Sensory Neuropathy

What is Sensory Neuropathy?

Sensory neuropathies refer to several diseases causing loss of feelings or sensations in the body. These neuropathies can have various causes and may primarily involve our body’s small or large fibers. Small fiber neuropathies usually result in pain, and large fiber neuropathies commonly lead to lack of coordination (ataxia).

Treatment and management depend on the type of sensory neuropathy. This classification is based on the size of the nerve affected and the level of their myelination (a protective layer on nerves). In the case of small fiber neuropathies, the small Aδ and C fibers are most important. They help transmit pain and temperature sensations and control functions of our nerves, like heartbeat and digestion. Disruptions in these fibers can result in burning, shooting pain and a sensation of tingling or prickling (paresthesia).

In contrast, large fiber neuropathies involve the larger Aβ fibers, which help us sense vibration and touch. People with sensory ataxia usually have damage to the dorsal columns of the spinal cord and the dorsal root ganglia—clusters of nerve cells. While ataxia is a classic sign of large-fiber sensory neuropathy, smaller fibers can also be damaged over time. Some diseases can affect both small and large fibers like diabetes mellitus, presenting substantial challenges for public health.

People with sensory neuropathy often describe feeling “pins and needles” or “electricity” in the affected areas, usually in a pattern that resembles a stocking or glove. Diagnosing sensory neuropathy involves a neurological examination and skin biopsy, which is currently the gold standard for diagnosing small fiber neuropathy. Unfortunately, there are no specific treatment guidelines for sensory neuropathies. Most treatments are based on expert opinions and research and could include a range of options-from injections of immune-boosting proteins, anti-inflammatory drugs, and various other medications depending on the cause.

What Causes Sensory Neuropathy?

It’s crucial in delivering effective treatment to understand the variety of causes linked to sensory neuropathy. Sensory neuropathy refers to damage to the nerves that manage your senses, which can lead to symptoms such as pain, numbness, or tingling. Sometimes, it might not be clear what’s directly causing the neuropathy and we might have to consider unexplained or ‘idiopathic’ sensory neuropathy, which accounts for 20%-30% of cases.

Some of the potential causes we keep in mind include:

Immune-related conditions like sarcoidosis, Sjögren syndrome, systemic lupus erythematosus, and celiac disease. All of these are diseases where your immune system attacks your own body, causing various symptoms that can affect the nerves.
Metabolic issues like diabetes or high cholesterol (or hyperlipidemia). Both of these can harm your body’s normal functions, including nerve function.
Nutritional deficiencies, including lack of vitamin B12, copper, vitamin E, and folic acid.
Exposure to toxins, such as chemotherapy drugs, alcohol, and other drugs that can harm nerves.
Genetic causes, such as hemochromatosis, Fabry disease, Ehlers-Danlos syndrome, and Friedreich ataxia. These are all inherited conditions that can affect nerve function.
Infections, including herpes simplex, varicella-zoster virus, leprosy, HIV, and hepatitis C. These infections can damage nerves either directly or indirectly.
Other causes that don’t fall into the above categories, such as unexplained causes, fibromyalgia (a chronic pain disorder), and vasculitis (inflammation of the blood vessels).

Risk Factors and Frequency for Sensory Neuropathy

Sensory neuropathy is a condition that affects a small percentage of the general population, usually between 1% and 3%. This figure increases to about 7% in older adults. Interestingly, the prevalence of this condition is lower in developing countries, likely due to differences in life expectancy. Looking at this globally, it’s more common in Western countries and slightly more prevalent in women. In developing countries, infectious diseases like leprosy are the main causes of neuropathy, but in Western countries, it’s usually associated with conditions like diabetes, excessive alcohol use, use of certain drugs, and heart disease.

For those working in public health, it’s crucial to know that the main cause of peripheral neuropathy worldwide is diabetes. As many as half of all older adults with diabetes will develop some form of distal peripheral neuropathy. This condition affects their ability to feel pain and changes in temperature. The famous orthopedic surgeon, Dr. Paul Brand, did a lot of work in this field. He discovered that the loss of peripheral sensation (or “gift of pain”) was causing significant scarring and ulceration in his patients in India, who had Hansen disease. In the same way, distal peripheral neuropathy puts people with diabetes at a high risk of developing complications with their feet.

