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What is a secondary hyperalgesia?

What is a secondary hyperalgesia?

Secondary hyperalgesia refers to the increase in sensitivity to mechanical nociceptive stimuli delivered outside the area of tissue injury.

What is punctate hyperalgesia?

Punctate hyperalgesia is the increase in pain above normal levels perceived to mechanical stimulation produced by a small contact diameter probe such as a von Frey hair.

What is the difference between primary and secondary hyperalgesia?

Primary hyperalgesia is characterized by increased responsiveness to both heat and mechanical stimulation in the area of injury. By contrast, secondary hyperalgesia is generally associated with increased responses to mechanical but not heat stimuli.

What chemical induces wind up during secondary hyperalgesia?

Injection of capsaicin induced a tenderness to mechanical stimuli in adjacent uninjured skin (secondary hyperalgesia), including hyperalgesia to light touch (allodynia) and hyperalgesia to punctate stimuli.

What is wind up phenomenon?

Wind-up is a phenomenon described in terms of neuronal responses to repetitive electrical stimulation. It can be defined as a progressive and frequency-dependent facilitation of the responses of a spinal cord neuron observed on the application of constant and high intensity repetitive electrical stimuli.

What is the definition of neuropathic pain?

Neuropathic pain is now defined by the International Association for the Study of Pain (IASP) as ‘pain caused by a lesion or disease of the somatosensory nervous system’.

What is non-noxious?

Some noxious stimuli, particularly in the viscera, do not cause nociceptive responses. Other non-noxious stimuli may cause visceral pain or afferent discharges, comparable to those from damaging stimuli. Algogenic stimuli are those that do give rise to pain and are commonly, but not invariably, noxious.

What contributes to hyperalgesia at the location of an injury?

Hyperalgesia is induced by platelet-activating factor (PAF) which comes about in an inflammatory or an allergic response. This seems to occur via immune cells interacting with the peripheral nervous system and releasing pain-producing chemicals (cytokines and chemokines).

What is visceral hyperalgesia?

Visceral hyperalgesia is an increased sensitivity to pain in the internal organs of the body, like the stomach, pancreas or intestines.