He denies any medical problems. The photograph shows what you see on examination.
What injury are you concerned about, and what is your management plan?
See p. 27.
Diagnosis: Fight Bite
Clenched-fist injuries sustained from striking the mouth are a serious injury with an annual estimated incidence of 11.8 per 100,000 persons. (Am Fam Physician 2004;69:1949.) Also known as a “fight bite,” these injuries are most often caused by the fist striking the victims teeth, creating a small laceration (3 to 15 mm) or puncture wound over the dorsal third and fourth metacarpophalangeal joint of the assailant's dominant hand. (Am Fam Physician 2003;68:2167.)
These wounds may appear innocuous because of their small size, but extension of the hand after the fight deeply inoculates oral bacteria into the wound with potential involvement of the deep compartments, deep tendon spaces, and fascial layers of the hand and joint capsule, putting these patients at risk for deep soft tissue infection, septic arthritis and osteomyelitis. (Initial management of animal and human bites. UpToDate. 2011 July 25.)
The majority of patients with clenched-fist injuries are young men (median age 27 years). (Clin Infect Dis 2003;37:1481.) Delay in seeking care may contribute to the advanced nature of these infections because patients often present 24 hours or more after the acute injury because of pain, swelling, or purulent discharge. This delay in seeking medical care often results in established infection at time of presentation, often requiring hospitalization for treatment. (Clin Infect Dis 2003;37:1481; Soft tissue infections due to human bites. UpToDate. 2011 May 16.)
Patients with a suspected assault-related injury should be managed following standard trauma resuscitation algorithms. A thorough muscular and neurovascular examination of the affected upper extremity should be performed and documented if a fight bite is suspected. One study of 191 patients with clenched-fist injuries found that 75 percent of patients had some type of tendon, bone, joint, or cartilaginous injury. Extensor tendon injuries require specialized repair, and the extensor tendon function should be specifically assessed. (Am Fam Physician 2003;68:2167.)
The extensor carpi radialis longus and brevis insert at the dorsal base of the index and middle metacarpal, respectively. They are evaluated by asking the patient to make a fist and extend the wrist forcibly. These tendons are the primary extenders of the wrist. The extensor pollicis longus passes around Lister's tubercle on the dorsal aspect of the radius and inserts on the distal phalanx of the thumb. It forms the ulnar border of the anatomic snuffbox, and can often be visualized during thumb extension in a patient with limited subcutaneous fat. It is tested by asking the patient to hyperextend the distal aspect of the thumb against resistance.
The extensor digitorum communis and extensor indicis proprius are tested by asking the patient to flex the interphalangeal joints into a tight claw and actively extend the metacarpophalangeal joint. This permits the examiner to visualize the extensor digitorum communis. The examiner asks the patient to make a fist to test the extensor indicis proprius and extensor digitorum minimi, and then extend digits 2 and 5 while 3 and 4 remain flexed. The extensor carpi ulnaris, which inserts at the dorsal base of the fifth metacarpal, is evaluated by asking the patient to ulnar deviate the hand while the examiner palpates the taut tendon over the ulnar side of the wrist just distal to the ulnar head. (Emergency Orthopedics. 6th Ed. New York: McGraw-Hill; 2011.) Radiographs should be obtained to evaulate for fracture, foreign bodies such as embedded teeth, air in the joint or soft tissues suggestive of joint violation, or osteomyelitis. The presence of a bony fracture, open joint space, infection, or lack of adequate soft tissue or skin covering the wound are contraindications to repairing an extensor tendon in the ED. A tendon laceration as a result of a human bite wound is a contraindication to close and repair the injury given the high likelihood of infection. Consultation with an orthopedist or hand specialist is recommended. (Emergency Medicine Procedures. Ch. 64. New York: McGraw-Hill; 2004.)
Patients who present within hours of the injury do not have evidence of infection (tenderness, erythema, swelling, purulent drainage, lymphangitis, and fever), fracture, retained foreign body, extensor tendon injury, or joint violation, and may be candidates for ED repair. Patients with high-risk comorbid conditions such as diabetes, peripheral vascular disease, and immunocompromise, those with wounds more than 24 hours old, and patients with limited follow-up or history of noncompliance should also be considered high-risk for infection. They typically require hospital admission and intravenous antibiotics. (Am Fam Physician 2003;68:2167.)
