Orthopedic Surgery for Hand Infections

Background

Hand infections include the following [1:

These infections can range from routine problems (treated with oral antibiotics, immobilization, and limited incision and drainage) [2to catastrophic surgical emergencies (resulting in significant compromise of hand function). They will continue to be a routine problem encountered by emergency physicians, primary care physicians, and hand specialists. [3 The purpose of this article is to provide a systematic approach to the diagnosis, evaluation, and treatment of hand infections.

Clinicians need to be aware of the increasing incidence of infections with more virulent microorganisms. [4Community-acquired infections with methicillin-resistant Staphylococcus aureus (MRSA) are encountered in nearly every area of the body, and the hand is no exception. [567In addition, with the growing number of cancer survivors, transplant patients, and patients living with HIV infection, the surgeon can anticipate treating more complex polymicrobial hand infections. [8]

For patient education resources, see the Skin Conditions and Beauty Center, as well as Hand Injuries and Finger Infection.

Etiology

Hand infections usually result from an injury, most commonly a laceration or an animal bite. [910Most patients recall an inciting event that resulted in the inoculation of bacteria into the hand. Infections of the nail and of the nail folds can result from a nail deformity. One study found that the most common etiologies of wrist-joint infection were gout, pseudogout, and cellulitis; the incidence of septic arthritis was low. [11]

Acute paronychia

Acute paronychia involves the soft tissue around the fingernail and usually results from the inoculation of bacteria (most commonly S aureus) into the paronychia tissue from nail trauma or nail manipulation.

Drain superficial abscesses with limited incision and drainage. Obtain cultures if possible. If the infection resulted from an ingrown nail, excision of the radial or ulnar one fourth to one half should be performed at the time of incision and drainage. Infections that involve the eponychial fold can be drained by elevating the eponychium, either sharply or with a freer or elevator.

The patient should receive a course of oral antibiotics with good staphylococcal coverage (eg, intravenous [IV] cefazolin or oral cephalexin). In addition, the patient should soak the finger in antiseptic solution 2-3 times a day.

Chronic paronychia

Chronic paronychia usually is caused by Candida albicans and occurs most commonly from chronic immersion in water (as in dishwashers), previous trauma, or nail defects. Treatment with topical antifungal agents and behavior modification is occasionally successful. Excision of a portion of the nail or removal of the entire nail may be necessary.

Felon

felon is a subcutaneous abscess over the distal pulp of a digit or thumb. Felons usually result from a penetrating injury. The pulp contains multiple compartments separated by fibrous septa that make infections in this area complex.

Surgical drainage is necessary when an area of palpable fluctuance is present. Use of several incisions has been described for drainage. However, the preferred incision is radial or ulnar longitudinal. Incisions directly over the finger pad or tip are avoided. Subcutaneous septa should be broken up to drain all areas of infection, and the wound is left open.

After drainage, warm antiseptic soaks and oral antibiotics are administered. The antibiotic is based on the nature of the infection. Parenteral antibiotics should be considered in patients with diabetes or in those who are immunocompromised. Persistent chronic paronychial infections may also require IV antibiotics.

Deep-space infections

Deep-space infections in the hands are possible. The two deep spaces in the palm are the midpalmar space and the thenar space. Infections in these areas usually result from injuries such as bites or puncture wounds. Such infections may cause cellulitis, fluctuance, or pain.

In addition, the second, third, and fourth web spaces are potential sites for infection. Web-space infections can spread from the palmar subfascial space in a dorsal direction, forming what is commonly referred to as a "collar button abscess." On examination, patients typically have pain, swelling, and fluctuance on the palmar or dorsal web-space surface.

Flexor tenosynovitis

Flexor tenosynovitis is a potentially devastating infection that can result in significant scarring of the flexor tendon sheath with resultant compromise in hand function. [121314 These infections usually are caused by a penetrating injury (eg, bite, puncture wound). In the early 1900s, Kanavel described the following tetrad of physical findings in patients with flexor tenosynovitis:

  • Flexed position of the digit
  • Fusiform swelling of the digit
  • Pain with passive extension
  • Excruciating tenderness over the course of the flexor tendon sheath

Flexor tenosynovitis may also occur without Kanavel signs, particularly in immunocompromised patients.

