Neuropathic Ulcer

What is Neuropathic Ulcer?

Neuropathy refers to a condition where some or all of the senses or abilities of movement in certain areas might be lost. This can either be because of paralysis that can affect body parts according to a nerve map or because of other conditions that affect the nerve endings, often in the arms or legs. Such conditions are usually related to diabetes, but can also be caused by shingles, lack of B12, alcoholism, exposure to toxins like chemotherapy, a protein called amyloid, underactive thyroid, autoimmune disorders, Lyme disease, syphilis, HIV, or inherited conditions like Charcot-Marie-Tooth and demyelinating polyneuropathy. Nerve-related ulcers, which are sores that don’t heal, often occur on the bottom of the feet and affect areas like the heel and the heads of the metatarsal bones, which lead to the toes, or areas where friction causes a hardened skin area called a callus.

Peripheral nerves, the nerves that supply the arms and legs, are of three types – motor, sensory, and autonomic. Motor nerves help muscles and tissues move, and if they are damaged, it can lead to weakness and sudden uncontrolled muscle contractions. Sensory nerves carry signals from the tissues to the brain, helping us feel different sensations like sharp or dull, rough or smooth, hot or cold, and damage can result in numbness, tingling, and pain. Autonomic nerves control automatic or semi-automatic bodily functions that help maintain a stable internal environment. If these nerves are damaged, it can cause issues like nausea, vomiting, diarrhea, and the inability to control other bodily processes. Frequently, people with severe neuropathy have some kind of damage in each of these nerves. However, how the neuropathy advances depends on its root cause and varies from patient to patient. There are often patterns in terms of which nerves are affected and in what order that can give clues to the underlying disorder.

What Causes Neuropathic Ulcer?

Neuropathic sores, or ulcers, usually develop when the inside structure of a part of the body pushes out and causes unusual pressure spots on the outer surface. It’s often seen in feet, especially when walking, where these internal pushes lead to pressure. Because these body parts are numb and lack ordinary feeling, the person is less likely to notice any discomfort or changes to how the area feels, due to the ulcer.

Peripheral neuropathy, a condition that affects the nerves, can be divided into four categories: anatomic, systemic, metabolic, and toxic. Anatomic causes include damage or pressure on the sciatic nerve, fibular nerve, or nerve damage due to surgery or accidental injury. Systemic causes can be anything from HIV infection, cancer, paraneoplastic syndrome, monoclonal gammopathy, amyloidosis, sarcoidosis, Sjogren’s syndrome, to even tick bites. Metabolic causes are things like diabetes, thyroid disease, kidney disease, and chronic liver disease, while Toxic causes are due to vitamin deficiencies (B1, B6, B12), excessive vitamin B6, heavy metal poisoning, drug-induced neuropathy, organophosphate exposure, and alcohol use. Each or any combination of these can negatively affect the body in their own unique ways.

Peripheral neuropathy is very common among people with diabetes. It is thought to be caused by cell death resulting from inflammation and oxidative stress in the tissues, which then interferes with nerve function. This effect is made worse by high blood sugar levels and resistance to insulin, which disrupt many metabolic routes inside the body, increasing the number of reactive oxygen species (ROS) within the tissues. ROS directly harm the nerves, leading to peripheral polyneuropathy – a condition that affects multiple nerves. Initially, it affects the nerves without a myelin sheath (a protective layer around the nerve), then later it causes demyelination of the nerves that are covered by myelin. This is why neuropathy affects sensation, automatic processes, and motor functions.

Insufficient blood flow and reduced sensitivity often lead to a condition called Charcot neuroarthropathy. This is an inflammatory condition that leads to the misalignment of the bones, joint dislocation, and bone fractures. As a result, it alters the shape of the foot. There are several theories about what causes Charcot neuroarthropathy, and managing it can be difficult as it has different stages, each with its own timeline, and varies in cause. It’s also known to lead to neuropathic ulcers and bone infections.

