Neuropathic Pain: Definition, Causes, Symptoms & Treatment

What is neuropathic pain?

Neuropathic pain is a type of chronic pain that results from damage to the somatosensory nervous system. It is not caused by injury to muscles or bones, but by the nerves themselves. In this condition, the nerves send incorrect pain signals to the brain. This type of pain often persists for long periods and can significantly affect a person’s quality of life.

How is it caused?

Neuropathic pain occurs when there is damage to the nerves that transmit sensory information such as touch, temperature, and pain. It may involve nerves of either the peripheral nervous system or the central nervous system (brain and spinal cord).

This damage may occur for several reasons, including injury, diabetes mellitus, or herpetic infection.

Neuropathic pain may appear without an active painful stimulus, or it may occur as an exaggerated response to a mild or moderately painful stimulus. Damaged nerve axons involved in pain transmission send incorrect or excessive electrical signals to the brain.

It may manifest as:

• Paresthesia (an abnormal but not unpleasant sensation, either spontaneous or provoked)

• Dysesthesia (an abnormal and unpleasant sensation, either spontaneous or provoked)

• Allodynia (perception of a normally non-painful stimulus as painful)

• Hyperalgesia (perception of a painful stimulus as excessively painful)

Epidemiology

It is estimated that approximately 7–10% of the general population experience some form of neuropathic pain. It is more common in individuals over the age of 50, but it can occur at any age depending on the underlying cause.

Causes

The main causes of neuropathic pain include:

• Diabetes mellitus (diabetic neuropathy)

• Herniated intervertebral discs, resulting in compression of nerve roots in the spine

• Surgical procedures

• Herpes zoster (postherpetic neuralgia)

• Multiple sclerosis

• Spinal cord injury

• Chemotherapy

• Radiation therapy

• Alcoholism

• Stroke

• Trigeminal neuralgia

In some cases, the exact cause cannot be identified.

Symptoms

Neuropathic pain may present as burning, sharp, stabbing, or piercing (“knife-like”) pain, as a sensation of electric shocks, tingling, numbness, or prickling (pins and needles). It may be accompanied by increased sensitivity to touch or pain. Symptoms can be constant or intermittent and often worsen at night or during periods of relaxation.

Diagnosis

There is no specific diagnostic test that definitively establishes the diagnosis of neuropathic pain. Diagnosis is primarily based on a detailed medical history, clinical examination, and the use of diagnostic questionnaires.

General laboratory tests (blood tests) and imaging studies are often recommended to identify or rule out underlying causes and to guide appropriate treatment.

Neurophysiological testing (such as nerve conduction studies and electromyography) may also be performed to assess the function of peripheral nerves.

Psychological evaluation may also be important, as neuropathic pain is frequently associated with depression and anxiety disorders.

Treatment

Treatment of neuropathic pain is individualized and requires a multidisciplinary approach that may include pharmacological therapy, psychological support (behavioral therapy), and physical therapy.

Treatment is primarily symptomatic and aims to improve the patient’s functionality and quality of life. Comorbidities and the patient’s current medication regimen must also be taken into account.

Common pharmacological treatments include:

• Antidepressants, such as tricyclic antidepressants and serotonin–norepinephrine reuptake inhibitors (SNRIs) (e.g., duloxetine, venlafaxine)

• Antiepileptic medications (e.g., pregabalin, gabapentin, carbamazepine, oxcarbazepine, lamotrigine)

• Opioids (e.g., tramadol, tapentadol)

• Topical treatments such as lidocaine and capsaicin

In some cases, interventional therapies, such as neuromodulation, may also be considered.