Preventing Amputation In Patients With Diabetes
- Volume 21 - Issue 3 - March 2008
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The World Health Organization and the International Diabetes Federation have stated that up to 85 percent of diabetic lower extremity amputations are preventable. There are approximately 82,000 diabetes-related lower extremity amputations (LEA) annually at an estimated cost of over $11 billion.1,2 Eighty-five percent of amputations are preceded by a foot ulcer.3 Diabetic foot ulcers are caused by neuropathy, deformity and repetitive microtrauma.4 The treatment of diabetic foot ulcers may cost the United States healthcare system as much as $19 billion yearly.2 Diabetic foot ulcers lead to amputations and both conditions are largely preventable. Pecoraro reported that 86 percent of amputations in his study were preceded by an identifiable and preventable pivotal event.3
The diagnosis of diabetes is not a condemnation to future amputation. Several “steps” take place prior to the loss of a limb. The six steps are diabetes, neuropathy, ulceration, vascular disease, infection and amputation. Each of these steps is preventable and one can take action to prevent the patient from escalating to the next step.
The first step is the diagnosis of diabetes. Diabetes is associated with the comorbid conditions of macrovascular disease (heart attack, stroke, peripheral arterial disease (PAD)) and microvascular disease (retinopathy, nephropathy, neuropathy). Diabetes is the sixth leading cause of death.1 Type 1 diabetes accounts for approximately 5 percent of all diabetes cases and there are no known methods for prevention.
However, type 2 diabetes (95 percent of cases) is associated with decreased physical activity, obesity, older age and a family history of type 2 diabetes.1 Some of these risk factors are modifiable and one can improve impaired glucose tolerance with exercise and diet modifications.5 If patients make these modifications early in the disease process, they can prevent complications or delay the onset of the disease.
Keys To Screening For Peripheral Neuropathy
Peripheral neuropathy affects up to 65 percent of patients with diabetes.6 The onset is typically eight to 12 years after the diagnosis of diabetes. Diabetic peripheral neuropathy (DPN) affects all three divisions of the peripheral nervous system (sensory, motor, autonomic).
Sensory neuropathy can predispose patients to unperceived repetitive microtrauma and is the main risk factor for foot ulceration.
Motor neuropathy causes muscle atrophy, which leads to hammered digits and equinus. Autonomic neuropathy affects skin sweating and lubrication, which leads to xerosis.
Autonomic neuropathy may also play a role in Charcot foot. Autonomic neuropathy may be mediated through peripheral vasodilation and the “washing out” of the mineral content in the bones.
When it comes to patients with diabetes, one can determine if there is a loss of protective sensation (LOPS) by using a 5.07 Semmes-Weinstein monofilament or a biothesiometer. Diabetic peripheral neuropathy is a length-dependent process and affects the longest nerves first (the nerves to the toes). The 10-point monofilament test was developed for those with leprosy neuropathy, which is not a length-dependent process. Therefore, it is not necessary to test 10 points in those with diabetes.
To uncover LOPS in diabetes, one should test four points in each foot: the plantar hallux and plantar metatarsal heads one, three and five.7 Instruct patients to close their eyes and say “yes” whenever they feel the monofilament. Press the monofilament against the skin until it buckles. Failure to perceive one of the four sites is sufficient for the diagnosis of LOPS. The biothesiometer is a semi-quantitative measure of nerve function. Place the biothesiometer on the distal hallux and slowly turn the dial until the patient feels the vibratory sensation. Greater than 25 volts connotes LOPS and a future risk of ulceration.8
There are currently no FDA-approved or evidence-based treatments that reverse sensory loss due to diabetic neuropathy. Instead, we must prevent progression to the next step of ulceration.
What The Research Reveals About Preventing Ulceration