Treatment of Hand Infections

Benjamin Chang

Suhail K. Kanchwala

GENERAL PRINCIPLES

Infections of the hand result in pain, disability, as well as lost time and productivity at work. Prompt, accurate diagnosis minimizes disability and facilitates rapid recovery. In addition, infections in the hand are the presenting symptom in a number of systemic illnesses.

Evaluation of a hand infection includes an assessment of the extent of erythema, depth of infection, presence of an abscess, and range of motion of the affected digits. In addition, a medical history is obtained with emphasis on factors that affect immune response (diabetes, human immunodeficiency virus, and immunosuppression).

The anatomy of the hand, with numerous fascial compartments, allows the inflammatory response to infection itself to become pathogenic. For example, excessive swelling in the hand can result in increased pressure on tendons in the fingers and palm, leading to ischemia and tendon necrosis. Potential spaces, such as flexor tendon sheaths and the deep palmar space, can serve as conduits for infection.

Early infections in the hand, regardless of location, are managed initially by rest, elevation, antibiotics, close observation, and splinting in the intrinsic plus position. For those infections that have progressed or whose initial presentation indicates the presence of an abscess (i.e., fluctuance and drainage), the treatment includes surgical drainage and debridement of devitalized tissues. When a delay in operative treatment is unavoidable, the abscess cavity should be aspirated to reduce compartment pressures and the risk of tendon and neurovascular injury.

Antibiotics covering the most likely pathogens for each type of infection are started after wound cultures have been obtained. Antibiotics, however, are not a substitute for adequate surgical drainage and debridement. Infections in the hand are often polymicrobial—a critical consideration when making a selection of empiric antibiotic therapy (Table 72.1).1 All wounds that are a result of exposure to soil, animals, or the oral cavity (i.e., human bite wounds) require tetanus prophylaxis.

Drainage of hand infections can often be performed using regional anesthetic techniques (Chapter 71). However, the infiltration of local anesthesia directly into an area of cellulitis or infection is ill-advised and may spread the infection. For example, fingertip infections can be managed with digital blocks, but deep space infections of the hand should be drained under either axillary block or general anesthesia. A pneumatic tourniquet is used to avoiding excessive bleeding that can impair visualization. When using the tourniquet in the presence of infection, the extremity is exsanguinated by elevation and gravity, rather than compression to avoid the spread of the infection (Figure 72.1).

ACUTE PARONYCHIA

Paronychia or runaround infections of the fingertip are infections of the soft tissue fold surrounding the nail plate, typically with staphylococcal species. Risk factors for paronychial infection include hangnails, nail biting, manicures, and poor hand hygiene. Hallmarks of paronychial infection include pain, swelling, and erythema in the perionychium.

Initial management of paronychial infections includes warm soaks and oral antibiotics. When paronychial infections progress to abscess formation within the eponychial fold or under the nail plate, surgical drainage is necessary. When performing an incision and drainage of a paronychia, it is important to angle the blade away from the nail bed to avoid inadvertent damage to the nail bed and subsequent ridging of the nail. When the abscess extends under the nail plate, the nail is removed (Figure 72.2).

HERPETIC WHITLOW

Commonly confused with paronychial infections, herpetic infections of the hand typically involve the fingertip and soft tissues surrounding the nail plate. While herpetic infections may mimic bacterial infections of the hand, they can usually be distinguished by an adequate history and exam.

Herpetic infections in children and healthcare workers (dentists, respiratory therapists, etc.) are most often the result of viral inoculation from the oropharynx by the herpes simplex type 1 virus (HSV-1). In adults, however, HSV-2 predominates and is most often due to inoculation from genital herpes. Herpetic infections typically have an incubation period of 2 weeks after which patients experience pain and mild swelling in the affected digit. Small 1 to 2 mm vesicles then erupt in the affected digits and coalesce to form large bullae. A Tzanck smear is diagnostic.2

The management of herpetic hand infections does not involve surgery unless there is bacterial superinfection. In fact, surgical intervention in cases of herpetic whitlow can lead to systemic spread.3 Viral infection can lie dormant in the nervous system for many years and then reactivate (Figure 72.3).

CHRONIC PARONYCHIA

Chronic paronychia is a distinct clinical entity from acute paronychia. Chronic inflammation of the soft tissues surrounding the nail plate can lead to repeated episodes of erythema, pain, and drainage from the infected region. Patients who have repeated exposure to water (waiters, dishwashers, etc.) are at highest risk for developing chronic inflammation. Staphylococcus pyogenes, Staphylococcus epidermidis, and Candida are the most common causes of chronic paronychia.

The treatment of chronic paronychia involves the excision of a minimum 3 mm wide crescent of skin and subcutaneous tissue parallel to the eponychial fold running the entire width of the finger. This procedure is referred to as eponychial marsupialization. The wound is then left open for drainage and the patient is placed on a regimen of hand soaks in a variety of solutions such as dilute povidone-iodine solution. The warm soaks are continued until the inflammation/drainage has ceased. Nail irregularities caused by chronic paronychia can be treated by the removal of the entire nail.4 As long as the eponychial fold is appropriately stented, the nail usually regrows without abnormalities.

FELON

A felon is an infection in the soft tissue pulp on the volar aspect of the fingertip. The distal finger pad is an anatomically distinct structure from the rest of the finger. Numerous fibrous septae attach the dermis of the distal finger pad directly to the underlying bone, allowing the fingertip to be used for essential functions such as grasp. If a significant number of these septae are disrupted during drainage of a felon, a mobile, nonfunctional fingertip can result.5

TABLE 72.1 COMMON HAND INFECTIONS, MOST COMMON INFECTING ORGANISMS, AND RECOMMENDED EMPIRIC ANTIBIOTICS

▪	CONDITION	▪	MOST COMMON INFECTING ORGANISMS	▪	RECOMMENDED ANTIBIOTICS	▪	COMMENTS
	Paronychia, felon, pyogenic flexor tenosynovitis		Usually Staphylococcus aureus or streptococci; Pseudomonas, Gram-negative bacilli, and anaerobes may be present, especially in patients with exposure to oral flora		First-generation cephalosporin or anti-staphylococcal penicillin; if anaerobes or Escherichia coli are suspected, oral clindamycin (Cleocin) or amoxicillin-clavulanate potassium (Augmentin) or ampicillin-sulbactam (Unasyn); if MRSA is endemic in community, consider trimethoprim/sulfamethoxazole (Bactrim)		Incision and drainage should be performed if infection is well established. If infection is chronic, suspect Candida albicans. Early infections without cellulitis may respond to antibiotics alone.
	Herpetic whitlow		Herpes simplex virus types 1 and 2		Supportive therapy Antiviral therapy may be prescribed if infection has been present for less than 48 h		Consider antibiotics if secondarily infected. Incision and drainage are contraindicated
	Human bite, clenched-fist injury		S. aureus, streptococci, Eikenella corrodens, gramnegative bacilli, anaerobes		Intravenous first-generation cephalosporin or anti-staphylococcal penicillin and penicillin G or ampicillin-sulbactam or amoxicillin-clavulanate potassium or Second-generation cephalosporin such as cefoxitin (Mefoxin)		Oral antibiotics should be used if outpatient therapy is chosen. Wounds should be explored, irrigated, and debrided
Adapted from Wright PE II: Hand infections. In: Canale ST, ed. Cambell’s Operative Orthopedics. 9th ed. St Louis, MO: Mosby 1998.