Leg Ulcers

LEG ULCERS

A leg ulcer is an excavation of the skin surface that occurs when inflamed necrotic tissue sloughs off. About 75% of all leg ulcers result from chronic venous insufficiency. Lesions due to arterial insufficiency account for approximately 20%; the remaining 5% are caused by burns, sickle cell anemia, and other factors (Gloviczki & Yao, 2001).

Pathophysiology

Inadequate exchange of oxygen and other nutrients in the tissue is the metabolic abnormality that underlies the development of leg ulcers. When cellular metabolism cannot maintain energy bal-ance, cell death (necrosis) results. Alterations in blood vessels at the arterial, capillary, and venous levels may affect cellular processes and lead to the formation of ulcers.

Clinical Manifestations

The clinical appearance and associated characteristics of leg ulcers are determined by the cause of the ulcer. Most ulcers, especially in an elderly patient, have more than one cause. The symptoms depend on whether the problem is arterial or venous in origin (see Table 31-2). The severity of the symptoms depends on the extent and duration of the vascular insufficiency. The ulcer itself appears as an open, inflamed sore. The area may be draining or covered by eschar (dark, hard crust).

ARTERIAL ULCERS

Chronic arterial disease is characterized by intermittent claudica-tion, which is pain caused by activity and relieved after a few min-utes of rest. The patient may also complain of digital or forefoot pain at rest. If the onset of arterial occlusion is acute, ischemic pain is unrelenting and rarely relieved even with opioid analgesics. Typically, arterial ulcers are small, circular, deep ulcerations on the tips of toes or in the web spaces between toes. Ulcers often occur on the medial side of the hallux or lateral fifth toe and may be caused by a combination of ischemia and pressure (Fig. 31-17).

Arterial insufficiency may result in gangrene of the toe (digi-tal gangrene), which usually is caused by trauma. The toe is stubbed and then turns black (see Fig. 31-17). Usually, patients with this problem are elderly people without adequate circulation to provide revascularization. Débridement is contraindicated in these instances. Although the toe is gangrenous, it is dry. Man-aging dry gangrene is preferable to débriding the toe and causing an open wound that will not heal because of insufficient circula-tion. If the toe were to be amputated, the lack of adequate circu-lation would prevent healing and might make further amputation necessary—a below-knee or an above-knee amputation. A higher-level amputation in the elderly could result in a loss of indepen-dence and possibly institutional care. Dry gangrene of the toe in an elderly person with poor circulation is usually left undisturbed. The nurse keeps the toe clean and dry until it separates (without creating an open wound).

VENOUS ULCERS

Chronic venous insufficiency is characterized by pain described as aching or heaviness. The foot and ankle may be edematous. Ulcerations are in the area of the medial or lateral malleolus (gaiter area) and are typically large, superficial, and highly exuda-tive. Venous hypertension causes extravasation of blood, which discolors the gaiter area (see Fig. 31-17). Patients with neuropa-thy frequently have ulcerations on the side of the foot over the metatarsal heads.

Assessment and Diagnostic Findings

Because ulcers have many causes, the cause of each ulcer needs to be identified so appropriate therapy can be prescribed. The his-tory of the condition is important in determining venous or arte-rial insufficiency. The pulses of the lower extremities (femoral, popliteal, posterior tibial, and dorsalis pedis) are carefully exam-ined. More conclusive diagnostic aids are Doppler and duplex ultrasound studies, arteriography, and venography. Cultures of the ulcer bed may be necessary to determine whether the infect-ing agent is the primary cause of the ulcer.

Medical Management

Patients with ulcers can be effectively managed by advanced prac-tice nurses or certified wound care nurses in collaboration with physicians. All ulcers have the potential to become infected.

PHARMACOLOGIC THERAPY

Antibiotic therapy is prescribed when the ulcer is infected; the specific antibiotic is selected on the basis of culture and sensitiv-ity test results. Oral antibiotics usually are prescribed because top-ical antibiotics have not proven to be effective for leg ulcers.

DÉBRIDEMENT

To promote healing, the wound is kept clean of drainage and necrotic tissue. The usual method is to flush the area with nor-mal saline solution. If this is unsuccessful, débridement may be necessary. Débridement is the removal of nonviable tissue from wounds. Removing the dead tissue is important, particularly in instances of infection. Débridement can be accomplished by several different methods:

• Sharp surgical débridement is the fastest method and can be performed by a physician, skilled advanced practice nurse, or certified wound care nurse in collaboration with the physician.

• Nonselective débridement can be accomplished by applying isotonic saline dressings of fine-mesh gauze to the ulcer. When the dressing dries, it is removed (dry), along with the debris adhering to the gauze. Pain management is usually necessary.

• Enzymatic débridement with the application of enzyme ointments may be prescribed to treat the ulcer. The ointment is applied to the lesion but not to normal surrounding skin. Most enzymatic ointments are covered with saline-soaked gauze that has been thoroughly wrung out. A dry gauze dressing and a loose bandage are then applied. The enzymatic ointment is discontinued when the necrotic tissue has been débrided and an appropriate wound dressing is applied.

• Débriding agents can be used. Dextranomer (Debrisan) beads are small, highly porous, spherical beads (0.1 to 0.3 mm in diameter) that can absorb wound secretions. Bacteria and the products of tissue necrosis and protein degradation are absorbed into the bead layer. When the beads are saturated, they take on a grayish yellow color, at which point their cleansing action stops. They are then flushed from the wound with normal saline, and a fresh layer is applied.

• Calcium alginate dressings can also be used for débridement when absorption of exudate is needed. These dressings are changed when the exudate seeps through the cover dressing or at least every 7 days. The dressing can also be used on areas that are bleeding, because the material helps stop the bleeding. As the dry fibers absorb exudate, they become a gel that is painlessly removed from the ulcer bed. Calcium alginate dressings should not be used on dry or nonexudative wounds.

TOPICAL THERAPY

A variety of topical agents can be used in conjunction with cleans-ing and débridement therapies to promote healing of leg ulcers. The goals of treatment are to remove devitalized tissue and to keep the ulcer clean and moist while healing takes place. The treatment should not destroy developing tissue. For topical treatments to be successful, adequate nutritional therapy must be maintained.

WOUND DRESSING

After the circulatory status has been assessed and determined to be adequate for healing (ABI of more than 0.5), surgical dressings can be used to promote a moist environment. The simplest method is to use a wound contact material (eg, Tegapore) next to the wound bed and cover it with gauze. Tegapore maintains a moist environment, can be left in place for several days, and does not disrupt the capillary bed when removed for evaluation. Hydrocolloids (eg, Comfeel, DuoDerm CGF, Restore, Tegasorb) are also available options to promote granulation tissue and re-epithelialization. They also provide a barrier for protection because they adhere to the wound bed and surrounding tissue. However, deep wounds and infected wounds are often more appropriately treated with other dressings.

Knowledge deficit, frustration, fear, and depression can result in the patient’s and family’s decreased compliance with the pre-scribed therapy; therefore, patient and family education is neces-sary before beginning and throughout the wound care program.

STIMULATED HEALING

Tissue-engineered human skin equivalent along with therapeutic compression has been developed by Apligraf; it is a skin product cultured from human dermal fibroblasts and keratinocytes. When applied, it seems to react to factors in the wound and may inter-act with the patient’s cells to stimulate the production of growth factors. Application is not difficult, no suturing is involved, and the procedure is painless.