Assessing and Managing Mammal Bites Animal Bites Can Carry a Serious Risk of Broken Bones, Neurovascular Damage, Infection, and Psychological Harm

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URGENT CARE Special Section Assessing and Managing Mammal Bites Animal bites can carry a serious risk of broken bones, neurovascular damage, infection, and psychological harm. Here’s how to size up the situation. Urgent Care Section

umans interact with including wound care, infection other mammals ev- prophylaxis, and follow-up. H ery day: pets, farm livestock, service animals, zoo CASE #1: DOG BITE and laboratory animals, and A 5-year-old boy is bitten by a wild animals, both indigenous large neighborhood dog. The and nonindigenous. Add to that child’s parents, who witnessed Lisa D. Mills, MD Associate Professor the growing prevalence of non- the event, report that the dog Section of Emergency Medicine traditional companion animals held the boy’s arm and shook it Director, Emergency Ultrasound (NCAs), such as prairie dogs, violently. The dog is known to John Lilley, MD monkeys, and lemurs, and the have an up-to-date vaccination Resident Physician lifetime risk of being bitten by a profile. The child is tearful and Section of Emergency Medicine mammal rises to 50%. appears to be in pain. On exami- This article explores pertinent nation, you note that the forearm Louisiana State University Health Sciences Center aspects of managing mammal is bruised but the skin is intact,

New Orleans, Louisiana bites in the urgent care setting, and there is reduced mobility in left) Inc (lower Researchers, © 2009 Photo right) © 2009 Phototake (upper left, www.emedmag.com JANUARY 2009 | EMERGENCY MEDICINE 35 Urgent Care Section 36

cursory evaluation. bites arenotapparenton Many aspectsofmammal >> MAMMAL BITES

EMERGENCY MEDICINE FAST posed tolacerationsortears. are moreoftendeeppuncture woundsasop- perficial abrasions.Feline and largerodentbites patient. Forinstance,animalswithlarge,strong the bite,speciesofanimal,andsize and severityofinjurydependonthelocation tures, hemorrhage,andcontusions.Thetype tures, crushinjuries,tears,rips,avulsions,frac- because mostanimalbitesareunreported. but thatfigureunderestimatesthetrueincidence is estimatedtobearound2millioneachyear, actual numberofbitewoundsfromallmammals Centers forDiseaseControlandPrevention.The ries fromdogbitesalonewerereportedtothe year frommammalbites.In2006,310,710inju- or theircomplications.Ten to20peopledieeach care visitseachyearareformammalbiteinjuries About 1%ofemergencydepartmentandurgent COMMON BUTOFTENUNREPORTED any furtherevaluationortreatmentindicated? larly intact.Themanrequestsatetanusshot.Is without activebleeding.Thearmisneurovascu- ately vaccinated.Thewoundisasmallpuncture the forearmfromhisowncat.Thecatisappropri- A 45-year-old manpresentswithabitewoundon CASE #3:CAT BITE ment indicated? an associatedsuperficialabrasion.Isanytreat- exam, younoteabruisedareaonthechestwith patient recentlyhadatetanusimmunization.On monkey bitheronthechestearliertoday. The A 23-year-old womanreportsthatherpetgreen CASE #2:MONKEYBITE provide? further evaluation?Whatreferralsshouldyou zations areuptodate.Doesthischildneedany child hasnomedicalproblemsandhisimmuni- the shoulder. Therestoftheexamisnormal. The mostcommon biteinjuriesare from Animal biteinjuriesincludelacerations,punc-

