High-Risk Wounds

Wounds at high risk for infection include bites to the hands and feet, and all puncture wounds (see page 258). These should be rinsed copiously and never cinched shut by any method. Anyone who sustains such a wound should be given antibiotics for 4 days (see step 4 on page 409). Cat, human, and primate bites are enormously prone to infection, and require prompt attention by a physician. In a typical human bite, which occurs when a closed fist strikes an opponent’s teeth, the cut extends deeply into a knuckle and inoculates the underlying tendon sheath with saliva and bacteria. As the fist is opened, the wound becomes “closed,” and an infection can develop quickly. If a human bite is incurred in this manner, splint the hand in the position of function (see Figure 39) and administer cefuroxime axetil, ciprofloxacin plus erythromycin, or dicloxacillin plus ampicillin for 7 days.

Cat Scratch Disease

Cat scratch disease is most commonly caused by bacteria of the genus Bartonella. After the victim is scratched by a cat, commonly on the hand, wrist, or forearm, a reddened or purplish sore forms at the scratch site within a few days. The sore may blister and then settle into an ulcer that remains for days to weeks. Along with the sore, the victim typically complains of swollen lymph glands (nodes) directly upstream from the injury. In the case of a scratch on the hand, these would appear behind the elbow and in the armpit. The swollen nodes are often tender and sometimes matted together. On occasion, they may become severely inflamed, soften, and drain through the skin surface. The victim may also complain of fever and fatigue. Although the response to antibiotics is not consistent, the victim may benefit from azithromycin 500 mg by mouth once a day for 5 days, or from a 5-day course of ciprofloxacin or clarithromycin.

Rabies

Rabies virus infection occurs more frequently in wild than in domestic animals. In some foreign countries where immunization of animals is infrequently practiced, the risk is great even in domesticated animals. The virus is carried in saliva and is transmitted by bite or lick (if the skin is broken). It has been transmitted by bats in caves either by aerosolized saliva or undetected bites. Raccoons, dogs, cats, foxes, coyotes, skunks, wolves, bats, woodchucks, and groundhogs are the most common carriers. Rabies has not been reported in bears. Although rabbits, hares, mice, squirrels, chipmunks, rats, guinea pigs, and ferrets may be rabid, they are rarely involved in the transmission of rabies to humans. Domestic animals such as cattle, horses, and sheep become infected in regions where skunk or raccoon rabies is found. In developing countries in Asia, Africa, and South and Central America, dogs are the most common carriers.

Animals with rabies show abnormal behavior. In the “furious” phase, they are hyperactive, may have a fever, are overtly aggressive, and salivate excessively. With “dumb” rabies, they appear tired, lack coordination, and may become paralyzed.

Because of rabies risk, all wild animal bites or scratches, and bites or scratches of unregistered or strangely behaving cats and dogs, should be reported to the appropriate public health authority. If the animal is a pet with otherwise normal behavior, it should be observed for 10 days. If the animal is rabid, it will become very ill or die during that time, and its brain tissue can be analyzed for the presence of rabies. If the animal is a pet with unusual behavior, or a captured high-risk wild animal, it should be killed and examined. If it is a high-risk animal and cannot be captured, it must be presumed to be rabid.

Immediately scrub an animal bite wound or a wound that has been licked by a potentially rabid animal vigorously with soap and water. If benzalkonium chloride 1% (Zephiran); 10% povidone iodine (Betadine) solution (less effective); or, in a pinch, Bactine (benzalkonium 0.13%) antiseptic is available, one of these should be used to irrigate and deeply swab the wound, since they may kill rabies virus.