VENOUS LEG ULCERS
There are three types of leg ulcers: diabetic, arterial and venous.
It is estimated that about 70-90% of all leg ulcers are of the venous type cause by blood circulation problems. Venous leg ulcers are therefore the most common and studies have estimated that venous ulcers occur in 1-2% of the population – in other words, about 500,000 North Americans suffer from venous ulcers. Approximately 2/3 of people who develop a venous leg ulcer will go on to develop at least one more.
A venous ulcer can be a serious problem, best described as an open wound which can affect the deeper skin layers.
Venous leg ulcer sufferers can have their quality of life significantly affected; venous ulcers cause discomfort, pain and emotional distress, they lead to absence of work and can become a social disability due to embarrassing odors associated with the ulcers.
The good news is that, of all the different types of leg ulcers, the venous type is the most receptive to better lifestyle and self care practices so it is vital that the patient and caregiver strive to comply with both treatment and self help issues.
A venous ulcer can become a chronic problem where complete healing is difficult to achieve. This provides extra incentive to prevent venous ulcers from occurring in the first place, if possible.
New treatments, maintaining good self care habits and overall support for sufferers are helping to turn things around.
The purpose of this book is to help you understand how a venous ulcer develops, taking into account the various risk factors so that you can take actions to prevent one forming. If you are caring for someone with a venous ulcer, the various treatments and self care practices are highlighted to ensure healing takes place as quickly as possible.
CAUSES OF VENOUS LEG ULCERS
By understanding what causes venous leg ulcers can help in both preventing them and helping them to heal.
BLOOD FLOW IN THE LEG
The basic reason for venous ulcers developing is the lack of oxygen and nutrients reaching a damaged area of the skin on the leg, delaying the healing process. Blood flow carrying oxygen and nutrients in the leg is the critical factor so it is important to understand the blood flow (circulatory system) with the legs.
Two types of vessels carry blood throughout the body:
Arteries carry blood rich in oxygen from the heart to all parts of the body including the legs. These arteries have muscular walls which can squeeze the blood onwards through its own contractions. These arteries break down into smaller (narrower) components often called arterioles or capillaries to ensure the extremities of the body receive oxygen and nutrients, which in turn provide all the energy and material necessary for the cells to stay healthy.
Veins carry the blood that has given up its oxygen and nutrients to the cells of the body and return this depleted blood back to the heart and then on to the lungs for replenishment of oxygen and so the cycle continues. Unlike the arteries, the veins do not have muscles to pump the blood forward. The veins have to rely on other methods to pump the blood such as muscles regularly squeezing the veins.
VEIN PROBLEMS CAUSE VENOUS ULCERS
The force generated by the heart cannot unassisted overcome the forces of gravity and drive the blood back from the legs to the heart. Consequently, another mechanism is involved where the calf muscles of the legs, when they contract, squeeze the deep veins of the leg and drive the blood forward.
Downward flow of the blood is prevented by the presence of valves found at regular intervals of the deep veins. These valves divide the veins into sections, each valve forming a “floor” to support the blood above it.
At the end of each heartbeat, the valves in the deep veins close to stop the blood flowing backward.
These deep veins are connected to one another by perforating veins which carry blood from a superficial vein (nearer the surface and thinner). When the perforating vein meets a deep vein, reverse flow is prevented by a one-way valve.
If and when the perforating vein valves fail, blood from the deep veins system is forced at high pressure into the superficial veins (near the skin surface). This causes the superficial veins to become congested and dilate, leading to the appearance of varicose veins, close to the surface of the skin.
Varicose veins are a very common condition and often minimal treatment is necessary but this is the first part of the process for people who eventually develop venous ulcers.
CHRONIC VENOUS INSUFFICIENCY (CVI)
This is the next step in the venous disease process that can lead to venous leg ulcers.
The continuing demise of the vein valves means that “high pressure” blood during the contraction phase of the calf muscle pumping blood from the deep veins to the superficial veins creates pressure that the smaller superficial veins cannot tolerate.
Extensive damage can be done to the delicate tissues including capillaries (tiny blood vessels).
In the end, the smooth transition of fluid and oxygen exchanges between the small blood vessels is impaired.
The most significant and visual aspect of this process is the blood “pooling” in the lower leg venous system causing swelling. The swelling (edema) of the tissues can cause more fluid and substances to accumulate resulting in less oxygen to the tissues. This lack of oxygen is the major contributor to the formation of a venous leg ulcer.
DIAGNOSIS AND MONITORING
Observation alone permits diagnosis of an existing leg ulcer. Also, the symptoms listed previously can provide those all-important warnings that the person is at risk.
The physician and nurse have a range of objective ways of providing more in-depth information as to the nature of the problem; a commonly used test is the Doppler test to measure blood flow around the ankle, using a Doppler ultrasound device.
This device is the size of a large pen or pencil. It is used to listen to blood flow across your skin through the aid of a gel-like substance which is applied between the skin and the Doppler probe, which is a sort of sophisticated microphone.
The Doppler device is used for one of the most important blood circulatory diagnostic tests called the ANKLE BRACHIAL PRESSURE INDEX (ABPI) which tells the medical team how well your arteries are functioning. This is important because it allows the physician to determine how well fresh arterial (oxygenated) blood is getting to your legs and feet. With this information the medical team can decide on the appropriate treatment to heal the ulcer. More specifically, the physician can determine whether or not compression therapy should be used.
Aside from the Doppler and other tests, the medical team will keep records to monitor progress of the leg ulcer. By doing this, the progress of the ulcer can be evaluated and appropriate changes in treatment made to speed up healing.
This has to be done as objectively as possible, using measuring devices. A simple way is to use a ruler to measure the maximum and minimum widths. Alternatively, the outline of the ulcer can be traced on transparent material.
Here are some of the guidelines the medical team uses to document and subsequently monitor the ulcer: