About Neuropathic Pain
Neuropathic pain is defined as “pain caused by a lesion or disease or the somatosensory nervous system” by the International Association of the Study of Pain. It is a complex condition affecting physical, mental and professional quality of life, associated with high healthcare costs and occurs in about one percent of the population.
Central & Peripheral Pain
Neuropathic pain is divided into central and peripheral pain. Central neuropathic pain is defined as “pain caused by a lesion or disease of the central somatosensory nervous system” which means the brain or spinal cord. Peripheral neuropathic pain is defined as “pain caused by a lesion or disease of the peripheral somatosensory nervous system" which is anything that has branched off from your spinal cord.
Pain can either be intermittent or constant and spontaneous or provoked. Neuropathy symptoms are often described as: shooting, stabbing, electric shock, burning, painful tingling, pressing, itching, tight, numb, pricking and pins and needles. Other sensations that are reported are of allodynia (pain caused by a stimulus that does not normally cause pain), hyperalgesia (an increased pain response to a stimulus that is normally painful), anaesthesia dolorosa (pain felt in a numb area), and sensory gain or loss.
Causes
Neuropathy causes are very varied. It is present in; trigeminal neuralgia, radicular neuropathic pain and thalamic pain. Diabetic peripheral neuropathy affects 46% of diabetes patients. There are many forms of neuropathy related to cancer such as; chemotherapy-induced neuropathy, neuropathy secondary to tumour antigens or by neural structures compression. Post-stroke neuropathies are frequently reported and post-spinal cord injury neuropathy affects 31% of patients. In addition, complex regional pain syndrome (CRPS), multiple sclerosis, nervous compression syndrome after burn injuries and phantom limb pain also are all types of neuropathic pain.
There are a variety of models that describe why neuropathic pain occurs. There is peripheral sensitisation and central sensitisation. It is thought that in some patients, the nerve lesion triggers molecular changes in pain receptor neurons which makes them abnormally sensitive and develop abnormal spontaneous activity.
Changes may also occur in uninjured neurons driven by substances released by adjacent dying cells. This means that what you might normally feel as light touch, you feel as pain because the pain receptors are over active or you can experience spontaneous pain for no reason. This is peripheral sensitisation. The hyperactivity in pain receptors, in turn, causes secondary changes (hyperexcitability) in the spinal cord and brain and lead to central sensitisation. Neuroplastic changes in the central descending pathway which normally dampens down pain no longer performs its function and may lead to further hyperexcitability.
At the moment, the treatment of neuropathic pain relies mainly on pharmaceutical management. Despite the numerous medications available, the most appropriate medical treatment is only able to reduce pain in 70% of patients.
Learn more about how Mirror Therapy can help deal with Neuropathic Pain.