Pressure sores

Question 1

What are pressure sores?

Answer 1

Also called pressure ulcers. Localised injury to the skin, usually over a bony prominence, as a result of pressure.

Question 2

What is the aetiology of pressure sores? (x4)

Answer 2

• Pressure over bony prominences
• Shear: can cause direct damage which can predispose to pressure sore, or can lead to tearing of vasculature and contributing to pressure-induced damage
• Friction: produces tissue damage
• Moisture: faecal/urinary incontinence; can precipitate dermatitis which can later manifest as a pressure sore

Question 3

What are the risk factors for pressure sores? (x4)

Answer 3

Older people (limited mobility), impaired sensation (diabetic neuropathy), impaired tissue perfusion (peripheral vascular disease), admission to long-term care facilities.

Question 4

What is the pathophysiology of pressure sores? (x3 mechanisms)

Answer 4

• Where pressure is applied and exceeds capillary pressure, there is ischaemia and cell damage.
• May be associated with pressure-related blockage of lymphatic flow leading to accumulation of waste products
• Prolonged pressure may directly damage cells leading to cell death

Question 5

What is the pathophysiology of deep pressure sores?

Answer 5

Highest pressures are seen in the deep tissues, especially along bony prominences. These deep tissues also appear to be most susceptible to pressure damage. Consequently, pressure often causes extensive deep tissue injury with little apparent damage initially in the more superficial tissues. These deep tissue injuries may then initially present as an area of dark purple discoloration with intact overlying skin.

Question 6

What does slough refer to dermatologically?

Answer 6

Yellow/white appearance of necrotic tissue.

Question 7

What are the signs and symptoms of pressure sores? (x4 +1)

Answer 7

• Can be best described with staging of pressure sores:
• GRADE 1: localised erythema or purple discolouration of intact skin which may be painful
• GRADE 2: blister/shiny/dry shallow ulcer involving partial loss of dermis without sloughing
• GRADE 3: extends to subcutaneous layer with some slough; no bone/tendon/muscle involvement
• GRADE 4: involvement of fascia/bone
• Indicators of infection: warmth, development of odour, excess exudate

Question 8

Where do pressure sores present in a patient (i) lying on their back, (ii) lying on their side, and (iii) sitting?

Answer 8

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Question 9

What are the investigations for pressure sores? (x4)

Answer 9

• Clinical diagnosis
• Wound swab is signs of infection
• BLOODS: raised ESR and WCC suggests osteomyelitis (infection of bone)
• Deep tissue biopsy: definitive method for diagnosing infection
• MRI: appropriate when bony involvement