Chapter 29: Leg Ulcers

An understanding of the pathophysiology, diagnosis, and management of leg ulcers is very important to health care providers as these occur in a significant number of patients. Approximately 1% to 3% of the population, or up to 9 million people in the United States are affected.¹ The annual cost of leg ulcers is proposed to be $8 to $10 billion per year, with an estimated loss of 2 million workdays per year.² The majority of leg ulcers are seen in middle-aged to elderly patients, and there is a female:male predilection of 2:1. The three most common types of leg ulcers are venous, arterial, and neuropathic.

Introduction

Ulcers caused by venous insufficiency are the most common type of leg ulcerations, accounting for 70% to 80%. They are sometimes called stasis ulcers. About 10% to 20% of leg ulcerations have a mixed venous and arterial etiology. Leg ulcers caused by chronic venous insufficiency lead to significant morbidity and can have a long-term negative impact on an individual's quality of life. Diagnosis can be difficult, and management is often expensive and labor-intensive.

Pathophysiology

Venous ulcers most commonly arise secondary to varicose veins or postphlebitic syndrome. They may also be seen in patients with a history of a deep vein thrombosis (DVT), obesity, or previous leg injury or surgery. When a patient with normal venous return stands or walks, the calf muscle acts in concert with veins and associated valves to empty the venous system and reduce its pressure.³ Venous hypertension develops when the valves become incompetent. This leads to tissue hypoxia and ultimately to skin destruction and breakdown. In addition, wound healing processes are compromised and autolytic processes take action. The result is loss of the epidermis and dermis and the formation of an ulcer.

Clinical Presentation

History

Most commonly, patients complain of a heavy or swollen feeling in the affected leg. Pain ranges from mild with a superficial ulceration to severe with a deep ulceration. Patients may describe limitation of movement of the affected extremity, depending on the location of the ulcer. In addition, patients with venous stasis and dermatitis may have significant pruritus of the skin surrounding an ulcer.

Physical Examination

Most patients with venous ulceration have some degree of nonpitting or pitting edema. Varicosities may be visible, and there is often hyperpigmentation from hemosiderin deposition over the shin. Typically, venous ulcers occur over or proximal to the medial malleolus, but they may occur anywhere below the knee. They can be single or multiple, small or large, shallow or deep. They are usually well marginated with sloped borders, but can present with irregular shapes (Figure 29-1). Often, there is fibrinoid material and/or granulation tissue at the base. The surrounding skin may have an inflamed, eczematous appearance. These ulcers can sometimes have copious drainage.

Laboratory Findings

There are no specific laboratory findings that point toward a diagnosis of venous ulceration. However, a complete blood count (CBC), erythrocyte sedimentation count (ESR), and blood glucose can help to diagnose an underlying hematologic, inflammatory, or diabetic condition. A culture will likely yield mixed flora, and may not be relevant unless the wound appears clinically infected. A venous Doppler ultrasound can help to locate venous occlusion or incompetent perforating veins.

Diagnosis and Differential Diagnosis

The key diagnostic findings of venous ulcers are well-circumscribed ulcerations usually over the shin or medial malleolus, on a backdrop of hyperpigmentation, varicosities, and lower extremity edema. Pedal pulses are usually present. Fibrinoid material or granulation tissue is often observed at the base of the ulcer.

See Table 29-1 for the differential diagnosis of leg ulcers.

Management

One must always know the cause of an ulcer before designing a treatment plan. In treating venous ulcers, the primary goal is to reverse venous hypertension so that there is an environment amenable to wound healing.⁴ The most effective way to accomplish this is with compression, the gold standard for the treatment of venous leg ulcers. Compression reverses venous hypertension, has positive effects on microcirculation, reduces deep venous reflux, reduces lower leg edema, and allows for improved oxygenation of the skin. There are two categories of compression products available: inelastic compression products, which are used for reduction of edema and healing of ulcers, and elastic compression products, which are used for maintenance to prevent ulcer recurrence. The most widely used inelastic products are Unna boots or Profore boots. These are occlusive wraps that are applied as an ace wrap would be applied in the office and removed 1 week later. They may also be applied at the patient's residence by a trained home health professional. An important companion to the use of these leg wraps is frequent elevation of the legs. Elastic compression is achieved with products such as TEDS or Jobst stockings, which can be worn on a regular basis for maintenance, once a venous ulcer has healed. Compression should always be a component of treating a venous ulcer, but one must rule out the possibility of arterial insufficiency prior to applying a compressive dressing to a patient.

In addition to compression, the treatment of the wound itself is very important. The ulcer bed must be prepared so as to allow for optimum healing.⁵ Tissue removal or debridement may be necessary, as the fibrinoid material present in some wounds interferes with healing. This may be accomplished surgically or mechanically with scissors, a curette, or a scalpel, and may require local anesthesia. Enzymatic or proteolytic agents (eg, Santyl, Panafil, or Accuzyme) can also be used to more slowly debride a wound when necessary.

