Neuropathic pain is defined as pain arising from a lesion (a disease

or injury) that affects the somatosensory nervous system. Central

neuropathic pain arises from lesions to the central nervous system (CNS -

brain or spinal cord), with two of the most common causes being spinal

cord injury and stroke. Peripheral neuropathic pain arises from lesions

to the peripheral nervous system (PNS - nerves outside of the CNS).

Neuropathic pain can also be caused by cancer and diabetes.

Put simply, neuropathic pain is the result of sensory nerve cells becoming ‘maladaptive’ – unable to respond correctly to stimuli, although the precise underlying mechanisms are complex, variable and not fully understood.

The pain is commonly described as burning, cold, sharp or like electric shocks, and can accompanied by numbness, tingling, ‘pins and needles’, itching and weakness. Certain neuropathic painful conditions may also be accompanied by sweating, changes in skin colour, swelling and abnormal hair and nail growth. People with neuropathic pain may also experience hypersensitivity to light touch, painful stimuli (such as a pinprick) and changes in temperature.

Neuropathic pain conditions include Complex Regional Pain Syndrome (CRPS), diabetic neuropathy, neuropathic cancer pain, postherpetic neuralgia (pain that lasts more than 3 months after a herpes zoster / ‘shingles’ outbreak), failed back surgery syndrome (chronic back pain following spinal surgery) and other chronic pain originating from the spine, such as sciatica.

Treatment of neuropathic pain is usually multimodal and highly individualised. Medications include opioids (i.e. morphine, oxycodone, buprenorphine), anticonvulsants (i.e. gabapentin, pregabalin), antidepressants (tricyclic and serotonergic; i.e. amitriptyline, duloxetine, venlafaxine), and topical analgesics (patches and creams).

Procedures that aim to disrupt the transmission of pain signals may be performed and include nerve blocks (direct injection of anaesthetic) and radiofrequency neurotomy (delivery of electrical current via probe).

Advanced pain management may be required if conventional treatment is ineffective and includes neurostimulation (i.e. peripheral nerve or spinal cord stimulation) and implanted drug delivery (i.e. intrathecal pump). Treatment of neuropathic pain is most effective if diagnosed early.

References

1. International Association for the Study of Pain. 2014-2015 Neuropathic Pain. 2015; http://www.iasp-pain.org/GlobalYear/NeuropathicPain.
2. Votrubec M, Thong I. Neuropathic pain--a management update. Aust Fam Physician. 2013;42:92-97.
3. von Hehn CA, Baron R, Woolf CJ. Deconstructing the neuropathic pain phenotype to reveal neural mechanisms. Neuron. 2012;73:638-652.
4. Costigan M, Scholz J, Woolf CJ. Neuropathic pain: a maladaptive response of the nervous system to damage. Annu Rev Neurosci. 2009;32:1-32.
5. Rashbaum R.Treatment Options for Neuropathic Pain. Spine-health. 2001; http://www.spine-health.com/treatment/pain-management/treatment-options-neuropathic-pain.