Common Acute Hand Infections - December 1, 2003

COVER = ARTICLE
PRACTICAL=20 THERAPEUTICS

Common Acute Hand Infections

DWAYNE C. CLARK, CDR, MC, USN, Naval Hospital = Jacksonville,=20 Jacksonville, Florida

Hand infections can result in significant morbidity = if not=20 appropriately diagnosed and treated. Host factors, location, and=20 circumstances of the infection are important guides to initial = treatment=20 strategies. Many hand infections improve with early splinting, = elevation,=20 appropriate antibiotics and, if an abscess is present, incision = and=20 drainage. Tetanus prophylaxis is indicated in patients who have = at-risk=20 infections. Paronychia, an infection of the epidermis bordering = the nail,=20 commonly is precipitated by localized trauma. Treatment consists = of=20 incision and drainage, warm-water soaks and, sometimes, oral = antibiotics.=20 A felon is an abscess of the distal pulp of the fingertip. An = early felon=20 may be amenable to elevation, oral antibiotics, and warm water or = saline=20 soaks. A more advanced felon requires incision and drainage. = Herpetic=20 whitlow is a painful infection caused by the herpes simplex virus. = Early=20 treatment with oral antiviral agents may hasten healing. Pyogenic = flexor=20 tenosynovitis and clenched-fist injuries are more serious = infections that=20 often require surgical intervention. Pyogenic flexor tenosynovitis = is an=20 acute synovial space infection involving a flexor tendon sheath. = Treatment=20 consists of parenteral antibiotics and sheath irrigation. A = clenched-fist=20 injury usually is the result of an altercation and often involves = injury=20 to the extensor tendon, joint capsule, and bone. Wound = exploration,=20 copious irrigation, and appropriate antibiotics can prevent = undesired=20 outcomes. (Am Fam Physician 2003;68:2167-76. Copyright© 2003 = American=20 Academy of Family Physicians.)

A PDF version of this document is = available. Download = PDF=20 now (10 pages /239 KB). More=20 information on using PDF=20 files.

The hand can=20 easily be injured during everyday activities. Any trauma to the hand,=20 particularly a penetrating trauma, may introduce damaging pathogens. The = hand's=20 compartmentalized anatomy may contribute to the development of an = infection. If=20 an infection is not appropriately diagnosed and treated, significant = morbidity=20 can result.

See page 2113 for = definitions of=20 strength-of-evidence levels.

Some general wound-care principles apply to all hand=20 infections.^1,2 Most hand infections can be treated with an = initial=20 period of rest, immobilization, and elevation. Splint immobilization and = elevation can protect the affected area, minimize edema, and decrease = pain. If a=20 single digit is infected, a finger splint supporting the interphalangeal = joints=20 in extension is usually adequate. If the palm, the metacarpophalangeal = (MCP)=20 joint, or larger portions of the hand are infected, splinting in a = position of=20 function (Figure 1) can help protect against flexion=20 contractures and hasten rehabilitation.

FIGURE 1. The position of function, a safe = splint=20 position for the hand. The hand is held as if holding the bowl of = a wine=20 glass. The wrist should be extended approximately 25 degrees and = should=20 allow alignment of the thumb with the forearm. The = metacarpophalangeal=20 joint should be moderately flexed to 60 degrees, and the = interphalangeal=20 joints should be slightly flexed (10 degrees for the proximal=20 interphalangeal joint and 5 degrees for the distal interphalangeal = joint).=20 The thumb should be abducted away from the palm.

FIGURE 2. Acute paronychia of the index=20 finger.
Reprinted with permission from Lamb DW, Hooper G. = Colour=20 guide hand conditions. New York: Churchill Livingstone, 1994:56.=20

Open wounds should be gently, but copiously, irrigated to remove = debris and=20 purulent material. When an abscess has formed or pus is present, = incision and=20 drainage are necessary. Devitalized and contaminated tissue serves as a = potent=20 culture medium and should be promptly debrided. Minor infections may = resolve=20 with these measures alone.

