Neuropathy is damage or dysfunction affecting one or more nerves, most commonly in the peripheral nervous system, which includes all nerves outside the brain and spinal cord. These nerves transmit signals for motor, sensory, and automatic bodily functions. Disruption to these signals leads to symptoms like numbness, tingling sensations, muscle weakness, and pain. The condition stems from a wide range of underlying issues and affects millions globally.
Common Causes of Nerve Damage
The most frequent cause of peripheral neuropathy is diabetes, responsible for about half of all cases. High blood sugar levels impair nerve function by damaging the small blood vessels that supply nerves with oxygen and nutrients. This metabolic stress directly harms nerve fibers, leading to a progressive loss of sensation and function, particularly in the feet and hands.
Beyond diabetes, nerve damage has other origins. Certain chemotherapy drugs are neurotoxic, causing chemotherapy-induced peripheral neuropathy (CIPN). Chronic alcohol use is another contributor, as it has a direct toxic effect on nerve tissue and often leads to nutritional deficiencies that further harm nerves. Up to two-thirds of individuals with chronic alcohol abuse may develop neuropathy.
Autoimmune diseases, where the immune system attacks the body’s own tissues, can also cause neuropathy. Conditions like Guillain-Barré syndrome, lupus, and rheumatoid arthritis can cause inflammation that damages peripheral nerves. Deficiencies in vitamin B12 can compromise the protective myelin sheath around nerve fibers. Other causes include:
- Direct physical injury
- Infections like shingles or Lyme disease
- Kidney failure
- Inherited genetic disorders
In some instances, a specific cause cannot be determined, a condition known as idiopathic neuropathy.
Identifying Neuropathy Symptoms
Damage to sensory nerves produces recognizable symptoms. Individuals may experience a gradual onset of numbness or a prickling “pins and needles” feeling, which begins in the feet and hands and can spread upward. Pain is a common feature and can manifest as sharp, jabbing, or burning sensations. Some people develop a high sensitivity to touch, where even light pressure causes significant pain.
When motor nerves are affected, symptoms relate to movement. This can include muscle weakness, twitching, cramps, and a loss of coordination that increases the risk of falling. In some cases, there can be a thinning of muscles due to the lack of nerve stimulation. A sign known as foot drop, the difficulty lifting the front of the foot, can make walking challenging.
Damage to autonomic nerves disrupts the body’s involuntary functions. This can lead to issues such as a sharp drop in blood pressure upon standing, causing dizziness or fainting. Other symptoms may include digestive problems, abnormal sweating patterns, and issues with bladder control or sexual function. A person with neuropathy may experience symptoms from one or all of these nerve categories.
The Diagnostic Process
The diagnostic process begins with a physician consultation. A doctor will review a patient’s medical history, symptoms, lifestyle, and family history of neurological diseases. This is followed by a physical and neurological exam to test reflexes, muscle strength, and the ability to feel different sensations.
Blood tests are ordered to investigate underlying causes. These tests can detect conditions like diabetes, vitamin deficiencies, or metabolic issues known to cause nerve damage. This screening helps narrow down potential sources and guides further diagnostic steps.
If the initial evaluation suggests nerve damage, specialized nerve function tests are performed. A nerve conduction study (NCS) measures the speed and strength of signals traveling through a nerve. An electromyography (EMG) assesses the electrical activity within muscles. Together, these tests help determine if symptoms stem from a nerve or muscle disorder. Imaging tests like an MRI or a nerve biopsy may be used in less common situations.
Managing Neuropathy
Management focuses on treating the underlying cause to prevent further damage and on relieving symptoms. For instance, in diabetic neuropathy, managing blood sugar levels can slow the condition’s progression. If the cause is a vitamin deficiency, supplementation is a direct course of action.
Pain can be treated with over-the-counter medications, but many people require prescription drugs. Certain antidepressants and anti-seizure medications are effective because they alter chemical signals in the brain involved in pain perception. These medications can reduce the burning, stabbing, or tingling sensations of nerve pain.
Physical therapy is another component of managing neuropathy. A personalized exercise program can improve strength, balance, and coordination, which helps reduce fall risk and maintain mobility. Therapists may also use transcutaneous electrical nerve stimulation (TENS) to block pain signals. Lifestyle adjustments like regular exercise, a balanced diet, and quitting smoking also support nerve health. For those with neuropathy in their feet, meticulous foot care is necessary to prevent infections.