Acute Infections of the Hand

General Principles

Hippocrates’ principles for the treatment of hand infections are fundamentally valid today. Wounds were kept clean with frequent changes of wine-soaked dressings. Dressings were kept loose “so as not to intercept the pus, but to allow it to flow away freely.” Coupled with these early principles is the pioneering work of Dr. Alan Kanavel, a Chicago general surgeon who treated hand infections in the preantibiotic era. Much of our current understanding of the pathogenesis and treatment of hand infections must be credited to his extensive dissections and innovative injection studies. Through these studies, he demonstrated the potential spaces of the hand and the pathogenesis of infection. From this data, he developed the surgical principles that remain the cornerstone of modern treatment of hand infections.

Hand infections can result in severe disabilities, including stiffness, contracture, and amputation. These complications have been significantly reduced through the introduction of antibiotic therapy in conjunction with surgical treatment. Although antibiotics have dramatically reduced the morbidity associated with hand infections, their use does not supplant the need for expedient and proper surgical intervention. Several factors influence the outcome of hand infections. These include the location of the infection, infecting organism, timing of treatment, adequacy of surgical drainage, efficacy of antibiotics, and health status and immunocompetence of the host. In the words of one of the preeminent United States public health officials, Dr. Charles V. Chapin: “As it takes two to quarrel, so it takes two to make a disease, the microbe and the host.”

Host factors play a determining role in the severity and duration of infection. Many medical conditions reduce host defenses. Malnutrition, alcoholism, autoimmune diseases, chronic corticosteroid use, hepatitis, and human immunodeficiency virus (HIV) infection are some of the comorbidities to be considered. The most prevalent disease with associated immunosuppression is diabetes mellitus, which affects up to 11% of the adult population of the United States.

Early and superficial infections may respond to nonsurgical management. However, most acute infections of the hand represent surgical emergencies. Swelling and edema associated with an infection result in increased tissue pressure and can cause ischemia and tissue necrosis by a process resembling compartment syndrome. Furthermore, toxins produced by the offending pathogen can cause vascular thrombosis and tissue death. Patients with necrotizing fasciitis and gas gangrene need immediate surgical care.

Types of Infections

Cellulitis is an infection of the subcutaneous tissue, which is often diffuse and can be associated with lymphangitis. It is caused by a single organism, usually Staphylococcus aureus or β -hemolytic Streptococcus . Lymphangitic streaking is more commonly seen with β -hemolytic streptococcal infections. It generally has a more distal nidus and spreads proximally. It is a non–pus-forming infection and as such is initially treated nonsurgically. If the cellulitis is not responding to intravenous therapy over 12 to 24 hours, this often suggests the formation of pus ( abscess ) and more serious infection. Even in the absence of abscess formation, cellulitis associated with significant swelling resolves more quickly with surgical decompression. Cellulitis often requires hospital admission and close monitoring for response to antibiotic therapy. A specific type of staphylococcal infection is the staphylococcal scalded skin syndrome , primarily a disease of young children that results from an exfoliative toxin-producing staphylococcal organism. A high index of suspicion and early differentiation of this process from other skin conditions are important to treatment outcome. Although this syndrome is extremely rare in adults, it is associated with a high mortality rate, usually because of serious underlying illness, such as kidney failure or immunosuppression. Detection of the exfoliative toxin is required for diagnosis. New immunologic methods allow for more rapid detection. Prompt antibiotic therapy and local wound care are the mainstays of management. Necrotizing fasciitis is a serious life-threatening infection that may initially resemble cellulitis. Although purulence is not present, a watery discharge often described as “dishwater-like fluid” may be seen superficial to the fascia. Most other hand infections are generally pus forming and are discussed in detail throughout the chapter.

The most common infecting organisms are Staphylococcus and Streptococcus species, with staphylococcal organisms predominating. Many infections, especially those associated with bite wounds, those associated with gross contamination, or those seen in diabetics, are often caused by mixed species. Pasteurella multocida should be considered in most animal bites, and both streptococcal species and Eikenella corrodens should be considered in human bite wounds. Anaerobic infection is less common but should be considered more frequently in diabetics or intravenous drug users. Empirical antibiotic therapy should be tailored toward the most likely offending pathogen. The local prevalence of antibiotic-resistant organisms should be considered when starting empirical treatment. An infectious disease specialist is valuable in patient management because he or she is most familiar with the hospital-specific patterns of antibiotic resistance, can direct antibiotic therapy, and can follow outpatient intravenous therapy.