Risk Factors and Frequency for Neuropathic Ulcer

Peripheral neuropathy, a nerve condition, can affect up to half of people with diabetes at some point in their lives. The percentage of people with diabetes who get this condition can be as low as 6% or as high as 51%, with varying factors influencing this such as how well one’s diabetes is controlled, age, and type of diabetes.

Among people with type 1 diabetes, about 30% to 34% will develop peripheral neuropathy, usually at a younger age compared to those with type 2 diabetes. People with type 2 diabetes can develop this condition at rates ranging between 6% and 51%. However, it is typically observed affecting about 35% to 45% of these individuals.

• Peripheral neuropathy is seen more frequently in males, but does also occur in females with diabetes.
• A study showed that having a diabetic foot ulcer can increase the death rate from 3.1% to 17.4%.
• Several factors contribute to this increase, including the duration of diabetes, presence of nephropathy (kidney disease), and history of minor or major amputations.
• The same study showed that up to one-third of people diagnosed with a diabetic foot ulcer will need an amputation at some point, based on evaluations over 14 years.

Signs and Symptoms of Neuropathic Ulcer

People often notice they have an issue when they find blood in their socks or on their floors. This happens because they don’t often check their feet (perform routine pedal examinations). Information about the ulcer (sore spot) like what it’s like, where it came up, how long it’s been there, when it started, and whether anything makes it feel better or worse, are all important. Similarly, any treatments or dressing applied so far should also be noted.

Understanding the patient’s past medical condition is very important. Particularly, it’s crucial to know how long the patient has had neuropathy, what caused it, and any relevant information about that. For example, a lot of people with this condition have diabetes. So, it’s essential to know how long they’ve had it, how they manage it, and their blood sugar levels. The hemoglobin A1C test helps physicians understand how well the diabetes is managed. Likewise, past experiences with sores, surgeries or amputations on the feet, any known allergies, and current medication are all vital information. This helps to guide medication choices, especially for antibiotics.

A patient’s surgical history is also useful, especially a history of ulcers on the foot, surgeries such as amputation, or any history of vascular surgery. This can influence the decision about going for a surgery now. Knowing what they do for a living and how much they stress the affected area is beneficial. Substance abuse history also matters as smoking can reduce blood flow to the area, and alcohol can cause neuropathy.

• Pain description
• Duration of neuropathy
• Disease linked with the neuropathy
• Medication and diet control strategies for diabetes
• Past experiences with ulcers, surgeries or amputations
• Possible surgical interventions
• Occupation and stress on the affected area
• Substance use history

Sometimes, the ulcers can get infected and cause feelings of unwellness (nausea), a high body temperature (fever), vomiting, chills. In severe cases, difficulty in breathing (shortness of breath) and chest pain if sepsis occurs. The SIRS criteria can help determine if sepsis is setting in, although it’s not perfect.

The physical exam should look over all aspects of the ulcer, the patient’s blood circulation (vascular status), nerve function (neurological status), and any issues with the musculoskeletal system that could lead to an ulcer. For the physical exam of the skin, they’ll note what the wound looks like, if there’s any tunnelling, how deep it is, if it smells bad, if it touches the bone, and if there’s any coming out of it (drainage).

The vascular examination should include feeling the pulses in the area, using an ultrasound doppler to check on the waveform and blood flows, and the time the capillaries refill after being compressed. Good blood flow and tissue perfusion mean healing is likely and help evaluate the existence of peripheral arterial disease and vascular insufficiency.

The doctor will test the nerves by 2-point discrimination, comparing sharp and dull sensations, feeling the vibration, and monofilament testing. They can subject to nerve conduction velocity testing, but usually, the clinical evaluation provides enough information about the patient’s ability to feel (sensorium). They also need to note if it affects both sides of the body (asymmetric/symmetric) and which type of nerves is affected (sensory, motor, autonomic).

The doctor should also evaluate the musculoskeletal aspects of the patient, which can often be overlooked. The structures of the anatomy and how they move should be fully understood to judge the possibility of reducing deformities and decreasing the prominence of pressure points. For lower extremity ulcers, this should include a walking test(gait exam), checking the shoes, and evaluating the area’s biomechanics.

