WOUND CLASSIFICATION SYSTEMS Differential Diagnosis of Wound Etiology

WOUND CLASSIFICATION SYSTEMS

Avoid using any wound classifi cation system “in reverse” as a method of measuring wound healing. Biologically, wounds do not heal in the manner suggested by reversing a staging system, and classifi cation systems were not developed for use in assessing healing. This inappropriate use can actually hinder tracking of progress.

The fi ve wound classifi cation systems presented in this chapter are^116–118

1. Classifi cation by depth of tissue injury 2. NPUAP pressure ulcer staging criteria

3. Wagner staging system for grading severity of dysvascular ulcers

4. University of Texas Treatment-Based Diabetic Foot Classifi cation System

5. Marion Laboratories red/yellow/black color system. Table 3.2 presents the four wound classifi cation system discussed in this section and identifi es the types of wounds most appropriate for use with each system.

Classifi cation by Depth of Tissue Injury

In Chapter 2, we identified four types of wounds, distin- guished by depth of tissue injury: superficial, partial-thickness, full-thickness, and subcutaneous (see Table 3.3). This

“generic” classification system identifies specific anatomic levels of the tissues involved, but does not report their condition or color. It is commonly used for wounds that are not categorized as pressure ulcers or neuropathic ulcers, such as skin tears, donor sites, vascular ulcers (venous ulcers in particular), surgical wounds, and burns. However, in some cases, these classifications do have parallels in other systems.

For example, superficial wounds are equivalent to NPUAP stage I pressure ulcer or, on the Wagner scale, a grade 0 dysvascular ulcer.

Anatomic depth of tissue loss is predictive of healing.^29,69 Superfi cial wounds are often resolved by subcutaneous infl am- matory processes, with the exception of wounds with intact skin that also have deep tissue injury and can manifest later as deep wounds. Partial-thickness wounds, which heal by epithelialization, heal faster than full-thickness and subcutaneous wounds.

Full-thickness and subcutaneous wounds heal by secondary muscle pump function. They usually occur on the medial side

of the lower leg and are accompanied by edema that may be weeping. Skin changes including hemosiderosis and hyper- keratosis are signs that often accompany this condition. They often take a prolonged time to heal, frequently months to more than a year, and they commonly recur. Venous refl ux testing (Chapter 6) confi rms this diagnosis.

Arterial ulcers result from inadequate perfusion of skin and subcutaneous tissue, and they are primarily a complication of peripheral arterial disease (PAD). A punched-out appearance, with a pale, dry poorly perfused base is characteristic of arterial ulcers. The foot and leg may be cold, pale or bluish, with shiny, taut skin and dependent rubor, and possibly gangrenous toes.

Pain is common, especially after exertion or leg elevation. A decreased ABI confi rms the diagnosis (see Chapter 6). Arterial insuffi ciency may be slowly or rapidly progressive, and early diagnosis is critical to prevent further tissue death.¹¹⁵

Diabetic foot ulcers are a major complication, occurring in approximately 15% of people with DM, and are a preced- ing factor in approximately 85% of lower limb amputations.

Poor diabetes control may result in PN and vascular disease.

PN raises the likelihood of both trauma to the foot and inability to detect abnormal pressures that may predispose patients to develop foot ulcers. Sensory testing and vascular testing provide a differential diagnosis for neuropathic ulcers.

Wound Classifi cation Systems

A wound classifi cation system is a hierarchical system that classifi es or categorizes wounds by severity according to different characteristics, such as level of tissue involvement, color of wound, and so forth. Documenting assessment fi ndings and diagnosing wounds following a standardized classifi cation system allows you to communicate effectively with other health-care providers.

Note that each wound classifi cation system was researched and designed for use with one specifi c wound type; thus, it is inappropriate to use the same classifi cation system for all wounds you encounter. Since each system measures only one characteristic of the wound (e.g., the depth of tissue loss), it should not be viewed as a complete assessment independent of other indicators. A complete wound assessment and written description is still required.

Classifi cation by Depth of Tissue Loss 3.3

TABLE

Thickness of Skin Loss Defi nition Clinical Examples/Healing Process

Superfi cial wounds Effects only the epidermis Sunburn, stage I pressure ulcer, stage 0 diabetic ulcer; heal by infl ammation

Partial-thickness skin loss Extends through the epidermis, into, but not through, the dermis

Skin tears, abrasions, tape damage, blisters, perineal dermatitis from incontinence; heal by epidermal resurfacing or epithelialization

Full-thickness skin loss Extends through the epidermis and dermis into subcutaneous fat and deeper structures

Donor sites, venous ulcers, surgical wounds; heal by granulation tissue formation and contraction Subcutaneous tissue wounds Additional classifi cation level for full-

thickness wounds that extend into, or beyond, the subcutaneous tissue

Surgical wounds, arterial/ischemic wounds; heal by granulation tissue formation and contraction

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intention, a combination of fi broplasia or granulation tissue formation and contraction.

