by Prof. E. Gene Deune
Introduction
(July 24, New York, Sri Lanka Guardian) Animal bites are a common problem, affecting 2 to 5 million people annually in the United States. Treatment for animal bites account for 1 percent of all emergency room visits resulting in approximately $30 million in health care dollars. Dogs account for 85 to 90 percent of the injuries. Cats account for 5 to 10 percent, and rodents and humans are equal at about 2 to 3 percent each. About 10 percent of these bites will require wound repair with follow up care. 1 to 2 percent will require hospitalization. Bite wounds kill about 10 to 20 victims per year, primarily infants and children. A significant number of patients will suffer morbidity associated with the injuries associated with animal bites. These include disability, cosmetic problems associated with scar formation and loss of tissue and problems related to wound infections. Of particular concern if the animal bites affect the finger, hand, or forearm is the loss of function due to nerve, tendon, muscle, or bone damage.
Dog bites
Interestingly, these attacks are most often caused by a dog known to the victim. It is most often a family pet or the pet of a neighbor or relative. Large dog have tremendous power in their jaws. They can exert up to 450 pounds per square inch with their molar teeth. This type of force can lead to crushed tissue and very deep injuries. While the majority of injuries are scratches, abrasions and lacerations, on rare occasions these injuries can be fatal. A lethal injury usually involves penetration of a major vessel, the chest or direct penetration of vital organs. Dog bites to the head and neck are common in 60 to 70 percent of injuries to children below the age of 5 years. This is due to the fact of the proximity of the young child’s head to the level of the mouth in a large dog. A dog’s tooth can penetrate the skull of a small child causing a depressed skull fracture, local infection and even a brain abscess. In adults and older children, the extremities and, in particular, the dominant hand are the most frequent sites of injury. These injuries often times result in skin avulsion and/or injury to the underlying muscular structures. (see picture) Penetrating trauma to the fingers or the hand can result in tendon, nerve, or blood vessel injuries that require reconstruction. Left untreated, penetrating trauma can lead to osteomyelitis, requiring operative debridement and prolonged intravenous or oral antibiotics. (see pictures – to be included) The most common bacteria in dog bites are Pasturella, Staphylococcus, Streptococcus, Eikenella, and Proteus.
Cat bites
Cats usually cause wounds with their teeth or claws. In contrast to dog bites, which often occur without overt provocation in males and children, cat bites occur more often in females and adults. 89 percent of these bites are provoked. Two-thirds of cat bites involve the upper extremities. Scratches typically occur on the upper extremities or face. Deep puncture wounds are of particular concern because cats have long, slender, sharp teeth. When the hand is the target of such a puncture wound, bacteria can be inoculated below the periosteum or into a joint and result in osteomyelitis or septic arthritis.
Infection with Pasturella multocida, which is the most common organism, characteristically develops rapidly with redness, swelling, and intense pain evident as early as 12 to 24 hours after the bite. Systemic signs of infection, such as fever and swollen lymph nodes, are infrequent. Localized cellulitis caused by this organism can be subacute in onset, beginning 24 to 72 hours after the injury; systemic infection occurs in fewer than 20 percent of these cases. Other bacteria found in cat wounds include Actinomyces, Proprionibacterium, Bacteroides, and Fusobacterium.
Human bites
Although not technically an animal bite, injuries to the upper extremities secondary contact with the penetrating human mouth can inflict great morbidity similar to domestic animal bites. In the human child, the human bites are typically located on the face, upper extremities, or trunk. When a child receives a bite from another human, a semicircular or oval area of redness or bruising usually is visible. The skin itself may or may not be intact. In the adults, the breaks in the skin are often times associated with more damaging penetrating force due to the nature of the human bite. The clenched fist is often times the instigator in causing the penetrating wound, usually on the prominence of an MP joint or the PIP joint, when the fist is used to strike the mouth of an opponent. Occasionally, the instigator bites the opponent, and this usually results in deep penetrating injuries to the forearm, where there is more muscle mass. The force of either the blow or bite can drive oral bacteria deep into the tissue of the forearm or the hand and potentially spread to the adjacent joints or it can directly penetrate the joint. The end results in the destruction of the joint and the surrounding local tissue and tendons. (see picture) The bacteria most commonly found in human bites are Staphylococcus, Streptococcus, Eikenella corrodens, Clostridium tetani, and Bacteroides. The other major concern in human hand bites in the possible transmission of human viral pathogens such as hepatitis B, hepatitis C, herpes simplex virus, and HIV.