About 1% to 3% of the general population have sensory neuropathy, and this increases to 7% in older adults.
This condition is more common in Western countries and usually affects women more than men.
In developing countries, leprosy is often the cause of neuropathy. In contrast, in Western countries, the causes usually include diabetes, excessive alcohol consumption, certain drugs, and heart disease.
Around 50% of all older adults with diabetes will develop some form of peripheral neuropathy.
Peripheral neuropathy affects the patient’s ability to feel pain and temperature and can lead to complications such as severe scarring and ulceration as observed in Hansen disease patients.
People with diabetes and peripheral neuropathy are at a higher risk of developing foot problems.

Signs and Symptoms of Sensory Neuropathy

Sensory neuropathy is a condition where damaged nerve fibers disrupt the sensory signals from the skin and internal organs to the brain. This can cause a variety of symptoms. Initially, the most noticeable sign can be early-onset clumsiness or uncoordinated movements, mainly due to disturbances in the nerves that carry information from the body’s ends (like hands and feet) to the brain.

As the condition worsens, people might start to notice involuntary ‘writhing’ movements in the hands and feet, especially when they close their eyes. If smaller and medium-sized nerve fibers get impacted, people can experience sensations like ‘pins and needles’ or electric-like surges in the affected body parts. These sensations usually follow a pattern, akin to how a glove or stocking covers your hand or foot.

In people with conditions like diabetes, signs of sensory neuropathy might differ. They might feel numbness in the feet, which usually doesn’t follow any particular pattern and can affect multiple areas at once.

Early-onset clumsiness
Involuntary ‘writhing’ movements in hands and feet
Feeling of ‘pins and needles’ or electric-like surges
Patterned sensation disruption, like a glove or stocking
Multifocal numbness, often in feet

The progression of sensory neuropathy can vary significantly from person to person. Therefore, when doctors take a patient’s medical history, it’s essential for them to note the progression of the condition. In some case, sensory neuropathy occurs due to immune or post-infection complications and it progresses rapidly whereas in idiopathic cases (where we don’t know the cause), it progresses slowly. Moreover, sensory neuropathy usually does not involve motor weakness, but in some cases, like ones resulting from cancer, it could result in absent stretch reflexes.

Testing for Sensory Neuropathy

To diagnose sensory neuropathy, doctors often depend on two main methods, neurophysiological examination and skin biopsy. Sensory neuropathy relates to damage in the nerves that carry messages of touch, temperature, and pain to the brain.

In the neurophysiological examination, a test called electromyography (EMG) is used which checks the health of muscles and the nerves controlling the muscles. However, in cases of a specific type of sensory neuropathy called small fiber neuropathies, the EMG results may appear normal. For people with diabetic sensory neuropathy, a test using a tool called a Semmes-Weinstein 5.07 monofilament is often conducted on different parts of the foot to check for sensitivity changes.

Demyelination is a condition where there is damage to the protective covering (myelin sheath) of nerve fibers, causing issues with signal transmissions. People with this condition may show a slower than normal nerve conduction speed and a longer delay in nerve response. A common cause of demyelination is disorders like Guillain-Barre syndrome and chronic inflammatory demyelinating polyneuropathy, which affect the peripheral nerves.

There are also tests for autonomic sensory nerves, which control body functions that we do not consciously direct, like breathing and heartbeat. These tests involve checking for sensitivity to hot and cold sensations, changes in the sweat gland activity, and the ability of the skin to conduct electricity. Sweat tests can be particularly valuable in diagnosing small fiber neuropathies. However, these tests are not widely available yet.

A skin biopsy is currently the most reliable method for diagnosing small fiber neuropathy. The skin sample is usually taken from the lower leg or the thigh. Its benefits include uncomplicated procedure and low risk of complications. Unlike skin biopsy, a nerve biopsy is usually not required to diagnose sensory neuropathy.

Imaging is also an important tool to identify sensory neuropathies, especially when linked with cancerous growths. Techniques such as magnetic resonance imaging (MRI) are extensively used to visualize the health of specific parts of the nervous system.

