How To Treat Bite Injuries

By Tamara D. Fishman, DPM

As the warmer months emerge, people are more likely to tackle spring cleaning of cluttered areas, go outside without shoes and socks, and head to the beach for fun in the sun. Unfortunately, there is also an increased risk of lower-extremity bite injuries with these scenarios, whether the injuries are from dogs, insects, spiders or stingrays. Let’s start out by taking a closer look at dog bite injuries. Every 40 seconds, someone in the United States seeks medical attention for a dog bite-related injury, according to the Centers for Disease Control and Prevention (CDC). From 1979 to 1998, dog attacks killed more than 300 Americans. There is a dog bite epidemic in the United States. In a 10-year period, the number of dogs rose by 2 percent while the number of bites increased by 37 percent. There are almost 5 million victims annually and 800,000 of these people need medical attention. Children are at greater risk of injury and death from dog bites. In 1994, approximately 2.5 percent of U.S. children under 14 years old were bitten compared with 1.6 percent of adults over the age of 18. In 1997 and 1998, 27 people died from dog bites and 19 of them were children under 12. Children, especially boys ages 5 to 9, have the highest incidence rate for emergency department visits resulting from dog bites. When it comes to breeds that pose a high risk for dog bite injuries, the CDC says to be wary of pitbulls, rotweilers, German shepherds, huskies, Alaskan malamutes, Doberman pinschers, chows, Great Danes, St. Bernards and akitas. Dog bites can cause puncture wounds, lacerations and crush injuries. Dog bites may contain Pasteurella multocida, mixed anaerobes and staphylococcus. Cat bites are often puncture wounds that may contain Pasteurella multocida. Other aerobes and anaerobes include S. aureus. Bite wound treatment consists of: • obtaining a complete medical history (including any first aid that was performed); • administering appropriate tetanus prophylaxis; • performing appropriate wound care; • splinting lacerated legs; • elevating the extremity; and • administering prophylactic antibiotics if the animal’s teeth penetrated to bone or tendon sheath or if the wound is more than eight hours old. Amoxicillin/clavulanate covers most of the organisms found in dog and cat bite wounds. You may administer tetracycline as an alternative to augmentin. Overall, it’s important to clean wounds well, administer antibiotics if necessary and follow these patients closely. Essential Tips On Detecting And Treating Insect Bites Many patients are aware of an insect bite when it occurs. Patients may report localized reactions such as discomfort and moderate or severe pain. When treating these patients, you may note erythema, warmth and edema surrounding the bite site. These local reactions are rarely serious or life-threatening and can usually be treated with cold compresses after cleaning of the wound. Ice packs may be helpful for a large local reaction. For most insect bites, lab studies, biopsies and microscopic exams of scrapings from the wound are not necessary. While diagnosing an insect bite is difficult, keep an eye out for wheals or urticaria as these initial signs commonly appear within minutes of the insect bite. Trying to determine the insect responsible can be challenging. In your examination of the patient, you should pinpoint the bite location and identify any patterns as well as the number of bites. Be aware that some patients may have a systemic response to an insect bite. Patients who have such a response will complain of the aforementioned localized symptoms in addition to a rash, pruritis, uticaria and angioedema. If these symptoms progress, the patient may develop weakness, disorientation, syncope, hypotension, dyspnea and anxiety. Anaphylactic shock is the most notable immediate risk associated with insect exposures. Severe anaphylaxis can be fatal in as little as 10 minutes. Mortality associated with insect bites can be caused by either anaphylactic reaction or complications from infection. Reliable figures are not currently available. Estimates of mortality from insect-provoked anaphylaxis in the U.S. range from 50 to 150 people annually. Epinephrine is treatment for a known systemic reaction. The method of administration (subcutaneous, intramuscular and intravenous) will depend on the patient’s condition and your expertise or that of a referring doctor. That said, obtaining a consult from a department or a university entomologist may be helpful. If you suspect potential vector-borne disease transmission, consult an infectious disease specialist. If you suspect that the infection may be associated with recent travel to a tropical destination, consider contacting the CDC at (877) 394-8747. Thousands of people are allergic to bee, wasp and hornet stings. Insect bites for these patients can be deadly for these people within 10 minutes of the sting, but almost always within the first hour or so. What You Should Know About Spider Bites Black widow spider bites are very serious as black widow venom is 14 times more toxic than rattlesnake venom. While they are not aggressive, the female black widow spiders will bite when they are hungry, agitated or protecting the egg sac. These spiders are distinguished by an hourglass shaped red/white mark on the abdomen and are usually found in dry, secluded, dark areas. Those who experience a black widow spider bite may note that it first feels like a pinprick sensation that progresses to a dull ache. The neurotoxin from the bite causes little local reaction after the patient is bitten. However, it causes pain and spasms in the shoulder, back, chest and abdominal muscles within 30 minutes to three hours. Patients will also exhibit