Kameyama et al studied stenosing flexor tenosynovitis (SFTS) in diabetic patients and nondiabetic patients to identify the relative frequency of multiple-digit involvement in these two populations. According to the authors, diabetic patients showed a significantly higher prevalence of multiple-digit SFTS than nondiabetic patients did, and limited joint mobility in diabetic patients was found to be closely associated with multiple-digit SFTS. [15]

In most cases, patients with flexor tenosynovitis require urgent incision and drainage of the flexor tendon sheath. Broad-spectrum antibiotic coverage against staphylococci is initiated after cultures are obtained. Then, culture-specific antibiotics are given. There is some evidence that conservative treatment may be sufficient for some cases of uncomplicated flexor tenosynovitis. [16]

Septic arthritis

Septic arthritis usually occurs as a sequela of open skeletal trauma or a bite wound. Patients with inflammatory arthritis are at increased risk for joint-space infections. Tenderness and swelling of the joint are signs of potential infection. Puncture wounds over the joint should suggest potential septic arthritis. The differential diagnosis includes goutpsoriatic arthritis flare, and systemic lupus erythematosus.

Staphylococci and streptococci are most commonly isolated in septic joint cultures. Arthrotomy is the preferred treatment, as opposed to joint aspiration. The latter can be used to aid diagnosis; however, arthrotomy is required for adequate drainage of the infection. The interphalangeal (IP) joints (proximal and distal) can be accessed through a dorsal or midaxial incision. The collateral ligaments often must be released to allow access to the joint capsule. The metacarpophalangeal (MCP) joint can be accessed via a dorsal approach.

A 10-day course of culture-specific antibiotics is required.

Osteomyelitis

Osteomyelitis can occur from an acute event, such as a penetrating wound or open fracture, or as a late sequela of a fracture or other surgery. Patients with a history of diabetes or other immunocompromising conditions are at higher risk for osteomyelitis. Diagnosis of this condition is based on the signs seen with other infections: cellulitis, warmth, and tenderness. In addition, recurrent infections in the same location may be a sign of infection of the underlying bone. Laboratory studies and radiographs can assist in making the appropriate diagnosis (see Workup).

Treatment consists of debridement of the devitalized bone, as well as antibiotics, usually a prolonged course of 6 weeks.

Herpetic whitlow

Herpetic whitlow is a viral infection that is caused by the herpes simplex virus and that may resemble a felon or paronychia. [1718 These infections usually occur in medical or dental personnel. The history provides important clues to the diagnosis. The patient first notices pain, then erythema before the development of the herpetic vesicle.

Treatment of herpetic whitlow is nonoperative; therefore, differentiating these infections from bacterial felons and paronychia is important. The diagnosis can be confirmed by obtaining cultures of the vesicles. Overall, the infection has a self-limited course. Therapy consists of pain control. Topical antiviral agents have been recommended in patients who are immunocompromised. A 20% risk of reactivating the herpetic infection has been reported.

Prognosis

If the hand infection has been treated appropriately with measures such as eradication of the abscess and devitalized tissue, the risk of recurrence is minimal. Certain infections (eg, herpetic whitlow), however, have a 20% recurrence risk.

In patients with septic tenosynovitis of the hand, the presence of a subcutaneous abscess may be predictive of persistent 

Clinical Presentation


History

A thorough history of a hand infection includes determination of the onset, duration, any recent trauma, and any systemic symptoms (eg, fever, chills, diaphoresis). [3Most patients present with a 2- to 3-day history of cellulitis, swelling, and, occasionally, drainage.

Review of the patient's past medical history is important, because individuals with diabetes or an immunocompromised status require more aggressive treatment and closer observation. [23Obtaining the patient's immunization history is also important. If the patient's tetanus status is unknown or out of date, administer tetanus prophylaxis.