Methicillin-Resistant Staphylococcus aureus Infections

The increasing incidence of infection with methicillin-resistant S. aureus (MRSA) has been recognized throughout the surgical as well as infectious disease literature. A strain of S. aureus resistant to methicillin was mentioned in reports from the United Kingdom in 1961. This strain was soon identified worldwide and was associated with hospital-acquired infections (HA-MRSA). Only a handful of successful HA-MRSA clones are responsible for the majority of infections, and different clones dominate in different geographic locations. However, MRSA infections have been increasingly identified as community-acquired infections (CA-MRSA). There are unique microbiologic and genetic properties distinguishing the hospital-acquired and community-acquired strains. A community-acquired infection is defined as occurring in patients with MRSA identified by culture who have no history of a hospital or medical facility stay within the past year, who have no history of dialysis or surgery occurring within the past year, and in whom no indwelling catheters are present.

CA-MRSA is now the predominant strain in hand infections, found in up to 60% of S. aureus infections. The majority of CA-MRSA infections in the United States have been caused by a single clone (USA300). One of the distinguishing features in CA-MRSA is the frequent gene sequence encoding for Panton-Valentine leukocidin (PVL), a potent toxin that leads to the characteristic tissue necrosis commonly seen in the clinical setting.

MRSA infections frequently have a characteristic appearance of a dermonecrotic skin lesion ( Figure 2.1 ). They are often mislabeled as “spider bites” due to their dermonecrotic appearance and may not receive appropriate antibiotic therapy. More recently, we have not seen the extensive tissue necrosis with MRSA infections that we have in the past. Empirical treatment of hand infections has also changed to address potential MRSA infections. Successful treatment requires surgical débridement with excision of necrotic tissue in conjunction with appropriate antibiotic therapy.

Nosocomial Infections

The hand is a very well-vascularized region, making it less vulnerable to postoperative infection than other anatomic sites. S. aureus is the most common pathogen in clean surgical procedures. The use of perioperative intravenous antibiotics within 1 hour preceding surgery has greatly reduced the incidence of postsurgical infections in general orthopedic practice. However, the role of perioperative antibiotics in elective hand surgery is less clear. Several studies suggest that for soft tissue procedures of less than 2 hours’ duration, the routine use of prophylactic antibiotics is not indicated. Ultimately, the whole patient must be considered. Prophylactic antibiotics in patients with joint arthroplasties are recommended to protect the prosthesis more than to prevent surgical site infection. Patients with an altered immune response may have a potentially greater benefit from prophylactic antibiotics than an immunocompetent host. For surgical procedures that involve exposure of the bone or joint or those involving implants, we routinely give intravenous prophylaxis. *

* Editor’s note (DPG): I strongly disagree with the practice of giving “prophylactic” antibiotics for all clean bone and joint cases in the wrist and hand. This is not only unnecessary but harmful in the long term, creating superresistant bacteria. In my practice, I do not administer perioperative antibiotics in clean, elective cases unless there is a specific indication to do so. Unfortunately, many orthopedic surgeons give antibiotics indiscriminately purely as a defensive measure, fearing that if the patient does get an infection and no antibiotics were given, a plaintiff’s attorney will cite this as inappropriate care. In addition, many hospital policies now require the routine administration of preoperative antibiotics.

Patient Evaluation

Clinical examination remains the hallmark of diagnosis in hand infections. Pain (dolor), and increased temperature (calor), with or without erythema (rubor), and tenderness remain the prime features of hand infection. Temperature elevation is inconsistent. Abnormalities of the white blood cell (WBC) count and C-reactive protein (CRP) level are uncommon features of a hand infection. In one study, these were normal in 75% of patients. The erythrocyte sedimentation rate (ESR) was slightly more useful, with elevation of the ESR found in 50% of patients.

The initial evaluation and management in the emergency department should include a thorough medical history, assessment of risk factors for immunocompromise, and evaluation of tetanus immunization status. Appropriate tetanus prophylaxis should be administered based on immunization history and time of the last booster shot. Tetanus immune globulin (TIG; HyperTET®) and tetanus toxoid booster are given if the patient has not had a series of tetanus immunizations. Clinical evaluation of the affected extremity should include examination for fluctuance, warmth, edema, redness, tenderness, and lymphangitis or lymphadenopathy. Areas of cellulitis should be marked on the skin so that progression or regression of the infectious process can be monitored; if an open draining wound is present, a specimen should be sent for aerobic and anaerobic culture. Blood cultures should be taken in febrile patients. Blood should be drawn for a complete blood cell count (CBC), ESR, CRP, electrolytes, and random blood glucose measurements. Hand infection may be the first presenting complaint of undiagnosed diabetes. Radiographs are obtained to evaluate for the presence of a foreign body, gas within the soft tissues, underlying fracture, septic joint, or osteomyelitis.

