Chronic Wounds and Pressure Sores (Ulcerations)
Millions of people of all walks of life suffer from chronic open sores that may become seriously infected or cause significant pain or discomfort. Ulcers may occur on any part of the foot or leg. These ulcerations often may become gangrenous and some may lead to amputation. Chronic wounds are often due to limited blood flow which can slow the body's own healing process but may be caused by a variety of factors including: Diabetes, Arterial disease, Venous disease, Neuropathy, Pressure sores, Surgical wound breakdown, and Chemical or Thermal Burns.
Diabetic Skin Sores
Diabetes causes damage to blood vessels so that blood flow to the skin is diminished. Oxygen and nutrients are not delivered and the affected tissue dies (or becomes gangrenous). Poor blood flow might initially be identified by calf or foot pain with exercise or while at rest at night. The feet may feel cool or cold. Ulcers like these often begin as a discoloration or sore on the tip of a toe. Only 15-20% of diabetic ulcers however are due to poor circulation.
The majority of diabetic ulcers are due to damage to peripheral nerves (neuropathy). Neuropathy results in decreased sweating which leads to dry, cracked skin, that may become a source of ulceration. Neuropathy will also cause a loss of appropriate sensation of the skin which leads to abnormal pressure and breakdown of skin especially over areas of foot deformity such as hammertoes, bunions and other bony deformities. Pressure over these areas causes blisters or calluses which may also lead to ulceration.
At first glance, all of these sores may appear to be of minor consequence. However, the presence of an ulcer taxes circulation, and with less than adequate flow, healing becomes problematic. The prospect of limb loss without appropriate care can be totally unpredictable and devastating for individuals with diabetes who started with what seemed to be a relatively benign injury.
Arterial ulcers (ischemic ulcers) result from partial or complete blockage of arteries to a part of the body. This leads to tissue necrosis ulceration and gangrene. Signs of arterial insufficiency include: lack of pulses in the extremity, cool or cold skin, prolonged blanching of the skin with mild pressure, and shiny thin dry skin. Often pain in the back of the leg while walking (claudication) progressing to pain in a toe, foot or leg while at rest (ischemic pain) are the initial signs.
Arterial ulcers often begin on the end of a toe or the back of the heel but may be found anywhere on an extremity where prolonged pressure combined with arterial insufficiency exists. Arterial ulcers are painful and begin as small sores with well circumscribed edges. There is little drainage from the wound. Tissue immediately surrounding the ulcer may be warm and reddened but the remainder of the surrounding skin will be cool or cold. Arterial ulcers may progress slowly or rapidly depending on the size of the underlying arterial blockage with increasing tissue necrosis within.
Venous ulcerations result from the failure of the veins in our legs to properly move the blood back to the heart (venous insufficiency). This backflow of blood causes venous congestion, swelling (edema) and hardness in the legs. Often a brownish discoloration occurs on the inside of the lower leg and in extreme cases redness and a weeping discharge from the leg may be seen. The typical venous ulcer appears on the inside of the leg just above the ankle but may occur anywhere on the lower leg. The wound is shallow with irregular borders and not very painful. There is often a significant discharge from the wound as well.
Loss of sensation in the feet (neuropathy) may result in minor injuries that often go unnoticed. Most of these injuries are likely to occur on the sole of the foot but may be found wherever the neuropathy exists. Those that occur on the toes or soles of the feet often begin as a blister which may be caused by tight shoes. Those suffering from neuropathy also may not be able to detect sharp objects or areas of extreme heat accidentally encountered if barefoot. This may cause unnoticed open cuts or puncture wounds, or moderate to severe blisters or burns from sun or heating pads.
Neuropathic ulcers are irregular in shape with a deep center and necrotic edges. These ulcers are easily infected resulting in surrounding swelling redness and drainage.
Pressure ulcers arise due to a combination of situations and factors. On a cellular level ischemia occurs to the tissue when too much pressure is applied to one area for a prolonged period of time. The pressure is usually from a bony prominence on one side and a hard surface, such as a shoe or bed, on the other side. Common foot deformities including hammertoes, bunions and prominences of the ball of the foot cause corns and calluses which when severe may lead to ulceration. Those confined to bed or seated in one position for long periods of time may form pressure sores (decubiti) on the heels or sacrum. Soft tissue between these two surfaces is subject to abnormal pressure which leads to tissue necrosis.
