What is “Neuropathy?”
A Diagnosis That Raises More Questions Than It Answers
Every week, patients come in having been told by another provider that they have neuropathy. They have often been given this information as if it were a complete explanation for their symptoms. Sometimes they have been started on a medication. Sometimes they have simply been told there is not much to be done. They leave the appointment with a label but without an understanding of what that label actually means or what caused it.
Neuropathy is one of the most commonly used and least informative terms in medicine. It is not a diagnosis in the way that a broken bone or a herniated disc is a diagnosis. It is a description. It tells you that something is wrong with one or more nerves. It tells you nothing about which nerves, what kind of damage, where the damage is occurring, what caused it, or what can be done about it. Getting a meaningful answer to those questions requires going several steps further. This article explains what neuropathy actually is, why there are so many different kinds, and why identifying the specific type you have is essential for getting the right treatment.
What Does Neuropathy Actually Mean?
In the most literal sense it simply means nerve disease or nerve damage. That is it. The term by itself tells you nothing more specific than that a nerve somewhere in your body is not working correctly. To put this in perspective, calling something neuropathy without further qualification is a bit like a mechanic telling you there is something wrong with your car without specifying whether it is the engine, the transmission, the brakes, or a flat tire. The word describes a category of problem, not the problem itself.
The nervous system is an enormously complex structure. There are hundreds of named nerves in the human body, each supplying specific regions and performing specific functions. Those nerves can be damaged at different locations along their course, by different mechanisms, and to different degrees. The clinical presentation, the prognosis, and the appropriate treatment vary substantially depending on all of these factors. This is why simply knowing that you have neuropathy is not very useful without understanding what kind.
The Different Types of Neuropathy
Neuropathies are broadly classified in several ways: by how many nerves are affected, by which part of the nerve is damaged, by where along the nerve the damage occurs, and by what is causing it. Understanding these distinctions is what allows a physician to move from a vague description to a specific, actionable diagnosis.
By How Many Nerves Are Affected
Mononeuropathy refers to damage affecting a single nerve. This is the most anatomically specific category and often has the most identifiable cause. When one nerve is damaged, the symptoms it produces follow a predictable pattern determined by the territory that nerve supplies. Common examples include carpal tunnel syndrome, which involves compression of the median nerve at the wrist, cubital tunnel syndrome involving the ulnar nerve at the elbow, peroneal nerve palsy at the knee causing foot drop, and radial nerve palsy causing wrist drop. Because mononeuropathies follow the distribution of a single named nerve, they are often diagnosable with a careful history and physical examination, confirmed with electrodiagnostic testing.
Mononeuritis multiplex refers to involvement of multiple individual named nerves, but in a patchy, asymmetric pattern rather than a diffuse one. This pattern is characteristic of certain systemic diseases including vasculitis, diabetes in some presentations, sarcoidosis, and some infectious causes. The pattern of which nerves are affected and in what sequence is clinically meaningful and helps direct the diagnostic workup.
Polyneuropathy refers to diffuse involvement of many nerves simultaneously, typically in a length-dependent pattern. This means the longest nerves in the body are affected first and most severely, which is why polyneuropathy classically begins in the feet and lower legs before affecting the hands and arms. The classic stocking-and-glove distribution of numbness and tingling that many patients describe is the hallmark of polyneuropathy. This is the type most people are referring to when they say they have been diagnosed with neuropathy, and it is the type most commonly associated with diabetes, alcohol use, and other systemic conditions.
Plexopathy refers to damage affecting a network of nerves called a plexus rather than individual nerves. The brachial plexus supplies the arm and originates from nerve roots in the cervical spine. The lumbosacral plexus supplies the leg and originates from the lumbar and sacral spine. Plexopathies can result from trauma, radiation treatment, tumors, and inflammatory conditions, and they produce complex patterns of weakness and sensory loss that can be difficult to attribute to a single nerve or nerve root.
By Which Part of the Nerve Is Damaged
Axonal neuropathy involves damage to the axon, which is the long conducting fiber of the nerve that actually carries the electrical signal. Axonal damage tends to produce more significant and longer-lasting deficits because the axon itself must regrow to restore function, a slow process that occurs at approximately one millimeter per day. Diabetes, alcohol, and many toxic or metabolic causes tend to produce axonal neuropathies.