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JANUARY 2009 puncture wounds,andsu- equally amonglacerations, injuries aredividedabout tearing wounds.Dogbite inflict crush,avulsion,and jaws, especiallylargedogs, of abitecan fracture delicatebonesof the hand, pressures inexcessof450 psi.Thedirectforce even fracturebone.Large dogs canproducebite and crushinjuries. jured inavulsions,large lacerations, punctures, structures andtendonscanbeexposedin- all explorationandmanagement.Neurovascular tion distaltowoundsshouldprecedeandfollow assessment ofpulses,motorfunction,andsensa- along theirfullrangeofmotion.Aneurovascular tendons, bones,andjoints.Examinetendons contaminants andforeignbodies,suchasteeth. volvement. Flapsandavulsionsmayhidewound wounds canhaveextensivesubcutaneousin- cursory evaluation.Tears, punctures,andcrush aspects ofmammalbitesarenotapparenton to identifyadditionalinjuries. been mauledbyananimal,checktheentirebody particular, ifthepatientisayoungchildorhas so checkareasadjacenttothebiteaswell.In may distractthepatientfromadditionalinjuries, in mindthatthemostpainfulorobviousinjury or captured. the animalincludeswhetheritcanbeobserved its behavior. Otherimportantinformationabout ing vaccinationstatusandcurrenthealth), kind ofanimalinvolved,itshealthhistory(includ- includes askingaboutthetimingofinjury, the become infected.Athoroughhistoryoftheevent repair ofthewoundorbecausehas Patients usuallyseekmedicalcareafterbitesfor HISTORY ANDPHYSICALEXAMTIPS extremities. Adults morecommonlypresentwithbitestothe sent withbitewoundstotheface,neck,andhead. often thangirls.Childrenmostcommonlypre- children youngerthan10yearsold—boysmore significant morbidityandmortality. cause, withoutpropercare,thesebitescancause However, theywillbediscussedinthisarticlebe- mammals makeupaminorityofreportedbites. mals thatarenothouseholdpetsorfromNCA dogs, followedbycats.Bitewoundsfrommam- Bites fromlargemammals candamageand Be alertforinjuriestothevasculature,nerves, Examine thewounditselfmeticulously. Many Thoroughly examinepatientswithbites.Bear More thantwo-thirdsofbiteinjuriesoccurin www.emedmag.com Urgent Care Section 37

<< MAMMAL BITES MAMMAL MAMMAL BITES MAMMAL TRACK

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Maintain a low threshold for injecting joints. Missed open joints can lead to significant morbidity. >> JANUARY 2009 2009 JANUARY wounds with extensive devitalized tissue wounds with extensive crush injuries hand wounds puncture wounds wounds heavily contaminated from injury to treatment: prolonged time 6–12 hours on the body the face 12–24 hours on Animal Bites With a High Risk Bites With a Animal for Infection • • • • • • Some bite wounds have a higher risk of infectionSome bite wounds have a higher risk determin- Location plays a significant role in Older wounds are also early suture removal. Inform patients that wound early suture removal. Inform patients appropriate infections may occur in spite of the to look for care. Advise all patients at discharge increasing signs of infection, such as redness, pain, and purulent drainage. whether(see box). Puncture wounds, for instance, more oftenclosed or left open, become infected that extend more than other wounds. (Wounds puncturedeeply than their length are considered entry wound.)wounds, regardless of the size of the also properly, Crush wounds, even when debrided have an increased risk of infection. The over- ing the management of bite wounds. all infection rate of head and neck wounds that are primarily closed is low (1.4% to 6%). Despite the risk of infection, primary closure may be necessary because most wounds to the face are in cosmetically sensitive areas. Bite wounds to the hands have a higher potential for infection and significant morbidity as a result of infection. Although hand wounds are still commonly closed, consider leaving high-risk wounds open. at higher risk for infection. As a guideline, a wound 6 to 12 hours from the time of injury is considered old on the body. Face wounds 12 to 24 hours after the incident are Bites are tetanus-prone wounds. Patients who The practice pattern is to close the majority Large mammals who bite and shake can dis- Large mammals who retained Use plain radiography to assess for

