Damage to blood vessels and impairment of the immune system from diabetes make it difficult to heal these wounds. Bacterial infection of the skin, connective tissues, muscles, and bones can then occur. These infections can develop into gangrene. Because of the poor blood flow, antibiotics cannot get to the site of the infection easily. Often, the only treatment for this is amputation of the foot or leg. If the infection spreads to the bloodstream, this process can be life-threatening.
People with diabetes must be fully aware of how to prevent foot problems before they occur, to recognize problems early, and to seek the right treatment when problems do occur. Although treatment for diabetic foot problems has improved, prevention - including good control of blood sugar level - remains the best way to prevent diabetic complications.
Causes
Several risk factors increase a person with diabetes chances of developing foot problems and diabetic infections in the legs and feet.
(1) Footwear: Poorly fitting shoes are a common cause of diabetic foot problems.
- If the patient has red spots, sore spots, blisters, corns, calluses, or consistent pain associated with wearing shoes, new properly fitting footwear must be obtained as soon as possible.
- If the patient has common foot abnormalities such as flat feet, bunions, or hammertoes, prescription shoes or shoe inserts may be necessary.
(2) Nerve damage: People with long-standing or poorly controlled diabetes are at risk for having damage to the nerves in their feet. The medical term for this is peripheral neuropathy.
- Because of the nerve damage, the patient may be unable to feel their feet normally. Also, they may be unable to sense the position of their feet and toes while walking and balancing. With normal nerves, a person can usually sense if their shoes are rubbing on the feet or if one part of the foot is becoming strained while walking.
- A person with diabetes may not properly sense minor injuries (such as cuts, scrapes, blisters), signs of abnormal wear and tear (that turn into calluses and corns), and foot strain. Normally, people can feel if there is a stone in their shoe, then remove it immediately. A person who has diabetes may not be able to perceive a stone. Its constant rubbing can easily create a sore.
(3) Poor circulation: Especially when poorly controlled, diabetes can lead to accelerated hardening of the arteries or atherosclerosis. When blood flow to injured tissues is poor, healing does not occur properly.
(4) Trauma to the foot: Any trauma to the foot can increase the risk for a more serious problem to develop.
(5) Infections
(6) Smoking: Smoking any form of tobacco causes damage to the small blood vessels in the feet and legs. This damage can disrupt the healing process and is a major risk factor for infections and amputations. The importance of smoking cessation cannot be overemphasized.
Symptoms
- Persistent pain can be a symptom of sprain, strain, bruise, overuse, improperly fitting shoes, or underlying infection.
- Redness can be a sign of infection, especially when surrounding a wound, or of abnormal rubbing of shoes or socks.
- Swelling of the feet or legs can be a sign of underlying inflammation or infection, improperly fitting shoes, or poor venous circulation.
Other signs of poor circulation include the following:
- Fever or chills in association with a wound on the foot can be a sign of a limb-threatening or life-threatening infection.
- Red streaking away from a wound or redness spreading out from a wound is a sign of a progressively worsening infection.
- New or lasting numbness in the feet or legs can be a sign of nerve damage from diabetes, which increases a persons risk for leg and foot problems.
Exams and Tests
Medical evaluation should include a thorough history and physical examination and may also include laboratory tests, x-ray studies of circulation in the legs, and consultation with specialists.
Laboratory tests: Complete blood cell count, or CBC, which will assist in determining the presence and severity of infection. A very high or very low white blood cell count suggests serious infection. The doctor may also check the patient's blood sugar either by fingerstick or by a laboratory test. Depending on the severity of the problem, the doctor may also order kidney function tests, blood chemistry studies (electrolytes), liver enzyme tests, and heart enzyme tests to assess whether other body systems are working properly in the face of serious infection.
X-rays: x-rays studies of the feet or legs to assess for signs of damage to the bones or arthritis, damage from infection, foreign bodies in the soft tissues. Gas in the soft tissues, indicates gangrene - a very serious, potentially life-threatening or limb-threatening infection.
- Ultrasound:Doppler ultrasound to see the blood flow through the arteries and veins in the lower extremities. The test is not painful and involves the technician moving a non-invasive probe over the blood vessels of the lower extremities.
Consultation: The doctor may ask a vascular surgeon, orthopedic surgeon, or both to examine the patient. These specialists are skilled in dealing with diabetic lower extremity infections, bone problems, or circulatory problems.
Angiogram: If the vascular surgeon determines that the patient has poor circulation in the lower extremities, an angiogram may be performed in preparation for surgery to improve circulation.
Treatment
(1) Foot examination: Examine your feet daily and also after any trauma, no matter how minor, to your feet. Use a water-based moisturizer every day (but not between your toes) to prevent dry skin and cracking. Wear cotton or wool socks. Avoid elastic socks and hosiery because they may impair circulation.
(2) Eliminate obstacles: Move or remove any items you are likely to trip over or bump your feet on. Keep clutter on the floor picked up.
(3) Toenail trimming: Always cut your nails with a safety clipper, never a scissors. Cut them straight across and leave plenty of room out from the nailbed or quick.
(4) Exercise: Regular exercise will improve bone and joint health in your feet and legs, improve circulation to your legs, and will also help to stabilize your blood sugar levels.
(5) Smoking: If you smoke any form of tobacco, quitting can be one of the best things you can do to prevent problems with your feet. Smoking accelerates damage to blood vessels, especially small blood vessels leading to poor circulation, which is a major risk factor for foot infections and ultimately amputations.
(6) Diabetes control: Following a reasonable diet, taking your medications, checking your blood sugar regularly, exercising regularly, and maintaining good communication with your physician are essential in keeping your diabetes under control.
Medical Treatment
(1) Antibiotics: to treat the infection or the potential infection.
(2) Referral to wound care center: Here professionals of many specialties including doctors, nurses, and therapists work with the patient and their doctor in developing a treatment plan for the wound or leg ulcer. Treatment plans may include surgical debridement of the wound, improvement of circulation through surgery or therapy, special dressings, and antibiotics. The plan may include a combination of treatments.
(3) Referral to podiatrist or orthopedic surgeon: If the patient has bone-related problems, toenail problems, corns and calluses, hammertoes, bunions, flat feet, heel spurs, arthritis, or have difficulty with finding shoes that fit, a physician may refer you to one of these specialists. They create shoe inserts, prescribe shoes, remove calluses and have expertise in surgical solutions for bone problems. They can also be an excellent resource for how to care for the patient's feet routinely.
Prevention
Prevention of diabetic foot problems involves a combination of factors.
- Good diabetes control
- Regular leg and foot self-examinations
- Knowledge on how to recognize problems
- Choosing proper footwear
- Regular exercise, if able
- Avoiding injury by keeping footpaths clear
- Having a doctor examine the patient's feet at least once a year using a monofilament, a device made of nylon string that tests sensation
- Surgical treatment
Infections that involve gangrene almost universally go on to amputation and also carry a high risk of death. Ulcers larger than about 1 inch across have a much higher risk of progressing on to limb amputation, even with proper treatment. Infections involving deep tissues and bone carry a much higher risk of amputation.
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