Physical Examination

The physical examination should include a thorough examination of the hand, with particular attention to the following:

  • Lymphangitis
  • Areas of fluctuance
  • Range of motion
  • Foreign bodies
  • Presence or absence of Kanavel signs - (1) Flexed position of the digit, (2) fusiform swelling of the digit, (3) pain with passive extension, and (4) excruciating tenderness over the course of the flexor tendon sheath

The four Kanavel signs are used to differentiate between infectious tenosynovitis and a superficial or localized abscess. 



Laboratory Studies

A complete blood count (CBC) should be obtained. An elevated white blood cell (WBC) count can indicate the presence of infection. In the case of particularly severe infections, the CBC may provide a measure of the patient's progress.

A prothrombin time (PT) and an activated partial thromboplastin time (aPTT) should be obtained before surgical treatment in patients who are receiving long-term anticoagulant therapy.

Glucose levels should be checked in all patients with a history of diabetes. In those patients with active infections, blood glucose levels are often elevated and difficult to control. Furthermore, blood glucose control is important for wound healing. It is also important to check the glucose levels of any patient who has a history of frequent or particularly severe infections to rule out occult diabetes.

In general, the chemistry panel should be checked in patients who have a history of dehydration (secondary to vomiting or sepsis). The chemistry panel of elderly patients should be checked before surgery.

The erythrocyte sedimentation rate (ESR) is elevated in cases of septic arthritis and osteomyelitis. However, patients with inflammatory arthritis may have elevated ESRs without infection.

If there is a clinical suspicion of septic arthritis, a joint aspirate should be sent for Gram staining, culturing, and sensitivity testing. In addition, cell count assessment, glucose and protein level determinations, and crystal analysis help in distinguishing between an infected joint and a joint with inflammatory arthritis or gout/pseudogout.

Imaging Studies

Plain radiographs (with three views of the hand) are important to rule out the presence of foreign bodies, fractures, and subcutaneous air, which could indicate gas gangrene or acute or chronic osteomyelitis.

Magnetic resonance imaging (MRI) may be helpful for assessing soft-tissue abscess and osteomyelitis. In a study by Eshed et al, flexor tenosynovitis as identified on MRI of the hand and wrist was found to be a strong predictor of early rheumatoid arthritis, with a sensitivity of 60% and a specificity of 73%. When MRI was combined with a positive serum rheumatoid factor (RF), sensitivity was 83% and specificity 63%; and when MRI was combined with serum anti-cyclic citrullinated peptides (CCP), sensitivity was 79% and specificity 73%. [22]

Ultrasonography (US) may reveal one or more soft-tissue abscesses. [23]

Bone scanning, indium-111 (111In) radionuclide studies, or computed tomography (CT) may be useful for evaluating osteomyelitis. Multidetector CT (MDCT) appears promising for detecting acute infections of the hand and wrist.


Approach Considerations

Some early infections can be managed with antibiotics. For example, antibiotic treatment is appropriate for cellulitis, and oral antibiotics are usually the appropriate first line of treatment. However, persistent cellulitis or infections in immunocompromised patients should be treated with intravenous (IV) antibiotics until the cellulitis resolves. Then, completion of a course of oral antibiotics is appropriate.

If any signs of fluctuance or purulent wound drainage are present, incision and drainage is necessary. Furthermore, cellulitic infections that are unresponsive to antibiotics may require surgical exploration. Surgeons who undertake incision and drainage should be familiar with the anatomy of the hand, including the anatomy of the nail, the course of the digital neurovascular bundles, and the deep spaces of the palm. Furthermore, appropriate management requires close postoperative monitoring.

Medical Therapy

A few important guidelines assist in the management of hand infections. [25First, cellulitis must be treated with antibiotics. Most hand infections are caused by S aureus, [3and therefore, a first-generation cephalosporin (eg, cephalexin) is usually the first drug of choice. However, the potential exists for infections with different organisms.

