PATHOPHYSIOLOGY OF NEUROPATHIC PAIN: A SYSTEMIC REVIEW

Neuropathic pain is considered as an inappropriate response caused by a lesion or dysfunction in the PNS or CNS). Neuropathic pain can manifest itself as either without a stimulus (stimulus-independent pain) and/ or as pain hypersensitivity elicited after a stimulus (stimulus-evoked pain). Stimulus-independent pain includes symptoms described by the patient such as (a) continuous, burning pain (b) intermittent shooting, lancinating pain (c) some dysaesthesias. Conversely, stimulus-evoked pain describes signs the physician induces after mechanical, thermal or chemical stimulation, and usually involves hyperalgesia or allodynia. The mechanism(s) underlying neuropathic pain are not completely understood but are considered to be complex, multifactorial and to evolve over time. Neuropathic pain can be trauma (surgical and non-surgical), accidents, and exposure to toxins, infection, viruses, metabolic diseases, nutritional deficiency, ischemia, and stroke. Current research studies indicate that both peripheral and central mechanisms have been involved in pathogenesis of neuropathic pain.