Rendimiento Académico: Factores que inciden en los niveles de logro

Diabetic foot ulceration often result from a combination of two or more risk factors occurring together, the most important risk factors being neuropathy, foot deformities, peripheral arterial disease and trauma⁶¹.

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Ulcers can occur on any part of the foot but about half develop on the plantar side (including the toes) and the other half on other areas. Diabetic foot ulcers are divided into neuropathic, neuro-ischaemic and purely ischaemic lesions with partly overlapping pathophysiology.

PAD is a major factor contributing to the pathogenesis of foot ulceration and subsequent amputation in countries such as the USA, UK and Finland³³. However, in developing countries combination of factors such as neuropathy, foot deformity, trauma and inappropriate foot wear predominate^38,62. Various studies in Africa have shown that foot complications are mostly caused by infection and/or peripheral neuropathy⁶¹. In Nigeria, peripheral neuropathy is the major risk factor underlying diabetic foot ulcers as was shown in the studies done on the risk factors for foot ulceration amongst Nigerians with diabetes^63-65.

Studies done by Akanji et al in university college Hospital in 1990 showed prevalence of neuropathy to be 68% while that of ischaemia to be 54% in persons presenting with major diabetic foot lesions.

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Diabetes Mellitus

Neuropathy

Angiopathy

Motor Sensory Autonomic

Limited joint

mobility Postural and coordination deviation

Decreased pain sensation and

propriocepsis

Diminished sweating Foot deformities stress

and shear pressure Dry skin fissures Callus

Trauma

Foot ulcers Inadequate

footwear, non- compliance, neglect,

unawareness, lack of patient and staff

education Amputation

Micro Angiopathy Peripheral Vascular disease

Altered blood flow regulation

Ischaemia

Trauma Gangrene

Infection

Fig. 1: Pathway to diabetic foot ulceration adopted from reference⁶¹

xxxviii 2.9.1. Classification of diabetic foot ulcers

Ulcer classification helps in the assessment of treatment schemes and in standardization and analysis of multicenter research⁶⁶. Many different classification systems have been documented for daily practice. These include the Wagner wound classification system and the University of Texas (UT) diabetic wound classification system; both provide descriptions of ulcer to varying degrees and are easy to use among health care providers and both can give guidance to planning treatment strategies.⁶⁶

The Wagner classification is the simplest and most widely used. It is based strictly on ulcer description and depth and ignores the importance of infection and ischaemia in determining severity of the ulceration. It uses grades 0 – 5 as shown in Table 2.2.

The university of Texas Diabetic wound classification takes into consideration the ulcer depth and the presence or absence of infection and ischaemia and is a better predictor of outcome. It is shown in Table 2.3.

Another classification system is the PEDIS, introduced in 2003 by the International Working Group on the Diabetic Foot (IWGDF), developed to facilitate communication in the field of research⁶⁷. It uses five parameters which are relevant items for research projects in diabetic foot ulcers. These parameters include: perfusion, extent/size of wound, depth/tissue loss, infection and sensation. For each parameter, a grading system is provided that describes severity within each group and this is shown in Table 2.4.

Other classification system, include the Van Acker/Peter classification (VA/P), Knighton’s, Forrest’s, Gibbon’s,Frykberg’s, Coleman’s and the Ten-level Seattle wound classification system⁶⁸.

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Table 2.2: The Wagner system of ulcer classification⁶⁹ Grade Description

Grade 0 High-risk foot, no ulcer present.

Grade 1 Superficial ulcer, not infected

Grade 2 Deep ulcer with or without cellulitis but no abscess or bone involvement

Grade 3 Deep ulcer with bone involvement or abscess formation.

Grade 4 Localized gangrene (toe, fore foot, heel) Grade 5 Gangrene of the whole foot

Table 2.3: University of Texas Wound Classification System⁷⁰ A. Stages

Stage A-No infection or Ischeamia Stage B-Infection present

Stage C- Ischeamia present

Stage D- Infection or Ischeamia present B. Grading

Grade 0- Epithelialized wound Grade 1- superficial wound

Grade 2- wound penetrates to tendon or capsule Grade 3- Wound penetrates to bone or joint

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Table 2.4: PEDIS system; wound classification⁶⁷ Perfusion:

Grade 1: No symptoms or signs of PAD in the affected foot

Grade 2: Symptoms or signs of PAD, but not of critical limb ischaemia (CLI)

Grade 3: Critical limb ischaemia, as defined by:

 Systolic ankle blood pressure < 50mmHg or

 Systolic toe blood pressure < 30mmHg or

 Tcp02< 30mmHg Sensation:

Grade 1: No loss of protective sensation on the affected foot detected, defined as presence of sensory modalities described below.

Grade 2: Loss of protective sensation on the affected foot is defined as the absence of perception of one of the following tests in the affected foot.

 Absent pressure sensation

 Absent vibration sensation Infection:

Infection of diabetic foot ulcers is defined as invasion and multiplication of microorganisms in body tissues associated with tissue destruction or a host inflammatory response.

Grade 1: No symptoms or signs of infection

Grade 2: Infection involving the skin and subcutaneous tissue only Grade 3: Erythema > 2cm plus one of the items described above

(swelling, tenderness, warmth, discharge) or infection involving structures deeper than skin and subcutaneous tissues such as abscess, osteomyelitis, septic arthritis, fasciitis.

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Grade 4: Any foot infection with the signs of a systemic inflammatory response syndrome (SIRS).

Extent/Size

Wound size (measured in square centimetres) should be determined after debribement, if possible. The outer border of the ulcer should be measured from the intact skin surrounding the ulcer.

Depth and tissue loss

Grade 1: Superficial full thickness ulcer, not penetrating any structure deeper than the dermis.

Grade 2: Deep ulcer, penetrating below the dermis to subcutaneous structures involving fascia, muscle or tendon.

Grade 3: All subsequent layers of the foot involved, including bone and/or joint.