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Clinical Summary

Bite wounds (abrasions, lacerations, and punctures) are a frequent emergency care challenge, although most are minor. Dog bites account for the majority, followed by cats, humans, and, rarely, other animals (eg, raccoons, foxes, livestock, zoo animals).

Bite wounds are frequently contaminated with mixed aerobic and anaerobic bacteria. Pasteurella multocida (a gram-negative anaerobe) has been cultured from up to 80% of cat bites and 25% of dog bites. Eikenella corrodens has been recovered from human bites. Capnocytophaga canimorsus (formerly known as DF-2), a virulent organism that can be normal oral flora in dogs (16%) and cats (18%), can lead to sepsis, disseminated intravascular coagulation, gangrene, or death in susceptible individuals (eg, immunocompromised, asplenic, or diabetic). The hand is at highest risk for developing infection, while the face is the most infection resistant. Puncture wounds, especially from cats, are also prone to infection. Simple abrasions, regardless of animal, are unlikely to become infected with proper wound care.

FIGURE 18.24

Dog Bite. Extensive facial wounds secondary to a dog bite. (Photo contributor: David Effron, MD.)

Management and Disposition

All wounds should be thoroughly cleaned and debrided. Radiographs should be obtained to exclude bony injury or retained dentition. Contusions and superficial abrasions can be treated with local wound care.

FIGURE 18.25

Dog Bite. This patient sustained multiple avulsion injuries to her hand and forearm from a pit bull attack. (Photo contributor: Selim Suner, MD, MS.)

Recommendations vary regarding timing of wound closure. Closure of facial and head wounds can be performed up to 12 hours (and in some reports up to 24 hours). Puncture wounds (especially if caused by a cat), hand lacerations, or high-risk wounds (wounds > 12 hours or clinically infected) should be considered for delayed primary closure. While a linear incision over a puncture wound may facilitate cleaning and exploration, efficacy of this is questioned. Human bites to areas other than the face and head should generally be left open and considered for delayed primary closure. Hand injuries caused by human bites are left open and managed in consultation with a hand specialist (see Chapter 11). One should maintain a high index of suspicion for human bite in any laceration near the metacarpals.

All sutured bite wounds should be reevaluated by a healthcare provider within 24 hours. Closed wounds that appear infected on reevaluation should be opened, irrigated, and allowed to close by secondary intention. Cyanoacrylate adhesives should never be used to close a bite wound.

Antibiotic recommendations for bite wounds differ widely. Antibiotics are not recommended for minor wounds. They are recommended for cat bites, hand wounds, and in persons with chronic diseases (eg, diabetes). Empiric therapy is started with broad-spectrum ampicillin-sulbactam, ...

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