Peripheral Neuropathy is a nerve condition that affects the arms, hands, legs, and feet. The most common form of peripheral neuropathy is due to diabetes.

Diabetic Peripheral Neuropathy

People with diabetes have an abnormal elevation of their blood sugar, and lack adequate insulin to metabolize the blood sugar. As a consequence, the blood glucose (sugar) abnormally enters certain nerve tissue and damages the nerve. This can occur in any type of diabetes. It does not matter if the patient is on insulin, is taking pills, or is diet controlled. The nerve damage that occurs is considered to be permanent.

As the nerve damage occurs, the protective sensations are affected. These include a person's ability to determine the difference between sharp and dull, hot and cold, pressure differences, and vibration. These senses become dulled and/or altered. The process begins as a burning sensation in the toes and progresses up the foot in a ""stocking distribution"". As the condition progresses, the feet become more and more numb. Some people will feel as though a pair of socks on their feet, when in fact they do not. Other patients will describe the feeling of walking on cotton, or a water-filled cushion. Some patients complain of their feet burn at night, making it difficult to sleep. The feet may also feel like they are cold, however, to the touch, they have normal skin temperature. Diabetic peripheral neuropathy is not reversible. The progression of the condition can be slowed or halted by maintaining normal blood glucose levels.

As the patient develops diabetic neuropathy, they have a greater risk of developing skin ulcerations and infections. Areas of corns and calluses on the feet represent areas of excessive friction or pressure. These areas, if not properly cared for by a foot specialist, will often break down and cause ulcerations. Ulcerations and infection can form under the callused area. These callused areas may not be painful. As a result, they can progress to ulceration without being noticed. Ingrown toenails can progress to severe infections in people with neuropathy. Simple things like trimming the toenails present a risk to these patients because they may accidentally cut the skin and not feel it. People with neuropathy must be very cautious and inspect their feet daily. They should not soak their feet in hot water or use heating pads to warm their feet. This can result in accidental burns to the skin. Barefoot walking should be avoided because of the risk of stepping on something sharp and not being aware of it. The inside of the shoes should be inspected before putting the shoes on to insure that no foreign object is inside the shoe ( see Do's and Don'ts-Diabetic Foot Care Tips).

Alcoholic Peripheral Neuropathy

Alcoholic neuropathy is caused by the prolonged use of alcoholic beverages. Ethanol, the alcoholic component of these beverages, is toxic to nerve tissue. Over time, the nerves in the feet and hands can become damaged resulting in the same loss of sensation as that seen in diabetic neuropathy. The damage to these nerves is permanent. A person with this condition is at the same risk, and should take the same precautions as people with diabetic peripheral neuropathy. Peripheral neuropathy can also be caused by exposure to toxins such as pesticides and heavy metals.

Treatment For Peripheral Neuropathy

Treatment for peripheral neuropathy is, for the most part, directed at the symptoms of the condition. Vitamin B12 injections may be helpful if the patient has a vitamin B deficiency. There are certain oral medications that may ease the burning pain that can be prescribed by your doctor. Topical ointments should only be used with the advice of your doctor. Magnetic therapy and Galvanic Stimulation are alternative forms of treatment but results are varied and difficult to quantify.

Malignant Melanoma

Pigmented lesions should always be inspected and observed. Most pigmented areas are nothing but freckles and moles. However a potentially deadly pigmented lesion that can occur on the foot and lower extremity is Malignant Melanoma. A physician should evaluate any pigmented lesion that suddenly occurs or a pigmented lesion that starts to change its appearance. These changes are usually subtle and may consist of increased size and depth of color, onset of bleeding, seepage of clear fluid, tumor formation, ulceration and formation of satellite pigmented lesions. The color is usually not uniform but is likely to be scattered irregularity, being brown, bluish black or black. An increase in pigmentation may precede enlargement of the lesion by several months. Although any part of the body may be affected, the most frequent site is the foot, then in order of frequency, the remainder of the lower extremity, head and neck, abdomen, arms and back. Malignant melanoma may also form under the nails of the feet and hands. The thumb and big toe are more commonly affected than the other nails. Quite often the adjacent skin to the nail is ulcerated. Usually a fungal infection is suspected and antifungal treatment may be administered for months before the true nature of the lesion is discovered. A black malignant melanoma of the toe can also be mistaken for gangrene. Overall, the incidence of malignant melanoma is quite low.

Actinic Keratosis

Another cancer causing lesion that can occur on the feet are called Actinic Keratosis. Although most commonly found in sun-exposed areas of the body such as the face, ears, and back of the hands, these lesion can also occur on the foot. They are characterized as either flat or elevated with a scaly surface. They can either be reddish or skin colored. On the foot they are frequently mistaken for plantars warts. These lesions are the precursor of epidermoid carcinoma. Treatment for these lesions should be through as they are definitely precancerious. Treatment consists of freezing the lesions with liquid nitrogen or sharp excision.