have not had tetanus immunization within the last five years should receive appropriate tetanus prophylaxis. For patients without the primary se- ries of tetanus immunizations, refer to the CDC guidelines. When deciding to close the of wounds primarily. wound, assess its location and size, degree of contamination, functional impairment, cosmetic Uncomplicated outcome, and time from injury. wounds greater than 1.5 cm in cosmetically sensitive areas can be primarily closed with minimal percent- expected that a small risk of infection. It’s age of wounds will become infected and require REDUCING THE RISK OF INFECTION to mam- Standard principles of wound care apply indicated and mal bites. (Routine cultures are not irri- are poor predictors of infection.) Copiously incidence of gate all bites; irrigation reduces the the wound viral and bacterial infections. Debride not function generously: Devitalized tissue does as a “biological dressing.” It acts as a nidus for infection and should not be retained. foot, and face. The crushing aspect of a large aspect of a face. The crushing foot, and bones. A detailed can fracture long animal bite to discover subtle is needed physical examination should be viewed af- fractures. Plain radiographs ter the exam. patients perform active range- locate joints. Have that are near bite wounds. of-motion with joints for disruption of the capsule Evaluate the joint injection with methylene blue (open joint). Joint nonoperative assessment is the most effective capsule disruption. Maintain technique for subtle injecting joints. Missed open a low threshold for joints can lead to significant morbidity. Computed to- foreign bodies and skeletal injuries. imaging have mography and magnetic resonance and subtle increased sensitivity for foreign bodies and nega- fractures. In cases of high suspicion techniques. tive plain films, use these imaging careful exami- Identifying foreign bodies requires field. Plain nation with ample light in a bloodless but do not films of the affected area complement, replace, exploration for foreign bodies. www.emedmag.com Urgent Care Section 38

MAMMAL BITES

Cercopithecinaeherpesvirus 1(B Eikenellacorrodens Enterobacteriaceae (non-human) primates ferret hamster Leptospira Escherichia rat Francisella Propionibacterium interrogans Bacteroides coli Pasteurella tularensis Pasteurella Staphylococcus cat Capnocytophaga septica Capnocytophaga multocida Rhabdoviridae Leptospira Porphyromonas epidermidis cynodegmi canimorsus Pasteurella (rabies) Pasteurella interrogans Staphylococcus dog Animal Bacteria canis multocida Infectious BacteriafromAnimalBites epidermidis EMERGENCY MEDICINE Enterococcus

virus) (frommacaques) Neisseria Staphylococcus Streptococcus Staphylococcus aureus Francisella tularensis Streptobacillus moniliformis Porphyromonas Fusobacterium Prevotella ␤ ␣ Staphylococcus aureus Fusobacterium Bacteroides Prevotella ␤ ␣ Staphylococcus aureus

| -hemolytic streptococci -hemolytic streptococci -hemolytic streptococci -hemolytic streptococci

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keep inmind. slower toappear. Staphyloccal andstreptococcalinfectionsare 24 hoursofthebiteandprogressrapidly. infections areusuallyclinicallyapparentwithin is knownforarapidonsetandspread.These polymicrobial (seetable wound infectionsfrommammalianbitesare by themouthofanimal.Themajority sion ofnativeskinfloraandbacteriaintroduced Infections ofbitewoundscomefrombothinva- species posesitsownuniqueinfectiousrisk. eralized toallbitewounds,eachmammalian Although principlesofwoundcarecanbegen- TAILORING THETREATMENT ject toobjectivescientificevaluation. for infection,butthispracticehasnotbeensub- that leavesgapswhentreatingwoundsatrisk “loose approximation”orsuturinginamanner factor indecidingwhethertoclosethewound. absolute, andshouldbeconsideredasonlyone considered old.Thesetimesarearbitrary, not is amoxicillin/clavulanic acid875mg orally and erythromycin.The first-line antibiotic tant toclindamycin,dicloxicillin, cephalexin, cat bites;unfortunately, fective for Antibiotic post-exposureprophylaxis thatisef- cida bites dobecomeinfected. clearly established. table onpage39).Durationoftherapyisnot mg/kg orallythreetimesdailyforchildren(see mg orallytwicedailyforadultsand10to15 line antibioticisamoxicillin/clavulanicacid875 dog bitesinvolve is usuallypolymicrobial.About50%ofinfected significant bitesareatriskforinfection,which bites arenipsratherthanatruebite.However, lead toinfection,largelybecausemostdog States islow. Similarly, fewdogbitesactually tual incidenceamongthesedogsintheUnited but whiledomesticdogsdocarryrabies,theac- Dog bites. Here aresomespecificconsiderationsto Pasteurella Some practitioners apply the concept of Some practitionersapplytheconceptof Cat bites. ispresentin70%to90%oftheinfections. P. multocida In contrasttodogbites,mostcat A big fear with dog bites is rabies, A bigfearwithdogbitesisrabies, , common in dog and cat bites, , commonindogandcatbites, Pasteurella canis isrecommendedforall ). P. multocida