Management of Animal Bites
The first step in management of bite wounds is the most important. The involved area should be washed thoroughly with an iodine-based soap and copiously irrigated with saline solution. It is important to be sure that no foreign bodies, such as teeth and other fragments, have been driven into the wound. Radiographs should be taken to look for foreign objects and to look for bone injuries such as fractures or avulsions. Infections developing in the deeper tissues should always be suspected in bite injuries of the extremities particularly the hands. A deep space infection is suspected in patients who exhibit pain with passive flexion or extension. Deep space infections and tendonitis frequently develop in bite wounds to the hands. Septic arthritis or osteomyelitis should be carefully ruled out. Elevation of the affected part and immobilization in a splint with the tendons at the “position of protection” are important parts of the management scheme following exploration of the wound.
There is considerable debate in the medical community as to whether all of these wounds can be sutured at the time of presentation and whether or not these patients require antibiotics to prevent infection. Studies done that look at both of these options, suturing the wound closed and use of antibiotics. Important factors in management where found to be debridement of all devitalized tissue from the wound and prompt attention to local wound care. (References to follow) These studies do not recommend wound closure in the cases of crush injuries, bites in the hands, or in patients with delayed presentation (more than 6-12 hours for extremity bites). In general, dog bites appear to carry less chance of infection compared to cat or human bites. Cat and human bites are complicated injuries and should not be closed immediately, except when those injuries are found on the face. Immunosuppressed hosts by definition, have complicated wounds, and are at high risk for developing wound infections. Management of these wounds, especially if in a child, will require going to the operating room for proper conditions and anesthesia. After proper treatment, the wounds should be carefully followed. Any suspicion of infection should be picked up early to avoid late complications. Should the wound become infected, it should be cultured and thoroughly debrided in the operating room. The patient should be started on intravenous antibiotics. In general Ampicillin-sulbactam will provides sufficient coverage for both dog and cat bites. An alternative for penicillin-allergic patients, would be clindamycin plus trimethoprim-sulfamethoxazole. Should there be concern that the wound be infected with hospital acquired or community acquired bacteria, broad-spectrum antibiotics should be employed until the causative agent(s) and antibiotic sensitivities have been identified and established.
The routine use of antibiotics is controversial in the treatment of animal and human bites and is discouraged in the low risk bites but should be given in high-risk patients and in high-risk wounds. High-risk patients would be young children, older patients, patients with chronic medical problems, and immunocompromised patients. High-risk injuries include those that are crush injuries, deep puncture wounds, and injuries to the hands. Again, attention should be paid considerably to the proper management of the wound, in cleaning the wound and decreasing the bacteria burden, and establishing a clean wound to decrease the risk of bacterial invasion. In human bites, a particular concern would be the proper vaccination for hepatitis and potential prophylactic treatment for HIV. Rabies while uncommon in the western world should always be considered when discussing animal bites, particularly if the attack was caused by an unprovoked stray or feral animal. Any contact with animal saliva via mucous membranes or a break in the skin can transmit rabies. Everyone should be aware of their vaccination status as well as their children’s. Tetanus prophylaxis in an important part of the management of all trauma patients. Tetanus toxoid and or tetanus immune globulin should be given if there is any question of the last dosing.
Late Care
Once the acute healing has occurred, scarring causing constricting, pain, or loss of function needs to corrected. This may be as straight forward as scar revision or as complicated as restoring soft tissue in extremities that have lost considerable tissue (picture to follow). Tendon injuries and nerve injuries if not addressed initially should be corrected if as soon as feasible.
Summary
Animal and human bites can cause considerable devastation. Although most pets and humans are well behaved, if provoked can attack with primal instincts, resulting in serious wounds that sometimes are fatal. It is best to avoid these injuries when possible.
