Neuropathic Ulcers Flashcards
How many Americans have diabetes?
24 million
The incidence of neuropathic ulcerations in diabetics is anywhere from __-__%
15-25
In the US, diabetes is responsible for how many amputations annually?
over 600,000
Of the 600,000 amputations occurring annually, what percentage are due to foot ulceration?
80%
__% of amputees will experience a contralateral foot ulceration within 18 months of their first amputation
50
__% of amputees will undergo a second amputation within 3-5 years
50
Diabetes mellitus is a disorder of carbohydrate, protein, and fat metabolism related to alterations in the body’s ability to produce or use _____.
insulin
Type I diabetes is diagnosed in what type of patient?
children or young adults
Describe the etiology of type I diabetes
Results from an immune mediated destruction of pancreatic beta cells therefore they are unable to produce insulin
Individuals with type I diabetes comprise approximately _-__% of all patients with diabetes
5-10
Type II diabetes is diagnosed in what type of patient?
Middle age or later
Approximately what percentage of type II diabetes patients are overweight?
80%
Describe the etiology of type II diabetes
Obesity causes insulin resistance
True or False
There is a genetic predisposition to developing type II diabetes
True
What ethnicities are m ore prone to developing type II diabetes?
Native Americans and Hispanic/Latino
Individuals with type II diabetes comprise approximately __-__% of all patients with diabetes
90-95
Describe the 3 hypotheses as to the mechanism of tissue damage due to hyperglycemia
1) hemodynamic changes and the resultant increases in microvascular pressures
2) glycosylation
3) accumulation of sorbitol
What are the 3 hyperglycemia changes that occur?
- RBCs become less deformable, less able to release oxygen, and more adhesive (therefore they stick to themselves and to endotheltial cells lining capillary walls)
- platelets become more adhesive and stick to endothelial cells at sites of minimal injury
- capillary walls to become thicker and less flexible due to the first 2 things
What is glycosylation?
Glucose passively binds to proteins due to hyperglycemia which causes tissue trauma
What is the accumulation of sorbitol due to?
the breakdown of glucose through the polyol pathway
Describe the mechanism behind the accumulation of sorbitol
Some tissues use the polyol pathway to transport glucose into cells without using insulin. The pathway converts glucose into sorbitol before finally changing it into fructose. Hyperglycemia increases the rate of this conversion, causing tissue damage
What are 9 risk factors contributing to neuropathic ulcers and delayed healing?
- Vascular disease
- Neuropathy
- Mechanical stress
- Abnormal foot function and inadequate footwear
- Impaired healing and immune response
- Poor vision
- Ulcer characteristics
- Disease characteristics
- Inadequate care and education
The prevalence of peripheral artery disease in patients with diabetes is estimated to be about __%
14
Diabetic patients with PAD also have an accelerated rate of what?
atherosclerosis
Diabetes has been shown to cause thickening of what membrane? What does this result in?
basement membrane
results in decreased delivery oxygen and nutrients to the tissues
True or False
PVD is the major contributing factor to neuropathic ulcers
False
Neuropathy is now to believed to be the number 1 contributing cause
Ischemia has been implicated as a causative factor in only _% of all amputations
5
What is the most common complication of diabetes mellitus. It affects __-__% of patients with type 2 diabetes and even higher percentage of individuals with type 1 diabetes
Neuropathy
30-40
What are 2 proposed causes of neuropathy?
- neural ischemia
- segmental demyelination
Neuropathy tends to be symmetrical and affects the _____ nerves first. Therefore it has the most significant impact on what body part?
distal
the feet
What systems does neuropathy affect?
- sensory
- motor
- autonomic
What percentage of patients are unaware that they have lost protective sensation?
50%
In addition to lack of protective sensation, sensory neuropathy may also be characterized by what?
paresthesis, such as burning pain, tingling, or aching
Patients who are unable to perceive __ grams of pressure (5.07 Semmes-Weinstein monofilament) should be considered at risk for ulceration
10
What does motor neuropathy lead to?
paralysis of the foot’s intrinsic muscles which may predispose patients with diabetes to plantar ulceration by increasing plantar pressures and shear forces
Loss of intrinsic muscle function may cause the foot to be less stable during the ____ phase of gait
stance
This loss of stability may lead to what excessive plantar and shear forces what metatarsal heads? It may also be associated with what type of deformities?
2nd and 3rd
hallux valgus and claw toe
How does autonomic neuropathy increase the risk of neuropathic ulceration
due to disturbances in sweating mechanics, callus formation, and blood flow
Autonomic neuropathy ______ the body’s ability to sweat
decreases
leads to dry, less elastic, and cracked skin
Individuals with autonomic neuropathy also have an _____ rate of callus formation, resulting in up to __% increase in local pressure
increases
26
What 2 types of blood flow changes associated with autonomic neuropathy lead to increased risk of NU?
- AV shunting which results in decreased perfusion of the skin and superficial structures, which reduces the skin’s ability to repair
- uncontrolled vasodilation causes an increase in blood flow to the bone which essentially leaches the bone of calcium and predisposes the bones of the foot to fracture
What can be defined as the amount of force applied per unit area?
pressure