Kaposi's Sarcoma

Yet another cancerous lesion that can occur on the foot is called Kaposi's Sarcoma. These lesions occur most commonly on the soles of the feet They are irregular in shape and have a purplish, reddish or bluish black appearance. They tend to spread and form large plaques or become nodular. The nodular lesions have a firm rubbery appearance. The appearance of these lesions is an ominous sign. In the late 1970's and early 1980's an outbreak of Kaposi's sarcoma occurred in San Francisco, California. It was later learned that the disease was associated with AIDS infection. It can occur without the concurrent AIDS infection but this is very rare.

Chronic athlete's foot can cause an increased pigmentation to the bottom of the foot. It is associated with dry scaling skin and may have a reddish appearance.

Venous Stasis

Generalized increased pigmentation occurs for a variety of other reasons. Dark patches of skin occur about the ankles and lower legs in persons who suffer from Venous Stasis. Venous stasis is caused by an accumulation of fluid in the lower extremities. This is due to poor venous return of blood to the heart. Venous blood flow back to the heart occurs by way of the veins in the feet and legs. Venous stasis is associated with varicose veins that do a poor job of returning blood to the heart. As a result the blood flow is slowed, becomes stagnant, and fluid accumulates in the ankles and lower legs. As the fluid accumulates in the lower legs, the small and medium-sized veins break or leak fluid into the tissues. As blood cells break up in the tissue, they deposit the iron that is part of hemoglobin in the blood cell. The iron stains the skin causing a light to dark brownish appearance. With time, the skin and subcutaneous fat becomes thinned and will break down creating weeping venous stasis ulcerations. At times, blistering will form with a clear, watery fluid weeping from the skin. This condition requires professional attention by a physician.

Diabetic Dermopathy

Another cause of generalized increased pigmentation is diabetes. The condition termed Diabetic Dermopathy occurs most frequently on the shins and lower legs. They may have the appearance of small scars. Their appearance may precede the diagnosis of diabetes by several years. The actual cause of diabetic dermopathy is not well understood, but it does not cause any particular problem or pose any particular health threat.

Small, spider-like areas of increased pigmentation on the ankles are caused by the break down of small veins in the area and are called Spider Veins; they also pose no health risks.

This is a question and answer that we felt was worth sharing.

Question:

I am age 67 and have been a diabetic since the age of 50. Insulin dependent for the last 5 yrs. My feet often have hard calluses on them which I have had trimmed by a podiatrist. Unfortunately, this has led to severe infection and have lost my big toe because of this. At the moment I am again battling an infection. I am wondering what is the alternative to trimming a callus. I understand Vitamin C is good for healing. Do you have any info on this? I would be greatful for any advice you could give me.

Answer:

Callus build up on the foot is due to abnormal pressure and friction as you stand and walk. It is important that the callus not get to thick or the skin under the callus can break down and cause an ulceration. It is not uncommon for me, when treating a diabetic patient with calluses on the feet, to trim a callus and find an ulcer under the callus. If the callus is not trimmed, then the infection can progress into the bone or deep into the foot. Good nutrition and vitamin supplements will help with healing but the most important issue is adequate blood flow. If you have bad circulation ask your doctor about hyperbaric oxygen treatment.

You should also discuss with your doctor about obtaining a diabetic shoe and molded insole to protect your foot.

This is an "Ask the Doctor Question" and the response. We felt that this question and answer was informative.

Question:

I would like to know how the cells in the body react when someone has diabetes and how is this different from someone who does not have diabetes?

Answer:

You have asked a complex question. I will try to explain this as clearly as I can. People who have diabetes have a lack of insulin in their blood. Insulin is made in an organ called the pancreas. Insulin is important to allow glucose (blood sugar) to get into the cells of the body. Put another way, insulin opens the door to let blood sugar to enter most cells in the body. Blood sugar is a food for the bodies cells. If insulin is low or absent in the blood then the cells don't get fed the blood sugar they need. If the blood sugar can not get into the bodies cells then it builds up in the blood stream and the sugar count increases on the blood tests that we do. Also, as the blood sugar increases and can not get into the bodies cells it has the effect of drawing water out of the cells and shrinks them up making them even less healthy.

The nerves in the body are affected a bit differently. Nerve cells will allow blood sugar in with out insulin, however without insulin present the sugar is not used by the nerve cell properly and the sugar accumulates in the cell. Over time this will damage the nerve cell and cause the nerve to die. This causes numbness and tingling in the feet and sometimes in the hands.  Blood vessels are also made up of cells. As the sugar builds up in these cells it swells them up and this causes a narrowing of the blood vessel. This causes a decrease in the circulation to the feet, the kidneys and the eyes. This is why people with diabetes often loose their legs their eye sight and kidney function.

