Diabetes   

Diabetes is a disease in which either not enough Insulin is produced by the pancreas (Type 1) or the insulin that is produced is not recognized by the cells of the body (Type 2). As a result, both types of diabetes lead to abnormally high blood sugar concentrations. High blood sugar (glucose) levels can lead to coma and death. In addition, chronic diabetes, through mechanisms that are still not completely understood, often results in complications involving many of the organ systems throughout the body. Some commonly affected organs are the kidneys(nephropathy), the eyes(retinopathy), the nerves(neuropathy) and the blood vessels( vascular disease). It is the neuropathy and vascular disease that may have a devastating effect on the feet. Both of these conditions can lead to amputation, particularly if the feet are neglected.

       Nerve Problems (Peripheral Neuropathy)

Neuropathy, the nerve disease associated with diabetes, often results in numbness and loss of protective sensation of the feet.Neuropathy can be the first manifestation of undiagnosed diabetes that prompts the patient to seek medical attention. Although pain is by definition an unpleasant experience, it is nonetheless a very important mechanism to alert us to danger. Without the ability to detect pain, one could walk around all day with a pebble in one's shoe and not know it. This could result in the development of an ulcer. Also, an infection could go unnoticed,  until  irreversible damage has already occurred. Neuropathy is probably responsible for more cases of ulcers, infections and amputations than vascular disease.  There are several tests that can be utilized to determine the presence of peripheral neuropathy. The Semmes-Weinstein monofilament test is a simple way of determining whether neuropathy has advanced to the stage at which there is a loss of protective sensation.This is a simple test in which a small filament of plastic, similar to bristle on a hair brush, which has been calibrated to bend at a specific amount of force is touched to the skin. If it can be felt, there is adequate sensation to protect against the development of ulcers. If not, there is a loss of protective sensation and the person is at risk for ulceration.

In addition to the loss of the ability to detect painful stimuli, some cases of neuropathy also result in a chronic, burning pain in the absence of any harmful stimulation. This neuropathic pain is often most severe at night, when resting and the person is not focusing on other things.

There is no effective treatment  to reverse the loss of protective sensation in the person with neuropathy once it has developed. But tight sugar control has been shown to reduce the risk of developing neuropathy in the first place. There are several treatments that may be used to try to reduce the discomfort associated with neuropathic pain but they are often ineffective. Mild neuropathic pain sometimes responds to capsacin cream applied 4 times daily. Sometimes Elavil is effective. Electrical stimulators have also been used to try to reduce neuropathic pain.

Neuropathy may also be seen in some people without diabetes. Alcohol abuse is another leading cause of neuropathy. It may also be  caused by certain drugs used to treat cancer and AIDS. Much of the early neuropathy research  was related to the study and treatment of Hanson's disease (leprosy). Fortunately, Hanson's disease is now very rare.

Deep Space Infections

Those with neuropathy are  susceptible to the development of deep space infections in the foot. Deep space infections have a high morbidity and may lead to amputation if not identified early . There are several compartments in the foot surrounded by various layers of muscle and connective tissue. The compartments in the foot communicate with compartments of the leg through tunnel-like spaces around the tendons that travel through both the leg and the foot. This allows for easy spread of the infection from the foot to the leg.  Frequently, there is no pain in the foot due to neuropathy. A deep space infection is a surgical emergency requiring hospitalization, immediate incision and drainage, and intravenous antibiotics.This type of infection can also easily cause blood poisoning (sepsis). Surgery involves creating a large incision, usually on the bottom of the foot, to completely drain all pus. Otherwise, an abscess may persist which is often resistant to antibiotic treatment alone. The wound that is created by opening the abscess is often packed open to allow for additional drainage.