If ED treatment is attempted, fully visualize the wound to verify that there is no tendon injury or retained foreign body. It is also important to evaluate the hand through full range of motion to exclude exclusion of joint capsule injury. If no injury to these structures is seen, the wound should be copiously irrigated and covered with a nonadherent dressing. Lacerations resulting from clenched-fist injuries should not be sutured but allowed to heal by secondary intention. (Tintinalli's Emergency Medicine: A Comprehensive Study Guide. Ch. 41, 8th Ed. New York: McGraw-Hill; 2014.) The hand should be splinted to the elbow with a volar splint, with the fingers flexed in the “wine glass holding” flexed position to the elbow in a position of function.
Fight bite injuries often are caused by polymicrobial pathogens. A 2003 multicenter prospective study of 50 patients with infected human bites most commonly found Streptococcus species (84%), followed by Staphylococcus (52%), and Eikenella corrodens (30%). (Clin Infect Dis 2003;37:1481.) Human bites are also known to transmit herpes, actinomycosis, syphilis, tetanus, and hepatitis B and C but no standard postexposure prophylaxis is currently recommended for this injury mechanism. (Tintinalli's Emergency Medicine: A Comprehensive Study Guide. Ch. 41, 8th Ed. New York: McGraw-Hill; 2014.)
A three- to five-day course of prophylactic antibiotics (typically amoxicillin-clavulanic acid 875 mg/125 mg twice daily) is recommended. Other options include one double-strength tablet trimethoprim-sulfamethoxazole twice daily, cefuroxime 500 mg twice daily, ciprofloxacin 500–750 mg twice daily, moxifloxacin 400 mg once daily plus clindamycin 450 mg three times daily. (Clin Infect Dis 2003;37:1481.) Tetanus immune globulin and tetanus toxoid should be administered to patients who have had two or fewer primary immunizations. Tetanus toxoid alone can be given to those who have completed a primary immunization series but who have not received a booster for more than five years. (Soft tissue infections due to human bites. UpToDate. 2011 May 16.) Close follow-up with reevaluation within one to two days is recommended for possible delayed primary closure if necessary and wound reevaluation. (Tintinalli's Emergency Medicine: A Comprehensive Study Guide. Ch. 41, 8th Ed. New York: McGraw-Hill; 2014; Soft tissue infections due to human bites. UpToDate. 2011 May 16.)
ED consultation with a hand surgeon is recommended if evidence of infection or joint and tendon involvement exists. Patients with obvious infection require systemic intravenous antibiotics, often ampicillin-sulbactam 3 g every six hours, or piperacillin/tazobactam 4.5 g every eight hours, ticarcillin/clavulanic acid 3.1 g every four hours, or ceftriaxone 1 g every 24 hours plus metronidazole 500 mg every eight hours, surgical exploration, irrigation, and debridement. Gram stain and aerobic/anaerobic cultures should be obtained from all suppurative wounds before antibiotic therapy is initiated. (Am Fam Physician 2003;68:2167; Tintinalli's Emergency Medicine: A Comprehensive Study Guide. Ch. 41, 8th Ed. New York: McGraw-Hill; 2014; Soft tissue infections due to human bites. UpToDate. 2011 May 16.)
Fourteen days of intravenous antibiotic therapy is recommended for bacteremia. Otherwise, cellulitis and skin abscess usually respond to five to 10 days of therapy. Intravenous antibiotic therapy may be switched to outpatient oral therapy with evidence of clinical improvement. (Soft tissue infections due to human bites. UpToDate. 2011 May 16.) One study found that 71 percent of clenched-fist injury patients required hospitalization, with the median length of stay of three days. (Clin Infect Dis 2003;37:1481.)
This patient was started on intravenous ampicillin-sulbactam in the ED. He was then taken to the operating room for incision and drainage by a hand specialist. No extensor tendon injury or joint involvement was noted during his operative examination, and he was discharged on oral amoxicillin-clavulanic acid. He was found to be healing well in the clinic one week later. (Photograph.)
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