Rodney L. McCaskill
EPIDEMIOLOGY
Only a small percentage of wounds contain a foreign body.
Most but not all foreign bodies may be discovered with thorough wound examination.
PATHOPHYSIOLOGY
Retained foreign bodies may lead to a severe local inflammatory response (eg, wood, thorns, spines), chronic local pain (eg, glass, metal, plastic), local toxic reactions (eg, sea urchin spines, catfish spines), systemic toxicity (eg, lead), or infection.
Infection is the most common complication of a retained foreign body and typically the infection is resistant to antibiotic therapy.
CLINICAL FEATURES
The mechanism of injury, composition and shape of the wounding object, and the shape and location of the resulting wound may increase the risk of a foreign body.
Lacerating objects that splinter, shatter, or break increase the risk of a foreign body.
Discoloration of the skin, palpable mass, sharp well-localized pain with palpation, and limitation of joint movement should heighten suspicion for a foreign body.
In adults, the perception of a foreign body more than doubles the likelihood of one being present.
Although all puncture wounds and apparently superficial wounds can hold foreign bodies, wounds deeper than 5 mm and those whose depths cannot be investigated have a higher association with foreign bodies.
Patients returning to the ED with retained foreign bodies may complain of sharp pain at the wound site with movement, a chronically irritated non-healing wound, or a chronically infected wound.
DIAGNOSIS AND DIFFERENTIAL
Imaging studies should be ordered if a foreign body is suspected.
No single imaging modality is ideal for all types of foreign bodies.
Most foreign bodies (80–90%) can be seen on plain radiographs. Metal, bone, teeth, pencil graphite, glass, gravel, sand, aluminum, and a few types of plastic are visible on plain film while most plastics and organic material specifically wood, thorns, cactus spines, and some fish bones cannot be seen on plain film.
CT scan is much more sensitive than plain film in detecting foreign bodies.
Ultrasound is probably less accurate than CT, but it reportedly has a >90% sensitivity for detecting foreign bodies larger than 4 to 5 mm in size.
MRI can detect radiolucent foreign bodies and is more accurate in identifying wood, plastic, spines, and thorns than the other modalities.
Fluoroscopy can be useful to detect metal, gravel, glass, and pencil graphite in real time.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Careful exploration of the depths of all wounds increases the likelihood of finding a foreign body. Extending the edges of the wound is often necessary to thoroughly investigate for foreign bodies.
Blind probing with a hemostat is less effective, but may be utilized if the wound is narrow and deep, and extending the wound is not desirable.
Not all foreign bodies need to be removed. Indications for foreign body removal include potential for infection, toxicity, functional problems, or potential for persistent pain.
Vegetative material and heavily contaminated objects should always be removed.
Radiopaque foreign bodies may be localized using skin markers and x-ray or fluoroscopy. Hypodermic needles may be inserted at 90° to each other near the foreign body to help with localization. Alternatively bedside ultrasonograpy may be used.
Most busy emergency physicians will only be able to dedicate 15 to 30 minutes to removal procedures.
Needles may be difficult to locate. If the needle is superficial and can be palpated, an incision can be made over one end and the needle removed. If the needle is deeper, then an incision can be made at the midpoint of the needle and the needle grasped with a hemostat and pushed back out through the entrance wound. If the needle is perpendicular to the skin, the entrance wound should be extended. Then pressure applied on the wound edges may reveal the needle so that it can be grasped and removed.
Wooden splinters and organic spines are difficult to remove because of their tendency to break.
Only splinters that are superficial should be removed by longitudinal traction. Otherwise the wound should be enlarged and the splinter lifted out of the wound intact. If the splinter is small and localization is difficult, then a block of tissue may be removed in an elliptical fashion and the remaining wound closed primarily. Since infection occurs frequently, subungual splinters should be removed with splinter forceps or by excising a portion of nail over the splinter and then removing the splinter intact.
Cactus spines may be removed individually or with an adhesive such as facial gel, rubber cement, or household glue.
Several techniques have been established to remove fishhooks, including the string-pull method, the needle-cover technique, or the advance-and-cut technique. Alternatively, the wound may be enlarged down to the barb and the fishhook removed. When using any of these techniques, anesthesia should be injected around the fishhook entry site.