It is very important that people with diabetes learn about their condition, control their blood sugar, and exercise.

The Charcot foot is a non-infective, destructive type of arthritis that affects between 1-2.5% of diabetics. The incidence of this arthritic process has increased recently due to patients with diabetes mellitus living longer. There is an equal distribution among males and females. The average age of patients developing a Charcot foot is 40 years. 30% of patients develop a Charcot foot in both feet and/or ankles. This form of arthritis can develop suddenly and without pain. In a very short period of time the bones in the foot and/or ankle can spontaneously fracture and fragment.

The final result in the development of a diabetic Charcot foot is severe foot deformity. These deformities may result in difficulty wearing standard footgear. As the deformity progresses the foot takes on the appearance of a "rocker bottom". As the arch of the foot collapses areas of pressure develop on the bottom of the foot that are prone to developing open sores or ulcerations. Loss of ankle stability may occur to such an extent that the patient may not be able to walk without the use of a brace. The vast majority of these deformities can be treated with non-operative care. New advances in technology and the development of new forms of lower extremity braces and splints have provided a wider range of treatment alternatives that are very effective in managing the Charcot foot.

There are situations where non-operative therapy is ineffective in managing a Charcot foot. Surgical management of the Charcot foot may be required to resolve some of the problems associated with the condition. Indications for surgery include: 1) chronic deformity with significant instability that is not amenable to brace treatment, 2) chronic deformity with increased plantar pressures and risk of ulceration, 3) a significant deformity with secondary ulceration that has failed to heal despite non-operative therapy and 4) recurrent ulcers that have initially healed with non-operative care.

Surgical Intervention

Various types of surgery are available and may be required to manage a Charcot foot. The type of surgery that may be necessary depends on 1) the anatomic location of the Charcot deformity (i.e. the midfoot, the ankle. etc.) 2) the stage of the Charcot process (there are three specific stages of the Charcot process) 3) whether or not an ulcer is present. 4) whether or not the deformity is unstable and 5) overall health status of the patient.

The types of surgical procedures include the following:

1. Ostectomy - Ostectomy is a surgical procedure where a portion of bone is removed from the bottom of the foot. This procedure is usually performed for a wound on the bottom of the foot that is secondary to pressure from a bony prominence. An ulcer may or may not be present. The goal of the surgery is to remove the bone causing increased pressure and thereby allowing the ulcer to resolve or prevent the area from ulcerating. This procedure is usually performed as an outpatient or may require a one-night stay in the hospital. The type of anesthesia selected depends upon the health status of the patient and the preference of the surgeon. Recovery time includes 3-4 weeks in a weight-bearing brace or cast. A patient can usually return to extra depth footgear with a diabetic insert following complete healing.
   
    
2. Midfoot Realignment Arthrodesis - This procedure is usually indicated when there is significant instability of the middle portion of the foot. Usually the foot has collapsed and there is significant bony prominence along the bottom of the foot. Surgery is indicated when a simple ostectomy will not be sufficient. The goal of surgery is to provide stability and a relatively normal arch to the foot. This procedure usually requires a one or two night stay in the hospital. This is usually performed under general anesthesia and requires various types of internal fixation to be placed within the foot. This may include screws and plates. The convalescence associated with midfoot realignment arthrodesis is approximately three months in a non-weight-bearing cast. A patient may then progress to a weight-bearing brace for approximately 1-2 months. The patient will then return to an extra depth shoe with a diabetic insert at 5-6 months following surgery.
   
    
3. Hindfoot and Ankle Realignment Arthrodesis - Hindfoot and ankle realignment arthrodesis is usually indicated when there is significant instability resulting in a patient being unable to walk. These types of procedures are recommended when bracing has failed. Patients are basically non-ambulatory and many times amputation of the limb is the only other alternative. Realignment arthrodesis of the hindfoot and ankle is a limb salvage surgery. The ultimate goals of the procedure are to maintain a functional limb such that one can transfer within their home and possibly do some walking with the use of a brace or ambulatory assistive device. This procedure usually requires a 1-2 night stay in the hospital. The procedure is performed under general anesthesia and requires the use of various types of internal and external fixation devices. This may include the use of screws, plates, intramedullary nails and external fixators. The postoperative course includes approximately four months in a non-weight-bearing cast followed by a 2-3 month period of walking in a protective rocker bottom brace. A patient will then progress to a custom made brace that may be required throughout the course of their lifetime.