More severe infections require oral or parenteral antibiotics and, = possibly,=20 surgical intervention. Moist heat may be used to increase local = circulation and=20 may enhance antibiotic delivery to the tissue. Photographs and diagrams = of the=20 hand may be helpful in assessing the success of therapy. All = tetanus-prone=20 wounds (e.g., soil, animal, oral, fecal exposure) require tetanus=20 prophylaxis.

It is important to assess the patient's underlying medical status as = well as=20 the circumstances of the infection (Table 1).^{1-10 =}Antibiotic selection is guided by a knowledge of the organisms = encountered=20 in common hand infections (Table 2).

TABLE 1
Host Factors and Important=20 Considerations in Common Hand Infections

Host factor	Considerations
Diabetes mellitus	Higher incidence of mixed and pure gram-negative = organisms=20 (approaching 30 to 40 percent) requiring use of = broader=20 spectrum antibiotics. Susceptible to more severe=20 infections and more likely to require=20 surgical intervention. Patients on renal dialysis = pose the=20 highest risk.⁸
Immunocompromised state (patients on = immunosuppressive=20 therapy and patients with HIV infection or AIDS)	More susceptible to opportunistic = infections. Pyogenic=20 flexor tenosynovitis as well as cutaneous abscesses = are known=20 potential sequelae of disseminated Neisseria=20 gonorrhoeae and are more common in patients who = are=20 immunocompromised.^1,3,5 Candidal flexor = tenosynovitis infection has been reported in patients = whoare=20 immunocompromised.⁷
Intravenous drug use	Mixed aerobic and anaerobic hand infections are = common and=20 usually caused by oral pathogens. Patients = commonly=20 present with subcutaneous abscesses and tendon = sheath=20 infections. They require the use of broader = spectrum=20 antibiotics.^1-4
Tropical fish aquarium exposure	The culprit organism is more likely to be Mycobacterium marinum. This organism = is quite=20 fastidious and often responsible for chronic, indolent = hand=20 infections.⁹
Possible sexually transmitted disease exposure	Flexor tenosynovitis as well as cutaneous abscesses = are=20 known potential sequelae of disseminated N.=20 gonorrhoeae infection.^1,3,5,6,10=20

HIV =3D human immunodeficiency virus; AIDS = =3D acquired=20 immunodeficiency syndrome.
Information from = references 1=20 through 10.

TABLE 2
Common Hand Infections, Usual = Offending=20 Organisms, and Appropriate Therapeutic Regimens

Condition=20	Most common offending = organisms=20	Recommended antimicrobial = agents=20	Comments=20
Paronychia	Usually Staphylococcus aureus or=20 streptococci; pseudomonas, gram-negative bacilli, and=20 anaerobes may be present, especially in patients with = exposure=20 to oral flora	First-generation cephalosporin or = anti-staphylococcal=20 penicillin; if anaerobes or Escherichia = coli=20 are suspected, oral clindamycin (Cleocin) or a = beta-lactamase=20 inhibitor such as amoxicillin-clavulanate potassium=20 (Augmentin)	Incision and drainage should be performed if = infection is=20 well established. If infection is chronic, suspect=20 Candida albicans. Early infections without=20 cellulitis may respond to conservative therapy. =
Felon	S. aureus, streptococci	First-generation cephalosporin or = anti-staphylococcal=20 penicillin	Incision and drainage should be performed if = infection is=20 well established. Oral antibiotic therapy usually = is=20 adequate.
Herpetic whitlow	Herpes simplex virus types 1 and 2	Supportive therapy	Antivirals may be prescribed if infection has been = present=20 for less than 48 hours. For recurrent herpetic = whitlow,=20 suppressive therapy with an antiviral agent may be = helpful.=20 Consider antibiotics if secondarily infected. = Incision=20 and drainage are contraindicated.
Pyogenic flexor tenosynovitis	S. aureus, streptococci, = anaerobes	Parenteral first-generation cephalosporin or=20 antistaphylococcal penicillin and = penicillin=20 G or Parenteral beta-lactamase = inhibitor such=20 as ampicillin-sulbactam (Unasyn) Use ceftriaxone=20 (Rocephin) or a fluoroquinolone if Neisseria=20 gonorrhoeae is suspected.	Early surgical assessment is suggested. N.=20 gonorrhoeae or C. albicans = should be=20 suspected in sexually active or immunocompromised = patients.=20 Incision and drainage with catheter irrigation of = the=20 sheath should be performed if no improvement within = the first=20 12 to 24 hours of conservative therapy.
Human bite, clenched-fist injury	S. aureus, streptococci, Eikenella corrodens, gram-negative = bacilli,=20 anaerobes	Parenteral first-generation cephalosporin or=20 antistaphylococcal penicillin and = penicillin=20 G or Beta-lactamase inhibitor such = as=20 ampicillin-sulbactam or amoxicillin-clavulanate=20 potassium or Second-generation = cephalosporin=20 such as cefoxitin (Mefoxin)	Prophylactic oral antibiotics should be used if = outpatient=20 therapy is chosen. Wounds should be explored, = copiously=20 irrigated, and surgically debrided. = Hospitalization and=20 parenteral antibiotics often are indicated.

