Mammalian Bites

Factors associated with increased risk of infection

Chronic illnesses

Cirrhosis

Renal failure

Systemic lupus erythematosus and other immune disorders

Diabetes mellitus

Raynaud’s

Medications

Corticosteroids

Methotrexate and other immunosuppressives

Alcoholism

Asplenia

Peripheral vascular disease

HIV

Conditions causing chronic edema of the bitten part

Mastectomy

Congestive heart failure with pedal edema

If you are going to give proph abx, give 3-5 days of:

Amoxicillin/clavulanate (relatively expensive withfrequent gastrointestinal side effects)

A second-generation cephalosporin with anaerobic activity (e.g., cefuroxime) (also expensive)

Penicillin plus a first-generation cephalosporin (cheap, but requires frequent dosing of two medications)

Clindamycin plus a fluoroquinolone or trimethoprimsulfamethoxazole (good options for those who are penicillin-allergic)

For human bites, you can use the above except for number 3, instead give PCN and Diclox (EM Practice)

Dog

Capnocytophaga Canimorsus (most virulent)-can result in rapid and deadly sepsis. Usually presents in 4 days but can take as long as 4 weeks to manifest. Can cause renal failure, DIC, endocarditis, and meningitis. May not have infection present at bite site.

Staph Intermedius

CDC NO-1

Pasteurella Multicoda-rapid, and virulent (patients have pain disproportional to injury and minimal lymphadenitis)

Presents early, while staph and strep present >24 hrs after bite. Pasteurella is the most common (EM Practice) followed by Staph and Strep.

Reasons dogs bite: pain response; territorial protection of home, environment, property; assertion and dominance; fear; some breeds unpredictable

Bite characteristics: combination penetrating-crushing injury; bite pressure 200 lb/in2 with average small- to medium- sized dog, up to 1800 lb/in2 in pit bull (can easily fracture adult male femur)

Canine pack behavior: social hierarchy consists of dominant male, dominant female, and subordinates; dogs protect pack, defend territory, defend food; humans part of pack

Wound care: vigorous saline irrigation (speaker does not recommend using Betadine [povidoneiodine] or hydrogen peroxide); débride necrotic tissue, consider wound closure

Facial injuries: seen mainly in 3-5 yr age group; dogs natural reaction to nuzzling within their own pack is to bite other dogs muzzle

Severe attacks: characterized by repeated biting, violent shaking of victim; difficult to end attack (must sometimes use deadly force); pack of dogs extremely dangerous; fatal attacks increasing; pit bull most common breed involved in fatal attacks, however, rottweilers most likely to bite

Fatal attacks: major problem bringing newborn into home with dog that has been in family for years; must acclimate child and dog to each other; never leave neonate alone with dog; 50% of all deaths occur in children <10 yr of age; 45% of 1- to 9-yr-old victims killed by loose dog on owners property (child invades owners yard, dog protects property), 29% by chained dog on owners property; 26% killed by loose dog roaming

Pit bull: repeat biter; grinding, holding bite; no threatening gestures; dogs assume wide stance, attack at great speed; call local police if pit bull seen running loose, stay away from animal; unprovoked attacks 42% for all breeds combined, 94% for pit bulls alone

Prevention: choose calm animal; educate children; modify dogs behavior; neuter animal; monitor interaction; do not enforce behavior of play-biting, roughhousing, tug-of-war; newborns can be threatening to dog; behaviors to avoid include hugging and kissing dog (face to muzzle), roughhousing, startling sleeping dog, invading dogs territory, interrupting feeding; dog does not recognize when child going to be aggressive and vice versa; teach children not to escalate level of activity, eg, by running away from dog; do not approach dog in hand-on-dogs-head position (dominant gesture); do not run up to or away from animal; allow dog to smell hand before petting dog under muzzle; suppress behavior of nipping, chewing, mouthing hand, growling, barking, guarding food, stealing food, tug-of-war

Choosing a dog: avoid anthropomorphism (dont make the dog a human in your family); assume dominant role (even smallest child needs to be dominant); adopt dog at 6-7 wk of age, socialize until 13 wk of age; be consistent; make certain when you walk up to dog that dog submissive (lying down with stomach exposed); choose dog that looks best for you, then pick up and hold dog by nape of neck; if dog struggles or tries to bite, dog may be aggressive when older; also, if dog does not struggle too often when turned on back or try to nip, thats a dog you may want to have; speaker does not recommend getting 1- to 2 yr-old dog from pound if children in home

Preventing attack: never scream or run; avoid direct eye contact; stand motionless; if knocked down, stay in fetal position and try not to fight off animal; most dogs (but not pit bulls or rottweilers) stop biting if they get victim on ground and victim stops moving; stand as still as possible and present least amount of body as possible (Audiodigest-James Betts, MD)

From EM Lit of Note

Suture Everything Closed

Management of dog bites still exhibits significant variability. Antibiotics, traditionally generally prescribed, are only selectively necessary. Another element of mythology, primary closure of wounds for optimal cosmesis, is the subject of this trial.

