62 The Diabetic Foot Journal Vol 18 No 2 2015
Article
Diabetic foot ulcer or pressure ulcer?
That is the question
Peter Vowden, Kathryn Vowden
Citation: Vowden P, Vowden
K (2015) Diabetic foot ulcer or
pressure ulcer? That is the question.
The Diabetic Foot Journal 18: 62–6
Article points
1. Confusion exists when
naming (diagnosing) and
treating pressure-related foot
ulceration in people with
diabetes, particularly when
ulceration occurs on the heel.
2. Diagnosis can and does affect
subsequent assessments
and management and
this could potentially
compromise outcome.
3. All people with diabetes and
foot ulceration, irrespective
of wound aetiology, should
beneft from multidisciplinary
foot team input.
Key words
– Care pathways
– Diabetic foot ulcer
– Pressure ulcer
Authors
Peter Vowden is Consultant
Vascular Surgeon, Bradford
Teaching Hospitals NHS
Foundation Trust and Visiting
Honorary Professor of Wound
Healing Research, University of
Bradford, Bradford, UK.
Kathryn Vowden is a Nurse
Consultant, Bradford Teaching
Hospitals NHS Foundation
Trust and University of
Bradford, Bradford, UK
The establishment of a correct diagnosis links care to established guidelines and
underpins all subsequent therapeutic activity. Problems can arise when definitions
of disease overlap, as is the case with diabetic foot ulceration and pressure ulcers on
the foot occurring in people with diabetes. In such cases, clinicians must ensure that
patients receive a care bundle that recognises both the wound causation (pressure and
shear) and the underlying pathology (diabetic neuropathy, potential foot architecture
disruption and ischaemia). All patients with diabetes who have foot ulceration,
irrespective of wound aetiology should, therefore, be seen by the multidisciplinary
diabetic foot team. Care can then be optimised to include appropriate assessments,
including assessment of peripheral perfusion, correct offloading, appropriate diabetic
management, and general foot and skin care.
W hat’s in a name? That which we call a rose by any other name would smell as sweet.
Romeo and Juliet (II, ii, 1-2)
Unlike in a Shakespearean play, where a name is
seen as an artificial and meaningless convention,
the whole basis of managing a patient’s illness is to
establish a diagnosis or name for the illness. Once
a healthcare professional has named a problem,
a treatment strategy — often laid out in specific
guidelines — follows. The name of an ulcer is,
therefore, key to its subsequent management.
What is a pressure ulcer?
According to the European Pressure Ulcer
Advisory Panel (EPUAP) guidelines (EPUAP and
Nation Pressure Ulcer Advisory Panel, 2014), a
pressure ulcer is defined as: “A localized injury
to the skin and or underlying tissue usually over
a bony prominence, as a result of pressure, or
pressure in combination with shear.” Although
intended to be specific, this definition is wide
reaching. It includes skin and deep tissue damage
caused by pressure and/or shear, irrespective of the
underlying medical condition of the patient or the
mechanism by which the damage occurred. The
EPUAP definition goes on to state: “A number
of contributing or confounding factors are also
associated with pressure ulcers; the significance
of these factors is yet to be elucidated.” This
indicates the complexity of pressure ulceration
and highlights the gaps in our knowledge both in
accurately identifying patients’ risk and confirming
ulcer aetiology.
This definition of pressure ulceration includes
pressure damage that occurs at the ‘end of life’,
sometimes referred to as ‘Kennedy ulcers’ (Schank,
2009), and also includes bandage trauma or
compression bandage damage, ulceration from
devices such as oxygen masks or nasogastric tubes,
urinary or other catheters, and pressure and shear
damage from plaster casts or footwear.