After removal of a foreign body, the wound should be adequately cleaned and irrigated.
If multiple foreign bodies were removed, a post procedure x-ray should be obtained.
If the potential for infection is low and all foreign bodies were removed, the wound may be closed primarily.
If there is a significant risk for infection, delayed primary closure is preferred.
If a foreign body is suspected or identified radiographically but cannot be located even after thorough wound evaluation, or if the foreign body is located in an area that prohibits removal, then the patient should be informed and referred to a surgical specialist for delayed removal. If the foreign body is near a tendon or joint, the limb should be splinted. Prophylactic antibiotics are widely prescribed, but their efficacy has not been determined.
For further reading in Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7th ed., see Chapter 49, “Soft Tissue Foreign Bodies,” by Richard L. Lammers.
17 PUNCTURE WOUNDS AND BITES
David M. Cline
PUNCTURE WOUNDS
PATHOPHYSIOLOGY
The plantar surface of the foot is the most common site for puncture wounds.
Puncture wounds may injure underlying structures, introduce a foreign body, and plant inoculum for infection.
Infection occurs in 6% to 11% of puncture wounds, with Staphylococcus aureus predominating (including methicillin-resistant S. aureus-MRSA). Pseudomonas aeruginosa is the most frequent etiologic agent in post-puncture wound osteomyelitis, particularly when penetration occurs through the sole of an athletic shoe.
Post-puncture wound infections and failure of an infection to respond to antibiotics suggests the presence of a retained foreign body. Organized evaluation and management is necessary to minimize complications.
CLINICAL FEATURES (SEE ALSO CHAPTER 11)
Wounds older than 6 hours with large and deep penetration and obvious visible contamination, which occurred outdoors with penetration through footwear, carry the highest risk of infectious complications.
Patients with a history of diabetes mellitus, peripheral vascular disease, immunosuppression, or advanced age are at increased risk of infection.
On physical examination, the likelihood of injury to structures beneath the skin must be determined. Distal function of tendons, nerves, and vessels should be assessed carefully.
The site should be inspected for location, condition of the surrounding skin, and the presence of foreign matter, debris, or devitalized tissue.
Infection is suggested when there is evidence of pain, swelling, erythema, warmth, fluctuance, decreased range of motion, or drainage from the site.
DIAGNOSIS AND DIFFERENTIAL
Multiple view, “soft tissue,” radiographs should be obtained of all infected puncture wounds and of any wound suspicious for a retained foreign body (see Chapter 16 for recommendations on the diagnosis and management of retained foreign bodies).
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Many aspects of the treatment of puncture wounds remain controversial.
Uncomplicated, clean punctures less than 6 hours after injury require only low-pressure irrigation and tetanus prophylaxis, as indicated.
Soaking has no proven benefit. Healthy patients do not appear to require prophylactic antibiotics.
Prophylactic antibiotics “may” benefit patients with peripheral vascular disease, diabetes mellitus, and immunosuppression.
Plantar puncture wounds, deeper wounds, especially those in high-risk patients, or through athletic shoes should be treated with prophylactic antibiotics.
Fluoroquinolones (such as ciprofloxacin 500 milligrams twice daily) are recommended for plantar wounds and are acceptable alternatives to parenteral administration of a cephalosporin and aminoglycoside.
For other at risk wounds, cephalexin 500 milligrams four times daily, or a macrolide, are recommended. In general, prophylactic antibiotics should be continued for 5 to 7 days.
Ciprofloxacin is not recommended for routine use in children for prophylaxis. Cephalexin 12.5–25 milligrams/kg/dose four times daily up to 500 milligrams/dose can be used with close follow-up.
Wounds infected at presentation need to be differentiated into cellulitis, abscess, deeper spreading soft tissue infections, and bone or cartilage involvement. Plain radiographs are indicated to detect the possibility of radiopaque foreign body, soft tissue gas, or osteomyelitis. Bedside ultrasound may identify abscess.
