Diabetes is a condition of uncontrolled blood sugar. Sugar in the blood is necessary for cellular energy, but it also can be destructive to the body tissues. Blood sugar levels normally are under tight control, which moderates this damage. With diabetes, however, high sugar levels cause damage to all of the body's tissues. The foot, being the farthest and lowest extremity, is particularly susceptible to the complications of diabetes.
The Body's Extremities
Because nerves and vascular tissues are more susceptible to damage from diabetes, the effects of glycosylation (sugar damage to tissues) are more pronounced in the extremities, where nerves and capillary beds tend to be more fragile. The circulation normally is more stagnant in the extremities, and the hands and feet tend to receive more damage in daily activities.
The foot is very often the first part of the body to show visible damage or complications of diabetes. Common complications of diabetes on the feet include: loss of sensation due to nerve damage, poor circulation, sores, infection and tissue death. The situation is compounded because of several factors: the feet normally are covered, they are more difficult to care for than other parts of the body and the feet support the body weight and are easily damaged from any excess weight.
Loss of Sensation
Paresthesia and other changes in skin sensation are some of the most common early symptoms of diabetes. When screening for diabetes, doctors will often will test for these changes on the legs and feet. Initially, this loss of sensation may be subtle, but it eventually can lead to inability to sense significant damage or wounds to the legs and feet.
Poor Circulation
Poor circulation is a common complication of diabetes. This leads to decreased ability to heal from even minor wounds and eventually can cause stasis ulcers or other tissue damage. When circulation diminishes, the affects of diabetes on the body--including nerve damage, infections and tissue death--begin to occur more rapidly.
Sores and Infection
Sores and infection are common complications of the diabetic foot. Stasis ulcers and pressure ulcers are small wounds that do not heal and tend to grow due to poor circulation. Infections are common for the same reason. When circulation is compromised, immune function also is inhibited and normal infections can become life-threatening.
Tissue Death
In severe cases, infections or ulcerations can cause widespread tissue death that can become life-threatening. Diabetes is the most common reason fro amputation, and the foot is the most common body part lost. In cases where infection or tissue death is severely advanced, amputation is necessary to protect the rest of the limb or the patient.
