When it comes to traumatic injuries seen in the emergency room or urgent care, animal bites rank fairly high on the list of most common injuries. Whether a cat, dog, hamster, raccoon, prairie dog, monkey, or shark, we have seen them all. As a provider, we need to know how to deal with this efficiently and effectively. At first, that can seem like a daunting task. By approaching each patient with the same, systematic approach you will quickly become more comfortable with treating these injuries. From the toddler who is bitten in the head by a dog, to an elderly woman who was bitten in the hand by one of her 14 cats, the evaluation all starts with the same basic approach. Here we will teach you how to treat animal bites.
The first thing that should evaluated in any patient with an animal bite is their stability. Are they conscious, maintaining their airway, and are they hemodynamically stable? While someone who was bitten on the finger by a hamster likely is completely stable, you can’t always assume that when it comes to bites to the head, face, and neck. Also, significant vascular injuries can occur with animal bites. These can result in large volume blood loss, so be aware of signs of hemorrhagic shock. Look for signs of vascular injury.
The distal extremity of the injury may be pale and cool. There may be delayed capillary refill if there is an arterial injury. Also remember, tachycardia is the first sign of hemorrhagic shock and can be seen before a drop in blood pressure. This sign shouldn’t be overlooked. Patients with the potential for significant vascular injury should have an IV and fluids ready resuscitation. Being prepared isn’t a bad idea.
Bleeding should be controlled by whatever means are necessary. Applying direct pressure on the wound is the first step. Clamping/ligating the bleeding vessel should follow (if it can be visualized), or a tourniquet should be applied. Don’t leave tourniqets on for too long, because they can cause tissue ischemia. Any findings suggestive of significant vascular injury should prompt an immediate consultation with vascular surgery for further evaluation.
Assess the Wound
Next, we need to asses the wound itself. Dog bites can range from small, superficial punctures to large, deep wounds with missing tissue. Cat bites are often small, deep punctures to the extremities. When evaluating the wound, it is important to note the proximity to any joint spaces or deep structures. These locations are prone to more infection and abscess formation. Make sure there is full function distal to the wound, and that sensation distal to the wound is intact.
Sometimes, pain control is required to get a good examination of function, so local anesthesia or parenteral pain medication may be required. Test sensation distal to the wound before giving anesthetic. This will prevent delaying the diagnosis of a nerve injury. Imaging of the affected area is not always warranted. These should be considered if there is loss of function, suspected foreign body, or obvious signs of fracture. Toddlers often sustain dog bites to the head and face. Sadly, the force of the bite can penetrate the skull and/or facial bones of these children. CT scan of the head and/or face is indicated for these injuries, especially if the child appears altered.
Clean The Wound
Once the wound has been thoroughly assessed, it needs to be cleaned and irrigated. Again, sometimes local anesthesia will be helpful and appreciated by your patient. This is especially true if the wound is heavily contaminated and will require debridement or scrubbing. Make sure the wound is irrigated well with sterile water or saline. An antiseptic soap, such as Providone iodine or Chlorhexidine should be used. I personally like to use Chlorhexidine because it is less caustic to the tissues. It is also less painful to use in wounds that have not been anesthetized. Puncture wounds that are of sufficient diameter should be irrigated using a syringe. All debris/foreign material should be removed and the wound should be re-assessed after it has been cleaned. Make sure to counsel your patient that not all small particles can be removed by irrigation alone.
To close, or not to close…
One of the most common questions students ask us is if we should close bites wounds. Well, that depends. Bites transmit bacteria that can cause human tissue damage. As such, typically, any bite that produces a puncture wound should be left to close by secondary intention. This prevents abscess formation. Bites to the face should be closed primarily, but only after they have been thoroughly cleaned. I personally loosely re-approximate these to help lessen the risk of infection. While this doesn’t provide as good of a cosmetic outcome, it is better than leaving the wound to heal secondarily. Large lacerations to the rest of the body can also be loosely closed. The exception to this is the hands and feet, however the general recommendation is to leave them open to heal by secondary intension in order to reduce the risk of infection.
On the topic of infection, let’s discuss antibiotic prophylaxis. The general consensus is that superficial wounds to the torso and extremities that are less than 8 hours old do not necessarily require antibiotic prophylaxis, with the exception of cat bites. Cat bites have a very high infection rate and I almost always give patients with cat bites antibiotics. Wounds that are greater than 8 hours old, deep, near a joint or bone, or are on the feet, face, or hands should be given antibiotic prophylaxis.
Pasteurella multocida is the organism most often associated with infected animal bites, so treatment should provide coverage for this organism. Typically amoxicillin-clavulanate is the drug of choice and is given for 10 days. Alternative combinations of doxycycline, Trimethoprim-sulfamethoxazole, or ciprofloxacin taken with metronidazole or clindamycin will also provide antimicrobial coverage. Of course, make sure that your patient’s tetanus vaccination is up to date. Follow your local protocols if there is concern for possible rabies exposure.
Now, if you have a wound with a fracture, or involves a joint or tendon, it is a good idea to get orthopedics involved early. They may want to take the patient for surgical washout and repair. If you are in an outpatient setting and do not have access to an orthopedic surgeon, consider sending them to one immediately. It may be a good idea to send your patient to the ER where they can obtain an orthopedic consultation.
Remember, no matter how exotic the animal was that bit your patient, caring for the wounds created is basically the same. A methodical, step-wise approach will make sure that you completely evaluate your patient’s injuries, and care for them in the most appropriate way.
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