Neuropathic pain
Neuropathic pain is pain caused by a lesion or disease of the somatosensory nervous system.[2][3] Neuropathic pain may be associated with abnormal sensations called dysesthesia or pain from normally non-painful stimuli (allodynia). It may have continuous and/or episodic (paroxysmal) components. The latter resemble stabbings or electric shocks. Common qualities include burning or coldness, "pins and needles" sensations, numbness and itching.[3]
Neuropathic pain
Neurology and psychiatry
Variable
Damage to the nervous system resulting from diabetes mellitus, multiple sclerosis, infection, injury, and stroke, among others
Diabetes mellitus; multiple sclerosis; exposure to neurotoxicants; alcoholism; history of chemo- and/or radiotherapy; & nutritional deficiencies, among others
Clinical interview; quantitative sensory testing; electroneuromyography; nerve stimulation; biopsy; imaging, & patient self-rating of symptoms
Diabetic and metabolic neuropathy; demyelinating disease (e.g., multiple sclerosis); malignancy; spinal cord injury; primary neuralgia; mononeuritis multiplex; sciatica; pruritic processes; fibromyalgia; and functional pain syndrome, among others
Physical therapy; exercise; psychotherapy; antidepressants; gabapentinoids; anticonvulsants; Tramadol; neuromodulation, and topical agents, among others
4.1%-12.4% (12-month prevalence, US adults)[1]
Up to 7–8% of the European population is affected by neuropathic pain,[4] and in 5% of persons it may be severe.[5][6] The pain may result from disorders of the peripheral nervous system or the central nervous system (brain and spinal cord). Neuropathic pain may occur in isolation or in combination with other forms of pain. Medical treatments focus on identifying the underlying cause and relieving pain. In cases of peripheral neuropathy, the pain may progress to insensitivity.
Causes[edit]
Neuropathic pain may be divided into peripheral, central or mixed (peripheral and central) types. Central neuropathic pain is found in spinal cord injury[10] and multiple sclerosis.[11] Peripheral neuropathies are commonly caused by diabetes, metabolic disorders, herpes zoster infection, HIV-related neuropathies, nutritional deficiencies, toxins, remote manifestations of malignancies, immune mediated disorders and physical trauma to a nerve trunk.[12][13] Neuropathic pain is common in cancer as a direct result of cancer on peripheral nerves (e.g., compression by a tumor), or as a side effect of chemotherapy (chemotherapy-induced peripheral neuropathy),[14][15] radiation injury or surgery.[3]
Comorbidities[edit]
Neuropathic pain has profound physiological effects on the brain which can manifest as psychological disorders. Rodent models where the social effects of chronic pain can be isolated from other factors suggest that induction of chronic pain can cause anxio-depressive symptoms and that particular circuits in the brain have a direct connection.[16][17] Depression and neuropathic pain may have a bidirectional relationship and relief of co-morbid depression may underlie some of the therapeutic efficacy of antidepressants in neuropathic pain. Neuropathic pain has important effects on social well-being that should not be ignored. People with neuropathic pain may have difficulty working exhibiting higher levels of presenteeism, absenteeism and unemployment,[18] exhibit higher levels of substance misuse (which may be related to attempted self-medication),[19][20] and present difficulties with social interactions.[21] Moreover, uncontrolled neuropathic pain is a significant risk factor for suicide.[22] Certain classes of neuropathic pain may cause serious adverse effects necessitating hospital admission, for instance trigeminal neuralgia can present as a severe crisis where the patient may have difficulty talking, eating and drinking.[23] As neuropathic pain may be comorbid with cancer, it can have important dose limiting effects on certain classes of chemotherapeutic.[24]
History[edit]
The history of pain management can be traced back to ancient times. Galen also suggested nerve tissue as the transferring route of pain to the brain through the invisible psychic pneuma.[63] The idea of origination of pain from the nerve itself, without any exciting pathology in other organs is presented by medieval medical scholars such as Rhazes, Haly Abbas and Avicenna. They named this type of pain specifically as "vaja al asab" [nerve originated pain], described its numbness, tingling and needling quality, discussed its etiology and the differentiating characteristics.[64] The description of neuralgia was made by John Fothergill (1712-1780). In a medical article entitled "Clinical Lecture on Lead Neuropathy" published in 1924 the word "Neuropathy" was used for the first time by Gordon.[65]