Pasteurella multo- www.emedmag.com . Thefirst- isresis- Urgent Care Section 39 <<

MAMMAL BITES MAMMAL TRACK

daily for daily for and can trans- FAST EMERGENCY MEDICINE

>> In contrast to dog bites, most cat bites do become infected.

Rodents, rabbits, and times daily for 14 days PO b.i.d. JANUARY 2009 2009 JANUARY Francisella tularemia , which causes Streptobacillus Primates in the United States rarely carry Rodent and rabbit bites. Domestic and wild rats prophylaxis is indicated based on the extent and lo- prophylaxis is indicated based on the principles ofcation of the wound. This follows the wound care. post-exposure antibiotics for general rabies. Most cases of rabies in primates in this country are found in animals recently imported from areas where rabies is endemic. hares carry mit this to humans through bites. The CDC does not recommend routine prophylaxis for tularemia from the bite of a rodent. in the United States carry and transmit moniliformis The CDC rec- rat bite fever. ommends post-bite prophylaxis after wild or domestic rat bites.The first-line antibiotic is amoxicillin/clavulanic acid 875 mg orally twice

A subgroup of primates called *acyclovir and valacyclovir considered equivalent TMP-SMZ = trimethoprim-sulfamethoxazole

Alternative adult 300 mg PO clindamycin cefuroxime 500 mg t.i.d. + fluoroquinolone acyclovir* PO b.i.d. doxycycline 800 mg PO 5 100 mg adult acid amoxicillin/clavulanic child acid amoxicillin/clavulanic valacyclovir mg PO b.i.d. 875 amoxicillin/ amoxicillin/clavulanic acid amoxicillin/clavulanic acid no pediatric b.i.d. 10–15 mg/kg PO t.i.d. amoxicillin/ 875 mg PO b.i.d. 10–15 PO 10–15 mg/kg PO t.i.d. PO 1 gm PO t.i.d. clavulanic dose acid mg/kg t.i.d. clavulanic for 14 days acid 875 mg Infection Prophylaxis for Mammal Bites for Mammal Prophylaxis Infection First line Dog bite Cat bite b.i.d. child Macaque bite Rat bite clindamycin 8–25 mg/ PO b.i.d. kg/day PO divided mg/kg/day cefuroxime 50 5 ml or t.i.d. + TMP-SMZ acyclovir* 20 suspension/10kg/day cefuroxime PO divided b.i.d. 20 ml PO b.i.d. up to mg/kg PO 5 50 mg/kg/ doxycycline 100 mg times daily day PO divided b.i.d. Cats have the highest incidence of rabies of all Primate bites. Primate bite wounds do not have unique bac-

domestic animals in the United States. However, domestic animals in the United States. However, transfer to humans remains rare. twice daily in adults, 10 to 15 mg/kg orally three twice daily in adults, 10 to 15 mg/kg therapy is not times daily for children. Duration of clearly established. the macaques (rhesus and green monkeys) carry B virus (Cercopithecine herpesvirus 1), usually by the age of 2. Though asymptomatic in the macaques, B virus causes fatal encephalitis in humans; 24 of the 25 humans known to be infected have died. The incidence of transmission is unknown, but it has been documented to occur from even trivial post-bite pro- wounds. Due to the high mortality, phylaxis is recommended for any macaque bite. First-line therapy is valacyclovir 1 gram orally ev- ery 8 hours for 14 days. terial infectious concerns. Post-exposure bacterial www.emedmag.com Urgent Care Section

