Diabetic Neuropathic Foot Ulcer
•Anatomical
Location
•Size
and Shape
•Grade
•Wound
Bed
•Wound
Edges
•Exudate
•Periwound
Skin
•Pain
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When taking care
of any person with an impairment in skin integrity, a comprehensive assessment
of both the wound and the patient must occur simultaneously. It can be important
to assess the “unwounded” limb as well.
Let’s review some
common characteristics of neuropathic wounds, remembering that while the
majority of these wounds are due to peripheral neuropathy, some patients have
angiopathy or an ischemic component to their wounds.
Location:
Neuropathic ulcers are located on the plantar or walking surface of the foot.
71% of ulcers occur on the forefoot , and the 3rd
metatarsal head is most affected followed by the great toe, and the 1st
and 5th
metatarsal head. Ischemic wounds, on the other hand, are usually found on the
lateral side of the foot, over the malleolus and toes, or on the heel. Wounds
found on the dorsum (or top) of the foot are usually due to trauma.
Size and shape:
Neuropathic ulcers tend to be small and have a round, punched-out (punctate)
appearance. Depth may range from partial thickness or may probe to bone, which
is a significant indicator of the presence of osteomyelitis. Ulcers may present
with or without sinus tracts, tunneling or undermining.
Grade:
While we use a staging system with pressure ulcers to indicate the depth of
tissue damage, a grading system is used for neuropathic foot ulcers to
facilitate a common language. The Wagner Ulcer Grade Classification grades
ulcers from 0-5 and provides descriptors for each grade, ranging from 0--intact
skin, preulcer lesion, healed ulcer, presence of bony deformity, to 5--gangrene
of the foot requiring disarticulation. The University of Texas classification
system offers both a stage (A-D) and grade (0-3) for each wound and addresses
infection and ischemia in their schemata.
Wound Bed or base of wound is usually red,
unless there is an ischemic component to their disease.
Wound edges or margins:
usually even and well defined. Often with neuropathic ulcers there will be an
area of callous which forms around the wound edges.
Exudate can vary in quantity and quality,
from small to
moderate amounts, serous in quality. Purulent, thick exudate may indicate
infection.
Periwound skin or surrounding skin:
Observe
and palpate the surrounding skin and feet noting any warmth, swelling or
induration which may indicate that an infection is brewing. Note character of
skin and any callus formation surrounding the ulcer indicating that pressure is
not being relieved in that area.
Pain:
It is
not surprising that these ulcers are usually painless due to the fact that the
patient has neuropathy and has lost sensation in that area. Anytime a patient
who has previously had an insensate foot starts to complain of pain, the
caregiver should get an immediate and urgent referral to a specialist in order
to prevent limb loss.
Offloading the Diabetic Foot
•Special
Boots: CROW, Prefabricated, L'NArd, Multipodus, Darco
•Assistive
Devices: Crutches, Walker, Wheelchar
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Selection of appropriate footwear needs to occur before ulceration or amputation.
The use of lambs wool between toes, padded socks, inserts and crest pads for
hammer or claw toes can be beneficial in providing pressure relief. The presence
of a diabetic foot wound demands offloading the foot 24/7 to relieve pressure
and strain to the affected area. In essence, the patient needs to be non-weight
bearing in order for the wound to close.
The total contact cast is especially useful in this regard and has been referred
to as the gold standard of treatment of non-infected neuropathic ulcers.
Pressures are totally redistributed away from the ulcer and the patient is
“forced” into compliance due to the nature of the cast. A non-randomized study
of 1350 diabetic foot ulcer patients demonstrated 88% ulcer closure in 5 weeks
using the total contact cast, 63% with the 3-D walker with custom insoles, and
55% closure with custom sandals with three layers of foam
(Hanft, 2000).
There is
little evidence that assistive devices facilitate wound healing.