Diabetic Foot Problems

Written by Robert Frykberg, DPM

Foot problems are leading causes of hospitalization for the 16 million persons in the United States with diabetes mellitus accounting for expenditures of hundreds of millions of dollars annually. It has been estimated that 15% of all diabetics will develop a serious foot problem at some time, which can potentially threaten their limb or even their life. The most common of these problems are infection, ulceration, or gangrene (death of the tissue) which can lead, in the most severe of cases, to amputation of a toe, foot, or leg.

The good news is that most of these problems can be prevented through regular podiatric visits, patient education, daily foot inspection and care, proper footwear, and early recognition and treatment of any suspected trouble areas. This can only be accomplished with active participation in your own care along with the help and guidance of your foot specialist.

People with diabetes can develop a variety of foot problems. Even ordinary problems can quickly get worse and lead to serious complications. Foot problems most often happen when there is nerve damage in the feet or when blood flow is poor. Inspect your feet every day, and seek care early if you do get a foot injury. Make sure your health care provider checks your feet at least once a year-more often if you have foot problems. Your health care provider should also give you a list and explain the do's and don'ts of foot care. (See below)

What Causes Foot Problems in Diabetes?

It is well established that the longer a person has the disease, the greater is the incidence and severity of complications of diabetes mellitus. Although good control of blood sugar and blood pressure are extremely important in maintaining your optimum health, other factors can be important in the development of diabetic foot disorders.

Foot problems in persons with diabetes are usually the result of three primary factors : Neuropathy (diminished sensation), Poor circulation, and a decreased resistance to Infection. Additionally, Foot deformities and Trauma play major roles in causing ulcerations and infections in the presence of neuropathy or poor circulation.

Neuropathy can generally be defined as a loss of sensation or alteration in sensitivity in the feet and legs. There may be a diminished or absent ability to detect painful sensations such as a pinprick or the heat of sand at the beach in the Summer or hot water. Your ability to detect the tightness of a shoe might also be affected. Neuropathy can prevent the recognition of injuries to the feet and permit them to remain untreated for lengthy periods of time. Continued walking on the injured or infected foot results in further trauma and injury.

Sometimes neuropathy can be painful and quite distressing, especially at night when you are trying to sleep. Painful neuropathy usually causes burning or sharp shooting pains in the feet. It is even possible for some people to have painful neuropathy in combination with an actual loss of external sensation as described above.

Neuropathy can also cause muscle weakness in the legs and feet. This might give rise to such conditions as "foot drop", where the foot cannot be raised at the ankle when walking. Other common deformities associated with this might be hammertoes or bunions; these are often also associated with corns or calluses.

Poor Circulation

People with diabetes often have varying degrees of circulation disorders to their legs and feet due to atherosclerosis and blockage of arteries. Common symptoms of peripheral vascular disease are cramping in the calf or buttocks when walking. Temperature and color changes in the feet, in addition to loss of hair and thickening of toenails, might also be attributed to circulatory changes.

Poor circulation results in reduced blood flow to the feet. Adequate delivery of oxygen and nutrients, which are required for normal maintenance and repair, is then restricted. This becomes critical when the foot is injured, infected, or ulcerated, since healing will be impaired or will not occur at all. Long a major cause of lower extremity amputation, peripheral vascular disease can now be frequently corrected by vascular bypass operations in the legs. This is similar to those operations performed in the heart for blocked arteries.

Infection

Infections are often a problem in persons with diabetes, since they have difficulty fighting off bacteria that enter the skin from cuts or other wounds. This is due, in part, to certain deficiencies in the activity of white blood cells. Apparently, uncontrolled high glucose levels impair normal immune responses to bacterial invaders. The result can be an overwhelming infection in the foot.

Without the ability to feel pain or without the ability to deliver white blood cells to the site of injury, infections can frequently become serious in a short period of time. The first sign of such serious infections might be very high blood sugars or flu-like symptoms, which I call the "Diabetic Foot Flu".

Unfortunately, fever is often absent or delayed in diabetic foot infections. Therefore, when you develop a fever, proper attention must be given to your situation immediately. Infections are the most frequent reason for hospitalizing diabetic patients and can progress to bone involvement in a relatively short period of time. Deep infections almost always require some type of surgery for treatment, so it is best to catch these problems early and avoid this serious complication.

Foot deformities such as hammertoes, bunions, and metatarsal disorders are common in the general population, but have a special significance in the diabetic population. When neuropathy or poor circulation is present, these deformities place the foot at increased risk for developing pressure lesions (corns, calluses, blisters, ulcerations, etc.) from tight shoes or simple walking. Serious infections can result if these lesions go untreated.

Special deformities can occur in persons with neuropathy and very good circulation. A Charcot joint, resulting from trauma to the insensitive foot, causes the foot to collapse and widen. This very destructive condition is often first heralded by persistent swelling and redness, increased warmth in the affected foot, some mild to moderate aching, and an inability to fit into your usual shoes. If this should occur it is extremely important to stay off your foot and immediately see your podiatric physician. Neglect of this complication can lead to continued collapse of the foot, progressive deformity, and subsequent ulceration.

What Is An Ulceration and How Can It Be Treated?

An ulceration or ulcer is usually a painless sore on the bottom of the foot or top of toes which results from excessive pressure at that site. Trauma in the form of heat, cold, shoe pressure, or penetration by a sharp object must all be suspected as potential causes. The trauma or injury that causes most of the problems for diabetics' feet doesn't happen all at once, like the injuries that we are most familiar with. Instead, they happen from repeated small injuries, happening over long periods of time; what doctors call "repetitive microinjuries".

