Venous ulcers are wounds that are thought to occur due to improper
functioning of venous valves, usually of the legs. They are the major occurrence
of chronic wounds, occurring in 70% to 90% of leg ulcer cases. Venous ulcers
develop mostly along the medial distal leg, and can be very painful.
Signs and symptoms Edema and fibrinous exudate leads to
fibrosis of subcutaneous tissues with localized pigment loss and dilation of
capillary loops. This is called atrophic blanche. This can occur around ankles
and gives an appearance of inverted champagne bottle to legs. Large ulcers
may encircle the leg. Lymphoedema results from obliteration of superficial
lymphatics. There is hypertrophy of overlying epidermis giving polypoid
appearance, known as lipodermatosclerosis.
Pathophysiology The exact cause of venous ulcers is not
certain, but they are thought to arise when venous valves that exist to prevent
backflow of blood do not function properly, causing the pressure in veins
to increase. The body needs the pressure gradient between arteries and veins in
order for the heart to pump blood forward through arteries and into veins.
When venous hypertension exists, arteries no longer have significantly
higher pressure than veins, and blood is not pumped as effectively into or out of
the area. Venous hypertension may also stretch
veins and allow blood proteins to leak into the extravascular space, isolating
extracellular matrix molecules and growth factors, preventing them from
helping to heal the wound. Leakage of fibrinogen from veins as well as
deficiencies in fibrinolysis may also cause fibrin to build up around the
vessels, preventing oxygen and nutrients from reaching cells. Venous
insufficiency may also cause white blood cells to accumulate in small blood
vessels, releasing inflammatory factors and reactive oxygen species and further
contributing to chronic wound formation. Buildup of white blood cells in small
blood vessels may also plug the vessels, further contributing to ischemia. This
blockage of blood vessels by leukocytes may be responsible for the "no reflow
phenomenon," in which ischemic tissue is never fully reperfused. Allowing blood
to flow back into the limb, for example by elevating it, is necessary but also
contributes to reperfusion injury. Other comorbidities may also be the root cause
of venous ulcers. It is in the crus that the classic
venous stasis ulcer occurs. Venous stasis results from damage to the vein
valvular system in the lower extremity and in extreme cases allows the pressure
in the veins to be higher than the pressure in the arteries. This pressure
results in transudation of inflammatory mediators into the subcutaneous tissues
of the lower extremity and subsequent breakdown of the tissue including the
skin. Wounds of the distal lower extremities
arising from causes not directly related to venous insufficiency may ultimately
fail to heal if underlying venous disease is not properly addressed.
Diagnosis = Classification=
A clinical severity score has been developed to assess chronic venous
ulcers. It is based on the CEAP classification system developed by an
expert panel. A high score gives a poor prognosis.
= Distinction from arterial ulcer= An arterial ulcer tends to occur on
lateral side of distal leg and leg is pulseless and cool. Venous ulceration is
typically seen just above the medial malleolus. Arterial ulcers are seen
distally and over bony prominences. Prevention
Compression stockings appear to prevent the formation of new ulcers in people
with a history of the same. Treatment
The main aim of the treatment is to create such an environment that allows
skin to grow across an ulcer. In the majority of cases this requires finding
and treating underlying venous reflux and National Institute for Health and
Care Excellence recommends referral to a vascular service for anyone with a leg
ulcer that has not healed within 2 weeks or anyone with a healed leg ulcer.
Most venous ulcers respond to patient education, elevation of foot, elastic
compression and evaluation, called the Bisgaard regimen. There is no evidence
for intravenous or by mouth antibiotics for venous leg ulcers. Silver products
are also not typically useful while there is some evidence for cadexomer
iodine creams. = Compression therapy=
Non-elastic, ambulatory, below knee compression counters the impact of
reflux on venous pump failure. Compression therapy is used for venous
leg ulcers and can decrease blood vessel diameter and pressure, which increases
their effectiveness, preventing blood from flowing backwards. Compression is
also used to decrease release of inflammatory cytokines, lower the amount
of fluid leaking from capillaries and therefore prevent swelling, and prevent
clotting by decreasing activation of thrombin and increasing that of plasmin.
Compression is applied using elastic bandages or boots specifically designed
for the purpose. Regarding effectiveness, compression
dressings improve healing. It is not clear whether non-elastic systems are
better than a multilayer elastic system. Patients should wear as much compression
as is comfortable. The type of dressing applied beneath the compression does not
seem to matter, and hydrocolloid is not better than simple low adherent
dressings. Recently there have been clinical studies on a multi-functional
botanical-based ointment in combination with compression therapy in the
treatment of difficult-to-heal wounds, including venous leg ulcers.
Intermittent pneumatic compression devices may be used, but it is not clear
that they are superior to simple compression dressings.
= Pentoxifylline= Pentoxifylline is a useful add on
treatment to compression stockings and may also help by itself. It works by
reducing platelet aggregation and thrombus formation.
= Skin grafts and artificial skin= Two layers of skin created from animal
sources as a skin graft has been found to be useful in venous leg ulcers.
Artificial skin, made of collagen and cultured skin cells, is also used to
cover venous ulcers and excrete growth factors to help them heal. A systematic
review found that bilayer artificial skin with compression bandaging is
useful in the healing of venous ulcers when compared to simple dressings.
= Surgery= A randomized controlled trial found that
surgery "reduces the recurrence of ulcers at four years and results in a
greater proportion of ulcer free time". Local anaesthetic endovenous surgery
using the thermoablation, perforator closure and foam sclerotherapy showed an
85% success rate of healing, with no recurrence of healed ulcers at an
average of 3.1 years, and a clinical improvement in 98% in a selected group
of venous leg ulcers. Prognosis
Venous ulcers are costly to treat, and there is a significant chance that they
will recur after healing; one study found that up to 48% of venous ulcers
had recurred by the fifth year after healing. However treatment with local
anaesthetic endovenous techniques suggests a reduction of this high
recurrence rate is possible. Without proper care, the ulcer may get
infected leading to cellulitis or gangrene and eventually may need
amputation of the part of limb in future.
Some topical drugs used to treat venous ulcer may cause venous eczema.
Current research The current ‘best’ practice in the UK is
to treat the underlying venous reflux once an ulcer has healed. It is
questionable as to whether endovenous treatment should be offered before ulcer
healing, as current evidence would not support this approach as standard care.
EVRA ulcer trial - A UK NIHR HTA funded randomised clinical trial to compare
early versus delayed endovenous treatment of superficial venous reflux
in patients with chronic venous ulceration opened for recruitment in
October 2013. The study hopes to show an increase in healing rates from 60% to
75% at 24 weeks. Research from the University of Surrey
and funded by the Leg Ulcer Charity is currently looking at the psychological
impact of having a leg ulcer, on the relatives and friends of the affected
person, and the influence of treatment. References