MAMMAL BITES can havepsychological sequelae, advise the par- identified. Inaddition, becausea violentattack Refer thepatient toanorthopedistif injuryis shoulder, andsofttissue injuryoftheshoulder. for bonyinjury totheforearm,dislocation ofthe erful shakingactionofthe dog. Inparticular, look ated foranorthopedicinjury inflictedbythepow- be asfollows: presented atthebeginningthisarticlewould Appropriate managementofthethreepatients CASE CONCLUSIONS fects fromtheevent. indicated forpatientswhoreportpersistentef- visits. Referraltoamentalhealthprofessionalis about psychologicalsequelaeduringsubsequent Patients’ primarycarephysiciansshouldinquire development, andpooracademicperformance. lead toaggressivebehavior, impairedlanguage experiences inchildren,suchasdogbites,can cal complicationsmaystillbeathreat.Traumatic port wasnotprovidedforanyofthesepatients. met partialcriteria.However, psychologicalsup- by dogsmetthefullcriteriaforPTSDand32% In onestudy, 23%ofchildrenwho hadbeenbitten disorder (PTSD)afteradogbiteisnotuncommon. have alastingimpact.Infact,post-traumaticstress quelae butanaggressiveattackormaulingcan with ananimalmaynotcreatepsychologicalse- pect ofanimalbites.Anaccidentinroughplay Practitioners oftenneglectthepsychologicalas- PSYCHOLOGICAL SUPPORT for smallrodentstocarryrabies. established. for children.Durationoftherapyisnotclearly adults and10to15mg/kgorallythreetimesdaily Case #1:Dogbite. As thewounditselfheals,long-termnonphysi- Despite thecommondistrustofrats,it’s rare This childshouldbeevalu- emergency departments. Weiss HB,etal.: Incidence ofdog biteinjuries treated in laxis? Turner TW: Do mammalianbitesrequireantibiotic prophy- cat bites. Talan DA,etal.: Bacteriologicanalysisofinfecteddogand reduce thechanceofinfectionfromBvirus. to saliva.Copiouslyirrigatethewound,whichwill through eventrivialwoundsandocularexposure anti-viral agent.Transmission ofvirusBoccurs her chest,needsprophylaxisforBviruswithan monkey inflictedasmall,superficialabrasionto health professionalisneeded. sician atfollow-up,incasereferraltoamental ents todiscussthiswiththeirprimarycarephy- bites inchildren. Peters V, etal.:Posttraumatic stressdisorderafterdog 25(1):159, 2007. als inwoundmanagement. Nakamura YandDayaM:Useofappropriateantimicrobi- CD001738, 2001. mammalian bites. Medeiros IandSaconatoH:Antibioticprophylaxisfor tice. Johnson-Delaney CA:Safetyissuesintheexoticpetprac- Clin InfectDis Goldstein EJ,etal.:Simianbitesandbacterialinfection. 2007 Gilbert DN,etal.: 2002. copithecine herpesvirus1). for preventionofandtherapyexposuretoBvirus(cer- Cohen JI,etal.;BVirus Working Group:Recommendations mal bitewoundinfections. Brook I:Microbiologyandmanagementofhumanani- SUGGESTED READING rigated andantibioticprophylaxisprescribed. this patient.Thewoundshouldbecopiouslyir- ate foraretainedtoothwouldbeappropriate Case #3:Catbite. Case #2:Monkeybite. Vet Clin NorthAmExotAnimPract . 37thed,AntimicrobialTherapy, Inc,2007. Ann EmergMed N EnglJMed 20(6):1551,1995. J Pediatr Sanford GuidetoAntimicrobialTherapy Cochrane DatabaseSystRev 44(3):274,2004. 340(2):85,1999. A plainradiographtoevalu- JAMA 144(1):121, 2004. Prim Care Clin InfectDis Emerg MedClinNorthAm 279(1):51, 1998. This patient,whose 30(1):25,2003.

8(3):515, 2005.

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