- Sri Lanka Guardian
Introduction
(July 24, New York, Sri Lanka Guardian) Animal bites are a common problem, affecting 2 to 5 million people annually in the United States. Treatment for animal bites account for 1 percent of all emergency room visits resulting in approximately $30 million in health care dollars. Dogs account for 85 to 90 percent of the injuries. Cats account for 5 to 10 percent, and rodents and humans are equal at about 2 to 3 percent each. About 10 percent of these bites will require wound repair with follow up care. 1 to 2 percent will require hospitalization. Bite wounds kill about 10 to 20 victims per year, primarily infants and children. A significant number of patients will suffer morbidity associated with the injuries associated with animal bites. These include disability, cosmetic problems associated with scar formation and loss of tissue and problems related to wound infections. Of particular concern if the animal bites affect the finger, hand, or forearm is the loss of function due to nerve, tendon, muscle, or bone damage.
Dog bites
Interestingly, these attacks are most often caused by a dog known to the victim. It is most often a family pet or the pet of a neighbor or relative. Large dog have tremendous power in their jaws. They can exert up to 450 pounds per square inch with their molar teeth. This type of force can lead to crushed tissue and very deep injuries. While the majority of injuries are scratches, abrasions and lacerations, on rare occasions these injuries can be fatal. A lethal injury usually involves penetration of a major vessel, the chest or direct penetration of vital organs. Dog bites to the head and neck are common in 60 to 70 percent of injuries to children below the age of 5 years. This is due to the fact of the proximity of the young child’s head to the level of the mouth in a large dog. A dog’s tooth can penetrate the skull of a small child causing a depressed skull fracture, local infection and even a brain abscess. In adults and older children, the extremities and, in particular, the dominant hand are the most frequent sites of injury. These injuries often times result in skin avulsion and/or injury to the underlying muscular structures. (see picture) Penetrating trauma to the fingers or the hand can result in tendon, nerve, or blood vessel injuries that require reconstruction. Left untreated, penetrating trauma can lead to osteomyelitis, requiring operative debridement and prolonged intravenous or oral antibiotics. (see pictures – to be included) The most common bacteria in dog bites are Pasturella, Staphylococcus, Streptococcus, Eikenella, and Proteus.
Cat bites
Cats usually cause wounds with their teeth or claws. In contrast to dog bites, which often occur without overt provocation in males and children, cat bites occur more often in females and adults. 89 percent of these bites are provoked. Two-thirds of cat bites involve the upper extremities. Scratches typically occur on the upper extremities or face. Deep puncture wounds are of particular concern because cats have long, slender, sharp teeth. When the hand is the target of such a puncture wound, bacteria can be inoculated below the periosteum or into a joint and result in osteomyelitis or septic arthritis.
Infection with Pasturella multocida, which is the most common organism, characteristically develops rapidly with redness, swelling, and intense pain evident as early as 12 to 24 hours after the bite. Systemic signs of infection, such as fever and swollen lymph nodes, are infrequent. Localized cellulitis caused by this organism can be subacute in onset, beginning 24 to 72 hours after the injury; systemic infection occurs in fewer than 20 percent of these cases. Other bacteria found in cat wounds include Actinomyces, Proprionibacterium, Bacteroides, and Fusobacterium.
Human bites
Although not technically an animal bite, injuries to the upper extremities secondary contact with the penetrating human mouth can inflict great morbidity similar to domestic animal bites. In the human child, the human bites are typically located on the face, upper extremities, or trunk. When a child receives a bite from another human, a semicircular or oval area of redness or bruising usually is visible. The skin itself may or may not be intact. In the adults, the breaks in the skin are often times associated with more damaging penetrating force due to the nature of the human bite. The clenched fist is often times the instigator in causing the penetrating wound, usually on the prominence of an MP joint or the PIP joint, when the fist is used to strike the mouth of an opponent. Occasionally, the instigator bites the opponent, and this usually results in deep penetrating injuries to the forearm, where there is more muscle mass. The force of either the blow or bite can drive oral bacteria deep into the tissue of the forearm or the hand and potentially spread to the adjacent joints or it can directly penetrate the joint. The end results in the destruction of the joint and the surrounding local tissue and tendons. (see picture) The bacteria most commonly found in human bites are Staphylococcus, Streptococcus, Eikenella corrodens, Clostridium tetani, and Bacteroides. The other major concern in human hand bites in the possible transmission of human viral pathogens such as hepatitis B, hepatitis C, herpes simplex virus, and HIV.
