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
Forefoot plantar pressures have been found to be as much as ___% greater than those in the rearfoot.
143
When does tissue failure occur?
When the rate of tissue breakdown exceeds the rate of repair
What are 3 things that adversely affect foot function?
- impaired motion
- foot deformities
- prior ulceration/amputation
In combination with sensory neuropathy decreased range of what motions leads to an increased risk of ulceration?
- great toe extension
- dorsiflexion
- subtalar joint motion
What are 4 deformities that create increased plantar pressures at the metatarsal heads during weightbearing?
- PF contracture
- forefoot varus
- forefoot valgus
- Charcot foot
The rate of ulcer recurrence after 2 years is as high as __%
35
What are the 3 plausible explanations for why previous pressure ulceration increases the risk for future ulcers?
- the immature cross-links and collagen bonds of newly formed connective tissue make it less able to tolerate mechanical stress
- scar tissue laid down during wound healing is less elastic and mobile than its predecessor
- those with a previous history are more likely to have a loss of protective sensation
Diabetes alters the body’s ability to build new tissue and fight infection. Individuals with diabetes have an increased frequency of certain types of infections, such as what 3 things?
- osteomyelitis
- soft tissue infection
- candida
Sustained hyperglycemia decreases all 3 phases of wound healing. Explain how…
- decreases the rate of collagen synthesis, angiogenesis, and fibroblast proliferation
- reduces tensile strength of incisional wounds
- impairs granulocyte chemotaxis, phagocytosis, and opsonization of bacteria
Diabetes is the leading cause of what 3 vision disorders?
- retinopathy
- glaucoma
- cataracts
What are 3 factors as to why patients with diabetes develop visual dysfunction?
- high blood glucose levels directly damage the retina
- the accumulation of sorbitol from the polyol pathway is known to cause eye disease
- vascular changes lead to microaneurysms and ischemia in the retina
What are the 2 ways in which impaired vision contribute to the development and progression of neuropathic ulcers?
- poor vision may lead to an increase in direct trauma to the foot such as stepping on an unseen obstacle
- severely hinders the ability to perform adequate foot care
What characteristic of diabetes leads to increased risk for ulceration?
Poor glycemic control associated with increased risk of long-term complications
What are 2 tests and measures clinicians must assess in patients prone for neuropathic ulcers?
- circulation
- sensory integrity
What should be assessed in patient with digital ulcers?
capillary refill
When is pulse examination indicated?
In all open wounds
What 3 pulses should be assessed?
- Dorsalis pedis
- Posterior tibial
- Popliteal
Under what 3 circumstances is a Doppler ultrasound or ABI indicated?
- pulses are decreased or absent
- signs and symptoms of arterial insufficiency
- history of PVD
Patients with an ABI less than __, delayed capillary refill, or abnormal Doppler studies should be referred to a physician for further evaluation
0.8
Patients with diabetes have artificially inflated ABI values due to what?
vessel calcification
Patients who fail to respond to conservative interventions must be referred for further assessment. What can be used to provide a more accurate representation of patient circulation?
Arteriography or transcutaneous oxygen measurements
What is the gold standard for light touch sensation?
Semmes-Weinstein Monofilaments
A ___ monofilament indicates that the patient has decreased sensation
4.17
A ___ monofilament indicates that the patient has a loss of protective sensation
5.07
A ___ monofilament indicates that the patient has lost all light touch sensation
6.10
What are the 3 indications for monofilament testing?
- All neuropathic ulcers
- All patients with diabetes
- All patients with plantar foot ulcers
Describe a grade 0 ulcer according to the Wagner Classification System
- No open lesions
- May have deformity or cellulitis
What integumentary preferred practice pattern do grade 0 ulcers fall?
A (at risk) or B (superficial skin involvement)
Describe a grade 1 ulcer according to the Wagner Classification System
Superficial ulcer
What integumentary preferred practice pattern do grade 1 ulcers fall?
C (partial thickness) or D (full thickness)
Describe a grade 2 ulcer according to the Wagner Classification System
Deep ulcer to tendon, capsule, bone
Describe a grade 3 ulcer according to the Wagner Classification System
Deep ulcer with abscess, osteomyelitis, or joint sepsis
Describe a grade 4 ulcer according to the Wagner Classification System
Localized gangrene
Describe a grade 5 ulcer according to the Wagner Classification System
Gangrene of the entire foot
What integumentary preferred practice pattern do grade 2, 3, 4, and 5 ulcers fall?