Treatment Options for Sensory Neuropathy

Specific treatment guidelines for sensory neuropathies, or nerve damage, are not clearly defined yet. Most treatment suggestions come from expert opinions and careful research. Some potential treatments include the use of intravenous immunoglobulins (proteins used by the immune system to fight bacteria and viruses), methotrexate (a medication used to treat certain types of cancer or to control severe psoriasis or rheumatoid arthritis), corticosteroids (a class of drug that lower inflammation in the body), infliximab (a medication used to treat a number of autoimmune diseases), and plasma exchange (a procedure that filters the blood and removes harmful antibodies). Other options are various oral and topical medications, depending on the cause of the neuropathy.

Recent studies suggest that symptoms generally stop getting worse after 7 to 10 months, so treatment is ideally started within this timeframe.

Oral medications like anticonvulsants (used primarily to treat epileptic seizures, but also used to treat some mood disorders and neuropathic pain), serotonin-norepinephrine reuptake inhibitors (a class of drugs used for depression and anxiety disorders), tricyclic antidepressants, opioids (a type of medicine used to relieve pain), and botulinum toxin A (commonly used in cosmetic treatments but can also treat a variety of medical conditions) have all shown to be more effective than a placebo in multiple controlled trials. The American Academy of Neurology also recommends the use of topical agents like lidocaine and capsaicin (used for minor aches and pain on the skin).

Future research possibilities include the potential benefit of physical exercise in sensory neuropathy in patients with diabetes. There seems to be an increase in nerve fiber density and lower pain response to exercise in patients with established neuropathy caused by diabetes. This research is particularly important given that neuropathy caused by diabetes is far more common than other causes.

In terms of managing specific neuropathies:

Diabetic neuropathy: The managing strategy includes controlling blood glucose levels, addressing risk factors such as high blood pressure, high cholesterol, and smoking, and controlling symptoms with medications along with lifestyle changes and physical therapy.
Guillain-Barre syndrome: This condition is managed with physical therapy, pain management, and assistive devices. In severe cases, intravenous immunoglobulin or plasmapheresis can help reduce inflammation and improve outcomes.
Uremic polyneuropathy: The key to managing this condition is controlling any underlying conditions that contribute to its development, like diabetes and high blood pressure. In terms of medications for symptom management, analgesics and antidepressants might be used .
Vitamin B12 deficiency: This type of neuropathy is managed by replacing vitamin B12 through supplements.
Chronic inflammatory demyelinating neuropathy: This condition is initially treated with corticosteroids but can also be managed using intravenous immunoglobulin, plasma exchange, and some immunosuppressant drugs (medications that reduce the body’s immune response).

Sensory neuropathy is a medical condition that can be caused by a variety of factors. When diagnosing sensory neuropathy, doctors might look for signs of several different conditions:

Diabetic neuropathy (Damage to nerves due to diabetes)
Alcohol neuropathy (Nerve damage caused by excessive alcohol intake)
Guillain-Barre syndrome (A rare neurological disorder)
Charcot-Marie-Tooth disease (A group of disorders that affect nerves)
Autoimmune neuropathy (Nerve damage caused by immune system attacking the body’s own nerves)
HIV-associated neuropathy (Nerve damage caused by HIV)
Nutritional deficiencies (For example, a lack of vitamin B12)
Infectious neuropathy (Caused by diseases like Lyme disease or leprosy)
Toxin-induced neuropathy (Caused by exposure to toxins like arsenic or lead)

However, in many people, the exact cause of sensory neuropathy isn’t clear, and the condition is labelled as idiopathic, or of unknown cause. Some research suggests that the body’s immune system might play a role in this type of neuropathy. Other conditions that might have similar symptoms include distal acquired demyelinating symmetric neuropathy, sensory chronic inflammatory demyelinating polyradiculoneuropathy, and other conditions affecting the nerves or immune system.