Testing for Neuropathic Ulcer

Understanding and diagnosing the cause of your nerve damage or ‘neuropathy’ is crucial, and ideally comes before the development of persistent sores or ‘ulceration.’ Different types of neuropathies can be identified through combined methods like a physical exam, electrodiagnostic testing, and laboratory markers. Electrodiagnostic tests (which include electromyography (EMG) and nerve conduction studies (NCS)) are performed when symptoms first appear and help evaluate sources of peripheral neuropathies, not the ulcerations caused by nerve damage.

Medical imaging like x-rays should be used immediately to examine all ulcerations. It can help tell the difference between neuropathic ulcers and ulcers caused by a lack of blood flow. This type of imaging helps doctors examine different aspects of the ulceration. For example, they can look at the body’s soft tissues to check for the presence of gas or assess bone structure for unusual growths or deformities causing the ulceration. The quality of the bone can also be inspected for signs of bone infection, known as ‘osteomyelitis.’

Vascular studies, which assess blood flow and the effectiveness of your arteries, can help doctors determine if the ulcer originated from nerve damage or poor blood flow. These tests also help guide doctors in deciding if you need surgery, and how well you may heal.

In the initial laboratory evaluation of a nerve damage ulcer, doctors will test your blood to look for signs of infection and inflammation. This includes tests like a complete blood count, metabolic profile, C-reactive protein, and others. These tests help doctors understand how your body is fighting off an infection and maintaining its balance of vital substances. However, these are general and not only for infection but can also show the severity of your illness.

At your first appointment, doctors will clean the wound area, remove any dead tissue, and even take a sample for testing. Any tests that come back positive can help doctors decide the best antibiotic to treat an infection.

Following the initial evaluation comes secondary evaluation, which might include more advanced imaging if needed. For example, your doctor might use a CT scan, MRI, or ultrasound to identify a deep tissue abscess or bone infection. An MRI may be the preferred imaging choice due to its high sensitivity in identifying infections, but other methods may apply depending on the situation. Finally, if bone infection or ‘osteomyelitis’ is suspected, a bone biopsy may be performed, although these results can sometimes depend on the doctor’s interpretation.

Treatment Options for Neuropathic Ulcer

When talking about neuropathic ulcers, which are a type of wound caused by damage to the nerves, the treatment and management process usually has two goals: to address the root cause of the nerve damage (neuropathy) and to treat the wound itself. Both parts of this process rely on a multi-pronged approach.

To understand the reason behind the nerve damage, there are a variety of tests that can help tailor treatment according to what is causing the problem for each patient.

For the wound, treatment is equally detailed and multifaceted. An important aspect is to nurture healing and prevent new wounds from forming. To do this, it’s crucial to understand the physical structures that are at risk. This knowledge influences the choices made in treatment, like which sort of foot support to use (orthotics), potential surgical procedures, and alterations to footwear to spread the pressure on the foot more evenly and prevent new sores.

Depending on the specifics of each wound, treatment could involve surgery for cleaning and removing dead tissue (debridement). If an infection is suspected, a sample, or culture, may be taken for testing, and antibiotics may be provided. If there’s a possibility of bone infection, a small piece of bone may be taken for lab analysis.

Another vital part of the treatment plan is to take the pressure off of the wound. By shifting pressure to surrounding areas, this helps prevent new wounds from forming and encourages the existing wound to heal. Various strategies can be used to achieve this, like using different types of casts and boots, or creating custom foot supports. Plantar wounds, which are those on the sole of the foot, find this particularly beneficial.

There have been recommendations that suggest the use of non-removable devices that reach up to nearly the knee, as a primary method for taking pressure off the wound. These offloading devices could be cast boots that align the ankle or forefoot.

In addition, depending on the wound’s characteristics, specifically its size, depth, level of moisture and whether it’s draining or not, different wound care products and grafts may be used to speed up healing.

What else can Neuropathic Ulcer be?

