Leukocytosis and coagulopathy can also develop EKG changes if present are usually consistent with myocardial infarction Acute kidney injury has also been reported No antivenom is commercially available, and treatment is mainly symptomatic with analgesia, plasma expanders, and epinephrine or other pressors MAMMALIAN BITES Goals of Treatment Treatment aims to decrease the overall morbidity of mammalian bites in terms of infectious complications, cosmesis, disability, psychological trauma, and medical expenses CLINICAL PEARLS AND PITFALLS Cat and human bites have a high infectious complication rate Wound closure can be delayed when there is a high risk of infection Local wound care is more important than prophylactic antibiotics in prevention of infection Current Evidence At least to million people in the United States are bitten each year, and about 1% of ED visits are prompted by bite wounds Dog bites account for the overwhelming majority (80% to 90%) of mammalian bites An estimated 4.5 million dog bites occur in the United States annually, with approximately 885,000 people seeking medical care The most common dog attacks involve 5- to 14year-old boys close to home, large-breed or mixed-breed canines, and head, neck, and upper extremity injuries The dog’s owner can be identified 85% to 90% of the time; in fact, in 15% to 30% of cases, the dog belongs to the victim’s family Usually, the dog has been provoked, although most often unintentionally Animal jealousy has been implicated in unprovoked biting of infants and accounts for about 10 fatal cases each year in the United States Other mammalian bites are perpetrated by cats (3% to 15%), rodents (2% to 3%), humans (2% to 3%), and other wild or domesticated animals such as ferrets Human and cat bites both have high infectious complication rates Clinical Considerations Anatomic wound characteristics and the microbiologic inoculum of the offending species determine the pathologic consequences of the bite Many dog bites cause crush injuries with infection-prone devitalized tissue, a result of the enormous pressures (200 to 400 lb/square inch) dogs can generate in their bites However, only 5% to 10% of dog bites become infected, probably because the resulting lacerations and abrasions are so accessible to good wound hygiene The risk of infection is directly related to the location of the bite, with highest risk in bites of the hands and feet The feline bite is a deep puncture wound that is difficult to irrigate or cleanse, hence its high infection rate (up to 50% in some series) The penetration of tendons, vessels, facial compartments, and bones also increases the risk of infection The hand offers all these anatomic components in a relatively small cross-sectional area, hence its increased risk of infection, regardless of the biting species Aerobic and anaerobic bacteria indigenous to mammalian oral flora are inoculated into the wound during biting The most commonly isolated bacteria in infected cat and dog bite wounds are Staphylococcus aureus and Pasteurella species, a gram-negative rod In one series, Pasteurella multocida and Pasteurella canis were found in 50% and 80% of infected dog and cat wounds, respectively Other more common bacteria have also been isolated: streptococci, coagulasenegative staphylococci, S aureus, and enteric bacteria Anaerobic bacteria are usually recovered only in mixed cultures with aerobes Human bite infections are mixed bacterial infections, with Streptococcus viridans or S aureus being the predominant organism Anaerobic bacteria, especially Bacteroides and Peptostreptococcus species, are commonly cultured More serious morbidity in infected human bite wounds of the hand has been associated with S aureus and Eikenella corrodens, a facultative anaerobe Finally, the multiple systemic diseases that may be transmitted by mammalian bites need to be considered Clinical Assessment Mammalian bite wounds cause a spectrum of tissue injuries from trivial to lifethreatening Scratches, abrasions, contusions, punctures, lacerations, and their complications are commonly seen in the ED The complications usually involve secondary infections that can be severe and lead to sepsis, meningitis, endocarditis, and peritonitis, or damage to structures that underlie the bite Dog bites are insignificant lesions in at least half of the cases that come to medical attention, 5% to 10% warrant suturing, and 2% require hospital admission Other than bites on the hand, the rate of secondary infection in dog bites given good local care approximates that of nonbite wounds Young children suffer more serious canine injuries, especially in the head and neck region On rare occasions, life-threatening injuries occur, including depressed skull fractures, intracranial lesions, major vascular injury, visceral penetration, and chest trauma Death is usually secondary to acute hemorrhagic shock Although cat bites are usually less destructive, due to their sharp teeth that cause deeper inoculation of bacteria, cat bites are more frequently complicated by infections, which occur in as many as 30% to 50% of cases P multocida infections characteristically present