Initial signs of ulceration include redness and swelling and in some instances blister formation. Pressure ulcers appear as shallow breaks in the skin with irregular borders and surrounding redness extending beyond the wound.
Surgical Wound Breakdown
Ulcerations due to surgical wounds occur from a variety of factors. Wounds may become infected postoperatively, vascular supply may be compromised at the time of surgery, abnormal tension may be placed on skin edges from improper surgical closure or excessive swelling may occur causing tissue ischemia. Surgical wounds appear as openings in part of the area of previous surgical closure. These ulcerations are usually deep with moderate drainage.
Chemical and Thermal Burns
Caustic chemicals or extreme heat will cause necrosis of tissue. This leads to ulceration of the affected area. Burns have been classified traditionally according to degree. A first-degree burn involves a reddening of the skin area. In a second-degree burn the skin is blistered. A third-degree burn is the most serious type, involving damage to the deeper layers of the skin with necrosis through the entire skin. In some cases the growth cells of the tissues in the burned area may be destroyed. Partial thickness wounds reveal some skin elements remain intact such as hair follicles. Full-thickness wounds in which all of the skin elements and those lining the sweat glands, hair follicles, and sebaceous glands are destroyed. Full-thickness burn often have a white, waxy appearance.
The sooner intervention occurs, the better the chances for healing. It is far easier to manage a superficial ulcer than it is to treat a deeper chronic ulceration. Wound healing is a complex process and may involve the knowledge and skill of multiple specialists including the podiatrist, wound care specialist, primary physician, vascular surgeon, endocrinologists nutritionist, orthotist and infectious disease physician. The approach must address the factors that caused the ulcer as well as those that complicate the wound healing; infection, blood flow, nutrition, swelling or pressure.
To adequately assess the underlying causative factors additional testing is often necessary. This may include; blood tests, x-rays, wound culture to identify infection, noninvasive vascular studies such as Doppler and ultrasound to evaluate both arterial and venous flow, as well as more advanced studies such as tissue perfusion studies(TCPO2), bone scans or MRI. General health, skin texture and turgor, patient's mobility and nutritional status must all be evaluated.
Diabetic wounds may first require control of blood sugar and/or adequate nutrition. Arterial ulcerations require increased blood flow to the area or revascularization of the limb. This may be accomplished surgically (with angioplasty or bypass) or medically (with oral pills). Venous ulcers require reduction and control of swelling and venous insufficiency. This is accomplished with medication, specialized compression bandages mechanical compression devices, gradient compression stockings and by promoting activity of the patient. Neuropathic and pressure sores may require avoidance of weight bearing activities, redistribution of weight bearing areas while standing, sitting or lying for long periods of time or possibly correction of bony abnormalities. When the use of crutches, a wheelchair, or rest is not feasible, plaster casts (total contact casting), braces healing sandals, or orthoses (special shoe inserts) can be used to protect the area while it heals. Infected wounds require antibiotic therapy which may be topical, oral or intravenous (IV) depending on the severity of the infection.
Once the causative factors have been identified and addressed for the specific type of wound, general wound care principles should be followed. Promotion and maintenance of an infection free environment is paramount . Removal of unhealthy tissue (wound debridement) inside the wound and hyperkeratotic tissue on the rim should be carried out on a regular basis as needed. Avoiding excessive discharge while maintaining a moist wound base and dry wound edges is accomplished with appropriate selection of wound dressing products.
In some cases more advanced wound care techniques may be necessary including the use of; growth factor medication, advanced wound dressings (genetically engineered grafting materials), Hyperbaric (high-pressure) oxygen treatment, and surgical intervention including, surgical debridement, skin grafting and plastic surgical techniques (skin flaps).
Appropriate wound management is best carried out by a certified wound specialist. The goal of any wound care specialist in treating chronic wounds should be the fastest possible healing achieved through appropriate treatment programs.