Differentiating Arterial vs. Venous Ulcers

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Introduction

This learning module will discuss the three most common types of leg/foot ulcers: venous stasis ulcers, neurotrophic (diabetic), and arterial (ischemic ulcers). Additionally, we will cover the main differences between arterial vs. venous ulcers, as this can become quite confusing at times. Following, we will review the circulatory system’s pathophysiology, ensuring an understanding of blood flow and the vital role arteries and veins have on circulation. Lastly, we will discuss the presentations of each type, the common causes, risk factors, generalized treatments, and patient education.  

As you work your way through the section questions, I hope you will be able to recall some patients you have cared for and gain a better understanding of why the wounds presented as they did.  

Okay, let’s get started!  

Circulatory Pathophysiology Review 

Pulmonary circulation is responsible for the circulation of oxygen-poor blood from the heart’s right ventricle going to the lungs via the pulmonary artery and then returning oxygen-rich blood back to the heart’s left atrium via the pulmonary vein (3). 

Systemic circulation is responsible for circulating the oxygenated blood from the heart to all the body systems. 

The vascular system supplies oxygen to the body and removes water through 5 types of blood vessels (arteries, arterioles, veins, venules, and capillaries (the smallest vessels- linking arterioles and venules). 

Venous Stasis Ulcers 

Pathophysiology

Venous ulcers begin due to capillary bed distention that is caused by increased pressure; causing a leakage of fibrinogen and eventually impeding the delivery of oxygen and nutrients, resulting in a hypoxic injury. Typically, this leads to fibrosis and then ulcerations. 

These ulcers are often chronic, and patients often battle from weeks to years. Cleveland Clinic states 500,000 to 600,000 people in US are affected by venous ulcers, and venous ulcers account for 80-90% of all leg ulcers. The financial burden of venous ulcers is estimated to be $2 billion per year in the United States (2).  

A common mishap is the confusion between arterial vs. venous ulcers, so let’s break them down individually by signs and symptoms, complications, risk factors, treatments, and patient education.  

Signs and Symptoms (1) 

• Wounds are usually located below the knee, can be one or both legs 
• Shallow painful ulcerations usually over the medial malleolus 
• Wound bed is beefy red and often has fibrin present 
• Borders are irregular, surrounding tissue is often discolored and swollen (can even feel warm) 
• Skin usually appears shiny and tight depending on edema  
• Elevation improves edema and relieves pain 
• Normal pulses are present  

Complications

• Cellulitis  
• Osteomyelitis 
• Sepsis  
• Amputation  

Risk Factors

• Poor Circulation  
• Venous insufficiency 
• Clotting disorders 
• Diabetes 
• Renal failure 
• Elevated cholesterol and triglycerides 
• Lymphedema 
• Obesity 
• Infections 
• Smoking 
• Uncontrolled hypertension 
• Inflammatory diseases (vasculitis, lupus, etc) 

Treatments

Compression treatments are the most widely used treatment for venous stasis ulcers. This could include ace wraps, compression stockings, and Unna boots. 

Dressings are ordered based on wound characteristics (do we need to dry the wound or add moisture). Dressings may include: 

• Moist to moist dressings 
• Hydrogels/hydrocolloids 
• Alginate dressings 
• Collagen wound dressings 
• Debriding agents 
• Antimicrobial dressings 
• Composite dressings 

Patient Education

• Inspect your feet and between your toes, look for cracks, cuts, blisters, redness, increased warmth, calluses 
• If you are a diabetic, see a podiatrist on a regular basis 
• Apply a lanolin-based cream to your legs and feet to prevent dry skin and cracking. Do not apply lotion between your toes or on areas where there is an open sore or cut.  
• If you have an open area, gently wash with mild soap and water daily, washing helps loosen dead skin and debris 
• If you cut your own toenails, do it after bathing when nails are soft and cut straight across 

Arterial (Ischemic) Ulcers 

Pathophysiology

The two most common causes of arterial (or ischemic) ulcers are progressive atherosclerosis and emboli. Other pathologic processes can cause arterial obstruction, leading to arterial insufficiency symptoms, but remember, the reason for all the issues is due to reduced blood flow which leads to ischemia of the affected extremity. Arteries carry the oxygen and nutrient-rich blood supply to the extremities and this process is blocked by some physiological reason (5).  

Since we now know how to identify and treat venous ulcers, we are one step closer to understanding the main differences between arterial vs. venous ulcers, let’s keep going! 

Signs and Symptoms

• Wounds are usually located distally on the dorsum of the foot or toes 
• Wound bed is usually grayish in color, and granulation tissue appears unhealthy 
• Little to no bleeding is noted 
• Painful, especially at night when supine-putting leg dependent will relieve pain (opposite of venous ulcers) 
• Pale skin, hairlessness 
• Diminished pulses, cool to touch 
• Intermittent claudication- is a reproducible discomfort of a defined group of muscles (usually lower legs) that is induced by exercise and relieved with rest (2) 

Remember, the extremity is not getting perfusion which limits, oxygen and nutrients! 

Complications

• Infection/gangrene 
• Tissue necrosis 
• Amputation  

Risk Factors

• Diabetes mellitus 
• Age (risk increases after 40) 
• Arteriosclerosis  
• Vasculitis  
• Foot deformity and callus formation which causes areas of high pressure 
• Obesity 
• peripheral neuropathy 
• Smoking 
• Limited joint mobility/ any trauma to lower extremities  

Treatments

Treatments vary, depending on the severity of the arterial disease, but the goal is to increase circulation. Ischemic wounds, unlike venous, are usually kept dry to reduce the risk of infection.  

