Many of the symptoms of diabetes eventually end up causing problems in the feet. Other than trauma, diabetes is the leading cause of amputation in the lower body, says "Harrison's Principles of Internal Medicine." According to an article in the August 1998 issue of the "American Journal of Surgery," the lifetime risk of developing a diabetic foot ulcer is 15 percent. Of those patients who do develop an ulcer, between 14 and 24 percent will eventually need some form of amputation. Diabetic ulcers and amputations result from the nerve and circulatory symptoms associated with the disease.
Loss of Pain And Pressure Sensation
Loss of nerve function, or neuropathy, is one of the complications of poorly controlled diabetes, according to an article in the "American Journal of Surgery." Patients with diabetic neuropathy frequently lose the sensations of pain and pressure. When patients cannot feel pressure, they are not aware of areas of their feet that are under unusual stress due to sustained pressure from standing or shoes.
Over time, this unusual stress can lead to the breakdown of skin, which is the first step in developing an ulcer. A patient with diminished pain sensation does not perceive the pain that would normally accompany this sort of breakdown, and the developing ulcer is often not noticed until much more significant damage has occurred.
Loss of Proprioception
The sense of body position in space, or proprioception, is also often lost in diabetic neuropathy. Proprioception is essential for coordinated control of movement and avoidance of collisions with obstacles. Due to decreased coordination, the gait of patients with decreased proprioception often changes in ways that increase pressure points when walking, says "Harrison's Principles of Internal Medicine."
In addition, patients with pain and proprioception problems frequently injure their feet without being aware of it. Special shoes that avoid pressure points, but still provide protection during collisions, are essential for preventing foot injuries in patients with diabetic neuropathy.
Loss Of Circulation
Another symptom of poorly controlled diabetes is diminished circulation, particularly in the extremities, due to damaged blood vessels. Good circulation is key to healing wounds, so when a diabetic patient suffers a foot injury, it often heals poorly. Even fairly minor injuries can develop into serious ulcers due to poor healing and continued mechanical stress on the area.
In addition, poorly controlled diabetes can depress immune function, according to the "American Journal of Surgery." So diabetic foot ulcers are more likely to become infected both because they remain open for longer periods of time and because the body is less able to fight off infection once it occurs. Chronic foot infections often cannot be controlled in diabetics even with extensive antibiotic treatment, and amputation becomes the only way to prevent further spread of the infection.
References
- "Harrison's Principles of Internal Medicine" 16th edition; Dennis L. Kasper, et. al. ed.; 2005
- "American Journal of Surgery"; The burden of diabetic foot ulcers; GE Reiber, et. al.; August 1998
- "The Lancet"; Diabetic foot ulcers; WJ Jeffcoate and KG Harding; May 2003