Most pressure ulcer prevalence studies (Barczak
et al, 1997; Clark et al, 2004; Vangilder et al, 2008;
Vowden and Vowden, 2009a) identify the heel area
as the second most frequent location for a pressure
ulcer, the most prevalent being the sacrum. The
heel accounts for between 23% and 28% of all
pressure ulcers (Barczak et al, 1997; Clark et al,
Diabetic foot ulcer or pressure ulcer? That is the question
64 The Diabetic Foot Journal Vol 18 No 2 2015
2004; Vangilder et al, 2008; Vowden and Vowden,
2009a; 2009d) and is the most frequent site for
pressure ulceration in specific patient sub-groups,
namely the critically ill, older people and people
with diabetes.
Salcido et al (2011) state that the heel is the most
common area for deep tissue injury. Heel pressure
ulcers are commonly found in both acute and
long-term care facilities (Vangilder et al, 2008), are
frequently associated with delayed wound healing
(Chipchase et al, 2005; Pickwell et al, 2013) and
have a significant impact on patients’ quality of
life (Spilsbury et al, 2007). In a small retrospective
study of 57 patients, Han and Ezquerro (2011)
reported that 42% (18 patients) of cases of heel
pressure ulcers required amputation due to
persistent infection or non-healing.
What is a diabetic foot ulcer?
In the International Consensus on the Diabetic Foot
(International Working Group on the Diabetic
foot, 2007), a diabetic foot ulcer is defined as:
“A full-thickness wound below the ankle in a
diabetic patient, irrespective of duration. Skin
necrosis and gangrene are also included in the
current system as ulcers.” This definition is
similar to that of the EPUAP, all-inclusive and,
as such, any pressure ulcer on the foot of a person
with diabetes is a diabetic foot ulcer — as is any
traumatic wound, including a thermal or chemical
injury. It constitutes part of the ‘diabetic foot’ —
an interrelated group of complications, including
infection, ulceration, neuropathy and peripheral
arterial disease that place the foot at risk of
amputation (Apelqvist, 2014).
Conflicting defnitions
This overlap between definitions causes problems
in wound management pathways. Describing
and classifying a wound helps guide clinicians’
subsequent management strategies and therapeutic
requirements. For example, a leg wound described
as a venous leg ulcer will receive compression
therapy with appropriate venous investigations in
line with the NICE guidelines for venous disease
(NICE, 2013). The Comprehensive Classification
System for Chronic Venous Disorders (Eklof et al,
2004) also allows a detailed description of both the
ulcer and the underlying pathology.
Identifying a wound as a pressure ulcer does
not offer such a detailed descriptive classification
system — limiting the classification to wound
depth and exposed tissue type — but should
still activate a care pathway that is in line with
the National Institute for Health and Care
Excellence (NICE) guidance for pressure ulcer
treatment (NICE, 2014). This triggers risk and
skin assessment, enhanced pressure relief and
repositioning, but does not define a specific
wound care strategy or identify care-supporting
investigations. However, it does trigger prevalence
and incident reporting, investigation and analysis
of the root cause.
Identifying a wound as a diabetic foot ulcer
may result in a more detailed descriptive
definition of the ulcer (Abbas et al, 2008)
and should also result in a care pathway that
follows the NICE guidance (NICE, 2004;
2011). This will include timely referral to the
multidisciplinary diabetic foot care team where
assessment of peripheral perfusion, neuropathic
status, wound and callus debridement, and
appropriate offloading with general foot and nail
care, as well as review of diabetes management,
would be performed.
Differing guidance for each wound type
impacts on care provision. The Bradford Wound
Care Audit (Vowden and Vowden, 2009a; 2009b;
2009c; 2009d; Vowden et al, 2009) highlighted
the differences that occur in management when
foot ulceration among people with diabetes is
classified as either a pressure ulcer or a diabetic
foot ulcer (Figure 1a and b). People with diabetes
in the community setting classified as having
a heel pressure ulcer rather than a diabetic foot
ulcer did not receive Doppler peripheral vascular
assessment, were not referred to the diabetic foot
service and did not, therefore, receive the benefits
of general foot care, offloading or orthotic
referral.
The mechanism of injury in both pressure
ulceration and diabetic foot ulceration is often
similar (Figure 2) and this can understandably
lead to problems in allocating a wound type to a
specific wound.