In fact, an increase in the incidence of community-acquired (CA) methicillin-resistant S aureus (MRSA) infections has been reported. [26456272829 In a retrospective review of 159 hand infection surgeries, Imahara and Friedrich found that 48 operations were performed for CA-MRSA, and IV drug use was found to be the only independent risk factor for CA-MRSA during that period; other factors were felon-type infection and prior hand infection. [29]

Evolving resistance patterns in MRSA should be considered. In one study of MRSA hand infections, the organism was found to exhibit significantly increased resistance to clindamycin and levofloxacin; only sporadically increased resistance to trimethoprim-sulfamethoxazole, tetracycline, gentamicin, and moxifloxacin; and no increased resistance to vancomycin, daptomycin, linezolid, and rifampin. [30 A subsequent study confirmed the finding of growing MRSA resistance to clindamycin and levofloxacin. [7]

Treatment of animal bites requires bacterial coverage that is particular to the offending animal. Human bites require coverage for Eikenella corrodens; penicillin and a first-generation cephalosporin are appropriate choices in these cases. Cat bites require coverage for Pasteurella multocida [31; IV ampicillin-sulbactam or oral amoxicillin-clavulanate is an appropriate choice in these cases.

Usually, oral antibiotics are sufficient as initial treatment. Many medical professionals recommend an initial limited wound irrigation in the emergency department or in the outpatient clinic. IV antibiotics should be considered for patients whose cellulitis does not resolve with oral antibiotics. In all cases, the final antibiotic coverage should be guided by culture and sensitivity results. Patients with a history of immunocompromise (including those with diabetes) should initially be treated with IV antibiotics.

Fungal infections can occur in or under the skin. Cutaneous fungal infection, or tinea, is treated with topical agents such as miconazole or clotrimazole. The most common subcutaneous infection is sporotrichosis; this condition can appear with an ulcerative lesion, along with lymphadenopathy. Gardeners are most commonly infected. Oral itraconazole for 3-6 months is the current recommended course of treatment. Fungal abscesses or disseminated fungal infections can occur and are usually found in immunocompromised patients. [9]

Surgical Therapy

As a rule, all abscess cavities must be drained. Antibiotics alone are not effective in treating pus. If the patient does not improve with antibiotics, suspect undrained pus or a foreign body. Immunocompromised patients should always receive IV antibiotics. [32]

Before surgery, obtain a thorough patient history, and perform a thorough physical examination. The operating surgeon must counsel each patient about the appropriate risks and benefits of each procedure. Furthermore, consent for sufficient latitude in performing the procedure (eg, possible amputation) is necessary. Patients should always be preoperatively informed that further operations may be necessary.

In the operating room, perform all explorations and debridements under tourniquet control. The extremity should be exsanguinated by gravity. Obtain wound cultures before the administration of antibiotics; then administer a dose of perioperative antibiotics because of the likelihood of a transient bacteremia after debridement.

Intraoperative cultures should include tests for aerobic, anaerobic, fungal, mycobacterial, and atypical mycobacterial organisms. Debride all devitalized tissue, and thoroughly irrigate all wounds. Treat larger wounds with pulse lavage and antibiotic irrigation. A repeat exploration and a second operative irrigation and debridement are necessary for certain wounds.

Flexor tenosynovitis

At the time of the operation, an incision is made in the distal area of the palm over the proximal end of the flexor sheath. The sheath is incised, and the presence of cloudy fluid or pus in the sheath is a clear indication of tenosynovitis. A second midaxial incision is made distally in the digit to provide access to the distal end of the tendon sheath. An irrigation catheter is placed through the sheath, and continuous irrigation of the sheath (usually with saline or antibiotic solution) is performed for 48 hours.

Be cognizant of the presence of digital swelling due to overly aggressive irrigation. It is possible to cause digital necrosis. If signs of infection have improved, the drainage system can be removed, and the patient should receive a course of antibiotics with elevation of the affected area.

Deep palm and web-space infections

The incision should be centered over the area of fluctuance. Incisions can be made along the palmar creases when possible. In the case of deep-space infections, wide exposure is important. The palmar fascia is incised, and the common digital nerves and vessels should be identified and protected when possible. A palmar and dorsal incision may be necessary, particularly in the case of collar button abscesses.

Septic arthritis

To treat septic arthritis adequately, arthrotomy is necessary. For the metacarpophalangeal (MCP) joint, a dorsal incision can be used. The extensor mechanism is split in the midline, and the joint capsule is incised. In the case of proximal interphalangeal (PIP) joint infections, a dorsal incision can be used, but when dividing the extensor tendon, one must be careful to preserve the central slip. Alternatively, a midaxial incision can be made. The joint is entered by incision of the accessory collateral ligament.