Possible Complications

Surgery in the diabetic patient always has significant risks. People with diabetes mellitus are more susceptible to infection due to their disease process. Therefore, these operations have a high complication rate. The arthrodesis procedures have a greater failure rate, increased risk of complications and longer convalescence relative to simple procedures such as ostectomy. It is recommended that a patient and their family have an extensive consultation with the surgeon to understand all potential risks including limb loss. A patient must be medically fit since this does require a general inhalation anesthesia and an extensive postoperative course. Preoperative work-up should include assessment of cardiac status and must be performed prior to surgical intervention.

Summary

Surgical management of the Charcot foot can be challenging and at times risky, but often the only alternative for limb-salvage. Many of the patients who undergo this type of surgery would otherwise go on to a below-the-knee amputation. Therefore, surgical management of the Charcot foot can be quite gratifying to the patient, the patient's family and the surgeon. The patient and the family should thoroughly understand the risks and benefits of the procedure and have an extensive preoperative consultation with the surgeon. It is recommended that surgery be performed by an experienced practitioner who has a thorough understanding of the disease process and experience with this type of surgery. It may be advantageous to have this type of surgery performed at a tertiary care facility to handle the potential complications that one might incur with these types of patients.

Ulcerations, infections and gangrene are the most common foot and ankle problems that the patient with diabetes must face. As a result, thousands of diabetic patients require amputations each year. Foot infections are the most common reason for hospitalization of diabetic patients. Ulcerations of the feet may take months or even years to heal. It takes 20 times more energy to heal a wound than to maintain a health foot.

There are two major causes of foot problems in diabetes:

1. Nerve Damage (neuropathy): This causes loss of feeling in the foot, which normally protects the foot from injury. The protective sensations of sharp/dull, hot /cold, pressure and vibration become altered or lost completely. Furthermore, nerve damage causes toe deformities, collapse of the arch, and dry skin. These problems may result in foot ulcers and infections, which may progress rapidly to gangrene and amputation. However: Daily foot care and regular visits to the podiatrist can prevent ulcerations and infections.
   
    
2. Loss of circulation (angiopathy): Poor circulation may be difficult to treat. If circulation is poor gangrene and amputation may be unavoidable. Cigarette smoking should be avoided. Smoking can significantly reduce the circulation to the feet significantly. There are certain medications available for improving circulation (Trental) and by-pass surgery may be necessary to improve circulation to the feet. Chelation therapy is an alternative form of treatment for circulatory problems that is not well recognized by the medical community at large. Daily foot care and regular visits to the podiatrist can often prevent or delay the need for amputation.

Do the Following to Protect Your Feet

1. Examine Your Feet Daily

Use your eyes and hands, or have a family member help. Check between your toes. Use a mirror to observe the bottom of your feet.   Look for these Danger Signs:

         Swelling (especially new, increased or involving one foot)
         Redness (may be a sign of a pressure sore or infection)
         Blisters (may be a sign of rubbing or pressure sore)
         Cuts or Scratches or Bleeding (may become infected)
         Nail Problems (may rub on skin, cause ulceration or become infected)
         Maceration, Drainage (between toes)
 

If you observe any of these danger signs, call your podiatrist at once.

2. Examine Your Shoes Daily Check the insides of your shoes, using your hands, for:

         Irregularities (rough areas, seams)
         Foreign Objects (stones, tacks)

3. Daily Washing and Foot Care Wash your feet daily. Avoid water that is too hot or too cold. Use lukewarm water. Dry off the feet after washing, especially between the toes. If your skin is dry, use a small amount of lubricant on the skin. Use lambs wool (Not cotton) between the toes to keep these areas dry.

4. Fitting Shoes and Socks Make sure that the shoes and socks are not to tight The toe box of the shoe should have extra room and be made of a soft upper material that can "breath" New shoes should be removed after 5-10 minutes to check for redness, which could be a sign of too much pressure: if there is redness, do not wear the shoe. If there is no redness, check again after each half hour during the first day of use. Rotate your shoes Ask your podiatrist about therapeutic (prescription) footwear, which is a covered benefit for diabetic patients in many insurance plans. Tell your shoe salesman that you have diabetes.

5. Medical Care See your podiatrist on a regular basis Ask your primary care doctor to check your feet on every visit. Call your doctor if you observe any of the above danger signs.

Do Not Do These Dangerous Acts

• Do Not Walk Barefoot - Sharp objects or rough surfaces can cause cuts, blisters, and other injuries.
• Do Not Use Heat on the Feet - Heat can cause a serious burn, especially if the patient has neuropathy.
• Do Not Apply a Heating Pad to the Feet
• Do Not Soak Your Feet in Hot Water
• Do Not Use Chemicals or Sharp Instruments to Trim Calluses - This could cause cuts and blisters that may become infected.
• Do Not Cut Nails into the Corners - cut nails straight across.
• Do Not Smoke - smoking reduces the circulation to your feet.