How is deep tissue injury diagnosed?

Diagnosis of Deep Tissue Injury

The most accurate diagnosis of deep tissue injury (DTI) requires a combination of thorough history assessment, visual skin examination with attention to skin tone differences, and appropriate imaging studies when indicated.

Clinical Presentation and Assessment

• DTI presents with purple or maroon discoloration in light skin tones, with defined borders and often surrounding erythema 1
• In patients with dark skin tones, persistent erythema and hyperpigmentation, rather than blanching, should be used to identify pressure injury 1
• Thorough history is essential to account for periods of pressure exposure, such as "time down" at the scene or periods when the patient was immobile 1
• DTI often begins in muscle tissue closest to the bone and may not be visible in early stages, with rapid deterioration despite preventive interventions 2
• Most common locations include the skin over the coccyx, sacrum, buttocks, and heels 2

Differential Diagnosis

• DTI must be differentiated from stage 2 pressure ulcers, incontinence-associated dermatitis, skin tears, bruising, hematoma, venous engorgement, arterial insufficiency, necrotizing fasciitis, and terminal skin ulcers 1
• Atypical presentations can lead to delays in necessary aggressive care or overzealous treatment for self-limiting conditions 3
• The National Pressure Ulcer Advisory Panel (NPUAP) guidelines provide descriptions of typical presentations, but many patients present atypically 3

Diagnostic Techniques

Thermographic Assessment

• Early DTI may show an increase of about 0.5°C in skin surface temperatures during initial inflammation, followed by a surface temperature decrease of about 0.2°C during persistent deep tissue ischemia 4
• These temperature differences can be detected by thermographic imaging, potentially allowing earlier diagnosis 4

Anatomical Assessment

• The Compression Intensity Index (CII) can help estimate loading intensity in muscle tissue during sitting in wheelchair users 5
• CII depends on body weight, radius of curvature of the ischial tuberosities, and thickness of underlying gluteus muscles 5
• This index can serve as a practical approximation of loading intensity in muscles of wheelchair-bound or bedridden patients 5

Risk Factors

• Advanced age and lower body mass index are associated with higher risk of DTI compared to other pressure injuries 2
• Patients with impaired motosensory capacities are at particularly high risk 5
• Sustained tissue loading and ischemic injury contribute to DTI development 4

Clinical Pitfalls and Considerations

• Early detection is challenging as lesions may not become visible on the skin surface until reaching an advanced stage 4
• DTI can rapidly deteriorate despite appropriate preventive interventions 2
• By 2010, DTIs accounted for about 9% of all pressure injuries and were more prevalent than stage 3 or 4 pressure injuries 2
• Working knowledge of dermatology is needed to distinguish DTI from other conditions that can present with similar purple hue or rapidly developing eschar 1