2008 Clinical Practice Guidelines - Canadian Diabetes Association

Foot Care
Canadian Diabetes Association Clinical Practice Guidelines Expert Committee
The initial draft of this chapter was prepared by Keith Bowering MD FRCPC FACP,
Jean-Marie Ekoé MD CSPQ and Timothy P. Kalla BSc DPM FACFAS
KEY MESSAGES
• Foot problems are a major cause of morbidity and mortality
in people with diabetes and contribute to increased
healthcare costs.
• Management of foot ulceration requires an interdisciplinary
approach that addresses glycemic control, infection,
lower extremity vascular status and local wound care.
• Uncontrolled diabetes can result in immunopathy with
a blunted cellular response to foot infection.
INTRODUCTION
Foot problems are a major cause of morbidity and mortality
in people with diabetes and contribute to increased healthcare
costs (1,2). The sequence of events leading to lowerextremity
amputation is well known. In people with
neuropathy (3) or peripheral vascular disease (4), minor trauma
to the foot leads to skin ulceration, infection and ultimately
gangrene, resulting in amputation (5-9). Foot
complications are a major reason for admission to the hospital
for people with diabetes, accounting for approximately
20% of all diabetes-related admissions in the North American
population (7,8,10-12).After amputation of 1 limb, the prognosis
for the contralateral limb is poor (13,14).
RISK ASSESSMENT AND PREVENTIVE CARE
A number of wound classification systems exist for documentation
of diabetic foot ulcers. Of these, the University of
Texas Diabetic Wound Classification System has been validated
as a predictor of serious outcomes in patients with diabetes
with foot ulcers (15) (Table 1).
Characteristics that have been shown to confer high risk
of ulceration include previous ulceration, neuropathy,
structural deformity and limited joint mobility, peripheral
vascular disease and microvascular complications (16,17).
Noninvasive assessments for peripheral arterial disease in
diabetes include the use of the ankle-brachial index, determination
of systolic toe pressure by photoplethysmography
(measurement of the intensity of light reflected from the
skin surface and the red cells below, which is indicative of
arterial pulse flow in the arterioles of the respective area),
transcutaneous oximetry (tcPO2), and Doppler arterialflow
studies (18,19).The ankle-brachial index may be arti-
ficially high in some individuals with diabetes due to medial
arterial-wall calcification in lower-extremity arteries
(20). Iodinated contrast arteriography has provided the
most definitive evaluation of peripheral atherosclerosis, but
can precipitate renal failure in individuals with renal insufficiency.
Advanced magnetic resonance angiography has
been used as an alternative to iodinated contrast studies in
people at risk for renal complications (21,22), although
caution may be necessary in view of a possible association
with the gadolinium-based contrast agents used in magnetic
resonance angiography and the development of nephrogenic
systemic fibrosis in individuals with poor renal
function (23,24).
Prevention of amputations necessitates the use of various
measures, including regular foot examination and evaluation
of amputation risk, regular callus debridement, education,
professionally fitted therapeutic footwear to reduce plantar
pressure and accommodate foot deformities, and early
detection and treatment of diabetic foot ulcers (10,25-28).
Callus should be considered a sign of increased pressure and
risk for ulceration (29). Foot examination should also
include skin temperature assessment. Increased warmth is
the first indicator of inflammation in an insensate foot and
may be the first sign of acute Charcot neuroarthropathy as a
complication of loss of protective sensation in the foot (30-
Table 1. University of Texas Diabetic
Wound Classification System (15)
Stage Grade
A (no
infection
or
ischemia)
0 I II III
Pre- or
postulcerative
lesion
completely
epithelialized
Superficial
wound not
involving
tendon,
capsule
or bone
Wound
penetrating
to
tendon
or capsule
Wound
penetrating
to
bone
or joint
B Infection Infection Infection Infection
C Ischemia Ischemia Ischemia Ischemia
D Infection
and
ischemia
Infection
and
ischemia
Infection
and
ischemia
Infection
and
ischemia
S143
COMPLICATIONS AND COMORBIDITIES