Cellulitis usually is localized without significant drainage, developing within 1 to 4 days. There is no need for routine cultures, and antimicrobial coverage should be directed at gram-positive organisms, especially S. aureus. Seven to 10 days of a cephalexin (dose above) is usually effective.
A local abscess may develop at the puncture site, especially if a foreign body remains. Treatment includes incision, drainage, and careful exploration for a retained foreign body. The wound should be rechecked in 48 hours. Serious, deep, soft tissue infections require surgical exploration and debridement in the operating room.
Any patient who relapses or fails to improve after initial therapy should be suspected of having osteomyelitis, septic arthritis, or retained foreign body. Radiographs, white blood cell count, erythrocyte sedimentation rate, and orthopedic consultation should be obtained. Definitive management frequently necessitates operative intervention for debridement. Pending cultures, antibiotics that cover Staphylococcus including MRSA and Pseudomonas species are started. A reasonable regimen is parenteral vancomycin 1 gram IV every 12 hours (in children, 20 milligrams/kg every 12 hours) and ceftazidime1 to 2 grams IV every 8 hours (in children, 30–50 milligrams/kg/dose every 8 hours, not to exceed adult dose).
Conditions for admission include wound infection in patients with high risk for complications, immuno-compromised states; wounds with progressive cel-lulitis and lymphangitic spread; osteomyelitis; septic arthritis; and deep foreign bodies necessitating operative removal.
Tetanus prophylaxis should be provided according to guidelines (see Chapter 18). Outpatients should avoid weight bearing, elevate and soak the wound in warm water, and have follow-up within 48 hours.
NEEDLE-STICK INJURIES
Needle-stick injuries carry the risk of bacterial infection in addition to the risk of infection with hepatitis B and C, and human immunodeficiency virus (HIV).
Because recommendations in this area are complex and evolving, each hospital should have a predesigned protocol developed by infectious disease specialists for the expeditious evaluation, testing, and treatment of needle-stick injuries, including hepatitis B and HIV prophylaxis.
HIGH-PRESSURE-INJECTION INJURIES
High-pressure-injection injuries may present as puncture wounds, usually to the hand or foot. High-pressure-injection equipment is designed to force liquids (usually paint or oil) through a small nozzle under high pressure.
These injuries are severe owing to intense inflammation incited by the injected liquid spreading along fascial planes.
Patients have pain and minimal swelling.
Despite an innocuous appearance, serious damage can develop.
Pain control should be achieved with parenteral analgesics; digital blocks are contraindicated to avoid increases in tissue pressure with resultant further compromise in perfusion.
An appropriate hand specialist should be consulted immediately, and early surgical debridement should be implemented for an optimal outcome.
EPINEPHRINE AUTOINJECTOR INJURY
These injuries typically occur when a patient attempts self-injection during a rushed attempt to treat an allergic reaction.
Patients present with pain due to the needle stick, paresthesias, and epinephrine-induced vasospasm to the injected area; the entire digit may be blanched and cold.
There is no clear evidence that active treatment is better than observation alone.
The only treatment that has been shown to be beneficial is phentolamine with lidocaine. A mixture of 0.5 mL of standard phentolamine solution (5 milligrams/mL concentration) and 0.5 mL of 1% lidocaine solution will produce a 1 mL total volume containing 2.5 milligrams of phentolamine that can be subcutaneously injected directly through the site of autoinjector puncture.
Once the ischemia is resolved (no blanching, warm digit), the patient can be discharged, as relapse appears very unlikely.
HUMAN BITES
Human bites produce a crushing or tearing of tissue, with potential for injury to underlying structures and inoculation of tissues with normal human oral flora.
Human bites are most often reported on the hands and upper extremities. Infection is the major serious sequelae (see Table 17-1 for common organisms).
CLINICAL FEATURES (SEE ALSO CHAPTER 11)
Of particular concern is the closed fist injury or clenched fist injury (CFI), or reverse bite injury, which occurs at the metacarpophalangeal (MCP) region as the fist strikes the mouth and teeth of another individual.
These hand injuries are at increased risk for serious infection, and any questionable injury in the vicinity of the MCP joint should be considered a CFI until proven otherwise (see Chapter 14 for more information).