Paronychia

Paronychia is an infection of the perionychium (also called = eponychium),=20 which is the epidermis bordering the nail. Paronychia results in = swelling,=20 erythema, and pain at the base of the fingernail (Figure = 2). A=20 review of acute and chronic paronychia was recently published in this=20 journal.¹¹ Acute paronychia is usually the result of = localized trauma=20 to the skin surrounding the nail plate. This infection is usually the = result of=20 dishwashing, a manicure, an ingrown nail, or a hangnail, and usually = becomes=20 evident two to five days post-trauma.^12,13 Paronychia in = children is=20 usually the result of thumb sucking.

The responsible organisms in acute paronychia are usually Staphylococcus aureus and Streptococcus = pyogenes;=20 pseudomonas organisms are rarely responsible.^3,4,11,12,14 = Warm water=20 soaks alone may be effective if an abscess has not formed. If = spontaneous=20 drainage does not occur or if an abscess is well established, incision = and=20 drainage are warranted. Surgical treatment techniques are well described = in the=20 medical literature.^3,4,11,12 Direct damage and incision to = the=20 cuticle are not recommended. For severe infections, an = antistaphylococcal=20 penicillin or a first-generation cephalosporin should be=20 given.^3,12,14 Clindamycin (Cleocin) or = amoxicillin-clavulanate=20 potassium (Augmentin) may be considered if anaerobes and Escherichia=20 coli are suspected organisms.^4,11A tetanus booster = should be=20 administered when appropriate. Chronic paronychia often is caused by a = candidal=20 infection that may respond to treatment with a topical = antifungal/steroid=20 agent.^11,12

FIGURE 3. The fingertip pulp, compartmentalized = by 15 to=20 20 fibrous septa running from the periosteum to the skin. The = small=20 compartments contain eccrine sweat glands and fat globules. The = sweat=20 glands provide a potential portal of entry for bacteria. An = abscess in=20 these noncompliant compartments is called a=20 felon.

Felon

A felon is an abscess of the distal pulp or phalanx pad of the=20 fingertip.^1,2,12,14,15 The pulp of the fingertip is divided = into=20 small compartments by 15 to 20 fibrous septa that run from the = periosteum to the=20 skin (Figure 3). Abscess formation in these relatively = noncompliant compartments causes significant pain, and the resultant = swelling=20 can lead to tissue necrosis. Because the septa attach to the periosteum = of the=20 distal phalanx, spread of infection to the underlying bone can result in = osteomyelitis.¹⁶

A felon usually is caused by inoculation of bacteria into the = fingertip=20 through a penetrating trauma. The most commonly affected digits are the = thumb=20 and index finger.¹⁵ Common predisposing causes include = splinters,=20 bits of glass, abrasions, and minor puncture wounds. A felon also may = arise when=20 an untreated paronychia spreads into the pad of the fingertip. Felons = have been=20 reported following multiple finger-stick blood tests.¹²

FIGURE 4. Felon of the fingertip. The patient = presented=20 with three days of increased swelling, redness, and severe pain of = the=20
fingertip.

