Dermatology · Pressure Ulcers
The facts most likely to be tested
A Stage 1 pressure injury presents as intact skin with non-blanchable erythema over a bony prominence.
A Stage 2 pressure injury involves partial-thickness skin loss with exposed dermis, presenting as a shallow, open ulcer or an intact/ruptured serum-filled blister.
A Stage 3 pressure injury involves full-thickness skin loss where subcutaneous fat may be visible, but fascia, muscle, tendon, or bone are not exposed.
A Stage 4 pressure injury involves full-thickness skin and tissue loss with directly palpable or exposed fascia, muscle, tendon, ligament, cartilage, or bone.
An unstageable pressure injury is defined by full-thickness tissue loss in which the base of the ulcer is completely obscured by slough or eschar.
A deep tissue pressure injury (DTPI) presents as persistent non-blanchable deep red, maroon, or purple discoloration indicating damage to underlying soft tissue from pressure or shear.
The primary management for all pressure injuries is pressure redistribution via frequent repositioning, use of support surfaces, and optimization of nutritional status.
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An 82-year-old male with advanced dementia is brought to the clinic for a follow-up. He is bedbound and requires total assistance for transfers. On physical examination, there is a 3 cm ulcer on his sacrum. The wound base is covered in yellow-tan slough and black eschar, preventing visualization of the underlying tissue depth. The surrounding skin is intact with no signs of cellulitis.
What is the most appropriate classification for this patient's pressure injury?
Unstageable pressure injury
The presence of slough and eschar obscuring the base of the wound makes it impossible to determine the depth of tissue loss, which is the defining characteristic of an unstageable pressure injury.
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Etiology / Epidemiology
Occurs in immobile patients due to sustained soft tissue ischemia. Key risks: impaired mobility, malnutrition, and incontinence.
Clinical Manifestations
Localized injury to skin/underlying tissue over a bony prominence. Non-blanchable erythema is the hallmark of Stage 1.
Diagnosis
Diagnosis is clinical. Use the Braden Scale to assess risk; score ≤18 indicates high risk.
Treatment
Frequent repositioning (q2h) and pressure-redistribution surfaces. Do not massage bony prominences.
Prognosis
High risk of osteomyelitis and sepsis. Mortality increases significantly with Stage 3 or 4 ulcers.
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Epidemiology & Etiology
Prevalent in elderly, spinal cord injury, and ICU populations. Primary drivers are mechanical pressure, friction, and shear forces. Chronic hypoperfusion leads to tissue necrosis.
Pertinent Anatomy
Common sites include the sacrum, heels, ischial tuberosities, and greater trochanters. These areas have minimal subcutaneous padding between skin and bone.
Pathophysiology
Sustained pressure exceeds capillary filling pressure (~32 mmHg), causing local ischemia. Reperfusion injury and inflammatory cascades follow. Ischemic necrosis progresses from deep tissue to the surface.
Clinical Manifestations
Stage 1: non-blanchable erythema. Stage 2: partial-thickness skin loss. Stage 3: full-thickness skin loss with visible subcutaneous fat. Stage 4: exposed bone, tendon, or muscle. Red flags include foul odor, purulence, or crepitus indicating deep infection.
Diagnosis
Diagnosis is clinical. Use the Braden Scale for risk stratification. MRI is the gold standard imaging modality if osteomyelitis is suspected.
Treatment
Management requires pressure relief, nutritional optimization (protein/calories), and wound care. Use hydrocolloid dressings for Stage 2. Avoid massage as it damages fragile capillaries. Surgical debridement is required for necrotic eschar.
Prognosis
Complications include osteomyelitis, bacteremia, and cellulitis. Stage 4 ulcers have the highest risk of mortality and require aggressive multidisciplinary management.
Differential Diagnosis
Venous stasis ulcer: located at the medial malleolus
Arterial ulcer: located on distal digits/toes with absent pulses
Neuropathic ulcer: located on plantar surface of foot in diabetics
Incontinence-associated dermatitis: diffuse erythema without pressure point localization
Pyoderma gangrenosum: rapid progression with violaceous, undermined borders