What to expect with Sensory Neuropathy

The effectiveness of treatment can widely vary for patients suffering from different forms of nerve damage affecting their senses. When nerves deteriorate rapidly, this leads to their complete breakdown both structurally and chemically, which may lead to a more uncertain outlook for recovery. The ability to regain normal function will depend largely on how well the severed nerve endings realign, the extent of any accompanying tissue damage and scarring.

For measurable improvement to be seen, the muscles and organs affected need to develop new nerve connections once sufficient nerve healing and restoration of the nerve lining has occurred. If the symptoms of nerve damage are due solely to the breakdown of this nerve lining, the outlook will be a lot more promising because recovery is quicker and return to normal function is faster. The sensations of pain and temperature are normally the first to return.

For those patients with irregular blood sugar levels, it’s essential to keep an eye on their hemoglobin A1c lab values to monitor the disease’s progression. Guidelines from the American Diabetes Association emphasize the importance of keeping this value below 7% along with maintaining a healthy lifestyle; such as a balanced diet and regular exercise, for those already diagnosed with diabetes.

Possible Complications When Diagnosed with Sensory Neuropathy

: Not getting timely treatment for sensory neuropathy can lead to some serious issues. Not only can patients get burns and other skin injuries more easily due to reduced sensitivity to pain, but the healing process can be slower, raising the risk of infection. Sensory neuropathy can also make older people more prone to falls since balance and strength can decline.

Patients with diabetes who also have sensory neuropathy face some severe challenges. Because they’ve lost a lot of protective sensation, it’s possible for them to step on something sharp without feeling it right away, leading to significant injuries and frequent hospital visits.

One very severe potential outcome of this is infection that can turn into sepsis or even gangrene in the lower legs, often due to untreated ulcers, or because a foreign body stays lodged in a wound. People with diabetes face a risk of getting a diabetic foot ulcer of about 2% per year, but that increases drastically to around 7% for those who also have sensory neuropathy. In fact, this is a common reason why amputations are performed. This risk can be reduced with proper education from the healthcare team on how to manage their condition.

Main Risks of Untreated Sensory Neuropathy:

Burns and skin injuries
Increased infection risk
Higher risk of falls in older people
Stepping on sharp objects unknowingly
Sepsis and gangrene due to foot ulcers or foreign objects in wounds
Potential need for amputation

Preventing Sensory Neuropathy

If you want to effectively manage this illness, it’s important that you fully understand the potential signs and symptoms we’ve discussed earlier. It’s equally essential to adjust your daily lifestyle habits if you start noticing any of these symptoms. If you are already experiencing sensory neuropathy, which is nerve damage often causing weakness, numbness, and pain, you should avoid extreme temperatures and pay close attention to any sudden changes in the way you walk. This will reduce the impact of recurring small movements on your feet. You might also need to change your footwear.

For patients with diabetes, a daily routine of checking your feet should be followed to spot possible sores or wounds early. Regular podiatrist check-ups, ideally every 2 to 3 months, are also important. This regular check-up is part of a comprehensive approach to manage your sensory neuropathy. Lastly, you’re also advised to frequently consult with your primary doctor or an endocrinologist, a doctor who specializes in hormone-related diseases like diabetes. This will help in overall management of your diabetes and limit the symptoms of sensory neuropathy.

Frequently asked questions

The prognosis for sensory neuropathy can vary widely depending on the individual and the specific type and cause of the neuropathy. Factors that can affect the prognosis include the rate of nerve deterioration, the extent of tissue damage and scarring, and the ability of severed nerve endings to realign and develop new connections. Recovery and improvement in function are more likely if the symptoms are solely due to the breakdown of the nerve lining, and if the individual maintains a healthy lifestyle and manages any underlying conditions such as diabetes.

There are various causes of sensory neuropathy, including immune-related conditions, metabolic issues, nutritional deficiencies, exposure to toxins, genetic causes, infections, and other unexplained causes. The main cause of peripheral neuropathy worldwide is diabetes.

