Archive for the ‘Arterial Ulcers’ Category

Venous vs. Arterial Ulcers: What’s the Difference?

Friday, July 21st, 2017

Content updated in March 2021

When it comes to arterial and venous ulcers one would think that the difference would be fairly obvious since we are talking about two entirely different etiologies.

Unfortunately, due to the lack of comprehensive chronic wound management education available to clinicians in their post-secondary education, many clinicians may not truly understand or appreciate the unique manifestations associated with each wound type.

Let’s break them down into recognizable criteria so that diagnosis and/or differentiation can be done more accurately.

Determining the etiology, or underlying cause, is key to establishing an appropriate treatment plan. The vascular system can be viewed as a network of plumbing that ensures that the blood — which carries the vital oxygen, nutrition, and other important cells — reaches to all areas and tissues of the body. There is a delivery side (arteries) and a return side (veins).  Let’s dissect arterial ulcers first.

Arterial Ulcers Up Close

Arterial ulcers are a result of arteries (delivery system) becoming narrowed or blocked resulting in reduced supply of blood to the tissues. The most common cause of this narrowing or blockage is atherosclerotic plaque formation on the walls of the arteries. This leads to ischemia and ultimately tissue death.

The ABI (ankle brachial index) results are < 0.9 and can progress to CLI (critical limb ischemia = ABI < 0.5), where tissue viability is not sustainable.  Tissue death can be spontaneous and is usually seen at the most distal aspects of the extremities (i.e. toes) or in conjunction with trauma, which often manifests in areas such as the dorsum of the foot, lateral edge of the foot, lateral malleolus, and anterior tibial area. The ulcers most often present fairly deep with well demarcated edges and even in shape.

The wound beds initially are necrotic with minimal exudate and as they are debrided generally reveal a pale wound base. The surrounding tissue (periwound and lower leg) is often blanched, dry, shiny, and decreased in temperature. Other manifestations may include thickened toenails, loss of hair on the lower leg, cyanosis, and claudication pain.

Treatment generally involves surgical intervention (revascularization or angioplasty) and/or medications to reduce the blockage/narrowing and increase blood flood to reestablish the delivery side of the plumbing network. Let’s now take a look at issue with the return side.

Venous Ulcers Up Close

Unlike the arterial side, which has an inherently higher pressure to push the blood out to the body, the venous side has a much lower pressure to ensure proper return of the blood back to the heart. A number of mechanisms have to be involved and properly functioning. I often refer to them as the 3 P’s: pumps, pressure, and plumbing.

Since the venous side does not have the benefit of the heart to move the blood as effectively as it does for the arterial side, the veins rely on muscles to “pump” the blood uphill against gravity. Every time the calf muscles contract with walking, they squeeze the veins creating pressures upwards of 300 mmHg. If we remember back to physics class, we know a liquid will move from high to low pressure, hence the blood is forced away from the contracting muscle. However, that is not enough. The veins (plumbing) have one-way valves that direct the blood in one direction towards the heart.

When this system of the 3 Ps begins to fail, the blood will begin to pool in the lower extremities and stagnate in the venous system. The intravenous pressure increases and then fluid begins to leak out into the interstitial space resulting in edema. Left unchecked, this will lead to a multitude of changes in the tissue including potential ulcerations.

Unlike arterial ulcers, venous ulcers are not spontaneous, as about 75% are triggered as a result of trauma, burns, cellulitis, and insect bites to name a few; and the other 25% are being studied to what triggers them.

Venous ulcers are typically located on the medial aspect of the lower leg from mid-calf to medial malleolus, but they can be found on other areas of the lower leg. The ulcers are often irregular in shape and shallow in depth.  Wound beds often present with slough, granulation, or a mix of both, and exudate is moderate to heavy initially. The surrounding tissue can be dry and scaly or wet and weepy, and dermatitis is very common.

Pitting edema appears initially, however as the lymphatic system becomes compromised and fibrotic changes occur in the tissue, it will change to non-pitting edema. As red blood cells begin to leak out of the capillaries, rupture, and then release hemoglobin, a reddish-brown discoloration of the skin called hemosiderin staining can begin to appear.

Other manifestations can include such things as atrophie blanche, lipodermatosclerosis, and varicose veins. Treatment requires therapeutic-level graduated compression, calf pump activation, and elevation to reduce the edema, followed by appropriate topical wound management. Some medications such as Trental, Doxycycline, and Vasculera can also be helpful.

As we have shown, arterial and venous ulcers, although both a result of a compromised vascular system, are very different in their etiology and management. You can see the importance of properly differentiating the two ulcers in the overall treatment of these wounds, and I hope this information presented makes that process much easier.  Until next time ……..Heal on!!

Venous, Arterial or Mixed Ulcer…How Do I Know For Sure?

Monday, December 15th, 2014

Proper assessment is essential for differentiating between venous and arterial ulcers.

Your patient has a lower extremity wound. You aren’t sure what exactly you are dealing with. You know you need to measure the ankle-brachial index (ABI), but as you wait for results, some of your wound assessment findings offer clues.

Characteristics of Venous Ulcers

Let’s start with the venous ulcer, typically found on the medial lower leg, medial malleolus and superior to the medial malleolus. Seldom will you see them on the foot or above the knee. They tend to be irregular in shape, are superficial, have a red wound bed, have moderate to heavy amount of exudate and the patient may have no pain or a moderate level of pain. Surrounding skin can be warm to the touch, edematous, scaly, weepy and you may see hemosiderin staining present. An ABI provides a definitive answer and will come back at 0.9.
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