The physical examination should include assessment of the direct injury and a careful evaluation of the underlying structures, including tendons, vessels, nerves, deep spaces, joints, and bone.
Local anesthesia usually is required to perform a careful wound exploration. In a CFI, the wound must be examined through a full range of motion at the MCP joint to detect extensor tendon involvement, which may have retracted proximally in the unclenched hand.
The examination also must assess a potential joint-space violation.
Radiographs are recommended, particularly of the hand, to delineate foreign bodies and fractures.
Human bites to the hand frequently are complicated by cellulitis, lymphangitis, abscess formation, tenosynovitis, septic arthritis, and osteomyelitis. Infections from human bites are polymicrobial, with staphylococcal and streptococcal species being common isolates in addition to species-specific Eikenella corrodens.
TABLE 17-1 Common Bites and First-Line Treatment
DIAGNOSIS AND DIFFERENTIAL
History and physical examination usually will indicate a straightforward diagnosis.
There are times, however, when a patient may try to conceal or deny the true etiology of a human bite, and a high degree of suspicion is warranted, particularly when the wound is on the hand.
It is important to keep in mind that viral diseases also can be transmitted by human bites (eg, herpes simplex, herpetic whitlow, and hepatitis B).
The potential risk of acquiring HIV through a human bite appears to be negligible due to low levels of HIV in saliva.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Copious wound irrigation with a normal saline solution and judicious limited debridement of devitalized tissue are critical to initial management.
Human bites to the hand initially should be left open. Other sites can undergo primary closure unless there is a high degree of suspicion for infection.
Prophylactic antibiotics should be considered in all but the most trivial of human bites. Amoxicillin/clavulanate 500 to 875 milligrams PO twice daily (12.5–5.22 milligrams/kg/dose twice daily in children) is the antibiotic of choice.
See Chapter 14 for management of closed/clenched fist injury. Herpetic whitlow is treated with acyclovir or valacyclovir (see Chapter 184 for discussion).
Wounds that are infected at presentation require systemic antibiotics after cultures are obtained. Local cellulitis in healthy and reliable patients may be managed on an outpatient basis with immobilization, antibiotics, and close follow-up.
Moderate to severe infections require admission for surgical consultation and parenteral antibiotics. Appropriate coverage includes ampicillin/sulbactam 3 grams IV every 6 hours (in children, 25–37.5 milligrams/kg/dose every 6 hours) or cefoxitin 2.0 grams IV every 8 hours (in children 27–33 milligrams/kg/dose IV or IM up to 2.0 grams every 8 hours). Penicillin-allergic patients may be treated with clin-damycin (5–10 milligrams/kg/dose IV four times daily, up to 600 milligrams/dose) plusciprofloxacin (10 milligrams/kg/dose every 12 hours IV; maximum: 400 milligrams/dose).
All patients should receive tetanus immunization according to guidelines.
DOG BITES
CLINICAL FEATURES
Dog bites account for 80% to 90% of reported animal bites, with school-age children sustaining the majority of reported bites.
Infection occurs in approximately 5% of cases and is more common in patients older than 50 years, those with hand wounds or deep puncture wounds, and those who delay in seeking initial treatment over a 24-hour period.
A thorough history and examination as outlined in the section on human bites are required to assess the extent of the wound and the likelihood of infection.
Infections from dog bite wounds are often polymicro-bial and include aerobic and anaerobic bacteria.
DIAGNOSIS AND DIFFERENTIAL
Radiographs are recommended if there is evidence of infection, suspicion of a foreign body, bony involvement, or large dog intracranial penetration bites to the heads of small children.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
All dog bite wounds require appropriate local wound care with copious irrigation and debridement of devitalized tissue.
Primary closure can be used in wounds to the scalp, face, torso, and extremities other than the feet and hands. Lacerations of the feet and hands should be left open initially. Large, extensive lacerations, especially in small children, are best explored and repaired in the operating room.
Puncture wounds, wounds to the hands and feet, and wounds in high-risk patients should receive 3 to 5 days of prophylactic antibiotics with amoxicillin/clavulanate 500 to 875 milligrams PO twice daily (12.5–5.22 milligrams/kg/dose twice daily in children) or clindamycin (5 milligrams/kg/dose four times daily, up to 450 milligrams/dose PO) pluscipro-floxacin (15 milligrams/kg/dose every 12 hours; maximum: 500 milligrams/dose PO).
