Neuropathic pain is the result of an injury or problem with the nerves themselves. The pain is often triggered by an injury or an operation. Any event that can cause an injury to your body has the potential to damage the nerves at the same time.
For example, if a muscle is crushed, then the nerves within the muscle may also be crushed. Nerves can also be damaged or squeezed by tumours and scar tissue, or irritated by an infection.
Neuropathic pain often feels like burning, stabbing, or an electric shock. Strong pain from a light touch is also common. Neuropathic pain may last for months or years – long after the injury appears to have healed. Such pain means the problem is with the nervous system itself.
Examples: Failed Back Surgery Syndrome, Neuralgia, reflex sympathetic dystrophy (nerve damage), certain cancer pain, phantom limb pain, a trapped nerve, and peripheral neuropathy (widespread nerve damage).
There are many causes of peripheral neuropathy, diabetes being the most common. But it can also be caused by chronic alcohol abuse, exposure to toxins (unhealthy chemicals), lack of certain vitamins and a large variety of other problems. The cause is often never known.
What is neuropathic pain?
Neuropathic pain can happen if your nervous system is damaged or not working correctly. You can feel pain from any of the various levels of the nervous system—the peripheral nerves, the spinal cord and the brain. Together, the spinal cord and the brain are known as the central nervous system. Peripheral nerves are the ones that are spread throughout the rest of your body to places likes organs, arms, legs, fingers and toes.
Damaged nerve fibers send the wrong signals to pain centers. Nerve function may change at the site of the nerve damage, as well as areas in the central nervous system (central sensitization).
Neuropathy is a disturbance of function or a change in one or several nerves. Diabetes is responsible for about 30% of neuropathy cases. It is not always easy to tell the source of the neuropathic pain. There are hundreds of diseases that are linked to this kind of pain.
What are some of the sources of neuropathic pain?
Neuropathic pain can be caused by diseases, including:
- Facial nerve problems.
- HIV infection or AIDS.
- Central nervous system disorders (stroke, Parkinson’s disease, multiple sclerosis, etc.)
- Complex regional pain syndrome.
- Shingles. (Pain that continues after your bout with shingles ends is called postherpetic neuralgia.)
Other causes include:
- Chemotherapy drugs (cisplatin, paclitaxel, vincristine, etc.).
- Radiation therapy.
- Amputation, which can cause phantom pain.
- Spinal nerve compression or inflammation.
- Trauma or surgeries with resulting nerve damage.
- Nerve compression or infiltration by tumors.
What are the symptoms of neuropathic pain?
Many symptoms may be present in the case of neuropathic pain. These symptoms include:
- Spontaneous pain (pain that comes without stimulation): Shooting, burning, stabbing, or electric shock-like pain; tingling, numbness, or a “pins and needles” feeling
- Evoked pain: Pain brought on by normally non-painful stimuli such as cold, gentle brushing against the skin, pressure, etc. This is called allodynia. Evoked pain also may mean the increase of pain by normally painful stimuli such as pinpricks and heat. This type of pain is called hyperalgesia.
- An unpleasant, abnormal sensation whether spontaneous or evoked (dysesthesia).
- Trouble sleeping, and emotional problems due to disturbed sleep and pain.
- Pain that may be lessened in response to a normally painful stimulus (hypoalgesia).
How is neuropathic pain diagnosed?
Your healthcare provider will take a medical history and do a physical exam. If your provider knows or suspects you have nerve injury, they will recognize typical neuropathic pain symptoms. Your provider will then try to find the underlying cause of the neuropathy and trace the symptoms.
How is neuropathic pain treated?
The goals of treatment are to:
- Treat the underlying disease (for example, radiation or surgery to shrink a tumor that is pressing on a nerve).
- Provide pain relief.
- Maintain functionality.
- Improve quality of life.
- Gabapentin (Neurontin®).
- Pregabalin (Lyrica®).
- Topiramate (Topamax®).
- Carbamazepine (Tegretol®).
- Lamotrigine (Lamictal®).
Doctors also prescribe antidepressants such as
- Amitriptyline (Elavil®).
- Nortriptyline (Pamelor®).
- Venlafaxine (Effexor®).
- Duloxetine (Cymbalta®).
Getting a prescription from your pain specialist for anti-seizure drugs or antidepressants does not mean you have seizures or are depressed. However, it’s true that chronic pain can be made worse by anxiety or depression.
Topical treatments like lidocaine or capsaicin—patches, creams or ointments—can be used on the painful area. Opioid analgesics are less effective in treating neuropathic pain, and negative effects may prevent their long-term use.
Neuropathic pain that has not responded to the therapies mentioned above can be treated with spinal cord stimulation, peripheral nerve stimulation and brain stimulation.