At the beginning of Chapter 2, we defi ned a chronic wound as “one that deviates from the expected sequence of repair in terms of time, appearance, and response to aggressive and appropriate treatment”.¹¹⁹ When the response to wounding does not conform to the described acute phased model of wound recovery after a period of 2 to 4 weeks, the wound may have become “stuck” and unable to progress through the phases of healing without intervention. This wound would then be classifi ed as a chronic wound.

The typical medical model for diagnosing chronic wounds is to use the pathophysiology associated with ulcers. For example, there are ischemic arterial ulcers, diabetic ulcers (both vascular and neuropathic), pressure ulcers, vasculitic ulcers, venous ulcers, and rheumatoid ulcers. All of the ulcers listed in Exhibit 3.4 are considered chronic wounds.

National Pressure Ulcer Advisor Panel Pressure Ulcer Staging System

The NPUAP pressure ulcer staging system is probably one of the most widely known wound classifi cation systems. It was developed by the NPUAP and used by the Agency for Health Care Research and Quality (AHRQ) based upon an earlier pressure

ulcer staging system proposed by Shea. The earlier four-stage systems described pressure ulcers using depth of anatomic tissue loss and the involvement of soft tissue layers and was rede- fi ned in 2007 by adding two stages on deep tissue injury and unstageable pressure ulcers with descriptions of each. It is a diagnosis of severity of tissue insult before healing starts. The NPUAP system is most often applied to pressure ulcers, but it is also used (sometimes inappropriately) to classify other types of wounds. It is best used for wounds with a pressure or tissue perfusion etiologic factor, such as with arterial/ischemic wounds and diabetic neuropathic ulcers.

The NPUAP staging system is widely accepted and commonly used to describe wound severity, organize treatment protocols, and select and reimburse treatment products for pressure ulcers. For example, the AHRQ adopted the NPUAP staging system for use in two sets of clinical practice guidelines.^71,121 The new defi nitions are included in the 2009, International Prevention and Treatment of Pressure Ulcer Clinical Practice Guideline with the addition of the term category/stage. Figures 3.9, 3.13, 3.17, and 3.22–3.28 present diagrams and photos illustrating the NPUAP and European Pressure Ulcer Advisory Panel (EPUAP) 2009 Pressure Ulcer Classifi cation system.²⁶

The pressure ulcer staging system has many problems. For example, the defi nition of a category/stage I pressure ulcer does not account for the severity of soft tissue trauma beneath the unbroken skin, such as that seen with purple ulcers. Thus, NPUAP proposes that this trauma should be referred to as

“ suspected pressure-related deep tissue injury under intact skin” or “suspected deep tissue injury (sDTI).”⁹⁷

Furthermore, category/ stage I lesions vary in presentation and pose validity concerns. For example, some stage I lesions indicate deep tissue damage that is just beginning to manifest on the skin, whereas others indicate only superfi cial insult in which damage may be reversible and may not be indicative of underlying tissue death. There are also problems reliably assessing stage I ulcers in dark-skinned patients. Identifi cation and interpretation of skin color changes in darkly pigmented skin require special assessment strategies described later in this chapter. An ultrasound scanner image that can detect tissue damage and provide early identifi cation of stage I pressure ulcers is demonstrated in Figure 3.29A–C). Chapter 26 discusses has information to interpret with 1

FIGURE 3.22 Diagram Normal Skin © National Pressure Ulcer Advi- sory Panel. 2007.

EXHIBIT 3.4

Examples of Chronic Wounds

● Ischemic arterial ulcers

● Diabetic vascular and neuropathic ulcers

● Venous ulcers

● Vasculitic ulcers

● Rheumatoid ulcers

● Pressure ulcers

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FIGURE 3.25 A: Diagram Stage III: Full-thickness tissue loss. Subcutaneous fat may be visible but bone, tendon, and muscle are not exposed. Slough may be present but does not obscure the depth of tissue loss. May include undermining and tunneling. Further description: The depth of a stage III pressure ulcer varies by anatomical location. The bridge of the nose, ear, occiput, and malleolus do not have subcutaneous tissue and stage III ulcers can be shallow. In contrast, areas of signifi cant adiposity can develop extremely deep stage III pressure ulcers. Bone/tendon is not visible or directly palpable. (Copyright © National Pressure Ulcer Advisory Panel. 2007.) B: Photo of category/stage III pressure ulcer.