The signs and symptoms of Sensory Neuropathy include: - Early-onset clumsiness or uncoordinated movements, particularly in the hands and feet. - Involuntary 'writhing' movements in the hands and feet, especially when the eyes are closed. - Sensations like 'pins and needles' or electric-like surges in the affected body parts. - Patterned disruption of sensation, similar to how a glove or stocking covers the hand or foot. - Numbness in the feet, which may not follow a specific pattern and can affect multiple areas at once, particularly in individuals with conditions like diabetes. It's important to note that the progression of sensory neuropathy can vary from person to person. In some cases, it may progress rapidly, especially when caused by immune or post-infection complications. In other cases, where the cause is unknown (idiopathic), it may progress slowly. Sensory neuropathy typically does not involve motor weakness, but in certain cases, such as those resulting from cancer, it could lead to absent stretch reflexes.

To properly diagnose sensory neuropathy, a doctor may order the following tests: 1. Neurophysiological examination: - Electromyography (EMG) to check the health of muscles and the nerves controlling the muscles. - Semmes-Weinstein 5.07 monofilament test to check for sensitivity changes in diabetic sensory neuropathy. 2. Skin biopsy: Currently the most reliable method for diagnosing small fiber neuropathy. A skin sample is taken from the lower leg or thigh. 3. Autonomic sensory nerve tests: - Sensitivity tests for hot and cold sensations. - Sweat gland activity tests. - Skin's ability to conduct electricity. 4. Imaging techniques: - Magnetic resonance imaging (MRI) to visualize the health of specific parts of the nervous system, especially when linked with cancerous growths.

The doctor needs to rule out the following conditions when diagnosing Sensory Neuropathy: - Diabetic neuropathy (Damage to nerves due to diabetes) - Alcohol neuropathy (Nerve damage caused by excessive alcohol intake) - Guillain-Barre syndrome (A rare neurological disorder) - Charcot-Marie-Tooth disease (A group of disorders that affect nerves) - Autoimmune neuropathy (Nerve damage caused by immune system attacking the body's own nerves) - HIV-associated neuropathy (Nerve damage caused by HIV) - Nutritional deficiencies (For example, a lack of vitamin B12) - Infectious neuropathy (Caused by diseases like Lyme disease or leprosy) - Toxin-induced neuropathy (Caused by exposure to toxins like arsenic or lead) - Distal acquired demyelinating symmetric neuropathy - Sensory chronic inflammatory demyelinating polyradiculoneuropathy - Other conditions affecting the nerves or immune system.

When treating sensory neuropathy, there can be potential side effects from the various treatments. Some of these side effects include: - Intravenous immunoglobulins: Possible side effects include headache, fever, chills, nausea, and vomiting. - Methotrexate: Side effects may include nausea, vomiting, diarrhea, mouth sores, and hair loss. - Corticosteroids: Potential side effects include weight gain, increased blood pressure, mood changes, and increased risk of infection. - Infliximab: Side effects may include headache, nausea, diarrhea, and increased risk of infection. - Plasma exchange: Possible side effects include allergic reactions, infection, and changes in blood pressure. It's important to note that these side effects can vary from person to person, and individuals should consult with their healthcare provider for more information.

You should see a neurologist for Sensory Neuropathy.

About 1% to 3% of the general population have sensory neuropathy, and this increases to 7% in older adults.

Specific treatment guidelines for sensory neuropathies are not clearly defined yet. However, some potential treatments include the use of intravenous immunoglobulins, methotrexate, corticosteroids, infliximab, plasma exchange, and various oral and topical medications. Recent studies suggest that symptoms generally stop getting worse after 7 to 10 months, so treatment is ideally started within this timeframe. Oral medications like anticonvulsants, serotonin-norepinephrine reuptake inhibitors, tricyclic antidepressants, opioids, and botulinum toxin A have all shown to be more effective than a placebo in multiple controlled trials. The American Academy of Neurology also recommends the use of topical agents like lidocaine and capsaicin. Future research possibilities include the potential benefit of physical exercise in sensory neuropathy in patients with diabetes. Managing specific neuropathies involves controlling underlying conditions, addressing risk factors, and using medications along with lifestyle changes and physical therapy.

Sensory neuropathy refers to diseases that cause loss of feelings or sensations in the body. It can be caused by various factors and can affect small or large nerve fibers, resulting in pain or lack of coordination.

Neurology Neuropathy Paresthesia Sensory Deficits