Demographic Social Diabetes related 2. Features that contribute to the onset of an ulcer/lesion, and that may delay healing Deformity Co-morbidity Unrelated disease or treatment 3. Features of the limb or the ulcer/lesion Limb Site, side Ischaemia Neuropathy Ulcer/lesion Bacterial infection Area Depth
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Features of the Person Aspects of an individual may determine the outcome of any established lesion.
These may include demographic details, details of the diabetes, its management and its complications, other co-morbidities, and social factors such as social deprivation, occupational risk and use of tobacco and alcohol.
Not all are relevant to every circumstance (or may not be captured on a routine basis), and the items can be selected to meet the needs of individual practice.
Some of the detail may also vary with time: for example, new co-morbidities may arise, and the quality of glycaemic control may change.
In general terms, it is better to record less than more.
Features that Contribute to the Onset of an Ulcer/Lesion, and that May Delay Healing Three abnormalities of the limb can both contribute to the development of an ulcer or lesion and affect its rate of healing. These are deformity, co-morbidity and unrelated disease (Table 7.3).
Table 7.3 Features that may contribute to the onset of an ulcer/lesion, and that may delay healing
Deformities of the foot (a) Changes in the nails (b) Deformity leading to increased forces applied to the bones and joints of the foot (e.g. consequences of motor neuropathy, shortening of the Achilles tendon or of previous surgery) (c) Other deformity Co-morbidity (e.g. immobilisation from other illness, oedema, varicose veins) Unrelated disease of the skin or treatment, e.g. eczema or psoriasis, systemic glucocorticoids
Features of the Limb and the Ulcer/Lesion The limb
Site and side It will be necessary to define the site and side for the purposes of both communication and record keeping. It may also be required for population definition, even though there is currently no evidence that outcome is affected by the site of the lesion.13,14
Arterial disease The diagnosis of significant peripheral arterial disease is essentially clinical, and relies on recognised signs of ischaemia associated with loss of palpable pedal pulses. Although the use of pedal pulses is known to be poorly reproducible15 and is of even less value in the presence of peripheral oedema, it is a method that is easily applied and may in practice be no less robust than quantitative measures that appear to be more precise. A good correlation with both ulcer incidence16 and ulcer outcome17, 19 has been demonstrated when the extent of peripheral
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arterial disease has been assessed using pulse palpation alone.
The value of documenting ankle, brachial pressure index (ABPI) is limited by false elevation of the apparent systolic pressure as a result of arteriosclerosis.
Systolic pressure in the toe is a more reliable guide to reduced perfusion but can be difficult to determine.
Transcutaneous oxygen tension (TcpO2 ) predicts outcome in limbs that are known to be ischaemic,20,21 and has been shown to be reproducible,22 but it is time consuming and the equipment is not widely available.
The result is that no single measure is sufficiently reliable for use on its own.
Subclassification (grading) of peripheral arterial disease. Given the imprecision of the clinical methods, and the limitations of investigational tools, it can be difficult to grade the severity of peripheral arterial disease. The options are to grade peripheral arterial disease (or tissue ischaemia) in one of the following ways:
(i) Present/Absent; (ii) in some form of subjective ranking (such as None, Slight, Moderate, Severe); or (iii) by some means of objective measure of microcirculatory function (e.g. ABPI, toe pressure, TcpO2 ).
The aim is to use a system of grading that is as precise as possible, and also practicable.
The problem with using objective measures of peripheral limb blood flow is that they can be time consuming and impractical during the course of routine clinical care.
They are, therefore, really applicable only to research.
But even when used in a research classification, their value can be limited by their unreliability (poor reproducibility) and lack of specificity, and any attempt to overcome these limitations may result in a formula that appears unduly complicated (see Table 7.4).
Table 7.4 Potential subclassification of peripheral arterial disease
Grade 1 No symptoms or signs of peripheral arterial disease plus Both pedal pulses palpable or ABPI >0.9 and <1.1 Toe brachial pressure index >0.6 or TcpO2 >60 mm Hg Grade 2 Symptoms or signs of peripheral arterial disease, but without critical limb ischaemia: Intermittent claudication (confirmed by arterial imaging) or ABPI <0.9 but with ankle pressure >50 mm Hg or Toe, brachial pressure index <0.6 but systolic toe pressure >30 mm Hg or Other test results compatible with peripheral arterial disease but not critical limb ischaemia Grade 3 Critical limb ischaemia: Systolic ankle pressure <50 mm Hg or Systolic toe pressure <30 mm Hg or TcpO2 <30 mm Hg
Adapted from Schaper10 . These criteria were designed to overcome the inherent imprecision of individual methods, as well as to be compliant with the TASC guidelines for critical limb ischaemia.
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Neuropathy In practice, the assessment of peripheral neuropathy for this purpose is largely based on doc- umentation of loss of sensation.
While the modified Neuropathy Disability Score (NDS) is the best validated in terms of correlation both with other measures of nerve damage and with outcome,16,23 it is time consuming in practice because of its reliance on different measures (tem- perature sensation, vibration perception threshold (VPT), pinprick and ankle tendon reflexes).
Measurement of temperature sensation (warm or cold) threshold is impractical in routine prac- tice and this alone limits the use of the NDS to research.
For the detection of VPT, some will have access to a quantitative measure (e.g. biothesiometer or neurosthesiometer), while the majority will rely on the use of a 128-Hz tuning fork.
VPT correlates with ulcer incidence.16,23,24 For assessment of fine touch (pinprick) sensation, the majority now use a 10-g monofilament, al- though products such as the Neurotip R and Neuropen R are also used.
Remarkably, and despite considerable study, there is no consensus as to which, and to how many, sites these stimuli should be applied, and how the results are interpreted.
Guidelines exist,25 but these are based more on opinion and pragmatism than on scientific evidence.
The evidence to date suggests that testing for fine touch can be limited to two sites , under the first and fifth metatarsal heads26 , or even to one , at the base of the hallux nail.27 At the moment, it has to be accepted that measures of loss of protective sensation from neuropathy are imperfect, but that VPT (biothesiometer), tuning fork, Neurotip and 10-g monofilament all have potentially equivalent and acceptable receiver-operating characteristics.27
Subclassification (grading) of neuropathy. As in the case of arterial disease, the option exists for grading sensation as simply Present/Absent, or to attempt some form of subjective grading into None, Mild, Moderate or Severe. It is acknowledged that significant nerve damage may be present, even when the results of clinical testing are normal.28
Features of the Limb and the Ulcer/Lesion The ulcer/lesion
Bacterial infection The definition, or exclusion, of bacterial infection can also be difficult.
Microbiological stud- ies cannot be used to diagnose infection , only to help identify (some or all of) the organ- isms that are present: the diagnosis is essentially clinical.
The clinical signs are dependent on (i) local signs , pus, exudate and smell, (ii) evidence of soft tissue inflammation, and (iii) systemic reaction , fever, ill health.
Systemic reaction is, however, rare.
The signs of inflammation may also be misleading, because they may be attenuated in those with poor peripheral arterial flow.
On the other hand, patients with neuropathy may have redness and swelling that persist for some weeks after the apparently successful elimination of an infective episode.
Subclassification of infection. Cases of bacterial infection can be subdivided in one of two ways: into the tissues affected or into grades of severity. The overlap between the two is only
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partial. If the first , subclassification according to tissues affected , is used, a distinction may be made between
(i) superficial colonisation (slough and debris on the wound surface without signs of clinical infection); (ii) infection of soft tissue; (iii) infection of bone and joints.