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Diabetic Foot Ulcer by Diane Voyatzis Norwood, MS, RD, CDE

Definition

Ulcers are slow healing wounds on the skin. Diabetic foot ulcers occur on the feet of people with type 1 and type 2 diabetes . Up to 15% of people with diabetes are at risk for developing foot ulcers. Diabetic foot ulcers usually occur on the bottom of the foot.

The sooner a diabetic foot ulcer is treated, the better the outcome. Ulcers that do not heal or develop a severe infection may lead to amputation of the foot. About 80% of leg amputations in the US started off as diabetic foot ulcers.

Foot Ulcer

Causes

Diabetes can damage the nerves of the legs and feet. This may make it difficult to feel a blister or sore. If you don't care for a sore it may become larger and infected.

Diabetes also can causes problems with blood flow. Poor blood flow can make it difficult to heal.

The ulcer itself is usually caused by:

Repetitive trauma or pressure on the foot
Puncture wound on the foot
Objects in the shoe that can damage the skin (such as a small rock)

Risk Factors

The following factors increase your chance of developing diabetic foot ulcers. If you have diabetes and any of these risk factors, tell your doctor:

Neuropathy (numbness, tingling, or burning sensation in your feet)
Peripheral vascular disease (poor circulation in your legs)
Improperly fitted shoes
A foot deformity
Not wearing shoes
A history of smoking

Symptoms

Tell your doctor if you have any of these symptoms:

Sores, ulcers, or blisters on the foot or lower leg
Pain
Difficulty walking
Discoloration in feet: black, blue, or red
Fever, skin redness, swelling, or other signs of infection

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will be done. Your primary doctor may refer you to a foot specialist.

Tests may include the following:

Wound culture to determine if an infection is present
X-ray —a test that uses radiation to take a picture of structures inside the body, especially bones; to determine if there is evidence of infection in the bones ( osteomyelitis )
CT scan —a type of x-ray that uses a computer to make pictures of structures inside the body; to evaluate a suspected pocket of pus called an abscess or to look for infections in the bone
MRI scan —a test that uses magnetic waves to make pictures of structures inside the body; to evaluate a suspected pocket of pus called an abscess or to look for infections in the bone
Ankle-brachial pressure—a test to determine if blood is flowing well to your feet
Doppler or arteriographic studies —to assess for adequate blood flow to feet, which is necessary for healing
Blood glucose and glycohemoglobin test
Complete blood count to determine if there is an infection—A high white blood cell count may mean that there is an infection.

Treatment

Talk with your doctor about the best treatment plan for you. Treatment options include the following:

Wound Care

Good wound care is important to help the ulcer heal and prevent infection. Follow your doctor's instructions for wound care. Make sure to clean the wound regularly. Change the dressings often to prevent infection.

No Weight-bearing

Constant pressure on the ulcer can make it difficult to heal. Your doctor may ask you to take some pressure off of the ulcer area. You may be given a special cast or boot. These will take the pressure off of your foot but still allow you to walk.

Blood Sugar Control

Infected ulcers can raise high blood sugar levels. High blood sugar levels can then lower the body's ability to fight infections. The high level also keeps the wound from healing.

Improved blood sugar control will help you fight any infections and heal your wounds. This control is often done with adjustments in your diet or medicine. Sometimes insulin shots are needed in the short-term until your are healthy again.

Healthy Habits

If you smoke, quit. Smoking can impair healing.

Wear proper footwear. Make sure it fits well.

Skin Graft

Some large skin ulcers may have a hard time fully healing even with treatments above. They may need a patch of skin to help close the wound. This process is called a skin graft. Bioengineered skin graft or human skin graft may be used.

Medication

If the ulcer is infected, your doctor may recommend antibiotics. You may need to take the medicine for 4-6 weeks. Do not skip doses. Finish the medication as directed.

Your doctor may also recommend a medication to place on the ulcer. These medicine may help speed up healing.

Surgery

Dead tissue can build up inside and around the wound. This tissue will slow or prevent healing. You may need a surgery to remove the dead tissue and clean the wound. This surgery is called debridement .

Bypass surgery may be needed to improve blood flow to the legs. This surgery uses healthy blood vessels to carry blood past areas of unhealthy blood vessels. The improved blood flow may help with wound healing.

Sometimes an infection is too severe or does not respond to treatment. As a last resort, amputation surgery may be needed. This is the removal a body part to stop the infection from spreading to the rest of the body.

Other Treatments

Hyperbaric oxygen therapy may help with healing. This therapy is delivered in a chamber. Pure oxygen is pumped into the chamber. This helps to increase the amount of oxygen in the blood. The extra oxygen can improve healing.

Another option to help accelerate healing is using negative pressure wound therapy. A vacuum device and dressing are used to create negative pressure on the wound. This can help the wound heal faster.

If you are diagnosed with a diabetic foot ulcer, follow your doctor's instructions .

Prevention

To help reduce your chance of getting diabetic foot ulcers, take the following steps:

Clean your feet daily. Dry them thoroughly, especially between the toes, before putting shoes and socks on.
Do not wear garters and tight stockings around the legs.
You may want to use petroleum jelly or an unscented lotion to moisturize dry, leathery feet. Do not put lotion between the toes. The extra moisture may attract bacteria.
Inspect your feet daily. Look for sores that you may not be able to feel. Use a mirror or the assistance of another person to see all parts of your feet.
Your doctor should look at your feet and test the feeling in them at least once a year. If you find a sore at any time, make an appointment to see your doctor right away.
People with diabetes may have toenails that are brittle and difficult to cut. You may also want to have a foot specialist trim your toenails regularly.
Buy properly fitted shoes. Some insurance companies will pay for custom-made shoes with inserts. A doctor can give you a prescription for the shoes.
Avoid smoking.
Talk to your doctor about exercise. Daily exercise will help to improve blood flow and blood sugar levels.
Calluses can increase the pressure on the foot and lead to foot ulcers. Have your foot doctor remove any calluses. This could reduce the risk of developing a foot ulcer.
Ask your doctor if you should use a special infrared thermometer. It can check the temperature of your feet.

RESOURCES:

American Diabetes Association http://www.diabetes.org/
American Podiatric Medical Association http://www.apma.org/

CANADIAN RESOURCES:

Canadian Diabetes Association http://www.diabetes.ca/
Podiatrists in Canada http://www.podiatrycanada.org/

References:

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2/7/2008 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Lavery LA, Higgins KR, Lanctot DR, et al. Home monitoring of foot skin temperatures to prevent ulceration. Diabetes Care. 2004;27:2642-2647.
4/8/2011 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance : Löndahl M, Landin-Olsson M, Katzman P. Hyperbaric oxygen therapy improves health-related quality of life in patients with diabetes and chronic foot ulcer. Diabet Med. 2011;28(2):186-190.

Last reviewed September 2012 by Brian Randall

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