Neuropathic pain
What is neuropathic pain?
Usually, pain is felt when special nerve endings sense that something is wrong with your body and send pain signals to your spinal cord and brain. Neuropathic pain occurs when the nerves themselves are damaged by disease or injury, causing them to misfire and send pain signals to the brain. The resulting pain is often severe and can be difficult to treat.
Neuropathic pain is usually described as shooting, stabbing or burning, sometimes it feels like an electrical shock, and is often worse at night than during the day. The pain may be constant or it may come and go, and it may be accompanied by tingling sensations or numbness.
People with neuropathic pain are often extremely sensitive to painful stimuli. They may also have increased sensitivity to touch or cold, and may perceive non-painful stimuli, such as light touch or gentle brushing of the skin, as severe pain.
What causes neuropathic pain?
Neuropathic pain is caused by damage to, or dysfunction of, the nervous system. The pain can be due to problems in the central nervous system (the brain or spinal cord) or the peripheral nervous system (the nerves in the rest of the body — i.e. the nerves in your face, arms, legs and torso).
While doctors are sometimes unable to pinpoint the cause of neuropathic pain, there are several known causes, including:
- trauma;
- vitamin B12 or thiamine (vitamin B1) deficiency;
- alcohol abuse;
- multiple sclerosis;
- nerve compression or invasion by a tumour;
- stroke;
- certain medications;
- infections such as shingles and HIV/AIDS; and
- diabetes.
Some examples of neuropathic pain include:
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Painful diabetic peripheral neuropathy.
Diabetes can damage the peripheral nerves, especially those in the legs and feet, causing pain as well as numbness and tingling.
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Trigeminal neuralgia.
Trigeminal neuralgia is a disorder of the trigeminal nerve — the nerve that supplies sensation to the face and controls some of the muscles involved in chewing. It causes episodes of severe facial pain that last from a couple of seconds to several minutes.
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Post-herpetic neuralgia.
About one in every 5 people with shingles (a painful rash also known as herpes zoster) develops post-herpetic neuralgia — ongoing pain in the area that was affected by the rash. It occurs when the shingles virus damages the underlying nerves, and the resulting pain can last for months or years.
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Phantom limb pain.
This condition affects people who have had an arm or leg amputated, causing pain or discomfort in the now-missing limb. The exact cause of phantom limb pain is not known, but it is thought to be due to changes in both the peripheral and central nervous systems following amputation.
How is neuropathic pain diagnosed?
If your doctor suspects you have neuropathic pain, he or she will ask about the pain and perform a physical examination, testing the nerves in the affected area. You may need to have blood tests, nerve conduction studies (to measure how quickly your nerves can carry electrical signals) or an MRI scan. Sometimes a nerve biopsy is needed to examine a small portion of nerve fibres for any abnormalities.
Are there any treatments available?
In general, if you have neuropathic pain, your doctor will most likely suggest you try regular pain medications such as aspirin, paracetamol or a non-steroidal anti-inflammatory medication (NSAID) to start with. But while they are worth trying, these medicines may not always relieve neuropathic pain.
The good news is that there are different medications available that can help treat this type of pain. Not all of the medications are available on the PBS, however, your doctor will be able to guide you. The medications include:
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Tricyclic antidepressants
A class of antidepressant medications known as tricyclic antidepressants (tricyclics) has been found to relieve neuropathic pain in many people. These medications have a pain-relieving effect that is separate to their antidepressant effect, and may be especially useful in relieving constant, burning pain. Amitriptyline is the most commonly used tricyclic for treating neuropathic pain. It seems to be the most effective pain reliever for this condition, but it is not always well tolerated because of its side effects.
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Anticonvulsants
Anticonvulsant medications — the same medicines that are used to control seizures in people with epilepsy — also seem to be effective in treating neuropathic pain, and work by slowing or blocking uncontrolled pain signals. Anticonvulsants may be better than tricyclics for treating sharp, shooting neuropathic pain.
Carbamazepine is one type of anticonvulsant medication that can be used. It is usually the preferred medication choice for trigeminal neuralgia, but may be less effective in treating painful diabetic neuropathy.
Gabapentin is another anticonvulsant medication that can relieve neuropathic pain, and has been found to be useful in treating painful diabetic neuropathy and post-herpetic neuralgia. It typically has fewer side effects than tricyclics and the other anticonvulsants.
If tricyclics and anticonvulsants have not relieved your pain, you doctor may suggest you try other types of medication, which may need to be prescribed by a specialist pain physician. They include:
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Other anticonvulsants
. Sodium valproate may be tried if carbamazepine and gabapentin fail to relieve pain, or are not well tolerated due to side effects. Pregabalin is another anticonvulsant that can be used to treat neuropathic pain — studies have found it can relieve pain in people with diabetic neuropathy and post-herpetic neuralgia.
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Antiarrhythmics
(e.g. mexiletine or flecainide). These medicines are normally used to stabilise abnormal heart rhythms, but are sometimes effective in controlling neuropathic pain. People with heart problems may not be able to use these medications.
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Clonidine
, a medication that is usually used to control high blood pressure, may relieve pain in some people.
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Other medications
. Local anaesthetics (e.g. lignocaine cream or skin patches) and capsaicin cream (which contains a substance extracted from red chilli peppers) may also be effective in treating some types of neuropathic pain, such as post-herpetic neuralgia. Strong pain relievers (such as tramadol and oxycodone), anaesthetic medications (such as ketamine), and injections of medications directly into the spine can also be tried.
A combination of several medications can be effective for some people, especially those who have a partial response to one or more medicines.
Are there any other treatments that can be tried?
There are some other treatments that may help to control neuropathic pain, including:
- acupuncture;
- relaxation techniques, which are used to reduce any muscle tension that is contributing to pain;
- psychological treatments, such as cognitive behavioural therapy (CBT), which can help you gain a sense of control over pain and reduce distress; and
- transcutaneous electrical nerve stimulation (TENS), which uses mild electrical currents (from electrodes that are taped to the skin near the site of the pain) to block the transmission of pain sensations to your brain.
Last Reviewed: 01 July 2008
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