• Endovascular therapy, bypass surgery, revascularization 
• Medications that cause blood vessels to dilate 
• Modify contributing factors (smoking, weight, control DM, take meds as prescribed) 
• Boot pumps  
• Hyperbaric oxygen therapy (HBOT)  
• Negative pressure wound devices (wound vacs)  
• Monitor signs and symptoms of infection, ensuring no tunneling or tracking 
• Amputation- last resort 

Patient Education

• Examine feet (especially between the toes) and legs daily for any unusual changes in color or the development of sores  
• Manage blood pressure, cholesterol, triglyceride, and glucose levels 
• Quit smoking 
• Avoid cold, caffeine, nicotine, and constrictive garments  
• Walking (most doctors want these patients to walk daily) 
• Take medications as directed  
• Teach patient signs and symptoms of wound infection 

Neurotrophic (Diabetic) Ulcers 

Pathophysiology

Although it does not present as similarly between arterial vs. venous ulcers, neurotrophic ulcers are quite common. Neurotrophic or diabetic ulcers may have neuropathic, vascular, and immune system components. Most of these ulcers are caused by a hyperglycemic state due to diabetes (1). When patients are in a hyperglycemic state, it produces oxidative stress on nerve cells and leads to neuropathy, common in diabetic patients. As the nerve damage continues, it damages the nerve cell protein and leads to further ischemia, resulting in even more impaired healing for wounds. These cellular changes manifest in 3 ways: 

1. Motor nerve damage- leads to an imbalance of flexors and extensors, anatomic deformities, and eventual skin ulcerations 
2. Autonomic nerve damage- impairs sweat gland function leading to reduced moisture thus causing epidermal cracks and skin breakdown 
3. Sensory nerve damage- reduced sensation thus patients do not feel pain with injury or ulcers (4) 

Vascular changes are also related to a hyperglycemia state which causes changes in the peripheral arteries. The endothelial cell changes lead to vasodilation resulting in poor perfusion, which leads to hypercoagulation in the peripheral arteries. All these changes lead to ischemia and increase the risk of ulceration (4). 

Immune changes that occur reduce the healing response; these patients have an increased T lymphocyte response, inhibiting healing. As you see these are complex patients that generally have multiple factors influencing their wound healing (4).  

Signs and Symptoms

• Wounds are located at increased pressure points on the plantar surface and surrounded by callus 
• Appearance at wound base is variable, depending on patient’s circulation, may appear pink/red or brown/ black 
• Wound borders have a punched-out appearance, while the surrounding skin is often calloused 
• Patient may complain of tingling, numbness or burning 
• Undermining is often present along the wound edges 

Complications

• Osteomyelitis 
• Infections 
• Amputation 

Risk Factors

1. Previous lower extremity amputation 
2. History of a foot ulcer 
3. Anatomic foot deformity 
4. Peripheral vascular disease 
5. Diabetic nephropathy  
6. Diabetes especially with poor glycemic control 
7. Smoking 
8. Hypertension 

Treatments

• Avoiding pressure and weight-bearing on the affected leg 
• Regular debridement is necessary to allow healing 
• Autolytic debridement:  lysis of necrotic tissue by the patient own WBC and enzymes (occurs naturally) most of the time this is not enough 
• Chemical debridement: a topical medication prescribed by provider; examples include: Collagense (Sanytl) Papain with urea (Accuzyme, Gladase) 
• Mechanical debridement: wet to dry dressings (not common as they are not selective), whirlpool treatments 
• Sharp debridement: sterile scalpel to remove dead tissue 
• Surgical debridement: operating room to remove dead tissue (6) 
• Frequently, special shoes or orthotic devices must be worn 
• Negative pressure wound devices (wound vacs)  
• Hyperbaric oxygen therapy (HBOT)  

Patient Education

• Avoid smoking 
• Avoid going barefoot, even at home, especially on hot decks and hot sand 
• Test water temperature before stepping into a bath 
• See podiatrist regularly 
• Wash feet in lukewarm water, dry thoroughly (including between the toes), and check feet daily for any skin breakdown 
• Shoes should be snug, but not tight, and customized if feet are misshapen or have ulcers 
• Change socks daily 
• Avoid cold, caffeine, nicotine, and constrictive garments  

Diagnostic Tests for Ulcers (6) 

Non-Diagnostics for Ulcers

Complete Medical and Social History

Medical and social history are key in identifying current contributing factors that could be playing a role in wound healing. 

Wound Consultant

Often done to ensure the best treatment is being done, and often wounds are followed by a wound care center program ensuring frequent assessments and continual monitoring.  

Nutrition Consultant

Adequate nutrition is needed for wound healing, and a registered dietician is often consulted to ensure adequate protein and other nutrients are part of the patient’s plan of care.  

Conclusion

Understanding the pathophysiology of venous stasis ulcers, neurotrophic (diabetic), and arterial (ischemic ulcers) along with the circulatory system will assist you in identifying key differences and similarities in these types of wounds. As a nurse, the ability to differentiate the signs, symptoms, complications, and treatments of all ulcers, specifically arterial vs. venous, is an invaluable skill to possess. It is important for patients to understand the “why” in their disease process. I believe that being able to connect and explain things in simple, plain language to patients increases their engagement and empowers them to take control of their disease or chronic condition. 

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