Ulcers frequently may form under a pre-existing corn or callus which was permitted to build up too thickly. Neuropathy allows these lesions to develop because the normal warning sense of pain has been lost and they go unrecognized. This would be called a Neuropathic ulcer. Continued pressure or walking on the injured skin creates even further damage and the ulcer will worsen. The open sore will frequently become infected and may even penetrate to bone. Poor circulation can also be a predisposing factor for ulcerations, since the skin is often unable to heal minor cuts or blisters. Instead of healing normally, these minor irritations can also worsen into full thickness ulcers in the skin. Ischemic ulcers, as these might be called, are usually quite painful, unless neuropathy is also present at the same time. In the latter instance, such ominous lesions would be called Neuro-ischemic ulcers.

Treatment relies heavily on early recognition of the ulceration, avoidance of weight bearing (walking), and early intervention by your foot doctor. Debridement, or trimming away callus and dead tissue, is an essential part of ulcer treatment. In fact, frequent debridement has been shown to lead to higher rates of healing than when such frequent care was not given. Recently, new agents such as topical growth factors or tissue replacements have become available, which can also speed the rate of wound healing when blood supply and good wound care is practiced. Aside from local wound care, dressings, and antibiotics, a variety of other measures may be necessary to adequately relieve pressure from the area. When crutches, wheelchair, or bedrest are not feasible, plaster casts, braces, healing sandals, special shoe inserts or padding may be used to protect the foot while it heals. If circulation is inadequate to allow healing, your podiatrist may recommend that you consult a vascular surgeon for appropriate evaluation and possible vascular reconstructive surgery. Multidisciplinary management is more the rule than the exception for diabetic foot ulcers, because no one specialist can adequately treat all aspects of the disease and its complications. Other health professionals on the team usually include your internist or endocrinologist, cardiologist, orthopedist, neurologist, nurse, diabetes educator, therapist, and pedorthist.

Once your wound is healed, it is extremely important to see your foot doctor regularly for check ups and foot care. Special footwear and inserts will be recommended to protect your feet and prevent new or recurrent lesions from developing.

Foot Surgery in the Diabetic Patient

Realizing the potential danger of foot deformities in the diabetic patient, corrective foot surgery is an option when you are in generally good health and have good circulation. Most deformities progressively worsen over time, as do the effects of neuropathy and vascular disease. Therefore, if such foot deformities cannot be effectively managed with conservative care (orthoses, footwear, and podiatric care) corrective surgery may be indicated.

Podiatric surgery can often be performed as an outpatient under local anesthesia, to minimize potential complications. Your foot surgeon will properly evaluate your situation and coordinate your care with your medical doctor, to ensure that conditions are optimum before undertaking such surgery. In certain circumstances, such as in the presence of an active ulceration, hospitalization may be necessary to properly monitor your postoperative progress. In fact, surgery may be required to heal an ulceration or to eradicate some infections- especially those involving the bone.

Patient compliance is essential for satisfactory outcomes. You must take part in both the decision making and your care, to effectively achieve the goal of a healed, ulcer free foot. Once healed, you must vigilantly guard against injury and provide the daily care necessary to maintain your feet in a healthy status.

Footwear Guidelines

Shoes are meant to protect your feet, not to hurt them. Therefore, shoes must always fit comfortably, with adequate width and depth for the toes. If a shoe is hard to put on, then don't wear it. It is most likely too small for your foot and can cause serious damage, especially if you have neuropathy or poor circulation. Shoes should preferably be made of leather, which will easily adapt to the shape of your feet over time, as well as allow your feet to "breathe". Athletic shoes, jogging shoes, and sneakers are usually an excellent choice, as long as they are well fitted and provide adequate cushioning. In some cases, your podiatrist may recommend "extra depth" shoes or custom molded shoes to accommodate unusually shaped or difficult to fit feet. Also, special insoles or custom orthoses may be prescribed, to provide cushioning and support.

Always check your shoes for foreign objects or torn linings before putting them on. Each day you should wear two or three pair of shoes, so that one pair is not worn for more than four to six hours. New shoes should be worn only for a few hours at a time, taking care to inspect your feet for any points of irritation. Socks should be well fitted without seams or folds and should not be so tight that your circulation is stopped. Well padded socks can be very protective, as long as there is adequate room in your shoes for them.

Above all else, do not walk barefooted . Avoid wearing open - toed shoes or sandals until you have discussed this with your foot doctor. At the beach or pool, however, these might be acceptable, as well as neoprene "aquatic shoes".

Footcare Guidelines

Inspect your feet daily for blisters, bleeding, and lesions between toes.
Use a mirror to see the bottom of the foot and heel.
Do not soak your feet.
Avoid temperature extremes - don't use hot water bottles or heating pads on your feet.
Wash daily with warm, soapy water and be sure to dry them well, especially between the toes.
Use a moisturizing cream or lotion daily, but avoid between the toes.
Do not use acids or chemical corn removers.
Do not perform "bathroom surgery" on corns, calluses, or ingrown toenails.
Trim your toenails straight across and file them gently. Have a foot doctor treat you regularly if you cannot trim them yourself without difficulty.
Call your foot doctor immediately if your foot becomes swollen, red or painful. Stay off your foot until you see your doctor.
Don't smoke.
Learn all you can about your diabetes and how it can affect your feet.
Have regular foot examinations by your foot doctor and be sure to remove both shoes and stockings at each visit with any doctor.