The joint space must be copiously irrigated, and the fibrinous and synovial debris is debrided. The wound can be packed to allow for continuous bedside irrigation, or if joint debridement has been adequate, the wound can be loosely closed.

Osteomyelitis

In cases of chronic osteomyelitis, surgical debridement is required. The sequestrum or devitalized bone must be removed. Similarly, in cases of acute osteomyelitis, debridement of the denuded bone is important for obtaining microbiologic cultures and for treatment. Once acute and chronic infections have been resolved, bony reconstruction may be necessary.

Postoperative Care

Immobilization, with splinting of the hand in the position of safety (wrist extension of 15-30°, MCP flexion of 70-90°, and interphalangeal [IP] extension), is important in reducing joint contractures. Furthermore, elevation is a critical aspect of hand infection management. Often, adequate elevation and immobilization require that the patient be hospitalized. Once the infection resolves, patients should begin early mobilization therapy. The patient should begin range-of-motion exercises and be seen by a hand therapist as soon as possible to minimize postinfection stiffness.

Complications

Most complications from hand infections result from inadequate treatment. Inadequacies in treatment can be life-threatening in patients who are immunocompromised. [2 Joint contracture from prolonged immobilization can be functionally devastating.

Recurrent infection or polymicrobial infection of the hand frequently complicates the care of the immunocompromised patient. [22633]

Long-Term Monitoring

Patients require close follow-up for the first several weeks after the infection. The surgeon should remain vigilant for any recurrence of infection and for appropriate compliance with wound care and hand therapy.

Once the infection resolves, aggressive hand therapy regimens should be started. Swelling from the infection itself and prolonged immobilization lead to the significant formation of adhesions and joint stiffness. Encourage patients not to guard their hands but, rather, to use them as much as possible. This step is particularly crucial if the patient has undergone surgical debridement, including treatment for tenosynovitis.



Medication Summary

The goals of pharmacotherapy are to eradicate the infection, reduce morbidity, and prevent complications.

Antibiotics

Cephalexin (Keflex, Daxbia)

This antibiotic is a first-generation cephalosporin that arrests bacterial growth by inhibiting bacterial cell-wall synthesis. It has bactericidal activity against rapidly growing organisms. Its primary activity is against skin flora; it is used for skin infections or prophylaxis in minor procedures.

Cefazolin

A first-generation semisynthetic cephalosporin that arrests bacterial cell-wall synthesis, inhibiting bacterial growth. It is primarily active against skin flora, including Staphylococcus aureus, and is typically used alone for skin and skin-structure coverage. Intravenous (IV) and intramuscular (IM) dosing regimens are similar.

Clindamycin (Cleocin)

Clindamycin is active against anaerobic gram-negative bacilli. It is a lincosamide that is useful in treating serious skin and soft tissue infections caused by most staphylococcal strains. It is also effective against aerobic and anaerobic streptococci, except enterococci. Clindamycin inhibits bacterial protein synthesis by inhibiting peptide chain initiation at the bacterial ribosome, which is where it preferentially binds to the 50S ribosomal subunit, causing bacterial growth inhibition. Cultures should be performed to test for possible resistance.

Levofloxacin (Levaquin)

Levofloxacin is indicated for pseudomonal infections and for infections that are due to multidrug-resistant, gram-negative organisms. Cultures should be performed to test for possible resistance.

Trimethoprim/sulfamethoxazole (Bactrim, Bactrim DS)

Inhibits bacterial synthesis of dihydrofolic acid by competing with para-aminobenzoic acid. This results in the inhibition of bacterial growth.

Tetracycline

Tetracycline inhibits bacterial protein synthesis by binding with 30S and possibly 50S ribosomal subunits. Primarily bacteriostatic, it has anti-inflammatory activity and is active against a wide range of gram-positive and gram-negative organisms.