Patients present with rapid onset of severe, throbbing pain, with = associated=20 redness and swelling of the fingertip (Figure 4). The = pain=20 caused by a felon is usually more intense than that caused by = paronychia. The=20 swelling will not extend proximal to the distal interphalangeal joint.=20 Occasionally, the high pressure in the fingertip pad will cause a felon = to=20 spontaneously drain, resulting in a visible sinus.

If diagnosed in the early stages of cellulitis, a felon may be = amenable to=20 treatment with elevation, oral antibiotics, and warm water or saline=20 soaks.^4,12,15 Bone and soft tissue radiographs should be = obtained to=20 evaluate for osteomyelitis or a foreign body. Tetanus prophylaxis should = be=20 administered when necessary.

If fluctuance is present, incision and drainage are appropriate. The=20 preferred techniques^3,4,12,14,15 are a single volar = longitudinal=20 incision or a high lateral incision (Figure 5). = Potential=20 complications of a felon and felon drainage include an anesthetic = fingertip, a=20 neuroma, and an unstable finger pad. The family physician's comfort = level and=20 the availability of a surgeon may determine whether this procedure is = performed=20 in the family physician's office, or the patient is referred.

Incision techniques not recommended include the "fish-mouth" = incision, the=20 "hockey stick" (or "J") incision, and the transverse palmar=20 incision.^3,4,12 These incisions are more likely to result in = painful,=20 sensitive scars and damage to neurovascular structures.

Volar = longitudinal or high=20 lateral incision and drainage are indicated if a felon is=20 fluctuant.

Postoperative care includes loose packing, splinting, and elevation = of the=20 hand for approximately 24 hours. Dry dressing changes with twice-daily = saline=20 soaks, range-of-motion activities and, eventually, scar massage may = accelerate=20 return to normal activity.¹²

Gram stain should guide initial antibiotic therapy. As with = paronychia, the=20 most common isolated organism is S. aureus. Empiric = antibiotic=20 coverage with a first-generation cephalosporin or antistaphylococcal = penicillin=20 usually is adequate treatment for an uncomplicated felon. The = recommended length=20 of treatment varies from five to 14 days and depends on the clinical = response=20 and severity of infection.^3,12 Methicillin-resistant S.=20 aureus has been reported in felons and other hand infections; = clinical=20 response, as well as bacterial cultures, should be followed=20 closely.^17,18

FIGURE 5. Felon drainage. The incision location = should=20 avoid injury to the flexor tendon sheath, digital neurovascular=20 structures, and nail matrix. The incision is performed under = digital=20 anesthesia, and a tourniquet may be applied to enhance = visualization of=20 the surgical field. Of two commonly used techniques, the volar=20 longitudinal incision and the high lateral incision, the former is = preferred. (A) The incision starts 3 to 5 mm = from the=20 distal interphalangeal (DIP) joint flexor crease and extends to = the end of=20 the distal phalanx. The depth of the incision is to the dermis. (B) The subcutaneous tissues are then gently = dissected and=20 explored with a small hemostat. Necrotic skin edges are excised, = and the=20 abscess is decompressed and irrigated. The high lateral incision = is made=20 on the nonoppositional side of the appropriate digit (ulnar side = of the=20 index, middle, and ring fingers, and radial aspect of the thumb = and fifth=20 digit). (C) The incision starts 5 mm distal to = the flexor=20 DIP crease and continues parallel to the lateral border of the = nail plate,=20 maintaining approximately 5 mm between the incision and the nail = plate=20 border. This distance should allow for avoiding the more volar=20 neurovascular structures. (D) The incision is = extended to=20 end slightly distal to the unattached portion of the nail plate. = The=20 subcutaneous tissue is sharply dissected just volar to the volar = cortex of=20 the distal phalanx. The wound is bluntly dissected and explored, = and the=20 abscess is decompressed and irrigated. (E) In = both=20 techniques, the wound may be packed with sterile gauze. The gauze = should=20 be removed in approximately 24 to 48 hours, and the wound allowed = to close=20 by secondary intention.