Demyelinating neuropathy involves damage to the myelin sheath, the insulating layer that surrounds the axon and allows signals to travel quickly and efficiently. When myelin is damaged, nerve conduction slows significantly even though the axon itself may be relatively intact. Demyelinating neuropathies can sometimes recover more readily than axonal ones because remyelination can occur without requiring the full regrowth of the nerve fiber. Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy are classic examples of demyelinating neuropathies.
Mixed axonal and demyelinating neuropathy involves damage to both components simultaneously and is common in advanced cases of various neuropathic conditions.
By Where the Damage Occurs
Radiculopathy is damage or compression occurring at the nerve root, which is the point where the nerve exits the spinal canal. This is one of the most common types of neuropathy seen in a spine practice and is caused by disc herniations, bone spurs, or spinal stenosis compressing the nerve at its origin. Radiculopathy produces symptoms in the distribution of the affected nerve root, which is why a pinched nerve in the lumbar spine causes pain and numbness that travels down the leg in a specific pattern, and a pinched nerve in the cervical spine causes symptoms that travel down the arm.
Entrapment neuropathy occurs when a peripheral nerve is compressed at a specific anatomical location along its course, such as the median nerve at the carpal tunnel of the wrist or the ulnar nerve at the cubital tunnel of the elbow. These are among the most common and most treatable forms of neuropathy.
Peripheral neuropathy in the classic sense refers to damage occurring in the peripheral nerves themselves, beyond the spinal cord and nerve roots, and is the category that encompasses most of the length-dependent polyneuropathies described above.
By What Is Causing It
This is perhaps the most clinically important classification because identifying the cause is what determines whether the neuropathy can be treated, slowed, or reversed.
Diabetic neuropathy is the most common cause of polyneuropathy in the developed world. Chronically elevated blood sugar damages nerve fibers in a length-dependent fashion, producing the classic stocking-and-glove pattern of sensory loss. Tight blood sugar control can slow progression and in early cases may allow some recovery.
Toxic and medication-induced neuropathy can result from alcohol, heavy metals, and a number of medications including certain chemotherapy agents, some antibiotics, and some cardiac medications. Identifying and removing the causative agent is the primary treatment.
Nutritional deficiency neuropathy most commonly involves deficiency of vitamin B12, which is essential for nerve health and myelin maintenance. B12 deficiency neuropathy is reversible with supplementation if caught early enough, making it one of the most important causes to identify and one of the most treatable.
Inflammatory and autoimmune neuropathy includes conditions such as Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, and neuropathies associated with autoimmune diseases like lupus and rheumatoid arthritis. These conditions involve the immune system attacking nerve tissue and may respond to immunomodulatory treatments.
Hereditary neuropathy includes conditions such as Charcot-Marie-Tooth disease, which is one of the most common inherited neurological disorders. These conditions are caused by genetic mutations affecting nerve structure or function and are typically slowly progressive.
Idiopathic neuropathy is the term used when no identifiable cause can be found despite a thorough workup. This accounts for a meaningful proportion of peripheral neuropathy cases, particularly in older adults. While not having a specific cause to target is frustrating, it does not mean nothing can be done about the symptoms.
Why the Specific Diagnosis Matters So Much
The reason it matters to identify what type of neuropathy you have goes beyond academic classification. Different types of neuropathy have different prognoses, different risks, and critically, different treatments.
A patient with carpal tunnel syndrome causing numbness and tingling in the hand has a compressive mononeuropathy that responds very well to splinting, activity modification, a corticosteroid injection, or surgical release at the wrist. Telling that patient they have neuropathy and prescribing a nerve pain medication treats the symptom while completely missing the structural problem that is causing it.
A patient with B12 deficiency neuropathy causing progressive numbness in the feet has a condition that is potentially reversible with B12 supplementation. Diagnosing them with neuropathy and stopping there means missing a straightforward treatment that could prevent further nerve damage.
A patient with Guillain-Barré syndrome has a rapidly progressive demyelinating neuropathy that can become life-threatening if it affects the nerves controlling breathing, and that requires urgent treatment with intravenous immunoglobulin or plasmapheresis. Missing this diagnosis by treating the presentation as generic neuropathy has serious consequences.
