The pathophysiology of chronic pain can be divided into three basic types. Nociceptive pain is associated with ongoing tissue damage. Neuropathic pain is associated with nervous system dysfunction in the absence of ongoing tissue damage. Finally, psychogenic pain has no identifiable cause. 3 Many chronic pain states begin with an episode of nociceptive pain and then continue with neuropathic or psychogenic pain. For example, an acute injury with fracture involves nociceptive pain, but an associated nerve injury may lead to neuropathic pain. Chronic disability may lead to psychogenic pain. Nociceptive pain results from the stimulation of nociceptors in tissues or organs by noxious mechanical, thermal, or chemical stimuli. Chemical mediators of inflammation such as bradykinins and prostaglandins are essential elements in the pathophysiology of nociceptive pain. Examples of chronic nociceptive pain include cancer pain and pain due to chronic pancreatitis. Patients with nociceptive pain usually respond well to centrally acting analgesics. Neuropathic pain is caused by disease of the central or peripheral nervous system. Examples of neuropathic pain include complex regional pain type II (causalgia), postherpetic neuralgia, and phantom limb pain. Neuropathic pain responds poorly to common analgesics, including narcotics. Psychogenic pain is a diagnosis of exclusion and can be difficult to establish in the ED. Patients with psychogenic pain believe their pain is physical and tend to strongly reject the concept that it is psychological.
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Do You Suffer From Chronic Pain? Do You Feel Like You Might Be Addicted to Pain Killers For Life? Are You Trapped on a Merry-Go-Round of Escalating Pain Tolerance That Might Eventually Mean That No Pain Killer Treats Your Condition Anymore? Have you been prescribed pain killers with dangerous side effects?