Herpetic Whitlow

Viral infections of the hand are rare, with the exception of the = clinical=20 entity known as herpetic whitlow. Herpetic whitlow results from = autoinoculation=20 of type 1 or type 2 herpes simplex virus into broken skin. The infection = may=20 occur as a complication of primary oral or genital herpes lesions. = Health care=20 workers exposed to oral secretions (e.g., dental hygienists, respiratory = therapists) can be affected if they are not using universal = precautions.

FIGURE 6. Herpetic whitlow mimicking a felon. = In a=20 patient with whitlow, the pulp of the finger pad should be soft; a = felon=20 will feel significantly tense.
Reprinted with permission = from Lamb=20 DW, Hooper G. Colour guide hand conditions. New York: Churchill=20 Livingstone, 1994:62.

Signs and symptoms of herpetic whitlow include the abrupt onset of = edema,=20 erythema, and significant localized tenderness of the infected finger. = Often,=20 the pain is out of proportion to the physical findings. Fever, = lymphadenitis,=20 and epitrochlear and axillary lymphadenopathy may be present. Small, = clear=20 vesicles initially are present. These may eventually coalesce and, as = the fluid=20 becomes cloudier, mimic a pyogenic bacterial infection. If in a distal = location,=20 herpetic whitlow may mimic paronychia or felon (Figure = 6). A=20 history of localized trauma to the nail cuticle may be helpful in = distinguishing=20 herpetic whitlow from paronychia. A diagnosis of herpes simplex virus = infection=20 may be confirmed with a Tzanck test, viral culture, or DNA amplification = technique.

Herpetic whitlow usually is self-limited and resolves in two to three = weeks.=20 Treatment within the first 48 hours of symptom onset with acyclovir = (Zovirax),=20 famciclovir (Famvir), or valacyclovir (Valtrex) may lessen the severity = of=20 infection, but randomized controlled trials have not been=20 performed.^19-21 Because viral shedding continues until the = epidermal=20 lesion is healed, contact with the lesion should be avoided by keeping = the=20 affected digit covered with a dry dressing. Incision and drainage of the = lesion=20 may cause viremia or bacterial infection.^2-4 Patients should = be=20 advised that the infection recurs in 30 to 50 percent of cases, but the = initial=20 infection is typically the most severe. Treatment with antivirals may be = beneficial for recurrent herpetic whitlow if initiated during the = prodromal=20 stage.^19-23

Pyogenic Flexor Tenosynovitis

FIGURE 7. Pyogenic flexor tenosynovitis. = Appreciable pain=20 along the tendon sheath with passive extension of the digit often = is the=20 first clinical sign of this hand = infection.

The flexor tendons of the hand are enclosed in distinct synovial = sheaths. The=20 flexor tendon sheaths of the index, middle, and ring fingers extend from = the=20 distal phalanges to the distal palmar crease, and generally do not = communicate.=20 The sheath encompassing the fifth finger extends from its distal phalanx = to the=20 mid-palm, where it expands across the palm to form the ulnar bursa. The = thumb=20 flexor sheath begins at the terminal phalanx and extends to the volar = wrist=20 crease, where it communicates with the radial bursa. Anatomic variations = are=20 frequent. For example, the radial bursa can communicate with the ulnar = bursa at=20 the wrist (an infection of this area is called a "horseshoe = abscess").The=20 synovial sheaths, poorly vascularized and rich in synovial fluid, = provide an=20 optimal environment for bacterial growth. Once inoculated, infection can = spread=20 rapidly within the confines of the sheath.²Infection of the = flexor=20 tendon sheath, known as pyogenic flexor tenosynovitis (Figures 7 and=20 8), warrants early surgical evaluation.^2-4,14,24

