Type 2 diabetes mellitus is one of the leading chronic health conditions among adults in the United States. It results from developing resistance in the body’s tissues to the effects of insulin. Risk factors include advancing age, sedentary lifestyle, consumption of a high-calorie diet and obesity.
Diabetes involves an elevation of sugar levels in the blood stream because sugar does not enter the cells, which require it for fuel. This produces many potentially toxic effects throughout the body including structures in the eye, blood vessels and nerves.
One area of the body that is particularly susceptible to the toxic effects of elevated blood sugar is the lower limbs, and especially the feet.
The greatest distance from the heart and brain for arteries and nerves to travel respectively is the feet. Therefore, the cumulative effects of nerve or blood vessel damage from elevated blood sugar levels are most pronounced in the feet.
Diabetes can cause the buildup of plaques that clog both the large and small blood vessels, which provide blood flow to the legs and feet. This is known as peripheral vascular disease. Common coexisting disorders such as high blood pressure and high cholesterol also contribute to peripheral vascular disease.
When circulation to the feet is impaired, injury or wounds may fail to heal properly, and they are more prone to become infected. The most severe complication of peripheral vascular disease is gangrene, in which tissues die because of a lack of blood flow.
Diabetic nerve damage contributes to foot problems. Two types of nerves are affected by elevated blood sugar.
Autonomic nerves control the sweat glands in the feet. Autonomic nerve damage may lead to foot dryness which contributes to formation of calluses as well as skin cracking and breakdown. Large calluses may sometimes ulcerate, leading to wound formation.
Peripheral nerve damage affects the sensation and muscles in the feet. Diabetic peripheral neuropathy can lead to burning sensation in the feet followed by development of numbness.
As a result, people with diabetic neuropathy are more susceptible to foot injury and they may not notice foot injuries or wounds until they are more advanced. This can include pressure sores.
Loss of nerve function on the feet can lead to muscle atrophy, which in turn changes the architecture of the feet. In its worst form, this can result in a deformity known as Charcot foot. The result may be increased susceptibility to callus formation and skin breakdown.
The best form of foot protection in diabetes is good blood-sugar control from the time the condition is diagnosed. This can prevent nerve and artery damage from occurring. People with diabetes should always wear protective footwear, keep feet clean and moist, keep nails trimmed and inspect feet daily for calluses or wounds.
A complete foot exam by a medical provider or podiatrist is recommended at least yearly for all diabetics.
Dr. Matthew A. Clark is a board-certified physician in internal medicine and pediatrics practicing at the Ute Mountain Ute Health Center in Towaoc.