The moisture balance in an ulcer can have a significant effect on healing. In particular, wounds heal more quickly in a moist environment. This is accomplished by using dressings that absorb excess fluid in a very exudative wound, or that retain fluid in an otherwise dry wound.⁶ When there is significant exudate, some appropriate absorptive dressing choices are Kerlix, gauze sponges, surgical pads, hydrophilic foam dressings (eg, COPA), or hydrocellular polyurethane dressings (eg, Allevyn). When a wound is dry, some appropriate dressing choices are Telfa, Vaseline petroleum gauze, or a nonadhering oil emulsion dressing (eg, Curity).

An ulcer often needs help with reepithelialization. There are several products that aid in providing contact between the wound edges so that they are stimulated to grow back together. Hydrocolloid dressings (eg, Duoderm or Restore) provide this function. Extracellular matrix dressings (eg, Oasis, or Matristem) create a scaffold over which growth factors and keratinocytes can migrate, thus bringing a wound together. Biologic agents (eg, Apligraf or Dermagraft) provide the building blocks for new skin to regenerate.

One last item to be addressed in the treatment of a venous ulcer is the possibility of infection. Most ulcers are colonized with bacteria, but this is not often to the level of actual infection. These ulcers do not require antibiotic treatment. Certainly, if there are clinical signs of infection such as thick odorous exudate, surrounding erythema, or increasing pain, one should consider the use of an oral antibiotic after a culture has been taken. If a patient has stasis dermatitis adjacent to an ulcer, this should be treated with a midpotency topical steroid, such as triamcinolone ointment, 0.1%. The latter will help to maintain the integrity of the skin, thus decreasing the risk of cellulitis.

Ongoing treatment may be necessary for many months before a venous ulcer will heal. Recurrence is common, seen in 54% to 78% of all venous ulcers.⁷

Indications for Consultation

If the underlying etiology of a leg ulcer cannot be determined, a specialist such as a vascular surgeon or a dermatologist should be consulted. If an ulcer is not healing despite appropriate treatment, referral to a wound care clinic should be considered. Also consider referral if the necessary management products are not available at the patient's primary clinic.

Introduction

About 6% to 10% of leg ulcers are found in the setting of peripheral arterial disease, and are usually referred to as arterial or ischemic ulcers. Some ulcers have a mixed venous–arterial component. It is very important to determine the underlying etiology so that the appropriate management plan can be followed.

Pathophysiology

The major risk factors for arterial ulcers are peripheral arterial disease, cigarette smoking, and diabetes. Other factors that contribute to the risk are hyperlipidemia and hypertension. In contrast to venous ulcers, arterial ulcers are seen more commonly in men. The underlying etiology in most cases is a decrease in or complete obstruction to arterial blood flow in the lower extremities. This is often the result of narrowing of the vessel lumen by an atherosclerotic plaque. The compromised blood flow leads to tissue ischemia and necrosis, and ultimately a skin ulceration forms.

Clinical Presentation

History

The most common complaint of a patient with an arterial ulcer is intermittent claudication. The patient experiences pain around the calf muscles during exercise early in the disease and at rest in late disease. The pain tends to be relieved when the patient places the leg in a dependent position.⁸ In general, arterial leg ulcers are significantly more painful than venous ulcers. The patient may report that their feet are usually cold, and they may notice that their feet and legs become pale with elevation.

Physical Examination

Arterial ulcers present in distal locations, often over bony prominences such as the toes. They tend to have a round, punched-out appearance with sharp edges (Figure 29-4). The base of the ulcer is often dry and may be covered with necrotic debris, presenting as an eschar. These ulcers are sometimes so deep that bone or tendon might be visible. Perhaps the most important clinical feature in making a diagnosis of an arterial ulcer is the absence of pedal pulses. The skin on the lower legs of these patients is often shiny and atrophic appearing with little or no hair.

Laboratory Findings

It is very important to measure the ankle-brachial index (ABI) in a patient who is suspected of having arterial insufficiency. This is the ratio of the ankle systolic pressure of the affected limb to the higher of the brachial systolic pressures measured in each arm. An ABI <0.8 indicates occlusive arterial disease.⁹ A Duplex ultrasound can also be helpful to identify arterial occlusion or atherosclerotic disease. As with venous ulcers, a CBC, ESR, and blood glucose can help to diagnose an underlying hematologic, inflammatory, or diabetic condition. A culture will likely yield mixed flora, and may not be relevant unless the wound appears clinically infected.

Diagnosis and Differential Diagnosis

The key diagnostic findings of arterial ulcers are punched-out appearing, well-circumscribed, and sometimes quite deep ulcerations, usually present in distal locations over bony prominences such as the toes. Pedal pulses tend to be absent. The base of the ulcer tends to be dry and might appear necrotic. The surrounding skin is often shiny and hairless.

