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HAND INFECTIONS:
GENERAL INFORMATION
KEY FIGURE:
Hand infections are relatively common problems. Seemingly minor in-juries can sometimes lead to significant infections. Proper treatment isvital to prevent long-term disability.
Cellulitis vs. Abscess
Cellulitis is a diffuse infection of the soft tissues. No localized area of
pus can be drained. The affected area is described as indurated (i.e.,
warm, red, and swollen). The hand is also painful. A component of
lymphangitis (infection involving the lymphatics) may be indicated by
red streaking in the tissues, progressing proximally up the arm. The
treatment of cellulitis centers on the administration of the appropriate
antibiotic regimen.
An abscess is a localized collection of pus, often with a component of
cellulitis in the surrounding soft tissues (with the above signs). One
sign of an abscess is an area of fluctuance. When you apply gentle dig-
ital pressure over the area of the presumed abscess, you feel a "give,"
indicating the presence of fluid beneath the skin. Another sign is that an
abscess often seems to "point"; that is, the skin starts to thin from the pres-
sure of the fluid underneath. The primary treatment of an abscess is in-
cision and drainage (I & D)-cutting open the roof of the abscess to
allow the pus to drain. Antibiotic therapy may be needed, but the in-
fectious process will not resolve with antibiotics alone.
From the above information, you can see that the distinction betweenthe two entities is important because their treatments are different. I & Dis indicated for an abscess, whereas cellulitis does not warrant thisintervention.
Practical Plastic Surgery for Nonsurgeons Gangrene
The term gangrene is used to describe tissues that are dead. There aretwo subtypes of gangrene, wet and dry. The distinction is important.
Dry gangrene describes tissues that are generally black and dried out.
There is a distinct border between the dead tissue and surrounding
healthy tissue. Sometimes the dead tissues fall off on their own; dry
gangrenous fingertips can fall off with minimal manipulation. However,
debridement usually is required, but it is not emergent. Dry gangrene
usually places the patient at no health risk as long as it does not
become infected (see below).
In contrast to dry gangrene, wet gangrene can be a significant health
risk. Wet gangrene connotes active infection (noted by pain, swelling,
redness, and drainage of pus) in the tissues surrounding the obviously
dead tissue. Urgent debridement is required to prevent further tissue
loss and worsening of soft tissue infection.
Necrotizing Fasciitis
Necrotizing fasciitis is a serious, potentially life-threatening infectionof the fascia (the thin connective tissue overlying the muscle under theskin and subcutaneous tissue). The popular press calls it the disease offlesh-eating bacteria.
Necrotizing fasciitis is not common. However, it must be considered inthe evaluation of patients with a hand infection that seems to berapidly progressing proximally up the forearm. Necrotizing fasciitisshould also be considered when the patient is sicker than you wouldexpect for simple cellulitis.
The skin is swollen, but often without the typical signs of cellulitis. Theskin simply does not look "right." You may be able to feel subcuta-neous air in the soft tissues of the arm, or you may see air in the softtissues on x-rays (normally, no air is present in soft tissues on x-ray).
The patient is often quite ill (high fever, low blood pressure, generalweakness, and even shock may be present). The infection can spreadquickly up the arm and into the chest. Radical debridement and evenamputation may be necessary to save the patient's life. Treatment requires aggressive operative debridement (opening up thesoft tissue spaces, as with an abscess) to remove diseased tissue, intra-venous antibiotics, and close monitoring for aggressive treatment ofsepticemia. Hyperbaric oxygen also may be indicated but does not re-place aggressive operative treatment. Patients with necrotizing fasciitisshould be treated by a surgeon with critical care expertise.
Evaluation of an Infected Hand
Ask the patient about events that may have led to the development ofthe infection. This information may help to guide your treatment.
A history of being cut by glass or sustaining a puncture wound shouldraise concern about the presence of a foreign body in the soft tissues. Ask whether the patient was bitten by an animal. An animal's canineteeth, especially those of a cat, may penetrate much deeper into the un-derlying tissues than you expect. Find out what type of animal was in-volved; different animals have specific bacterial organisms that mayrequire a particular antibiotic. Ask about the possibility of rabies expo-sure (see chapter 6, "Evaluation of an Acute Wound," for informationabout rabies prevention).
If the patient has a wound over a metacarpophalangeal knuckle, youmust ask specifically whether the wound is due to human teeth. Peopleare often embarrassed to admit that they have been in a fight. Askpoint-blank: Did you punch someone in the mouth? Did someone biteyou? This information is important because the human mouth hasstrong pathogens that can lead to significant soft tissue destruction.
Choice of specific antibiotics is based on the usual organisms found inthe human mouth.
Well-managed swimming pools usually are treated adequately withchemicals, and the ocean has such a high salt content that neithervenue is associated with specific organisms that cause infection.
However, streams, ponds, lakes, and aquariums are associated withspecific bacteria that can cause significant infections. In addition, askwhether the injury occurred while the patient was working on a boator fishing.
Patients with diabetes often develop infections that are unexpectedlydifficult to treat. You must treat such infections aggressively andensure that blood sugar is well controlled.
Ask about the patient's tetanus immunization status.
Practical Plastic Surgery for Nonsurgeons 1. The classic signs of a hand infection are redness, warmth, swelling, and pain. The swelling associated with a hand infection is oftenquite pronounced.