E (skin involvement
extending into fascia, muscle, or bone)
What are the 6 typical characteristics of neuropathic ulcers?
- pain
- position
- presentation
- periwound characteristics
- pulses
- temperature
Describe the typical pain reports in patients with neuropathic ulcers
Pain is typically absent or significantly reduced. Patients may report paresthesias if anything
Where do neuropathic ulcer tend to occur?
In areas of increased pressure such as the plantar aspect of the metatarsal heads
Where do ulcers tend to occur in cases of hallux rigidus?
on the plantar great toe
Where do ulcers tend to occur in cases of claw toe?
dorsal aspects of the toes
Where do ulcers tend to occur in cases of Charcot deformity?
plantar aspect of the midfoot
Describe the general presentation of neuropathic ulcers
They commonly present as round, punched out lesions with a characteristic rim of callous indicative of increased plantar pressure and shear forces
Describe the drainage associated with neuropathic ulcers
Usually minimal unless infected.
The same is true in regards to eschar or necrotic tissue
What does the periwound area look like around a neuropathic ulcer?
The skin is typically dry and cracked with calluses present
Describe the temperature changes typically associated with neuropathic ulcers
They are more normal than arterial/venous wounds however areas of increased temperature may indicate reactive hyperemia or infection
Overall the prognosis for neuropathic ulcers is dependent upon size and duration of ulcer. Explain…
Small, superficial (Wagner grade 1 or 2) ulcers tend to heal better than larger ulcers.
Ulcer that have been present for less than 2 months tend heal quicker than those that have been around for awhile and have become infected.
Wound healing is considered poor if the ulcer does not decrease by __-__% within the first month of treatment
20-50
The risk of amputation ___ times greater with infected ulcers
154
What is the average time to neuropathic ulcer healing?
12-14 weeks
Clinicians should be aware of 3 precautions when working with patients with neuropathic ulcers, what are they?
- they may not show the cardinal signs of infection due to decreased inflammatory response and concomitant PVD
- patients should be educated in foot care guidelines due to extremely high risk of sensory loss
- it is important to monitor blood sugar
What is hyperglycemia common with?
infections and uncontrolled diabetes
An order for a bone scan or x-ray should be requested if there is exposed capsule or bone to rule out the presence of what?
How is this condition treated?
osteomyelitis
The infected bone must be promptly surgically removed before allowing the wound to close
What are the 4 keys to local wound care?
- offload the neuropathic ulcer
- pare the callus so that it is flush with the epithelial surface
- use petroleum-based moisturizer daily
- use toe spacers if enclosing toes in bandage
Total contact casting is an efficient and effective method of treating what grades of neuropathic ulcers?
1 and 2
Describe the 5 ways in which total contact casting assist in wound healing
- Cast is molded to foot and leg, dispersing weight-bearing forces over large area
- Cast rigidity controls edema
- Immobilizes the foot and ankle leading to a reduction in shearing forces
- Completely encloses the patient’s insensate foot, protecting it from trauma and microorganisms
- Assists with patient adherence
What are the 5 contraindications to total contact casting?
- Osteomyelitis
- Gangrene
- Fluctuating edema
- Active infection
- ABI less than 0.45
What are 3 ways to unload the affected tissues during gait?
- PWB on the involved extremity
- patients with ulcers of the great toe or forefoot should use step-to pattern to decrease plantar pressures
- modify footwear
What 3 ROM exercises should be assessed?
- great toe extension
- talocrural dorsiflexion
- subtalar joint motion
Why is aerobic exercise important in patients with neuropathic ulcers?
It assists with glycemic control and weight loss
What are 4 requirements for permanent footwear?
- should be approximately ½ inch longer than the longest toe with a snug heel fit
- last should match foot shape
- extra-depth toe box
- heel height less than 1 inch
A 1% decrease in hemoglobin A1c is associated with a __% decrease in microvascular complications and a __% reduction in amputations
25
36
Cultures of neuropathic ulcers average - different microbes, with the most common being what?
4-5
staph aureus
What is the gold standard for detecting osteomyelitis?
bone scan
When is amputation indicated?
in gangrene wounds, and Wagner grades 4 and 5