Patients with pyogenic flexor tenosynovitis present with the four = cardinal=20 signs as described by Kanavel: (1) uniform, symmetric digit swelling; = (2) at=20 rest, digit is held in partial flexion; (3) excessive tenderness along = the=20 entire course of the flexor tendon sheath; and (4) pain along the tendon = sheath=20 with passive digit extension.²⁵ Pain with passive extension = has been=20 reported as the most clinically reproducible of these four=20 signs.^24,26

FIGURE 8. Pyogenic flexor tenosynovitis of the = index=20 finger of the right hand.
Reprinted with permission from = Lamb DW,=20 Hooper G. Colour guide hand conditions. New York: Churchill = Livingstone,=20 1994:58.

Patients typically recall some antecedent trauma or puncture wound. = The=20 trauma often is at a flexor crease; this is where the tendon sheath is = most=20 superficial. Hematogenous spread to the sheath (i.e., Neisseria=20 gonorrhoeae) occurs rarely but should be suspected if there is no = puncture=20 wound or history of trauma.^5,6

Early diagnosis and treatment of pyogenic flexor tenosynovitis is = necessary=20 to prevent tendon necrosis, adhesion formation, and spread of infection = to the=20 deep fascial spaces. Distinguishing a subcutaneous abscess from a tendon = sheath=20 infection can be challenging. A subcutaneous abscess should not have = tenderness=20 over the entire sheath, and passive mobility of the uninvolved segments = should=20 be painless.¹⁵ Elevated sheath pressures consistent with = compartment=20 syndrome pressures (i.e., higher than 30 mm Hg) have been documented in = flexor=20 tenosynovitis.²⁷ Ultrasound examination may show an abnormal = effusion=20 or abscess in the tendon sheath.²⁸

Infections in the early stage may respond to nonoperative treatment = that=20 includes splinting, elevation, and intravenous antibiotics. Rings should = be=20 removed from the affected finger and other fingers of the hand as soon = as=20 possible.

Causative agents for flexor tenosynovitis typically include = Staphylococcus=20 and Streptococcus species.^1,2,24 Mixed infections should be = suspected=20 in patients who have diabetes or are immunocompromised.^8,24=20 Disseminated gonorrhea⁵ and Candida=20 albicans⁷ infection have been reported as causes of = flexor=20 tenosynovitis in immunocompromised patients.

Gram stain and wound culture growth should guide antibiotic therapy. = Empiric=20 therapy should include parenteral penicillin plus either an = antistaphylococcal=20 penicillin or a first-generation cephalosporin.^1,3,4,24=20 Alternatively, a parenteral beta-lactamase inhibitor may be used as = monotherapy.=20 Tetanus prophylaxis should be administered if necessary.

If medical = treatment of=20 pyogenic flexor tenosynovitis shows no improvement in 12 to = 24=20 hours, surgery is necessary.

If there is no improvement within 12 to 24 hours, surgical = intervention is=20 warranted. Early surgical treatment should be considered if the patient = is=20 immunocompromised or has diabetes.²⁴ Surgical treatment = involves=20 proximal and distal tendon exposure, and careful insertion of a catheter = or=20 feeding tube into the tendon sheath with copious intraoperative=20 irrigation.^1,4,15,24,25 Postoperatively, the catheter may be = left in=20 place for 24 hours to allow for further low-flow irrigation. One = retrospective=20 study²⁹ questioned the utility of postoperative irrigation = and found=20 no difference in outcome whether the catheter was left in or taken out.=20 Parenteral antibiotic therapy should be continued for at least 48 hours. = Comparable oral antibiotic therapy should then be instituted and = continued for=20 an additional five to 14 days on an outpatient basis. Physical and = occupational=20 therapy should be initiated to reduce long-term disability from scarring = and=20 contractures.