These Greek authors randomized 182 patients to either primary suturing or non-suturing of traumatic bite lacerations. Obviously, the lacerations receiving primary closure had much improved cosmetic outcome. The infection rate of suturing was 9.7% vs. 6.9% without, and this study was underpowered to confirm whether this small difference occurred by chance alone. The main predictor of subsequent infection was treatment >8 hours after injury. All patients, unfortunately, received local scrubbing with povidone-iodine and were prescribed amoxicillin/clavulanic acid, neither of which were likely helpful.

I think it’s absolutely reasonable to approximate wound edges for dog bite lacerations after gentle and thorough cleansing. This study doesn’t provide any truly conclusive guidance for wounds >8 hours old – as they had similarly poor outcomes, regardless – other than to offer information to patients on their sub-optimal prognosis.

“Primary closure versus non-closure of dog bite wounds. A randomised controlled trial”
http://www.ncbi.nlm.nih.gov/pubmed/23916901

Cat

1) Pasteurella multocida. More than 50% of cat bite wounds become infected and P. multocida is found as a pathogen over 75% of the time. Infection with P. multocida is characterized by extremely rapid onset. Local pain and inflammation often occur within 4 to 6 hours of the injury and almost always within 24 hours. Purulent discharge is seen with P. multocida in 40% of cases. 2) Beta hemolytic streptococcus. This pathogen is also a common cause of cat bite infections and also is known to be associated with a rapid onset of infection. The air in the soft tissues suggests streptococcal infection, but it is by no means pathognomonic. Staph is also quite common. Ampicillin/sulbactam. The choice of antibiotics in penicillin-allergic patients is more difficult and is based primarily on in vitro sensitivity since data on clinical efficacy are less than adequate. intravenous doxycycline (coverage against P. Multocida) and clindamycin (excellent streptococcal coverage).

Rodent

Plague

Yersinia pestis from flea or rat bite

Buboes

Pneumonic plague from hematogenous spread, inhalation of biowarfare

Tularemia,

Rat Bite Fever: Asymmetric polyarthritis, irregularly relapsing fever, and maculopapular rash of the extremities

Intravenous penicillin. Alternatives include streptomycin or erythromycin

Hanta (From Droppings)

Primate

B Virus-herpes family, can be fatal, starts c vesicles. Simian Herpes Virus. Usually from old world manqué monkeys

Seal

Seal finger: Acute pain, swelling, discharge; may

involve the joint Tetracycline

Human

Divided into CFIs (Closed fist injuries) and occlusional bites (caused by the closure of the teeth on a body part)

Strep, Staph, and Anaerobes

eikenella corrodens

Fight Bites-eikenella corrodens is resistant to multiple antibiotics, including clindamycin, erythromycin, and the first-generation cephalosporins, and is felt to be at least partially responsible for the high morbidity of human bite wounds.

Rabies

Local Wound Care

Must SWAB c 20% soap solution then irrigate

HRIG

20 iu/kg ( ½ wound, ½ IM is outdated rec)

In 1999, the Advisory Committee on Immunization Practices (ACIP), a domestic group that advises the Centers for Disease Control and Prevention on vaccine use and policy, issued their own recommendation calling for as much of the RIG as anatomically feasible to be given at the site of the bite(s) The WHO has recommended the same (Volume 27, Issue 1, Pages 1-99 (July 2004)

HDCV for Rabies (Human Diploid Cell Vaccine)

for 5 doses in DELTOID 1 cc IM. Days 0,3,7,14,28

Cryptogenic rabies is seen c bat guano, but one case report of raccoon rabies in a patient with no known exposures nor outdoor activities. (MMWR 2003 Nov 14; 52:1102)

Ketamine, midazolam, ribavirin, and amantadine saved an unvaccinated patients life (NEJM 2005;352:2508)