Causes

Diabetes and Foot Problems

Foot problems are the leading cause of hospitalizations for patients with diabetes. Foot problems develop from problems in the blood vessels and in the peripheral nervous system (the nerves that reach the limbs). About half of patients with diabetes have nerve damage (neuropathy), which can cause numbness, pain, and weakness in the feet or other parts of the body. Diabetes can also cause changes in the bone structure and soft tissue of the feet.

• Infections and Ulcers. People with diabetes are at particularly high risk for infections, such as those resulting from blood vessel injury, which may be severe enough to cause ulcers in the legs and feet. If an infection does not heal, it may spread to the bone (called osteomyelitis). Numbness from nerve damage, which is common in diabetes, compounds the danger posed by even minor infection since the patient may not be aware of injuries. Untreated minor infections can easily develop into severe complications. Poor blood flow in those with diabetes makes it more difficult for wounds to heal, which can lead to more severe infections. Being overweight also increases the risk for foot infections. About one-third of foot ulcers occur on the big toe. Some research suggests that early risk factors for ulcers here may be problems with movement in the toe or ankle.
• Charcot Foot. Charcot foot or Charcot joint (medically referred to as neuropathic arthropathy) is of particular note. Between 1 - 2.5% of people with diabetes have this condition. It is caused by abnormalities in the nerves in the feet, which can numb the feet so that the sufferer does not feel pain at first and is not aware of injury. Instead of resting an injured foot or seeking medical help, the patient often continues to walk, causing further damage. Early changes appear like an infection, with the foot becoming swollen, red, and warm. A seriously affected foot can become deformed. The bones may crack, splinter, and erode, and the joints may shift, change shape, and become unstable.
• Risk for Amputations. Extensive surgery may be required, and, in extreme cases, amputation may be necessary. Diabetes is responsible for more than half of all the lower limb amputations performed in the U.S. each year, and every year there are more than 86,000 foot amputations due to this disease. According to a 2002 study, 25% of these amputations are performed on the toe, 6% mid-foot, 38% below the knee, and 21% above the knee. The remaining 10% of amputations are performed on the hip, pelvis, knee, and other sites.
• Risk for Falling. The numbness caused by nerve damage makes patients with diabetes four times more likely to fall than those who do not have the disease.

Prevention of Foot Disorders in Diabetes

Preventive foot care could reduce the risk of amputation in people with diabetes by 44 - 85%. Some tips for preventing problems include the following:

• Patients should inspect their feet daily and watch for changes in color or texture, odor, and firm or hardened areas, which may indicate infection and potential ulcers.
• When patients wash their feet, the water should be warm (not hot), and the feet and areas between the toes should be thoroughly dried afterward. Check water temperature with the hand or a thermometer before stepping in.
• Moisturizers should be applied, but not between the toes.
• Corns and calluses should be gently pumiced and toenails trimmed short and the edges filed to avoid cutting adjacent toes. Use an emery board, not a metal file, to avoid cutting your skin when you file your nails.
• Patients should not use medicated pads or try to shave the corns or calluses themselves.
• Well-fitting footwear is very important. In a 2001 study, 30% of diabetes patients wore shoes that were too narrow. Patients should also avoid high heels, sandals, thongs, and going barefoot. Specific therapeutic shoes, boots, and insoles do not appear to add advantage over careful attention and monitoring of the feet. However, people who are not attentive might do better with such footwear. For example, custom-molded boots (such as the Conformer Diabetic Boot) are designed to increase the surface area over which foot pressure is distributed. This reduces stress on the ulcers and allows them to heal. Special insoles (such as the Rocker insole) have also been designed to reduce pressure on the front of the foot.
• Shoes should be changed often during the day.
• Wear socks, particularly with extra padding (which can be purchased).
• Patients should avoid tight stockings or any clothing that constricts the legs and feet.
• Foot pain, numbness, or tingling is worse at night. Diphenhydramine (Benadryl) may help.

You should consult a specialist in foot care if you have any problems with your feet.

Treating Foot Disorders in Diabetes

About one-third of foot ulcers will heal within 20 weeks with good wound care treatments. Some treatments are as follows:

• Antibiotic therapy. However, research published in 2005 suggests that long-term antibiotic therapy may not be enough to heal many infections.
• In virtually all cases, wound care requires debridement, the removal of injured tissue until only healthy tissue remains. Early treatment with debridement can increase the chances of saving toes and feet from amputation. Debridement may be done with chemicals (enzymes), surgery, or irrigation. Hospitalization and intravenous antibiotics for up to 28 days may be needed for severe foot ulcers.
• Hydrogels (Nu-Gel, Intrasite Gel, Scherisorb, Clearsite, Duoderm, Geliperm) are proving to be effective in healing ulcers and are noninvasive and soothing. They should be applied and covered with a dressing.
• Charcot foot is initially treated with strict immobilization of the foot and ankle. Some centers use a cast that allows the patient to move and still protects the foot. A 2001 British study concluded that a single dose of pamidronate, a bisphosphonate, reduces bone turnover, symptoms, and disease activity. When the acute phase has passed, patients usually need lifelong protection of the foot using a brace initially and custom footwear.
• For diabetic neuropathy, surgical decompression (relief of pressure) of swollen nerves in the legs and feet can improve sensation and reduce pain.

Several recent investigative measures include the following:

• A new gene therapy may prevent nerve damage in patients with diabetes. The therapy stimulates growth of a patient’s own natural protein. Because it does not introduce foreign proteins, unlike some other gene therapies, the therapy does not cause adverse immune reactions. Initial results are promising. Clinical trials of this new therapy are currently underway.
• Several treatments that use human skin equivalent or HSE (Dermagraft, Apligraf, Regranex) are now available. These therapies stimulate new cell growth and help heal skin ulcers or use cultures of human skin cells. Studies are showing that HSE promotes healing, and the risk for rejection of such grafts is low. Adverse effects include infections at other sites.
• Silver-containing wound dressings (Acticoat, Silverlon) have shown promise for wound care in some studies due to their anti-microbial properties, and may provide new avenues for managing diabetic ulcers. However, one study suggested that silver may be toxic to some cell types.
• Administering hyperbaric oxygen (oxygen given at high pressure) is showing promise in promoting healing and preventing amputation.
• Granulocyte-colony stimulating factor, also called G-CSF (filgrastim, Neupogen, Amgen), is showing promise as an effective alternative to antibiotics. Studies are reporting that G-CSF accelerates healing and significantly reduces the need for surgery.
• Total-contact casting (TCC). This approach uses a cast that is designed to contact the exact contour of the foot and distribute weight along the entire length of the foot. It is usually changed weekly. In one trial, it healed ulcers in nearly 90% of selected patients. It is also useful for Charcot foot.
• A device that compresses the foot (NuPulse) appears to increase circulation, reduces edema (swelling), and improves wound healing.
• Light therapy called monochromatic near-infrared photo energy (MIRE) may help reduce pain, improve balance, and improve sensation in the feet of patients with peripheral neuropathy.