See Table 29-1 for the differential diagnosis of leg ulcers.

Management

If an arterial etiology is suspected, compression should not be part of the treatment plan as this can lead to ischemia and necrosis of tissue.

Therapy of arterial ulcers should be targeted at reestablishing adequate arterial blood supply. One should have a low threshold for referring the patient to vascular surgery for evaluation. In addition, the patient should be encouraged to stop smoking, eat a low fat diet, and gain better control of their blood pressure and blood sugar. Antiplatelet medications such as aspirin and clopidogrel (Plavix) can be helpful in preventing ischemic events.

Pain control is another important element of the care of arterial ulcers. This may include systemic medication in addition to good local wound care. If an arterial ulcer is exudative or there is surrounding erythema, one should consider a systemic antibiotic after culture.

Indications for Consultation

Most patients with arterial ulcers should be evaluated by and co-managed with vascular surgery as surgical intervention might be a necessary part of their treatment.

Introduction

Ulcerations secondary to peripheral neuropathy account for up to 10% of all leg ulcers. Some patients have both an ischemic and a neuropathic component to their ulcers. The most common cause of neuropathic foot ulcers in the United States is diabetes. Approximately 20% of those with diabetes (3 million people) will develop a foot ulcer in their lifetime.¹⁰ Unfortunately, up to 25% of these patients will eventually require an amputation.

Pathophysiology

The vast majority of diabetic patients have peripheral neuropathy that predisposes them to the development of an ulcer. The neuropathy interferes with the patient's ability to perceive pain thus leading to repeated trauma to pressure points on the feet. In addition, neuropathy can lead to the development of foot deformities resulting in further trauma to susceptible areas.¹¹ Lastly, autonomic dysfunction contributes to hypohidrosis which causes the skin to become fissured and calloused. The result is the formation of a neuropathic ulcer. Less common causes of neuropathic ulcers are spinal cord disease or injury, alcohol abuse, and leprosy.

Clinical Presentation

History

The neuropathic ulcer is usually painless. The patient will often complain of burning, numbness, or other paresthesias of the feet and lower legs.

Physical Examination

The typical location of a neuropathic ulcer is over a pressure point of the plantar foot, such as the great toe, metatarsal head, or heel. A callus often surrounds and hides the full extent of the wound (Figure 29-5). The patient may have claw toes, flat feet, or Charcot joints. These ulcers tend to be deep and bone or tendon might be visible.

Laboratory Findings

As with venous and arterial ulcers, a CBC, ESR, and blood glucose can help to diagnose an underlying hematologic, inflammatory, or diabetic condition. If infection is suspected, one should consider an X-ray or MRI to rule out osteomyelitis. Tissue and/or bone cultures should be taken prior to the initiation of antibiotic therapy.

Diagnosis and Differential Diagnosis

The key diagnostic findings of neuropathic ulcers are deep, punched-out appearing ulcerations mainly over pressure points of the plantar foot. These ulcers are often surrounded by callus and the foot might exhibit some deformity.

See Table 29-1 for the differential diagnosis of leg ulcers.

Management

Of paramount importance in the care of a diabetic patient is the prevention and early detection of lower extremity ulcers. The largest cause of amputation other than traumatic injury is a nonhealing diabetic foot ulcer.¹²

Proper care of the ulcer itself is very important, with a goal of keeping the ulcer environment moist. Once a wound is prepared properly, an engineered product such as Oasis or Dermagraft can be quite useful in helping an ulcer to reepithelialize.

Identification and early management of infection in a neuropathic ulcer will significantly decrease morbidity and even mortality. If osteomyelitis is suspected or confirmed, appropriate parenteral antibiotic therapy should be instituted promptly.

Aggressive debridement of the surrounding callus and nonviable tissue should be performed either surgically (with a scalpel), mechanically (with wet-to-dry dressings), or enzymatically (with collagenase).¹³

Another important component of treatment of a neuropathic ulcer is off-loading of pressure.¹⁴ Repeated trauma to high pressure areas of an insensate foot is the underlying cause of many neuropathic ulcers. There are a number of different devices used to reduce foot pressure and one should consider consultation with a podiatrist to aid in the selection of the appropriate device for a patient. Most commonly, orthotic devices with cushioning are chosen for this purpose.

Indications for Consultation

It is often useful to co-manage a patient with a neuropathic ulcer with a podiatrist who has expertise in orthotics and procedures involving the foot. If there is also an arterial component, consultation with a vascular surgeon might be appropriate as well.

Patient Information

• PubMed Health—Stasis ulcers: www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001837/

• American Diabetes Association: www.diabetes.org/living-with-diabetes/complications/foot-complications/

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