Animal Bite Infections Health Article

Diagnosis

Most animal bites that cannot be treated at home are examined by a doctor in the emergency room of a hospital. The medical examination involves taking the history of the injury and assessing the type of wound and damage. The child's record of tetanus immunization and general health status are checked. An x ray may be ordered to assess bone damage and to check for foreign objects in the wound. Wound cultures are done for infected bites if the victim is at high risk for complications or if the infection does not respond to treatment. If the child was bitten severely on the head, the emergency room doctor will call in a neurologist for consultation, particularly if the eyes, ears, or neck were injured or the skull was penetrated. The doctor may also consult a plastic surgeon if the bites are extensive, if large pieces of tissue have been lost, or if the functioning or appearance of the affected part of the body is likely to be affected.

Evaluation of possible exposure to rabies is also important. A biting animal suspected of having rabies is usually caught and restrained, tested, and observed for a period of time for evidence of pre-existing infection.

Treatment

Treatment depends on the wound type, its site, and risk factors for infection. All wounds from animal bites are cleaned and disinfected as thoroughly as possible. The doctor begins by injecting a local anesthetic in order to examine the wound thoroughly without causing additional pain to the child. The next step is to remove dead tissue, foreign matter, and blood clots, all of which can become sources of infection. This removal is called debridement. After debriding the wound, the doctor will cut away the edges of the tissue, as clean edges heal faster and are less likely to form scar tissue. The doctor then irrigates, or flushes, the wound with saline solution forced through a syringe under pressure. Irrigation is highly effective in lowering the risk of infection from animal bites; in one study of 45 children with a total of 145 dog bite wounds on the face, pressure irrigation combined with trimming the edges of the wounds resulted in an infection rate of 0.4 percent.

Bites to the head and face usually receive sutures, as do severe lacerations elsewhere. Puncture wounds are left open. If an abscess forms, the physician may perform an incision in order to drain the abscess.

If infection does occur, the doctor will prescribe antibiotic medications. Antibiotics may also be used for infection prevention. Since a single bite wound may contain many different types of bacteria, no single antibiotic is always effective. Commonly prescribed antibiotics are penicillin or a combination of amoxicillin and clavulanate potassium (Augmentin). Aztreonam (Azactam) has been reported to be effective in treating infections caused by P. multocida. In most cases, antibiotics taken by mouth are sufficient; however, some deep bites may require treatment with intravenous antibiotics.

Because rabies is caused by a virus, antibiotics are not effective against it. In addition, there is no known cure for the disease as of 2004 once symptoms become apparent. People with a high risk of contracting the disease should receive preexposure vaccination. Individuals bitten by an unknown or potentially rabid animal should receive postexposure vaccination, also called postexposure prophylaxis (PEP). The PEP regimen consists of one dose of vaccine given at the initial visit as well as one dose of human immune globulin. Additional doses of vaccine are given on days three, seven, 14, and 28.

Prognosis

Once a bacterial infection is halted, the bite victim usually recovers fully. There is no known cure for rabies once symptoms become evident and death is almost certain. WHO reports that 114 rabies deaths occurred in the Americas in 1997, with only four deaths occurring that year in the United States, thus emphasizing the importance of good animal control practice and postexposure prophylaxis.

The prognosis for restoring the function or appearance of a hand or other body part following a severe bite depends on the location of the bite, the promptness of treatment, and the availability of specialized surgical repair.