[Sandel]

Regulation of peripheral blood flow in Complex Regional Pain Syndrome: clinical implication for symptomatic relief and pain management.

http://www.biomedcentral.com/1471-2474/10/116

Quote:

Background
During the chronic stage of Complex Regional Pain Syndrome (CRPS), impaired microcirculation is related to increased vasoconstriction, tissue hypoxia, and metabolic tissue acidosis in the affected limb. Several mechanisms may be responsible for the ischemia and pain in chronic cold CPRS.

Discussion
The diminished blood flow may be caused by either sympathetic dysfunction, hypersensitivity to circulating catecholamines, or endothelial dysfunction. The pain may be of neuropathic, inflammatory, nociceptive, or functional nature, or of mixed origin.

End quote:

Hi,
This study discusses amongst other things the various pain states and what can cause them, exaberate them, and hopefully help.
It also sugests some newer treatments in their pharmacological section where they discuss the various new studies out and treatment regimes.

S.