Gentamicin

This aminoglycoside that may be used as an alternative to streptomycin, although there has been less clinical experience with gentamicin than with streptomycin in the treatment of tularemia. The drug may be administered intravenously or intramuscularly. Many dosing schedules are based on creatinine clearance (CrCl), volume of distribution, site of infection, and type of infection. Monitor serum levels after steady state is reached (usually after 3-4 doses). Trough levels are usually obtained 0.5 hour before the dose; peak levels are usually obtained 1 hour after the dose is infused.

Moxifloxacin (Avelox)

Moxifloxacin inhibits the A subunits of DNA gyrase, resulting in inhibition of bacterial DNA replication and transcription.

Vancomycin

Vancomycin is indicated for patients who have infections with resistant staphylococci. To avoid toxicity, the current recommendation is to assay vancomycin trough levels after the third dose is drawn 0.5 hour prior to next dosing. Use CrCl to adjust the dose in patients diagnosed with renal impairment.

Daptomycin (Cubicin)

Causes membrane depolarization by binding to components of the cell membrane of susceptible organisms. Inhibits DNA, RNA, and protein synthesis intracellularly. It is a bactericidal antibiotic.

Linezolid (Zyvox)

Linezolid is used as an alternative drug in patients allergic to vancomycin and for treatment of vancomycin-resistant enterococci. It is also effective against MRSA and penicillin-susceptible S pneumoniae infections.

This agent is an oxazolidinone antibiotic that prevents formation of the functional 70S initiation complex, which is essential for bacterial translation process. Linezolid is bacteriostatic against enterococci and staphylococci and bactericidal against most strains of streptococci.

Rifampin (Rifadin)

Rifampin is for use in combination with at least 1 other anti-tuberculosis drug. It inhibits RNA synthesis in bacteria by binding to the beta subunit of DNA-dependent RNA polymerase, which in turn blocks RNA transcription. Cross-resistance may occur.

Penicillin VK

Penicillin VK is the drug of choice for patients who can tolerate oral therapy. It inhibits the biosynthesis of cell wall mucopeptide. It is bactericidal against sensitive organisms when adequate concentrations are reached and is most effective during the stage of active multiplication. Inadequate concentrations may produce only bacteriostatic effects.

Ampicillin/sulbactam (Unasyn)

Drug combination of beta-lactamase inhibitor with ampicillin. Interferes with bacterial cell wall synthesis during active replication, causing bactericidal activity against susceptible organisms. Alternative to amoxicillin when unable to take medication PO.Covers skin, enteric flora, and anaerobes. Not ideal for nosocomial pathogens.

Amoxicillin/clavulanate (Augmentin, Augmentin ES-600, Augmentin XR)

Amoxicillin inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins. Addition of clavulanate inhibits beta-lactamase–producing bacteria.Good alternative antibiotic for patients allergic to or intolerant to macrolides. Usually is well tolerated and provides good coverage for most infectious agents. Not effective against Mycoplasma and Legionella species. Half-life of oral dosage form is 1-1.3 h. Has good tissue penetration but does not enter cerebrospinal fluid.

Antifungals, Other

Class Summary

Antifungal therapy should be started immediately after necessary cultures have been obtained from all suspected sites of infection. Azole antifungal agents are fungicidal at very high concentrations. Azoles function by selectively inhibiting the synthesis of an essential component of fungal cell membrane, ergosterol.

 

Miconazole oral (Oravig)

Inhibits biosynthesis of ergosterol, damaging fungal cell wall membrane, which results in fungal cell death.

Clotrimazole

Nonabsorbable imidazole. Broad-spectrum synthetic antifungal agent that inhibits growth of yeasts and fungal growth by altering cell membrane permeability, which causes fungal cell death.

Itraconazole (Onmel, Sporanox)

Has fungistatic activity. Synthetic triazole antifungal agent that slows fungal cell growth by inhibiting cytochrome P-450–dependent synthesis of ergosterol, a vital component of fungal cell membranes. Effective against broad range of fungi, including Candida species and is indicated for the treatment of cutaneous, oral, esophageal, and disseminated candidiasis. Available in IV, 100-mg capsules, and oral solution at 10 mg/mL.Capsules require gastric acidity for absorption and should be taken with food to increase absorption. Liquid formulation increases bioavailability and decreases need for acidity for proper absorption.



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