      Circulation Problems (Peripheral Vascular Disease, PVD)Charcot Joint ( Charcot Foot, Diabetic Neurotrophic Osteoarthropathy)Diabetics are more prone to the development of peripheral vascular disease than the non-diabetic. However, one certainly does not have to be diabetic to develop vascular disease. With peripheral vascular disease, arteries in the leg that carry blood to the foot become clogged. The earliest sign of PVD may be intermittent claudication which is a severe cramping of the leg or thigh that occurs while walking, usually at a predictable distance measured in blocks, and which may resolve after a period of rest. As the vascular disease worsens with time, the distance one can walk prior to feeling claudication pain becomes shorter. 
A later sign of PVD is rest pain. This is pain that is often felt at rest when laying in bed. Typically, the pain is relieved by putting the feet down on the floor which allows the blood to flow down to the feet more easily.
PVD may also result in ischemic ulcers or gangrene. These develop when the tissues of the feet do not get enough blood flow. Without enough blood, the tissues do not get enough oxygen and they die.Once gangrene develops, the tissue death is not reversible and an amputation is often required.    
Many limbs can be saved with procedures to restore blood flow to the feet. This may be accomplished in some cases with angioplasty, where a balloon is fed through the arteries and used to open the blockage. Sometimes a stent, a cylindrical piece of metal, is used to keep the area open. Other cases may benefit from the performance of a bypass procedure by a vascular surgeon. In a bypass, a vein or synthetic tube is used to bring blood around the blockage. A "Fem-Pop" bypass refers to a bypass connection the Femoral Artery in the thigh to the Popliteal artery near the knee. Blockages in diabetics may occur further down the leg and may require a bypass to an artery such as the posterior tibial or dorsalis pedis. 

It has been estimated that 2% of people with diabetes develop Charcot Joint. This is a condition in which certain joints, most commonly the midfoot, collapse and degenerate. This occurs only in people who have peripheral neuropathy. The earliest stage consists of a red, hot, swollen foot. This is often mistaken for an infection. X-rays will often show severe destruction and erosions of the involved joints. Later stages are without the inflammation but may show either a completely flattened arch or  the classical "rocker-bottom " foot. This can be a big problem since ulcers often develop beneath the collapsed bone.  
Treatment for a Charcot joint is aimed at reducing weightbearing pressure. This may be accomplished by using a wheelchair, complete bed rest or a contact cast. The treatment is usually continued until the inflammation has subsided and the bones have begun to fuse together. This may take 3 months or longer.Once the inflammation has subsided, treatment is aimed at preventing the development of ulcers and further breakdown. This is often accomplished with molded shoes and/or braces. Sometimes surgery may be needed to reconstruct the foot or to eliminate a prominent deformity. 
Surgery for the Charcot joint has traditionally been performed in the chronic stage, after all of the inflammation has resolved. Some podiatric surgeons have advocated a more controversial approach during the acute stages. Reconstruction of the Charcot joint may be extremely difficult due to the severity of the deformity and the condition of the bone. Reconstruction often involves cutting and fusing all of the metatarsal cuneiform and metatarsal cuboid joints in the midfoot. These bones are then held together with special metal screws and/or pins and plates. Casting is then usually required for two or three months. Other, less complex procedures may also be performed on the Charcot foot, such as the shaving or removal of isolated bony prominence. These types of procedures are most commonly utilized to help to eliminate an ulcer that has developed beneath such a prominence 
Mechanisms of Ulcer Formation in the Diabetic 

A. Ischemic Ulcers Poor blood flow prevents an adequate amount of oxygen to reach the tissue. As a result of poor nutrition, the skin and tissue beneath it either die directly or do not heal after an injury.