When a patient presents with an area of fluctuance, this should be provisionally treated with aspiration or decompression until formal surgical débridement is performed. The fluid should be sent for culture. For patients who do not clearly have an abscess, aspiration may be useful to identify a deep pyogenic infection. Swollen painful joints should be aspirated with caution. The site of aspiration should not be over an area of cellulitis, so as not to seed the joint with bacteria. The aspirated fluid should be sent for culture. Joint fluid analysis with cell count, glucose, and protein levels can be obtained if an adequate specimen is available. If the joint aspirate is not clearly pyogenic and there are not other indicators of infection, antibiotics are withheld. Nonsteroidal antiinflammatory drugs (NSAIDs) may be given to both treat the patient and help distinguish between an inflammatory process and sepsis. If the presentation is suggestive of an inflammatory process, antibiotics are withheld while the response to NSAIDs is observed. When infection is suggested, empirical antibiotic therapy should be started in the emergency department after a culture specimen has been obtained.

Differentiating between an infectious process and an inflammatory process, especially pseudogout, can be difficult. The suspicion of one process over the other depends on many factors, including the patient’s history, the presence of underlying diseases, and the clinical presentation. When to withhold antibiotic therapy can be a diagnostic challenge, and the use of antibiotics in some circumstances may be done more to treat the physician’s anxiety than the patient’s disease. Overnight observation in the hospital while antibiotics are withheld allows the disease process to be closely monitored and allows treatment to be changed if the anticipated improvement is not evident with NSAID therapy alone. When the level of suspicion for an infectious process is low, a corticosteroid dose pack (Medrol DosePak™) may be used. The patient is reevaluated in 24 to 48 hours. The importance of seeing the patient again within 48 hours cannot be overstated. If the process is noninfectious, the symptoms will be nearly resolved. It may take years to develop the clinical experience to recognize these different processes, and even the experienced eye can mistake these two conditions.

Patients with severe infections such as necrotizing fasciitis or gas gangrene or who are immunocompromised, including diabetics, should be immediately treated with broad-spectrum antibiotic therapy and emergent surgical intervention.

Treatment Principles

Surgical drainage should be done through a large incision. The incision should be planned so that it can be extended proximally or distally. Longitudinal incisions across a flexion crease should be avoided.

Excision of all necrotic tissue is imperative for infection control. In the 1800s, Louis Pasteur noted that it is the environment and not the bacterium that allows the propagation of infection. Cultures and surgical pathologic reports should be obtained. Fungal and mycobacterial organisms are slow growing and may be more rapidly identified by staining techniques. Most wounds can be left open, with moist gauze covering the exposed surfaces. Alternatively, large wounds can be managed with a negative-pressure sponge dressing. In an acute infection, these should be changed in 48 hours. Small wounds with a tendency to heal quickly should be kept open with a gauze wick. Multiple débridements may be necessary to control infection. Amputation may be necessary to eradicate infection. Functional results may be improved by amputation of a stiff, contracted, and painful digit. In cases of severe infection such as necrotizing fasciitis or gas gangrene, amputation may be a life-saving procedure.

Postoperatively, loose soft dressings are applied. A short period of immobilization for 24 to 48 hours with a splint may afford some pain relief to the patient. Early mobilization in the first 24 hours, under the guidance of a hand therapist, reduces edema, stiffness, and contracture associated with severe hand infections.

Empirical antibiotic therapy may be started after cultures have been obtained. In the case of cellulitis, where local cultures cannot be obtained, blood cultures may identify an organism and should if possible be obtained prior to initiating antibiotic therapy. The specific empirical therapy should be based on the most commonly encountered organisms for the type of infection being treated. The patient history, such as being exposed to an aquatic or a farm environment or being bitten by an animal, may help tailor the specific treatment to the patient. The relative prevalence of MRSA is increasing in many communities, and empirical treatment for MRSA is now commonplace. An infectious disease specialist is invaluable in guiding antibiotic recommendations for both specific infections and for resistant organisms that may be relatively prevalent in one’s community. Table 2.1 lists general antibiotic recommendations for common infections. Dosages should be adjusted for the patient’s age, weight, renal function, and allergic status. The duration of therapy depends on the clinical response to treatment, the location and depth of the infection, and the patient’s immune status. The use of peripherally inserted central venous catheters (PICC lines) can be a valuable method of providing outpatient parenteral therapy, but it comes with a risk of upper extremity venous thrombosis.

Critical Points

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