Clindamycin plus trimethoprim-sulfamethoxazole can be used for the penicillin-allergic patient.
Wounds obviously infected at presentation need to be cultured and antibiotics initiated. Reliable, low-risk patients with only local cellulitis and no involvement of underlying structures can be managed as outpatients with close follow-up.
Significant wound infections require admission and parenteral antibiotics. Examples include infected wounds with evidence of lymphangitis, lymphadenitis, tenosynovitis, septic arthritis, osteomyelitis, systemic signs, and injury to underlying structures, such as tendons, joints, or bones. Cultures should be obtained from deep structures, preferably during exploration in the operating room. Initial antibiotic therapy should begin with ampicillin/sulbactam 3 grams IV every 6 hours or clindamycin (5–10 milligrams/kg/dose IV four times daily, up to 600 milligrams/dose) plus ciprofloxacin (10 milligrams/kg/dose every 12 hours IV; maximum upto 400 milligrams/dose). If the Gram stain reveals gram-negative bacilli, a third- or fourth-generation cephalosporin or aminoglycoside should be added.
Tetanus prophylaxis should be provided according to standard guidelines.
CAT BITES
Cat bites account for 5% to 18% of reported animal bites, with the majority resulting in puncture wounds on the arm, forearm, and hand. Up to 80% of cat bites become infected.
CLINICAL FEATURES
Pasteurella multocida is the major pathogen, isolated in 53% to 80% of infected cat bite wounds.
Pasteurella causes a rapidly developing intense inflammatory response with prominent symptoms of pain and swelling.
It may cause serious bone and joint infections and bacteremia. Many patients with septic arthritis due to P. multocida have altered host defenses due to gluco-corticoids or alcoholism.
DIAGNOSIS AND DIFFERENTIAL
Radiographs are recommended if there is evidence of infection, suspicion of a foreign body, or bony involvement.
EMERGENCY DEPARTMENT CARE AND DISPOSITION
All cat bite wounds require appropriate local wound care with copious irrigation and debridement of devitalized tissue.
Primary wound closure is usually indicated, except in puncture wounds and lacerations smaller than 1 to 2 cm, because they cannot be adequately cleaned. Delayed primary closure also can be used in cosmetically important areas. Factors favoring delayed closure or avoiding simple primary closure include presentation beyond 6 hours, lack of cosmetic concern, complex repair needed, underlying injury requiring surgical intervention.
Prophylactic antibiotics should be administered to high-risk patients including those with punctures of the hand; immunocompromised patients; and patients with arthritis or prosthetic joints. The case can be made that all patients with cat bites should receive prophylactic antibiotics because of the high risk of infection. Amoxicillin/clavulanate 500 to 875 milligrams PO twice daily (12.5–5.22 milligrams/kg/dose 2 times daily in children), cefuroxime 500 milligrams PO twice daily (10–15 milligrams/kg/dose twice daily in children), or doxycycline 100 milligrams PO twice daily in adults (in children, 1–2 milligrams/kg/dose twice daily, up to 100 milligrams/dose) administered 3 to 5 days are appropriate.
For cat bites that develop infection, evaluation and treatment are similar to those for dog bite infections. Penicillin is the drug of choice for P. multocida infections.
Tetanus prophylaxis should be provided according to standard guidelines.
RODENTS, LIVESTOCK, EXOTIC AND WILD ANIMALS
Rodent bites are typically trivial, rodents are not known to carry rabies, and these bites have a low risk for infection.
Livestock and large game animals can cause serious injury. There is also a significant risk of infection and systemic illness caused by brucellosis (see Chapter 100), leptospirosis (see Chapter 100), and tularemia (see Chapter 99).
Aggressive wound care and broad-spectrum antibiotics are recommended. Specific agents are listed in Table 17-1.
For further reading in Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 7th ed., see Chapter 50, “Puncture Wounds and Bites,” by Robert A. Schwab and Robert D. Powers.