B. Neuropathic Ulcers 1. Large amount of pressure in a Short time     e.g. an acute traumatic injury This mechanism of injury produces an immediate ulceration when a sharp object such as a nail or a piece of glass pierces the skin. This may go unnoticed for some time due to the lack of sensation. For example, the injury may occur early in the day an may not be noticed until undressing in the evening and noticing blood on the socks. Therefore, it is important to avoid going barefoot and to check the insides of the shoes before putting them on. 2. Small amount of pressure over a long time(several hours)     e.g. a tight shoe This injury occurs as a result of a constant pressure on the skin over a period of time, e.g. 2 or 3 hours or more. If a shoe is worn that is too tight, the shoe squeezes the skin on certain areas of the foot. This causes the skin in those areas to blanche or turn white. Blanching occurs when the blood is squeezed out of a certain area due to pressure. You can demonstrate this yourself by pressing your finger against a window. Notice how the part of your finger that touches the window turns white. If you kept it there for several hours, that part of your finger would die and ulcerate.The same damage could occur with a tight pair of shoes . This is unlikely to happen in someone with normal nerve function because pain would soon develop and cause that person to remove the shoe. Someone with neuropathy, not sensing any pain, would continue to wear the shoe and develop an ulcer. 3. Moderate pressure that is repeated over a longer time.     e.g. a callous that turns into an ulcer This is the most common cause of ulcers on the bottom of the foot. To understand this mechanism, let us first look at the example of someone without neuropathy. During the course of walking, particular spots beneath the foot may be subjected to an increased amount of pressure. The person with normal nerve function either consciously or subconsciously changes the way they walk to transfer weight to another area of the foot thereby reducing pressure to that area. In the person who has neuropathy, there is no conscious or subconscious change in gait and as walking is continued, the area continues to be subjected to a repetitive, moderate amount of pressure. This leads to a localized area of inflammation which results in tissue breakdown and eventually ulceration. The potential location of a plantar ulcer can often be predicted based on the shape of one’s foot and the presence of calluses.Calluses usually develop beneath parts of the foot that bear an excessive amount of weight or are subjected to a lot of friction.   Accommodative orthoses can help to prevent ulceration by protecting the foot and dispersing weight more evenly. 4. Infection     An infection can develop if there is a break in the skin which allows bacteria to enter. To the sensate person, infections are usually very painful, causing the person to seek treatment. With neuropathy, the infection could go unnoticed for several days or longer resulting in severe tissue damage.

Managing Foot Ulcers
Identify the cause of the ulcer
    If there is vascular disease, have a vascular surgeon determine if a bypass or angioplasty is possible to increase blood flow
 If the ulcer is neuropathic (or a combination of neuropathic and ischemic), try to determine the cause. E.g. repetitive weightbearing over a bony prominence, tight shoe, burn etc.
Determine if there is an infection  
    This is usually done by clinical evaluation. E.g. redness, swelling, pain, pus all point to infection. Keep in mind that all ulcers will have some drainage. Since the skin, which is ordinarily a barrier to prevent dehydration, is disrupted, drainage which is usually watery or blood tinged will be present. (This is in distinction to drainage that is  thick, white and creamy which usually indicates pus and an infection) Also, culture swabs should not be used alone as an indication of infection since most diabetic ulcers will have bacterial colonization on the surface of the ulcer but which do not represent a true infection. Culture swabs are most useful as a means of determining which bacterial organisms are causing an infection once a diagnosis of infection has been made from clinical findings. Once a diagnosis of an infection has been made, antibiotics should be initiated. If there is an abscess, the wound should be incised and drained immediately. The podiatrist may do this in either the  office or the hospital, depending on the extent and depth of the abscess.
Debridement
Ulcers should be trimmed of all dead, infected, fibrous and/or callus tissue. If not debrided, these things can significantly slow down or prevent wound healing. In the case of infection, bacteria release enzymes which prevent healing. In the case of callus tissue, the thickened callus tissue causes pressure over or around the ulcer which prevents wound healing. Debridement may need to be done weekly by the podiatrist. Debridement of the ulcer often produces bleeding as the dead tissue is removed and healthy bleeding tissue is exposed. The bleeding is beneficial since it delivers platelets and growth factors to the ulcer bed. If bone is exposed, it may need to be debrided to remove infected tissue.