There are many different types of skin ulcers that physicians should consider when examining a patient. Sometimes, these ulcers can also mimic the appearance of certain cancers, thus it is necessary to conduct further assessment. The possible types or causes of skin ulcerations include:

• Ulcers caused by poor blood circulation (Venous stasis ulceration)
• Ulcers due to reduced blood supply (Arterial ulceration)
• Ulcers caused by injury (Traumatic ulcerations)
• Bedsores (Decubitus ulceration)
• Skin cancers
• High blood pressure-related ulcers (Hypertensive ulceration)
• Burns
• Skin diseases caused by infections (Cutaneous infectious diseases)
• Ulcers due to certain chemicals or medications (Chemotoxic or drug-induced ulceration)
• Side effects of certain treatments
• Side effects related to other health conditions (for example, Kaposi’s sarcoma)

These ulcers must be carefully examined as some can lead to severe health problems like gas gangrene and necrotizing fasciitis, which can endanger a person’s life or limb.

What to expect with Neuropathic Ulcer

Based on a large-scale study, it was determined that 17.4% of patients with diabetic foot ulcers, which are open sores or wounds that occur in people with diabetes, passed away within 14 years. This is compared to 3.1% of patients without such ulcers. In the group of patients with diabetic foot ulcers, 22% of them died within 5 years, and 71% within 10 years.

Additionally, around 29% of all these patients had to undergo some sort of amputation, which is the removal of a limb. Certain factors can predict an earlier death, such as having diabetes for more than 10 years, a history of kidney disease (known as nephropathy), and both minor and major amputations.

In short, having a diabetic foot ulcer increases the risk of amputation, complications, and a less favorable long-term outlook. The study also showed that about one out of every three people diagnosed with a diabetic foot ulcer ended up needing an amputation, which seems to increase over time.

Possible Complications When Diagnosed with Neuropathic Ulcer

Peripheral neuropathy, a type of nerve damage, can lead to several complications. The most serious is amputation, which is often required because a neuropathic foot develops ulcers that then become infected. In fact, about 80% of all non-accidental amputations in the United States are due to diabetes and peripheral neuropathy.

With each new foot ulcer or amputation, the rates of sickness and death rise. The risk for amputation on the other foot or even death also increases with each new ulcer and surgical procedure. It’s estimated that between 14% to 24% of patients with an ulcer on the foot end up needing all or part of that limb amputated.

A study about predicting amputation rates in patients with diabetic foot ulcers found that about 35.4% of patients needed an amputation. This study also pointed out that suffering from a soft tissue infection, osteomyelitis (an infection in the bone), long-lasting ulcers, or vascular insufficiency or peripheral arterial disease (conditions that limit blood flow) could significantly increase the amputation rate. Therefore, it is believed that a quick diagnosis and immediate, correct treatment can help reduce complications related to peripheral neuropathy. However, controlling the causes of the neuropathy is just as crucial. The previous sections have discussed many of these complications in detail.

Common Complications / Effects:

• Foot ulcers due to peripheral neuropathy
• Ulcer infections
• Amputations related to ulcers and infections
• Increased sickness and death rates with each new ulcer and amputation
• Increased risk of further amputations or even death
• Other complications like soft tissue infections, osteomyelitis, lasting foot ulcers, and vascular insufficiency or peripheral arterial disease

Preventing Neuropathic Ulcer

The process carried out when a doctor assesses a patient’s condition can vary between different health experts, but they all follow a common set of guidelines. For patients who have had ulcers in the past, have poor blood circulation, or who have lost a limb, it’s important to see a foot and ankle specialist every few months. Regular appointments with a primary care doctor are also recommended.

Let’s suppose a patient has a condition related to nerve damage in the limbs. That patient should visit their specialist at least once a year. They should also schedule regular appointments with their primary care doctor to maintain their overall health.

Patients should also perform a self-examination of their feet every day while at home. If it is difficult for them to inspect the bottom of their feet, a mirror placed on the floor could help. It’s important for them not to walk around barefoot and to wear shoes specifically designed for diabetics. Regularly checking the feet and treating the underlying causes of neuropathy, the condition that causes the nerve damage, is the best way to lower the chance of developing foot ulcers.