A patient with lumbar radiculopathy causing leg pain and numbness has a nerve root compression that may respond to an epidural steroid injection or physical therapy directed at the spine, not a peripheral nerve treatment.
In each of these cases, the word neuropathy describes what is happening at a surface level. The specific diagnosis determines what needs to be done about it.
How EMG and Nerve Conduction Studies Help
This is where electrodiagnostic testing becomes invaluable. An EMG and nerve conduction study, which I perform in the office as part of the diagnostic workup for patients with neuropathic symptoms, is the most powerful tool available for characterizing the type, location, severity, and in some cases the cause of neuropathy.
As described in our earlier post on EMG and NCS, the nerve conduction study measures how fast and how strongly electrical signals travel through specific nerves. The EMG measures the electrical activity inside muscles to assess whether their nerve supply is intact and functioning. Together these tests can answer questions that no other single test can address.
Specifically, in the context of neuropathy, EMG and NCS can determine the type, location, severity, and possibly the cause of neuropathy.
What EMG and NCS cannot do is equally important to understand. They evaluate the large myelinated nerve fibers that carry the signals measured by the test. Small fiber neuropathy, which affects the thinnest nerve fibers responsible for pain and temperature sensation, is not reliably detected by standard electrodiagnostic testing. If small fiber neuropathy is suspected based on symptoms, additional specialized testing such as a skin punch biopsy measuring intraepidermal nerve fiber density may be needed. This is an important caveat: a normal EMG and NCS does not rule out neuropathy entirely. It rules out large fiber neuropathy and localizable compressive lesions, which is still enormously useful information.
What Symptoms Should Prompt Evaluation
Not every episode of tingling or numbness requires an EMG. But certain presentations warrant a thorough electrodiagnostic evaluation to characterize what is happening and guide treatment appropriately.
You should discuss electrodiagnostic testing with your doctor if you are experiencing:
Numbness, tingling, or a burning sensation in the hands or feet that is persistent, progressive, or affecting your daily function
Weakness in the hands, arms, legs, or feet that is unexplained or out of proportion to pain
Symptoms that follow a specific nerve distribution, such as tingling in the thumb and first two fingers suggesting median nerve involvement, or numbness on the outer edge of the hand suggesting ulnar nerve involvement
Foot drop or difficulty lifting the foot during walking
Symptoms that have been attributed to neuropathy without a specific type or cause being identified
A known systemic condition such as diabetes, autoimmune disease, or a history of chemotherapy, with new or worsening neurological symptoms
Neuropathy symptoms that are not responding to current treatment, where clarifying the diagnosis might change the approach
The Takeaway
Neuropathy is not a diagnosis. It is a starting point. It tells you that something is wrong with one or more nerves. It does not tell you which nerves, what kind of damage, where it is occurring, or what is causing it. Without answers to those questions, treatment is at best a guess and at worst completely misdirected.
If you have been told you have neuropathy and the conversation stopped there, you deserve a more complete evaluation. Characterizing the type of neuropathy you have, identifying the cause where possible, and directing treatment at the specific problem rather than the generic label is what makes the difference between managing symptoms indefinitely and actually addressing what is wrong.
Electrodiagnostic testing is one of the most powerful tools available for getting those answers, and it is something I perform in the office as part of a comprehensive evaluation for patients with neuropathic symptoms. If you have questions about your neuropathy diagnosis or want a more thorough workup, that conversation is exactly what a consultation is for.
Questions to Ask Your Doctor
What type of neuropathy do I have, and how was that determined?
Has a cause been identified, and if not, what workup has been done to look for one?
Would an EMG and nerve conduction study help clarify my diagnosis?
Is my neuropathy likely to progress, stay stable, or improve?
Are there treatments directed at the cause of my neuropathy, or only at the symptoms?
Are there any reversible contributors to my neuropathy that have not been addressed?
What symptoms should prompt me to seek more urgent evaluation?
This article is for educational purposes only and does not replace a conversation with your physician. The evaluation and management of neuropathy requires individualized assessment by a qualified clinician. If you have symptoms that may represent neuropathy and have not had a thorough diagnostic evaluation, please schedule a consultation.