    
Off loading
The lack of effective off-loading is perhaps the single most important factor contributing to non-healing neuropathic ulcers. All the antibiotics in the world will not heal an ulcer if weight is not taken off the ulcer. Off-loading is best accomplished by complete bed rest. However, this is usually not practical. Wheelchairs are often effective as well. However, in order to keep the person with the ulcer walking and working, other measures are usually necessary. Sometimes, total contact casts(TCC) are utilized. These are special leg casts which take weight off the ulcer and allow ambulation. Another effective means of permitting ambulation and off-loading an ulcer is a healing sandal. These are specially made shoes with insoles that help to take weight off the ulcer site. Other devices used to off-load ulcers are Cam Walkers, removable walking casts as well as special leg braces such as a patellar tendon-bearing brace (PTB Brace) which transmits weight off the foot and onto the knee. Sometimes surgery is utilized to off-load an ulcer. This can sometimes be done by simply shaving off a prominent piece of bone. Other cases may involve reconstructive surgery where bones are repositioned to provide more balanced weightbearing.
Dressings
    There are many products that are used to treat ulcers. Some are designed to keep the ulcer free from infection (antibiotics), others are designed to assist with debridement (enzymes) and others are designed to promote wound healing. The type of ulcer and status of the ulcer may help to determine which of these products the treating doctor may select. Common dressing include saline(salt water) and Silvadene cream, an antibiotic cream. Certain products such as full-strength Betadine (povidone iodine) have fallen out of favor among many members of the wound care community because of its reported toxicity to healing (granulation) tissue. Also, keeping the wound moist, rather than allowing it to dry out, appears to help wound healing. Newer products, growth factors such as Regranex, are also gaining acceptance.
Maintenance and prevention of recurrence
    Once an ulcer is closed, it is important to take the proper steps to prevent recurrences. This involves reassessing shoe gear. Deep depth or custom molded shoes with accommodative orthotic insoles are often required. Sometimes a rocker placed in the sole of the shoe is necessary. Sometimes a double upright leg brace or patellar tendon-bearing brace is necessary. Daily inspection of the feet is required as are regular trips to the podiatrist.

Photos of ulcers healing with proper treatment:

Patient "H.B." Diabetic with neuropathic ulcer

         

     

Patient "K.F." Diabetic with Neuropathic ulcer

    

Patient "H.H." Diabetic with Neuropathic ulcer

    

Patient "L.G." Diabetic with Neuropathic Ulcer

   

Tips for proper foot care by the diabetic
Do's and Don'ts

Do

	Wash feet daily with warm water and mild soap
	Inspect your feet daily. Look for any areas of discoloration, scratches, blisters or changes of any kind. A small hand mirror is often useful to help see the bottom of the feet. This can be placed on the floor with the foot held over it. If it is difficult to see the bottom of the feet, have a family member check your feet for you each day.
	Check inside shoes before putting them on.
	Use a lotion or cream daily on your feet (but not between the toes) to keep them soft. The best time to do this is after bathing. There are a wide variety of creams. You do not have to use the most expensive items which often cost more because of perfumes and marketing expenses. Something as simple as vegetable shortening or Vaseline may be adequate.
	Wear soft, protective, roomy shoes that have good support. Diabetics with neuropathy and/or peripheral vascular disease may require deep-depth or custom molded shoes. (These are often covered by Medicare).
	Keep your blood sugar level well controlled. Studies have shown that tight sugar control lowers the occurrence of peripheral neuropathy as well as kidney disease and eye disease.
	See your podiatrist regularly

Don't  

	Do not go barefoot
	Do not use heating pads. These can cause burns and ulcers.
	Do not soak your feet, unless prescribed for a specific purpose by your doctor. Soaking can dry your feet by removing its natural oils. This could lead to cracking.
	If you have neuropathy or peripheral vascular disease do not trim your toenails yourself. If you do care for your nails yourself, use an emery board or nail file rather than scissors or a curved nail clipper. Trim nails straight across and do not make them too short.
	Do not try to cut corns or calluses yourself. see your podiatrist for this.
	Do not use "Corn Removers' or medicated pads. These contain acid that can burn a hole in your skin. It is usually o.k. to use simple non-medicated corn cushions.