Human Bite and Clenched-Fist Injuries

Human bite injuries to the hand usually result from a direct bite or = a "fight=20 bite" (also known as a "clenched-fist" injury).^30-32 Direct = human=20 bite injuries are often visually evident. A clenched-fist injury = typically is=20 characterized by a 3- to 5-mm laceration on the dorsum of the hand or = overlying=20 an MCP joint (Figure 9). Because of the innocent = appearance of=20 this injury, patients may not seek medical attention and commonly = present with=20 advanced infection.

Three fourths = of patients=20 with a clenched-fist injury also incur a tendon, bone, = joint, or=20 cartilage injury.

A clenched-fist wound is the result of a fist striking an object, = such as=20 another person's face, with considerable force. A tooth may penetrate an = extensor tendon and MCP joint capsule, sometimes fracturing a metacarpal = or=20 phalangeal bone. Because the injury occurs with the MCP joint in = flexion,=20 injuries to the extensor tendon and joint capsule can be overlooked = easily=20 during examination of the MCP joint in extension. In a study of 191 = patients=20 with clenched-fist injuries, 75 percent had an injury to tendon, bone, = joint, or=20 cartilage.³³

Recognition of the potential severity of the injury is important in = the=20 management of a clenched-fist injury. Radiographs should be obtained to = assess=20 for fracture, foreign body, gas, or osteomyelitis. A thorough = neurovascular and=20 musculoskeletal examination should be performed. Extensor tendon = function should=20 be documented.

FIGURE 9. Clenched-fist injury. Also known as a = "fight-bite" injury, this serious injury typically is = characterized by a=20 3- to 5-mm laceration on the dorsum of the hand or overlying the=20 metacarpophalangeal joint.
Reprinted with permission from = Lamb DW,=20 Hooper G. Colour guide hand conditions. New York: Churchill = Livingstone,=20 1994:60.

Puncture wounds should be extended proximally and distally while the=20 physician is looking for extensor tendon disruption or injury. The wound = should=20 be explored, copiously irrigated, and surgically debrided. Material for = Gram=20 stain and aerobic/anaerobic cultures should be obtained from deep within = all=20 suppurative wounds before therapy is instituted. Gram stain results = should guide=20 initial antibiotic therapy. The wound should not be sutured but allowed = to heal=20 by secondary intention. The hand should be splinted in a position of = function=20 and elevated. Occupational rehabilitation can be considered once the = infection=20 has cleared.

Human bite infections are often more virulent than animal bite = injuries and=20 are polymicrobial in nature.^30,31,34 Cultures grow an average = of five=20 different organisms, three of which are usually anaerobes.³⁰ = Isolated=20 anaerobes are commonly beta-lactamase producers. S. aureus = and=20 streptococci also are commonly isolated. Eikenella = corrodens, an=20 anaerobic gram-negative rod, has been found in 10 to 29 percent of=20 infections.³⁰

Patients who present early with uncomplicated wounds (i.e., no joint = capsule=20 penetration or tendon injury, and the injury happened less than 24 hours = earlier) should be given prophylactic antimicrobial therapy.

The use of early prophylactic antibiotics in uncomplicated wounds is=20 supported by one small, randomized prospective clinical trial.³⁵⁼²⁰[Evidence level B, lower quality randomized controlled trial] This = trial=20 compared mechanical wound care alone (N =3D 15) with wound care plus = prophylactic=20 oral cefaclor (Ceclor), N =3D 16, or intravenous cefazolin (Kefzol) plus = penicillin G (N =3D 17). Patients with joint capsule penetration, tendon = injury,=20 and bites older than 24 hours were excluded from the study. All patients = were=20 hospitalized. The trial was terminated early because the infection rate = in the=20 group that received mechanical wound care alone was extraordinarily high = (47=20 percent).

