For many people, neuropathy is a painful, highly frustrating, and sometimes debilitating disease of the nervous system. The broad definition of neuropathy is the disease, damage, or dysfunction of nerves. Since nerves conduct sensations, including pain, to the brain, it’s little wonder that neuropathy is one of the chief causes of chronic pain. Let’s take a look at the causes, symptoms, diagnosis, and treatment options for neuropathy.
Causes of Neuropathy
The pathology, or cause, of neuropathy largely remains a mystery. Despite the many medical breakthroughs in the study of neurology, much of why our nervous system behaves the way it does continues to elude us. Tracing the cascade of events that contribute to neuropathy is all the more difficult due to our limited understanding. Here’s what we do know.
Peripheral nerves run from the spinal column to the body, arms, and legs. Peripheral nerves are like one-way streets. One set of nerves carries messages from the brain, while the other carries information back.
Sensory nerves carry sensations to the brain from receptors throughout the body. These nerves are what allow us to feel hot, cold, soft, rough, or smooth. These nerves gather information from the sensory receptors that lie at the end of the nerve. In a single finger tip, there are over 3,000 receptors! In a fraction of a second, these nerves gather information and send it to your brain.
Motor nerves convey messages from the brain to the muscles in the body to create movement. Based upon the information gathered by the sensory nerves, the brain sends instructions via motor nerves about what kind of movement should be made.
One other type of nerve that is affected by neuropathy is the autonomic nervous system. These nerves control the normal functions of the body, including breathing, digestion, sweating, and heartbeat. These nerves run completely on autopilot under the guidance of the central nervous system.
When neuropathy is present, the messages to and from the brain are disturbed. In some cases, sensory signals are blocked completely which results in numbness. Other times, the sensations are hyperstimulated, sending signals to and from the brain with no reason. This can cause tremors if a motor nerve is involved or tingling, burning, and other pain sensations in the case of a sensory nerve. Neuropathy can also cause the nerve signal to be distorted. For example, instead of feeling the light weight of a sheet across your feet, it might feel unbearably heavy and painful.
The mystery lies in the exact ‘why’ behind the malfunction of the nerves. Some theories claim that chronic inflammation, or swelling, causes the blood vessels in areas like the hands and feet to be significantly decreased, to the point that the nerve endings are damaged. Other reasons that neuropathy might develop include direct damage to the nerve itself or chemical imbalances that permanently disrupt the body’s ability to transmit nerve impulses.
Neuropathy is frequently associated with several conditions:
- Chemotherapy patients
- Autoimmune Diseases like lupus and Sjögren’s syndrome
- Kidney and liver failure
- Idiopathic- which means no known cause. Almost ¼ of cases fall into this category.
The symptoms of neuropathy depend on what kind of nerves are being affected. They vary widely from person to person.
Common Motor Nerve Symptoms:
- Tremors of the hands, fingers, or feet
- Inability to move a specific limb
- Severe cramps- particularly in the calf and foot
- Profound weakness, feeling like the arm or leg is full of lead or too heavy to move
- Unable to maintain balance
- Uncoordinated movements
Common Sensory Nerve Symptoms:
- Extreme sensations of hot or cold that are inappropriate for the environment
- Tingling or ‘pins and needles’
- Pain in a variety of forms
Autonomic Nerve Symptoms:
- Excessive or complete absence of sweating
- Digestive issues
- Loss of bowel or bladder control
- Difficulty regulating blood pressure
- Severe heat intolerance
Neuropathy often develops very slowly, so these symptoms aren’t always attributed to neuropathy until they become persistent or even debilitating. Some people go years with incorrect diagnosis because of the vague and inconsistent presentation of neuropathy.
Physical exam, including a neurological exam and blood tests, correlated with a detailed medical history of risk factors and symptoms are the foundation for a diagnosis of neuropathy. In the most common types like diabetic and chemotherapy induced neuropathy, the diagnosis is typically straightforward. If the symptoms are present in the setting of these diseases, it’s easy to draw the conclusion that neuropathy is the cause. Neuropathy that develops outside of these situations can be incredibly frustrating to diagnose.
Medical Tests to Diagnose Neuropathy:
EMG (Electromyography)- This test measures the amount of electrical signals that are present in a muscle at rest and during contraction. Neuropathy can cause either a significant increase or decrease in the amount of electrical impulses in the muscle. Typically this test will be used to diagnose motor nerve neuropathy in the setting of unexplained weakness or paralysis.
NCV (Nerve conduction velocity)- Designed to test how well the impulse travels down a specific nerve, NCV uses an electrical impulse to stimulate a nerve and monitors how long it takes to reach the end of the nerve. A delayed response indicates nerve damage.
Skin biopsy– By taking a small sample of skin (usually a 3mm section), analysis can be done to see how many nerve receptors are present and examine the nerve endings in that sample. A lack of receptors or significant breakdown of the nerve endings indicate neuropathy. This test is usually called for in the case of sensory neuropathy.
Autonomic testing- Used only in suspected cases of autonomic neuropathy, several different types of stimulation to the autonomic nervous system are introduced and the reaction of the system is monitored, particularly blood pressure and sweating responses.
Neuropathy is typically not reversible, but it is manageable. Treatment is largely dependent on the cause of the neuropathy and mainly targets symptom management. Treatment must also address the cause, if known.
Potential Treatments include:
- Assistive devices (cane, walker, ect) and braces- particularly in motor nerve neuropathy involving weakness
- Physical therapy- stretches and strengthens affected areas
- Gabapentin and other ‘nerve’ medication- decrease electrical activity in nerves and work well in the setting of hyperstimulation causing pain or tremors
- Lidocaine cream and patches- absorbed through the skin, lidocaine numbs the nerve endings which leads to pain relief and works well for sensory nerve pain in a small, specific area
- Narcotics- block pain receptors throughout the body. These are generally avoided if possible due to side effects and dependency
- TENS units- external electrical stimulation provided by these units sometimes provides relief, particularly in the setting of muscle cramps
- Acupuncture- although the mechanism of this treatment isn’t fully understood, it is becoming an increasingly popular alternative therapy for pain, including neuropathy
- Massage- soothes tight muscles and stimulates blood flow to the affected areas
Regardless of the type of neuropathy and treatment plan, engaging in healthy behaviors is key to managing the symptoms. Exercise is important to maintain strength and mobility, and a healthy diet is critical to keeping the right balance of nutrients in the body, so it can function correctly. As with many chronic conditions, mental, emotional, spiritual wellness are also crucial to successful management of neuropathy. The Pathways app (download links below) (update Aug 2023: Pathways is now a web app! Start our program here) is a powerful tool that can assist you in total body wellness as you deal with chronic pain from neuropathy.
Neuropathy can be a relentless onslaught of frustrating and painful symptoms that can be incredibly difficult to control. To learn more about neuropathy check out The Foundation for Peripheral Neuropathy and National Institute for Neurological Disorders and Stroke. Purposeful management can give you the upper hand in dealing with this disease and allow you to live your life to its fullest!
Please note: This article is made available for educational purposes only, not to provide personal medical advice.