Management of Animal Bites
The first step in management of bite wounds is the most important. The involved area should be washed thoroughly with an iodine-based soap and copiously irrigated with saline solution. It is important to be sure that no foreign bodies, such as teeth and other fragments, have been driven into the wound. Radiographs should be taken to look for foreign objects and to look for bone injuries such as fractures or avulsions. Infections developing in the deeper tissues should always be suspected in bite injuries of the extremities particularly the hands. A deep space infection is suspected in patients who exhibit pain with passive flexion or extension. Deep space infections and tendonitis frequently develop in bite wounds to the hands. Septic arthritis or osteomyelitis should be carefully ruled out. Elevation of the affected part and immobilization in a splint with the tendons at the “position of protection” are important parts of the management scheme following exploration of the wound.
There is considerable debate in the medical community as to whether all of these wounds can be sutured at the time of presentation and whether or not these patients require antibiotics to prevent infection. Studies done that look at both of these options, suturing the wound closed and use of antibiotics. Important factors in management where found to be debridement of all devitalized tissue from the wound and prompt attention to local wound care. (References to follow) These studies do not recommend wound closure in the cases of crush injuries, bites in the hands, or in patients with delayed presentation (more than 6-12 hours for extremity bites). In general, dog bites appear to carry less chance of infection compared to cat or human bites. Cat and human bites are complicated injuries and should not be closed immediately, except when those injuries are found on the face. Immunosuppressed hosts by definition, have complicated wounds, and are at high risk for developing wound infections. Management of these wounds, especially if in a child, will require going to the operating room for proper conditions and anesthesia. After proper treatment, the wounds should be carefully followed. Any suspicion of infection should be picked up early to avoid late complications. Should the wound become infected, it should be cultured and thoroughly debrided in the operating room. The patient should be started on intravenous antibiotics. In general Ampicillin-sulbactam will provides sufficient coverage for both dog and cat bites. An alternative for penicillin-allergic patients, would be clindamycin plus trimethoprim-sulfamethoxazole. Should there be concern that the wound be infected with hospital acquired or community acquired bacteria, broad-spectrum antibiotics should be employed until the causative agent(s) and antibiotic sensitivities have been identified and established.
The routine use of antibiotics is controversial in the treatment of animal and human bites and is discouraged in the low risk bites but should be given in high-risk patients and in high-risk wounds. High-risk patients would be young children, older patients, patients with chronic medical problems, and immunocompromised patients. High-risk injuries include those that are crush injuries, deep puncture wounds, and injuries to the hands. Again, attention should be paid considerably to the proper management of the wound, in cleaning the wound and decreasing the bacteria burden, and establishing a clean wound to decrease the risk of bacterial invasion. In human bites, a particular concern would be the proper vaccination for hepatitis and potential prophylactic treatment for HIV. Rabies while uncommon in the western world should always be considered when discussing animal bites, particularly if the attack was caused by an unprovoked stray or feral animal. Any contact with animal saliva via mucous membranes or a break in the skin can transmit rabies. Everyone should be aware of their vaccination status as well as their children’s. Tetanus prophylaxis in an important part of the management of all trauma patients. Tetanus toxoid and or tetanus immune globulin should be given if there is any question of the last dosing.
Late Care
Once the acute healing has occurred, scarring causing constricting, pain, or loss of function needs to corrected. This may be as straight forward as scar revision or as complicated as restoring soft tissue in extremities that have lost considerable tissue (picture to follow). Tendon injuries and nerve injuries if not addressed initially should be corrected if as soon as feasible.
Summary
Animal and human bites can cause considerable devastation. Although most pets and humans are well behaved, if provoked can attack with primal instincts, resulting in serious wounds that sometimes are fatal. It is best to avoid these injuries when possible.
- Sri Lanka Guardian
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