within 12 to 24 hours of the injury and display rapid progression of erythema, significant swelling, and intense pain Local infections from other organisms usually present 24 to 72 hours after the bite in a less fulminant manner Viridans streptococcal infections are occasional exceptions to this generalization and may resemble a P multocida clinical course Cat scratches also commonly occur in the periorbital region and may involve corneal abrasions Cat-scratch disease, an uncommon complication of these injuries, is characterized by a papule at the scratch site and a subsequent regional lymphadenitis The primary lesion is typically a crusted, erythematous papule, to mm in diameter, which develops to 10 days after the scratch A tender regional lymphadenopathy occurs weeks after the primary lesion Malaise and fever are associated symptoms in approximately 25% of patients Rarely, encephalopathy, exanthem, atypical pneumonia, and parotid swelling may occur The disease is self-limiting, with resolution of the symptoms within to months Bartonella henselae is the causative organism An indirect fluorescent antibody test to Bartonella is useful in the diagnosis and is available through the Centers for Disease Control and Prevention Polymerase chain reaction assays are available in some commercial labs Human bites in older children and adolescents are most commonly incurred when a clenched fist strikes the teeth of an adversary Wounds that overlie the metacarpal–phalangeal joint may lead to bacterial penetration into the relatively avascular fascial layers Hand infections usually present with mild swelling over the dorsum of the hand to days after injury If there is pain with active or passive finger motion, a more serious deep compartmental infection or tendonitis should be suspected Osteomyelitis occasionally occurs in hand infections In younger children, human bites are more often on the face or trunk than on the hands Often, a playmate inflicts the wound, but child abuse must always be considered Systemic diseases that may be spread by human bites include hepatitis B, HIV, and syphilis Rodent bites usually occur in disadvantaged socioeconomic groups or among laboratory workers and have a relatively low incidence of secondary infection (10%) Ratbite fever is a rare disease that may present after a 1- to 3-week incubation period with chills, fever, malaise, headache, and a maculopapular or petechial rash There are two forms: Haverhill fever (Streptobacillus moniliformis ) and Sodoku (Spirillum minus ), both of which are responsive to IV penicillin Another uncommon bacterium for which lagomorphs, particularly rabbits, are hosts is Francisella tularensis Tularemia is usually spread to humans by rabbit bites, although contact with or ingestion of contaminated animals or insect vectors is sufficient for transmission Ulceroglandular tularemia is the most common form of the disease Tularemiais typically treated with gentamicin, ciprofloxacin, or doxycycline Streptomycin may be used but is no longer readily available in the United States Serious infections from multiple bacteria, including osteomyelitis, sepsis, endocarditis, and meningitis, have been reported as complications of mammalian bite wounds The risk of rabies or tetanus always must be considered in animal bites Management Meticulous and prompt local care of the bite wound is the most important factor in satisfactory healing and prevention of infection The wound should be forcefully irrigated with a minimum of 200-mL normal saline A 19-gauge needle or catheter attached to a 30-mL syringe will supply sufficient pressure for wound decontamination and will decrease the infection rate by 20-fold Stronger irrigant antiseptics—povidone-iodine, 20% hexachlorophene, alcohols, or hydrogen peroxide—may damage wound surfaces and delay healing Soaking in various preparations has not proved helpful in reducing infections Most open lacerations from mammalian bites can be sutured if local care is provided within several hours of the injury and good surgical technique is used Facial wounds often mandate primary closure for cosmetic reasons and, overall, are low infection risks because of the good vascular supply If there is a high risk of infection such as in hand bites, the emergency provider may elect to allow the wound to close by secondary intention or by delayed primary closure In large hand wounds, hemorrhage should be carefully controlled We suggest closing the subcutaneous dead space in these wounds with a minimal amount of absorbable suture material Cutaneous sutures can then be placed after to days if there is no evidence of infection Extremities with extensive wounds should be immobilized in a position of function and kept elevated as much as possible This is especially true of hand wounds, which should have bulky mitten dressings and be supported by an arm sling All significant wounds should be rechecked in follow-up within 24 to 48 hours ... because of the good vascular supply If there is a high risk of infection such as in hand bites, the emergency provider may elect to allow the wound to close by secondary intention or by delayed primary