An ulcer is a condition in which there is death of skin tissue (necrosis) resulting in an opening in the skin. (Similarly, a gastric or peptic ulcer is a break in the integrity of the lining of the stomach or gastrointestinal lining.) The skin serves an important role as a barrier to germs. When an ulcer develops in the skin, bacteria can enter the body and cause an infection.  A variety of different disease processes are responsible for ulcerations of the foot.  Effective treatment depends on correctly diagnosing the cause of the ulcer. A description of the most common ulcers follows:
Neuropathic ulcers occur when there is a nerve disease that results in numbness or the inability to feel pain. Although none of us likes to experience pain, it is an important warning sign and lets us know there is a problem that needs to be addressed. This type of ulcer is frequently associated with diabetics, who often develop a nerve condition known as peripheral neuropathy. Chronic abuse of alcohol may also result in neuropathy.  Neuropathic ulcers are most commonly seen on the bottom of the foot.  These ulcers may often start as a callus and may be hidden by a callus.These ulcers often occur in the presence of good blood circulation and will often heal well once weightbearing pressure is removed from them. The frequency  of these ulcerations may  be reduced by performing daily foot inspections, wearing properly fitting shoes and seeing a podiatrist regularly. Deep depth or custom molded shoes with special inlays or orthoses may also be required.

Ischemic ulcers  are caused by poor blood circulation (peripheral vascular disease or atherosclerosis.) The arteries, which carry blood from the heart to the rest of the body, become clogged. When this happens, not enough blood reaches the feet and tissue in the feet die and ulcerate due to lack of oxygen.  These ulcers are   often associated with diabetes since diabetics have an increased prevalence of vascular disease. They may also be seen in patients who are not diabetic but who have peripheral vascular disease. These ulcers most commonly involve the toes  rather than the bottom of the foot. These ulcers often lead to gangrene. These ulcers may also be painful although some people such as diabetics may have both neuropathy and vascular disease in which case they could have ischemic ulcers that are also painless.

Additional Material:

Foot surgery in the person with diabetes

Elective foot surgery may be performed safely in most diabetics, provided certain criteria have been met. The most important factors to be considered are vascular status, the level of blood sugar control and other metabolic factors. If the pulses of the foot are palpable, the blood sugar is under good control and there is no significant anemia or other metabolic problems, the same elective procedures performed in the non-diabetic can usually be  performed safely in the diabetic patient.

Vascular Considerations
If the pulses of the foot (dorsalis pedis and posterior tibial) are palpable, there is usually adequate blood flow to permit healing.Other clues that suggest good vascular status are warm, pink skin, the presence of hair on the toes and quick refill of the blood in the toes after they are squeezed.  Elective foot surgery is usually not performed when the pedal pulses are not palpable. If the vascular status is questionable after the physical evaluation, other tests may be utilized. Doppler ultrasound and ankle pressures are non-invasive ways to check the circulation status. Ankle pressure tests may not be reliable since many diabetics have calcified arteries which lead to artificially high readings. Sometimes non-elective surgery must be performed even in the patient with questionable vascular status. This may be the case when there is an infection or wound that needs to be treated. These cases may require an arteriogram to determine healing potential. An arteriogram is an invasive test where radiographic dye is injected into the body and x-rays are taken to determine if there are any blockages in the arteries. If blockages exist, a vascular surgeon may be able to perform a bypass procedure to restore blood flow.

Glucose control
High blood sugar levels increase the risk of infection and other complications. Therefore, good glucose control should be attained prior to undergoing any elective surgical procedures. (On the other hand, when it comes to non-elective surgery such as incision and drainage of an abscess, the infection often contributes to the high blood sugar levels and surgery must often be performed immediately to treat the infection. Once the infection is better controlled, the blood glucose is more easily controlled.)

Anemia
Diabetics, particularly those with diabetic kidney disease(nephropathy), are prone to chronic anemia. A reduction in red blood cells and hemoglobin elevates the risk of infection and delayed healing.