Determining the exact incidence of animal bite wounds in the United States is difficult, because many are never reported. Each year, an estimated 4.5 million dog bites occur, which result in hundreds of thousands of emergency department visits. Do you know the concerns associated with such injuries and how best to treat them? Test yourself with this short quiz.
Which of the following types of bites are a most often associated with dogs?
Avulsion
Crush-type bite
Laceration
Abrasion
The bite of a dog can yield between 150-450 lb of pressure per square inch, depending on the dog and its training. Therefore, although a dog bite may appear as a laceration or avulsion, it most likely has components of a crush injury. In this type of injury, debridement is required to remove any crushed tissues. Once debrided, the laceration injury is then amenable to suturing and primary closure.
A bite to which of the following regions carries the highest risk for infection?
The leg
The upper arm
The hand
The face
Bites of the hand generally have a high risk for infection because of the relatively poor blood supply of many structures in the hand and anatomical considerations that make adequate cleansing of the wound difficult. In general, the better the vascular supply and the easier the wound is to clean (ie, laceration vs puncture), the lower the risk for infection.
For more on the risk for infection with animal bites, read here.
Which of the following is the most common infection contracted from cat bites?
Pasteurella infection
Wolinella infection
Clostridium infection
Fusobacterium infection
Pasteurella multocida infection (the most common infection contracted from cat bites) also may be complicated by sepsis. Meningitis, osteomyelitis, tenosynovitis, abscesses, pneumonia, endocarditis, and septic arthritis are additional concerns in bite wounds. When rabies occurs, it is almost uniformly fatal.
For more on the mortality/morbidity associated with animal bites, read here.
Which of the following types of bites is associated with a higher rate of infection?
Crush-type wound
Puncture-type wound
Superficial laceration
Abrasions
The sharp, pointed teeth of cats usually cause puncture wounds and lacerations that may inoculate bacteria into deep tissues. Infections caused by cat bites generally develop faster than those of dogs. It may be difficult to appropriately irrigate small puncture wounds, especially those inflicted by the teeth of a cat. Given that these have a higher rate of infection, consideration should be given to opening the wound with a number 15-blade scalpel and creating a 1- to 1.5-cm incision that can be well irrigated and left open to heal by secondary intention.
For more on the treatment of animal bites, read here.
Which of the following wounds should be left open or treated by delayed primary closure?
A bite wound to the hand with a delay in presentation > 8-12 hours
A puncture wound to the leg that is still bleeding
A laceration on the abdomen that has been effectively cleansed
None of the above
Primary closure should be considered only in bite wounds that can be cleansed effectively. Bite wounds to the hands and lower extremities, with a delay in presentation (>8-12 hours old), or in immunocompromised hosts, generally should be left open or treated by delayed primary closure. Closure management decisions should be at the discretion of the provider after discussion with the patient and consultation with specialists if available. Deep sutures should be avoided because they can act as a nidus for infection.
For more on the treatment of animal bites, read here.