Chadwick, commenting on a pressure ulcer
prevalence survey in his local hospital that
showed a larger than expected increase in the
“Overlap between
defnitions causes
problems in wound
management
pathways.”
Diabetic foot ulcer or pressure ulcer? That is the question
The Diabetic Foot Journal Vol 18 No 2 2015 65
number of pressure ulcers, found that ward staff
were counting diabetic foot ulcers as pressure
ulcers and concluded that staff were struggling
to differentiate between pressure ulcers and
diabetic foot ulcers (Ousey et al, 2011). In the
same article, Cook commented: “The real
issue is not whether the ‘label’ of the wound
is correct, but that the patient receives the
most appropriate care through assessment and
correct referral within a prompt timeframe to a
‘specialist’ in that area.”
Although not directly relevant to a discussion
in relation to the naming of foot wounds among
people with diabetes, there may be histological
and transcriptional differences between diabetic
foot ulcers and pressure ulcers. Mendoza-Mari
et al (2013) demonstrated that in diabetic
foot ulceration granulation tissue cells exhibit
a molecular “imprinting” toward glucose
homeostasis failure.
Irrespective of the name applied to a foot
ulcer, any non-healing wound on the foot
should trigger detailed assessment of the limb’s
peripheral perfusion. Reliance on palpable pulses
and a Doppler ankle–brachial pressure index
may not be sufficient. The concept of foot and
lower-leg angiosome (Wright and Fitridge, 2014)
demonstrates the importance of identifying
regional perfusion within the ulcerated area and,
whenever possible, restoring in-line pulsatile
perfusion to that region.
Conclusion
When is a diabetic foot ulcer a pressure ulcer
and when should these ulcers be included
in pressure ulcer prevalence data? These are
questions that many clinicians struggle with. The
breadth of the definition of pressure ulceration
could be interpreted as including most diabetic
neuropathic and neuroischaemic foot ulcers as the
skin break, damage or ulceration is usually caused
by pressure and or shear.
The authors’ view is that people with diabetes
with an ulcer or wound on the foot should
have the benefit of assessment by a specialist
multidisciplinary team and treatment pathways
established by the diabetic foot services,
irrespective of the name placed on the ulcer.
Patients with ulceration on the heel are, as a
group, most likely to be classified as having
pressure ulceration. These patients frequently
struggle with impaired mobility and poor
healing and often fail to benefit from foot team
intervention in their management.
Effective working and communications
between healthcare professionals is essential
to allow implementation of complex care
for people with foot ulceration. To optimise
Figure 1. Differences in (a) the care pathway for foot pressure ulcer patients and (b) the
vascular assessment pathway (Doppler ankle-brachial pressure index performed, yes or no) for
foot ulceration in people with diabetes depending on classifcation as a diabetic foot ulcer or
pressure ulcer.
Foot ulcer Pressure ulcer – foot
5 0
10
15
20
25
30
35
Patients (n)
Podiatrist Podiatrist
and specialist
nurse
Neither
podiatrist nor
specialist nurse
Seen by
Foot pressure ulcer
Leg/foot ulcer
(a)
0
10
20
30
40
50
60
70
80
Patients (n)
No
Yes
(b)
Diabetic foot ulcer or pressure ulcer? That is the question
66 The Diabetic Foot Journal Vol 18 No 2 2015
outcomes, all people with foot ulceration
should benefit from the input of a foot care
team. Too many healthcare professionals focus
solely on the management of the wound and
ignore the integrated care benefits that follow
multidisciplinary team involvement. n
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Figure 2. Causes of non-traumatic heel and foot ulceration.
Ulceration
Pressure
and shear
Ischaemia
Neuropathy
l Diabetes
l Anaesthesia
l Cord/brain injury
l Peripheral neuropathy
l Immobility loading
l Mobility loading
l Anatomical abnormality
l Uncontrolled movement
l Support surface
l Medical equipment
l Foot wear
l Treatment
l PVD
l Central (cardiac/hypoxia
l Oedema
l Local ischaemia