2. Look closely for puncture wounds and other signs of trauma.
3. Determine whether the patient has a localized collection of pus that requires drainage or diffuse soft tissue infection. 4. Look for induration extending proximally up the forearm.
5. Look for red streaks extending up the arm.
6. If the forearm is involved, palpate for crepitus or subcutaneous air in the forearm tissues (signs of necrotizing fasciitis). To test for crepi-tus, press on the soft tissues. If air is present under the skin, it willfeel as if you are pressing on crinkled layers of cellophane or pop-ping air bubbles beneath the skin.
7. Look for signs of systemic illness (fever, chills, low blood pressure, 8. Look for evidence of enlarged lymph nodes in the armpit or back of The basic studies include complete blood count with a white blood cellcount and x-ray evaluation of the infected area. Include the forearm ifthe induration extends proximally up the forearm. Blood culturesshould be done if the patient is febrile or looks ill. If there is an openwound present, culture it.
3. Evidence of joint contamination: air in the joint, destruction of joint surfaces, foreign material in the joint. Any of these findings war-rants operative exploration.
4. Underlying bone infection: the bone edges appear irregular if bone is involved with the infectious process. If bone is involved, 4-6weeks of antibiotic therapy are needed.
5. Air in the soft tissues strongly indicates necrotizing fasciitis.
Localized air may be present in the soft tissues at the immediatevicinity of an I & D site, but diffuse air in the tissues is a sign ofnecrotizing infection.
Importance of Key Elements in the History
and Physical Examination
If a foreign body is located in the infected tissues, the infection will notresolve unless it is removed. However, a foreign body in soft tissues with-out cellulitis does not have to be removed unless it is causing symptoms.
Pasteurella multocida and Staphylococcus aureus are associated with catand dog bites. Treatment with an antipseudomonal and antistaphylo-coccal antibiotic (amoxicillin/clavulanate, cefuroxime) is required. Catbites often penetrate more deeply than you expect and may involveunderlying joints or tendons. Exploration and washout of the joint andtendon may be required. Cat bites have a much higher incidence ofsubsequent infection than dog bites (80% vs. 5%, respectively).
Eikenella corrodens, other anaerobes, and Streptococcus viridans are asso-ciated with infections caused by a human bite. If the patient is seenearly after the injury, before signs of infection have developed, treatwith amoxicillin/clavulanate. Once signs of infection are present, in-travenous antibiotics, such as amoxicillin/sulbactam or ticarcillin/clavulanate, are indicated. Operative exploration also may be requiredif the underlying joint is affected. In addition, abscess formation iscommon after a human bite.
If the infected tissues are swollen and red but not particularly hot ortender, the causative organism may be Mycobacterium marinum. Treat-ment requires long-term (3 months) administration of doxycycline orrifampin/ethambutol. An infectious disease specialist should be in-volved in the treatment of such patients. If the infected area has all of the typical signs of cellulitis, treatmentshould cover bacteria of the Vibrio species; tetracycline or an aminogly-coside may be used.
Aeromonas hydrophila is associated with freshwater infection. A fluoro-quinolone or trimethoprim/sulfamethoxazole should be used fortreatment.
Practical Plastic Surgery for Nonsurgeons Red streaking is a sign of lymphangitis, which means that the infectionis traveling through the lymphatic system. Staphylococcal infectionsare most commonly associated with this physical finding.
Enlarged Lymph Nodes Around the Elbow or Armpit The presence of enlarged lymph nodes may indicate cat-scratch dis-ease, a Mycobacterium marinum infection, sporotrichosis or nocardial in-fection. An infectious disease specialist should be consulted becausethese unusual infections can be difficult to treat.
General Initial Treatment
The infected hand is often diffusely swollen. Initially it may be difficultto determine whether the patient has an abscess in need of drainage. Ifthe patient otherwise looks well and has no signs of flexor tenosynovitis(see chapter 37, "Specific Types of Hand Abscesses"), underlying jointinfection, or necrotizing fasciitis, treat conservatively. Do not make cutsin the skin looking for an abscess; you may well find nothing.
1. Start the appropriate antibiotics.
2. Splint the hand in neutral position (see chapter 28, "Hand Splinting and General Aftercare"), and elevate the hand. These two interven-tions are the cornerstone of treatment for all hand infections.
Splinting and elevation significantly reduce swelling, thus makingit easier to determine whether an abscess is present.
The proper way to elevate an injured hand. The hand should be higher than theelbow to promote drainage and decrease swelling in the hand.
3. Warm (not hot) compresses applied to the inflamed area of the hand 4. After 24 hours reevaluate the hand.
• Significant improvement may be seen. If there is no evidence of an abscess, continue splinting, elevation, and antibiotics. The splintshould be removed once pain and swelling have resolved.
Regular exercise then becomes important to prevent stiffness.
Continue the antibiotics for 7-10 days until the infectious processhas resolved completely.
• Alternatively, a localized collection of pus in need of drainage may be identifiable. The following chapter discusses specific typesof hand abscesses and their treatment. Bibliography
1. Gilbert DN, Moellering RC, Sande MA (eds): The Sanford Guide to Antimicrobial Therapy, 29th ed. Vermont, Antimicrobial Therapy, Inc., 1999. 2. Lampe EW: Clinical Symposia: Surgical Anatomy of the Hand. 40th anniversary issue

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