None of the patients treated with antibiotics developed a subsequent=20 infection. The authors conclude that, in the treatment of uncomplicated=20 clenched-fist injuries, mechanical wound care alone is insufficient, and = oral=20 and intravenous antibiotics are equally efficacious for prophylaxis. = This trial=20 was emphasized in a recent Cochrane systematic review on antibiotic = prophylaxis=20 for mammalian bites.³⁶

Outpatient management for uncomplicated wounds (as described above) = can be=20 considered after the wound has been adequately cleaned and explored. In=20 outpatient therapy, one of three treatment options should be used: (1)=20 amoxicillin-clavulanate potassium; (2) penicillin (to cover E.=20 corrodens) plus an antistaphylococcal penicillin (such as = dicloxacillin); or=20 (3) penicillin plus a first-generation cephalosporin. First-generation=20 cephalosporins are not effective as monotherapy because some anaerobic = bacteria=20 and E. corrodens are resistant. In patients who are = allergic to=20 penicillin, clindamycin plus either a fluoroquinolone or=20 trimethoprim-sulfamethoxazole (Bactrim, Septra) should provide adequate=20 coverage. A tetanus booster should be administered if necessary.

Some clinicians believe that all clenched-fist injuries warrant = hospital=20 admission and surgical consultation.³⁴ If treated on an = outpatient=20 basis, the patient should return at 24 hours for a wound check. Hospital = admission with parenteral antibiotic administration should be considered = for=20 patients with any of the following: (1) diabetes or peripheral vascular = disease;=20 (2) immunocompromised state (secondary to disease or drugs); (3) wound = older=20 than
24 hours; (4) wound that involves injury to the extensor = tendon, joint=20 capsule, or bone; (5) questionable follow-up or compliance with = antibiotic=20 therapy; (6) systemic symptoms (e.g., fever, chills); or (7)=20 cellulitis.³⁰ If the patient is hospitalized, a = broad-spectrum=20 parenteral antibiotic (such as ampicillin-sulbactam [Unasyn] or=20 ticarcillin-clavulanate potassium [Timentin]), or a second-generation=20 cephalosporin such as cefoxitin (Mefoxin) should be administered.

Differential Diagnosis

Several noninfectious conditions, some of which can be difficult to=20 distinguish, can mimic a hand infection.^37,38 Crystalline = deposition=20 disease (e.g., gout, pseudogout), pyogenic granuloma, acute calcium = deposition,=20 acute nonspecific flexor tenosynovitis, brown recluse spider bites, = rheumatoid=20 arthritis, and foreign-body reactions can mimic an acute hand infection = and=20 should be considered in the differential diagnosis.

Members of various family practice departments develop = articles=20 for "Practical Therapeutics." This article is one in a series = coordinated by the=20 Department of Family Medicine at Naval Hospital Jacksonville, = Jacksonville, Fla.=20 Guest editor of the series is Anthony J. Viera, LCDR, MC, USNR.

The opinions and assertions contained herein are the = private=20 views of the author and are not to be construed as official or as = reflecting the=20 views of the U.S. Navy Medical Corps or the U.S. Navy at large.

The author indicates that he does not have any = conflicts of=20 interest. Sources of funding: none reported.

Figure 1 provided by David Klemm. Figure 4 provided by = Anthony=20 J. Viera, LCDR, MC, USNR.

The Author

DWAYNE C. CLARK, CDR, MC, USN, teaches in the Department = of Family=20 Practice at Naval Hospital Jacksonville, Jacksonville, Fla. He received = his=20 medical degree from Duke University School of Medicine, Durham, N.C., = and=20 completed a residency in family medicine at Naval Hospital = Jacksonville.

Address correspondence to CDR Dwayne C. Clark, = Department of=20 Family Practice, Naval Hospital Jacksonville, 2080 Child St., = Jacksonville, FL=20 32214 (e-mail: mailto:d_c_clark@%20sar.med= .navy.mil).=20 Reprints are not available from the author.

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Nathan R, Taras JS. Common infections in the hand. In: Hunter JM, = Mackin=20 E, Callahan AD, eds. Rehabilitation of the hand: surgery and therapy. = 4th ed.=20 St. Louis: Mosby, 1995:251-60.=20
Moran GJ, Talan DA. Hand infections. Emerg Med Clin North Am=20 1993;11:601-19.=20
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