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2 B

FIGURE 3.24 Diagram Stage II: Partial-thickness loss of dermis presenting as a shallow open ulcer with a red pink wound bed, without slough. May also present as an intact or open/ruptured serum-fi lled blister. Further description: Presents as a shiny or dry shallow ulcer without slough or bruising. This stage should not be used to describe skin tears, tape burns, perineal dermatitis, maceration, or excoriation. Bruising indicates sDTI. (Copyright © National Pressure Ulcer Advisory Panel. 2007.)

FIGURE 3.23 Diagram Stage I: Intact skin with nonblanchable redness of a localized area usually over a bony prominence. Darkly pigmented skin may not have visible blanching; its color may differ from the surrounding area. Further description: The area may be painful, fi rm, soft, warmer, or cooler as compared to adjacent tissue. Stage I may be diffi cult to detect in individuals with dark skin tones. May indicate “at risk” persons (a heralding sign of risk). (Copyright © National Pressure Ulcer Advisory Panel. 2007.)

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the information shown on the scan. Category/Stage II pressure ulcers are lesions that exhibit partial-thickness skin loss or a blister, which leads to superfi cial and partial-thickness damage to the epidermis and dermis²⁶ (Fig. 3.12). Pressure ulcers will present with a shallow open red/pink wound bed, without slough or maybe an open/ruptured serum-fi lled blister. Theoretically, pressure ulcer trauma starts at the bony tissue interface and works outward, eventually manifesting as damage on the skin.

Conversely, stage II lesions start at the epidermis or skin and can progress to deeper layers. Figure 3.20A shows a bloody fl uid-fi lled blister but it cannot be staged because the tissue under blister is not visible. Figure 3.20C shows the same wound as Figure 3.20A with the blister opened and it is now stageable.

EPUAP defi nes incontinence ulcers as “skin lesions not caused by pressure or shear.”¹²² This information is introduced here as a clarifi cation to reduce confusion and misdiagnosis

of lesions in this category. Distinguishing features of lesions caused by incontinence include location (not necessarily over bony prominences), edema, wet skin, incontinence of urine or feces, and color (more purple)¹²² (Fig. 3.21).

Pressure ulcers with necrotic tissue fi lling the wound bed are full-thickness wounds, category/stage III or category/stage IV (Fig. 3.26B). Staging of pressure ulcers covered by eschar and necrotic tissue cannot be accomplished until removal of necrotic tissue allows for determination of the extent of depth of tissue involvement and are designated as “unstageable—

depth unknown” (Fig. 3.28C). They remain unstageable until viable tissue is observed at the base of the wound. Then they are staged based on the anatomical structures exposed. Likewise, with deep tissue injuries, associated with pressure, the level of tissue insult cannot be categorized/staged until the full impact of the lesion manifests. It is also diffi cult to defi ne stages in

FIGURE 3.27 Diagram Suspected Deep Tissue Injury: Purple or maroon localized area of discolored intact skin or blood- fi lled blister due to damage of underlying soft tissue from pressure and/or shear. The area may be preceded by tissue that is painful, fi rm, mushy, boggy, warmer, or cooler as compared to adjacent tissue. Further description: Deep tissue injury may be diffi cult to detect in individuals with dark skin tones. Evolution may include a thin blister over a dark wound bed. The wound may further evolve and become covered by thin eschar. Evolution may be rapid exposing additional layers of tissue even with optimal treatment. (Copyright © National Pressure Ulcer Advisory Panel. 2007.)

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1 2

3 4

FIGURE 3.26 A: Diagram Stage IV: Full-thickness tissue loss with exposed bone, tendon, or muscle. Slough or eschar may be present on some parts of the wound bed. Often include undermining and tunneling. Further description: The depth of a stage IV pressure ulcer varies by anatomical location. The bridge of the nose, ear, occiput, and malleolus do not have subcutaneous tissue and these ulcers can be shallow. Stage IV ulcers can extend into muscle and/or supporting structures (e.g., fascia, tendon, or joint capsule) making osteomyelitis possible. Exposed bone/tendon is visible or directly palpable. Copyright © (National Pressure Ulcer Advisory Panel. 2007.) B: Photo of category/stage IV pressure ulcer. Necrotic fatty tissue. (Copyright

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FIGURE 3.29 Using the EPISCAN, pressure ulcers have been found to develop in the subcutaneous tissue over a hard prominence, typically a bone, and then spread out through the dermis to the epidermis, where at some point, an open wound often develops. Studies have shown that the early phases of pressure ulcer development can be used to initiate earlier and more targeted intervention, and that this can signifi cantly and cost-effectively reduce the occurrence of open pressure ulcers. (Copyright P. Wilson.)

patients with supportive devices because of the diffi culty in accurately assessing the wound without removal of the devices.

