DIABETES MELLITUS
and the Foot

Diabetes Mellitus- What It Is and What Does It Have To Do With Your Feet?

The answer to the above questions, as well as other related questions is of extreme importance to the 10 million Americans who suffer with the disease known as diabetes mellitus. The term is a Latin phrase describing a condition with excessive sweet urine. Although this disease has been known since 1500 B.C., it wasn't until the 1920's that it was further delineated. At that time, it was discovered that this disease is a result of a deficiency of insulin.

Insulin is a substance (or hormone) that is produced by the beta cells in the pancreas. When the pancreas produces inadequate amounts of insulin, or if the insulin is not effective, the body's regulation of sugar (glucose), starch, and other carbohydrates becomes defective. The condition is diagnosed in the laboratory by an elevated fasting blood glucose level (over 120 mg/dl) also known as hyperglycemia. Hyperglycemia frequently causes sugar to spill into the urine, and symptoms of increased thirst, increased urination, weight loss, blurry vision, or itching may occur as the first signs or symptoms.

Eighty percent of the 10 million diabetics in this country develop the disease after age 40 (known as adult onset diabetes) and may be treated with diet, exercise, use of oral medications, or insulin. Approximately 20 percent of diabetics are juvenile diabetics and must take injections of insulin to survive. Although treatments are available for both types of diabetes, there is no cure of the disease. It is for this reason that, for more than 60 years, the medical community has witnessed premature death and disease from complications of diabetes. The purpose of this handout is to help the diabetic patient prevent complications, specifically those which involve the feet.

INFECTION

Any diabetic patient, particularly one who runs very high blood sugars (ie: are out of "control"), is more prone to infection. When the blood sugar is higher than normal, white blood cells which normally fight infection do not work properly. As a result, bacteria and other organisms may invade tissues at a rapid rate, causing inflammation, abcess formation, and occasionally blood-borne infection (sepsis). Because the feet are frequently exposed to trauma, infection in the feet can be quite common. Once the skin is broken, bacteria may reach soft tissues (fat, tendons, ligaments, muscles) and cause cellulitis if the skin is involved, or osteomyelitis if the bone is involved. All diabetic patients can decrease their susceptibility to infection by maintaining their blood glucose levels, best achieved by maintaining proper diet, medication regimen and exercise prescribed by their physicians.

NEUROPATHY

After several years of poorly controlled diabetes mellitus, a complication known as neuropathy may ensue. Elevated blood glucose levels seem to cause deposition of a sugar protein complex known as glycoproteins in the nerves, particularly in the lower extremities. When the nerves of the feet are damaged, there is usually a decrease in sensation. However, symptoms of numbness are often preceded by symptoms of burning, tingling, 'pins and needles' sensations and restlessness of the feet at night. Thus, the patient with neuropathy may have difficulty in differentiating between hot and cold, sharp and dull, and other sensations. A diabetic patient with neuropathy could walk for many days on a carpet tack or insulin needle that is clearly protruding from the bottom of the foot, or worse embedded into the foot, and because the person does not feel the pain, continues to walk on this object. This sets up a secondary infection which can be devastating to the diabetic patient. Likewise, many patients end up losing a toe, foot or leg because they fail to test the water temperature of their bath water with their hand instead of their foot, or they sleep with hot-water bottles, electric blankets or heating pads set too high, leading to burns and infection.

Patients may have severe pain with neuropathy as mentioned previously. Pain that occurs during the night, frequently awakening individuals from their sleep, is characteristic. In addition, nerve damage may lead to a weakness in the small muscles of the foot and leg, creating imbalances. When muscle imbalances occur, the foot may be prone to developing contracture of the toes and joints, such as hammertoes and bunions, or other deformities. These deformities can cause abnormal pressure and friction when walking, and coupled with muscle imbalance and unstable balance, can cause calluses, skin breakdown and infection.

How does a diabetic patient know whether or not he or she has neuropathy? The diagnosis of neuropathy can be made very easily in the physician's or podiatrist's office. The doctor should evaluate and examine the feet, testing to see if reflexes are present, testing the patient's ability to choose between a sharp and a dull stimulus. Checking the sensation of the diabetic foot is mandatory. Classically, diabetic neuropathy causes a loss of the ankle-jerk reflex with preservation of the knee jerk. Marked decrease to pinprick and vibratory sensation in the so-called "stocking distribution" is also a frequent finding. In some cases, your doctor may want to perform special studies called nerve conduction velocity or electromyography to confirm the diagnosis of diabetic neuropathy. Additionally, a much simpler screening test can be performed by using the Current Perception Threshold (CPT) Neurometer test, which usually takes about 45 minutes and is completely non-invasive. This non-invasive test allows your physician to obtain a computer printout of your results, informing both you and your physician of a quantitative value or level of sensory neuropathy.

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