fever, rash, headaches, vomiting, nausea, flushing, sweating, anxiety and restlessness. These symptoms usually last 24 to 48 hours. Cold compresses should be applied and these patients should be quickly transported to a hospital where they can be treated for shock. A severe bite can lead to respiratory failure, coma and even death. While brown recluse spiders are most common in the Western and Southern United States, they may be found on the East Coast as well as other areas. These spiders generally frequent cluttered basements, closets, attics, cellars and garages. As far as the initial signs and symptoms go, a bite from this type of spider causes a stinging sensation and intense pain shortly thereafter. This type of ulcer may go unnoticed for about six to eight hours before reddening, swelling and a blistering of the patient’s skin appears. Within 24 to 36 hours, the patient may report a feeling of restlessness, fever, chills, nausea, joint pain and an overall general weakness. The presence of any additional symptomology will depend upon the amount of venom injected by the spider. A severe bite may produce a necrotic lesion that may require surgical intervention. The initial lesion may appear red, edema may also be present or the skin may appear blanched. A blue-gray halo may develop around the puncture area. The eschar formation may begin within several days after the bite as the lesion becomes necrotic. Severe necrosis of tissues may follow within hours to weeks. Early intervention and aggressive medical management is the key to preventing unnecessary amputation. A Key Guide To Snake Bites Snakes bite approximately 45,000 people every year in the United States. Only about one-third of all snake bites manifest in symptoms. When there are no symptoms present, it’s likely that no venom was injected into the person. For those bites that do produce symptoms, you’ll see immediate signs such as fang marks, immediate burning pain, swelling, erythema and ecchymosis. If left untreated, the edema may progress rapidly and involve an entire extremity within hours. Each year, there are 7,000 snake bites that involve a poisonous snake. More than half of the poisonous snake bites involve children and most commonly occur between April and October. About 15 percent of the 3,000 species of venomous snakes throughout the world are considered poisonous to humans. Rattlesnakes are the most venomous snakes and account for the most deaths. The different types of snake venom are complex substances and are made up of mainly proteins with enzymatic activity. The toxic properties of the venom are due to smaller polypeptides. Venom can affect the central nervous system, brain, heart, kidneys and blood. The degree of any venomous snake bite depends on: • the size and species of the snake; • the amount of the venom injected: • the number of bites; • the location and depth of the bite; • the age and size of the victim; • the time that has passed before treatment: and • the victim’s response to the venom. For example, signs and symptoms of a pit viper snake bite are severe burning pain and swelling around the fang marks, which typically occur within five minutes. A purplish discoloration around the snake bite usually occurs within two to three hours. You may also note numbness and possible blistering around the bite. Additionally, the victim will have nausea, vomiting, low blood pressure, weakness, rapid heartbeat and may faint. Victims may also experience sweating, fever, chills, muscular twitching, headache and convulsions. The priority emergency care for a snake bite is to maintain basic life support, airway, breathing and circulation. The victim should be transported to the nearest hospital without delay, with the bitten extremity kept at the level of the victim’s heart. How To Deal With Stingray Bites Stingrays are bottom-dwelling cartilaginous fish that have flattened bodies. They possess one or more stout spines on the tail, gill slits on the lower surface of the head, teeth modified into two large crushing plates, and no dorsal fin. While stingrays are not aggressive toward humans, injuries are very common. These injuries usually occur when an individual treads on the stingray while in the ocean surf, thus provoking the stingray to thrust its tail upward, driving the spine into the victim’s foot or leg. The stinger injects a protein-based toxin into the wound. Victims will feel severe pain immediately. The wound is jagged and will bleed freely. The patient may experience systemic symptoms such as diarrhea, muscle cramps, syncope, nausea, hypotension, seizures and diaphoresis. These injuries should be irrigated with the salt water at hand. Then the patient should immerse the extremity in hot water, as hot as he or she can tolerate. The stingray toxin is very sensitive to heat. If you see these patients in the office, you should initiate appropriate wound care depending on the wound characteristics. Radiographs may be useful to rule out the presence of any foreign bodies. You should administer the appropriate antitetanus drug and emphasize elevation of the affected extremity for several days. Dr. Fishman is Chairman of the Wound Care Institute in North Miami Beach, Fla.



References 1. Centers for Disease Control and prevention. Dog bite-related fatalities-United States, 1995-1996. MMWR Morb Mortal Wkly Rep. 1997; 46:463-467. 2. The Merck Manual- 17th Edition- Centennial Edition. White House Station, N.J. 1999. 3. Lane RP, Crosskey RW: Medical Insects and Arachnids. Chapman and Hall; 1993. 4. Hoffman DR: Allergic reactions to biting insects. In: Levine MI, Lockery RF, eds. Monograph on Insect Allergy. 1981: 69-74. 5. Weiss HB. Friedman DI, Coben JH. Incidence of dog bite injuries treated in emergency departments. JAMA 1998; 279:51-53.


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