Finally, accurate, meaningful communication is diffi cult, because clinicians may not have the experience necessary to recognize the various tissue layers that identify the category, stage, or grade. In addition, clinicians may defi ne stages dif- ferently. Staging requires practice and skill that develops with

time spent examining wounds. The NPUAP has a teaching aide for staging pressure ulcers available on its Web site www.

npuap.org.

We noted earlier that classifi cation systems are misapplied when used to monitor healing. This is as true for the NPUAP system as it is for other classifi cation systems. For example, a category/stage IV pressure ulcer cannot “heal” and become a FIGURE 3.28 A: Diagram Unstageable: Full-thickness tissue loss in which the base of the ulcer is covered by slough

(yellow, tan, gray, green, or brown) and/or eschar (tan, brown, or black) in the wound bed. Further description: Until enough slough and/or eschar is removed to expose the base of the wound, the true depth, and therefore stage, cannot be determined. Stable (dry, adherent, intact without erythema or fl uctuance) eschar on the heels serves as “the body’s natu- ral (biological) cover” and should not be removed. (Copyright © National Pressure Ulcer Advisory Panel. 2007.) B: Dia- gram of unstageable pressure ulcer. (Copyright © National Pressure Ulcer Advisory Panel 2007.) C: Photo of Unstageable pressure ulcer. (Copyright © B.M. Bates-Jensen.)

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Grade 0 I II III S

T A Preulcerative or postulcerative lesion; completely epithelialized

Superfi cial wound (not involving tendon, capsule or bone)

Wound penetrating to tendon or capsule

Wound penetrating to bone or joint

A B Infection Infection Infection Infection

G C Ischemia Ischemia Ischemia Ischemia

E D Infection and Ischemia Infection and Ischemia Infection and Ischemia

Infection and Ischemia

Reprinted with permission from Armstrong DG, Lavery L, Harkless LB. Validation of a diabetic wound classifi cation system: the contribution of depth, infection, and ischemia to risk of amputation. Diabetes Car PMID: 9589255 [PubMed - indexed for MEDLINE]. May 1998;21(5):855–859.

University of Texas, San Antonio Classifi cation 3.5

TABLE

category/stage II pressure ulcer. The purpose of staging pressure ulcers is to document the maximum anatomic depth of tissue involved (after all necrotic tissue is removed) and to determine the extent of tissue damage only. Staging can also aid examination of the wound severity, but not wound healing.

The SWHT, PUSH, and the BWAT are tools for monitoring wound healing attributes described in Chapter 6.

Wagner Ulcer Grade Classifi cation

The Wagner Ulcer Grade Classifi cation system is used to estab- lish the presence of depth and infection in a wound. This system was developed for the diagnosis and treatment of the

CLINICAL WISDOM

Reverse Staging or Back Staging of Pressure Ulcers Reverse staging or back staging of pressure ulcers is an inappropriate way to defi ne a healing wound. Once the ulcer is staged, the stage and wound severity diagnosis do not change;

rather, correct terminology is healing stage II (or III or IV).

Grade Characteristics

0 Preulcerative lesions; healed ulcers; presence of bony deformity 1 Superfi cial ulcer without subcutaneous tissue involvement

2 Penetration through the subcutaneous tissue; may expose bone, tendon, ligament, or joint capsule 3 Osteitis, abscess, or osteomyelitis

4 Gangrene of digit

5 Gangrene of the foot requiring disarticulation

Wagner Ulcer Grade Classifi cation 3.4

TABLE

dysvascular foot.¹¹⁸ It is commonly used as an assessment instru- ment in the evaluation of diabetic foot ulcers, but is limited in its ability to identify and describe vascular disease and infection as independent risk factors.¹²³ The system includes six grades, progressing from 0 to 5 in the order of severity of breakdown in the diabetic, neuropathic foot (Table 3.4). The 0 classifi cation evaluates for predisposing factors leading to breakdown; along with grades 1–3, it is used for risk management. Photos of the grades appear in Chapter 12.

The University of Texas Treatment-Based Diabetic Foot Classifi cation System

The University of Texas Treatment-Based Diabetic Foot Classifi cation System is a matrix of grades used for situations in which neuropathy is present and information is needed about infection, circulation (PVD), and the combination of infection and ischemia in order to assign risk and predict outcome (Table 3.5).¹¹⁷ Each ulcer is given both a numeric grade (0–III) and an alphabetic stage (A–D). Letter “A” denotes wound depth. Other letters denote ischemia and infection categories.

However, this system lacks consideration of biomechanics and neuropathy. Analysis of this system reveals that it is a better pre- dictor of group outcome than of individual patient outcome.¹¹⁷

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Dalam dokumen Sussman Physical Therapy, Inc. (Halaman 98-105)