Management of Leg Ulcers

The management of decubitus, arterial and stasis ulcers poses a major problem for many family physicians. Is an ulcer venous, arterial or mixed in origin? Which dressing is most appropriate? How can they be prevented? These are questions that we are confronted with on a daily basis and as the incidence of diabetes increases and as our population ages, we are likely to see even more ulcers.

Having a clear understanding of the physiology of wound healing and the appropriate type of dressing to use in each specific stage of the condition can make the therapeutic process much easier for the physician, and allow him/her to take charge of the situation, instead of delegating it to others.

In this article we will try to reveal some of the mystery of would healing.

The first thing to understand is that there are basic principles of wound management and healing that apply to all ulcers. These can be summarized using the acronym TIME.

• have a necrotic and exudative burden that needs to be removed to promote healing. Failure to adequately debride the wound:
• Provides ideal conditions for bacterial growth and infection
• Prolongs the inflammatory process and inhibits phagocytosis
• Prevents adequate assessment of would depth and the extent of tissue damage
• Limits the effectiveness of antibiotic therapy
• Adds to the odour and patient discomfort
• Inhibits epithelial cell migration and prolongs would closure.

• Surgically, by cutting dead tissue away with a scalpel or scissors.
• Mechanically, by using wet-to-dry gauze dressings or hydrotherapy
• Enzymatically, using a chemical agent that degrades the eschar.
• Autolytically, by covering the wound with a gel or hydrocolloid dressing and allowing the body's enzymes and moisture to soften and liquefy the eschar.

Each of these methods has its place, although it is generally felt that using wet-to-dry gauze dressings is the least effective and most time consuming method. It may actually retard healing.

Unless there is obvious need to surgically debride the wound, Autolytic debridement may be the preferred choice for home care nurses.

As surgical debridement is fast, safe and cost-effective, it likely is the preferred choice for physicians.

Infection or Inflammation: High bacterial counts will prolong inflammation and increase inflammatory cytokines and protease activity while decreasing growth factor activity in the wound. Symptoms of infection include:

• Increased exudate
• Surface discolouration
• Increased odour
• Superficial pocketing or bridging of the wound base
• Cellulitis of the surrounding skin
• Friable granulation tissue
• Abscess formation
• Increasing pain and tenderness

Locally infected wounds can be treated with topical antimicrobial dressings, often impregnated with silver or cadexamer iodine. Systemic antibiotics can be used, particularly if there is significant cellulitis present.

Moisture imbalance: If the wound is dry, epithelial cell migration will be slowed and accordingly so will wound healing. Excessive fluid will promote infection, slow wound healing and cause periwound maceration. It is therefore, important to have the optimum moisture balance that will increase cell proliferation, decrease inflammation and enhance re-epithelialization.

There are several products available to help provide the ideal wound environment. Wounds that have large amounts of exudate are best managed using Foam or Alginate dressings Hydrocolloid dressings are used in situations where the exudate is less severe. Hydro Gels and Transparent Films can be used to create the proper wound environment in wounds with little or n o exudate.

Edge of wound: Watch for undermining of the wound edge or for lack of advancement of the wound edge. Sometimes because of poor fibroblastic activity, vascular deficiency or impaired re-epithelialization, the wound will not heal. In this situation it may be necessary to surgical trim the wound edge, or use skin grafting or a human dermal substitute to promote healing..

The above principles apply to the management of all ulcers. In this article we are more concerned with lower limb ulcers, such as those seen in diabetics. These generally fall into the categories of Arterial, Venous and Neuropathic ulcers.

Arterial Ulcers

These are the result of arterial insufficiency and are usually found below the ankle. There may be other signs of decreased blood flow such as cooler temperature, hair loss, dependent rubor and lobster foot, feet with thin shiny skin, thickened nails and of course,( but not necessarily), reduced or absent pulses.

The ulcers typically are small, distal, with a steep "cliff edge" and a dry bottom. Pain is often present at night when the leg is elevated. The ABI is less than 0.8 and the patient may complain of intermittent claudication.

Treatment of theses ulcers is primarily aimed at restoring blood flow, and surgery may be warranted. It is imperative these patients stop smoking. There is some evidence that pentoxifylline may be helpful healing venous ulcers, but not arterial ones. Walking may help with the development of collateral circulation and underlying conditions such as diabetes and hypertension must be controlled. The patients must be educated about foot care. Elevating the head of the bed may help the gravitational pull and ease the leg pain at night. Compression is contraindicated with arterial ulcers.

As for the wound - avoid debridement if the circulation is severely compromised, and once the circulation is restored maintaining adequate moisture is all that is needed to promote healing.

Venous Ulcers

Venous Ulcers are by far the most commonly seen as more than 80% of leg ulcers are venous in origin. These ulcers develop when the venous valves become incompetent and blood pools in the lower limb. Red cells leak into the tissues, break down and give the skin a characteristic brown colour (brawny edema). This leakage also leads to inflammation and edema of local tissue, along with reactive collagen deposition which produces lipodermatosclerosis, or local induration, which is refractory to normal healing. Ultimately this all leads to breakdown of tissue and formation of an ulcer.

Conditions that will predispose to venous ulcers include family history, trauma such as tib-fib fractures, obesity, multiple pregnancies and previous deep vein thrombophlebitis.

The ulcers are usually found between the malleolus and the lower calf, are shallow with a beefy granulation base, and have irregular margins. They can vary from small to nearly encircling the leg.

The Tourniquent test can be done to assess venous incompetence. Lay the patient flat with the leg elevated 45 degrees for 30 seconds to drain the blood from the leg. Apply a tourniquet above the knee and have the patient stand. Remove the tourniquet. Filling of the saphenous vein within 20 seconds indicates venous valvular incompetence.

Compression dressings form the cornerstone of treatment of venous ulcers. Dressings such as the Unna Boot are stiff, and provide compression when the muscles of the calf are contracted. The more elastic dressings can provide resting compressions as well as active compression, and they can be applied to give a graduated compression, which further improves venous return. They are more expensive. ABIs should be done prior to application of a compression dressing and they should not be used if the ABI is <0.7. (Some authors say 0.6-0.8). Remember that stiff arteries such as those found in diabetics can give falsely high ABIs.

Elevation of the affected leg above the heart for 20 minutes 3 or 4 times a day is useful but most patients find this problematic to do. The underlying dressing will depend on the amount of eschar, exudate and infection. Wounds with a large amount of exudate may require a foam or alginate dressing, while those with less exudate may use a hydrocolloid dressing.

Neuropathic Ulcers

Neuropathic foot ulcers are frequently seen in diabetics. Poor glucose control leads to decreased sensation in the foot, loss of autonomic function and anhidrosis as well as loss of intrinsic muscle function producing changes in the foot architecture.

These ulcers are typically wet, very deep (often to bone) with sharp borders, and are often surrounded by callus. They are often located over pressure points. Without question, the cornerstone of treatment of neuropathic ulcers requires off loading of the weight on the pressure point. This may be accomplished with adjustments to footwear (perhaps utilizing expensive customized shoes) padding, or casting but may also require crutches, wheelchair or bed rest. Glycemic control is critical.

The general principles of wound care discussed above apply to these wounds as well, taking care to assess the arterial circulation.

It goes without saying that foot care and patient compliance and education is critical to the prevention of foot ulcers.

- John Hickey

Thanks to Dr. Michael Brennan, plastic surgeon in the Department of Surgery, St. Martha's Regional Hospital, Antigonish, Nova Scotia, for reviewing the draft copy of this article.

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You can search for abstracts of the above references by following this link: PubMed