Chronic
wounds
Several conditions are classified as varieties
of chronic wounds, although they may not clearly follow mechanical trauma.
Ulcers
An ulcer is any breach in an epithelial
surface. Chronic ulcers are wounds that fail to heal. In generally, they have a
fibrotic margin and a bed of granulation tissue which may include areas of
slough (necrotic tissue). Ulcers are particularly common in the lower third of
the lower limb and foot. They have a number of different aetiologies, often
being associated with arterial or venous insufficiency or a lack of normal skin
innervation. The wound healing process is delayed by a variety of mechanisms
including infection, mechanical irritation, ischaemia or other metabolic
factors. Ulcers are common in diabetes and rheumatoid arthritis. Treatment
consists of specific management of the underlying cause. The ulcer is managed
either by dressings to allow healing by second intention or by surgical excision
of granulation tissue and split-skin grafting. Recurrence is inevitable if the
underlying cause is not corrected.
These are chronic wounds following tissue
necrosis from pressure. They occur over bony prominences. Their pathogenesis
is identical to compartment syndrome in that they arise where there is
unrelieved pressure in the soft tissues overlying bone such that the external
pressure exceeds capillary perfusion pressure and ischaemic necrosis occurs.
They occur in paraplegic individuals who lack the usual sensory input that
tissue ischaemia is beginning and may lack the ability to move themselves and
relieve this pressure. They also occur in situations where perfusion pressure is
low, such as hypotension and peripheral vascular disease. Sacral and
trochanteric sores occur in bed-bound patients, both paraplegic and
nonparaplegic. Ischial pressure sores occur in chair-bound paraplegics. Patients
with peripheral vascular disease are prone to heel pressure sores. On occasions
almost any bony prominence may be involved. Prevention is better than cure. This
depends on an awareness of pressure sore risk in all patients and the
implementation of appropriate measures that may include turning or lifting the
patient, pressure-relieving mattresses and beds, special seating and cushions,
and educating the patient and their carers in taking responsibility for
pressure relief. When a sore occurs it is essential to identify and correct the
underlying cause. If this can be