthopedic service for infected human bites of the hand and those involving a fracture, joint space violation, or significant tendon injury. Consider consultation or agreed-upon protocols for other human bites to the hand.

• Consult plastic surgery or ENT service for significant injuries to the special structures about the face and for wounds involving significant tissue loss.

	MEDICATION	Section 7 of 10
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The only drug therapy of significance in human bites is antibiotic treatment. Bacterial flora include that of the mouth and skin. Theoretically, penicillin treats oral pathogens and may suffice for prophylactic treatment as Staphylococcus species probably only infect bite wounds secondarily. Unfortunately, no well-controlled studies have investigated using antibiotics to prevent infection in human bite wounds. Uncontrolled studies have involved cephalosporins and generally do not indicate a benefit of prophylactic antibiotics.

This lack of definitive literature has led to recommendations for prophylaxis based on experience with infected human bite wounds; therefore, expensive, broad-spectrum antibiotics are recommended commonly instead of penicillin.

Once a human bite is infected, beta-lactamase–producing staphylococci must be addressed. Eikenella corrodens may not be covered by first-generation cephalosporins. Additionally, Eikenella species are resistant to clindamycin, penicillinase-resistant semisynthetic penicillins, and metronidazole. A broad-spectrum antibiotic, rather than combination therapy, is the usual choice for infected bite wounds. A recent in vitro study of 50 infected human bites by Talan et al indicated that amoxicillin-clavulanic acid and moxifloxacin demonstrated excellent activity against common isolates.

	MISCELLANEOUS	Section 9 of 10
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Medical/Legal Pitfalls:

• Failure to elicit a careful history regarding the circumstances of a wound

• Failure to treat a human bite as a complicated laceration

• If either of these lead to a poor outcome, the physician can be faulted for taking an improper history. Key points are to be extremely cautious with wounds over the MCP joints, with hand wounds in general, and with small lacerations about the head and forehead in young children.

• Documentation of the mechanism reported is essential to avoid later questions regarding treatment.

• Failure to report suspected child abuse (reporting is mandatory for health care professionals in most jurisdictions)