A review of sympathetically maintained pain syndromes in the cancer pain population: the spectrum of ambiguous entities of RSD, CRPS, SMP and other pain states related to the sympathetic nervous system.
Accepted wisdom contends that sympathetically maintained pain is rare in cancer pain syndromes. But this may be more of an artifact of how we diagnose this condition than a reflection of its true prevalence. One area in which one might suspect this to be true is in postsurgical states. While there are case reports of sympathetically maintained pain occurring after radical neck dissection, orbital and maxillary exenteration, it has not been reported in the more common areas of postsurgical pain. For instance, although one should suspect that the nerve damage that accompanies post-thoracotomy and postmastectomy pain syndromes would bring into being a certain incidence of sympathetically maintained pain, it is difficult to find collaborative reports. This may have more to do with the difficulty inherent in diagnosing sympathetically maintained pain than its actual contribution to these persistent cancer pain syndromes. The reason that it is more commonly reported in limb amputation is less comprehensible since blocking the sympathetic fibers that travel to an extremity is easier than those going to the thoracic cavity. In addition to surgically induced sympathetically maintained pain, medical patients with lymphoma and leukemia may have an element of sympathetically maintained pain when they develop postherpetic neuralgia. While the contribution of sympathetically maintained pain in these cases is not totally ignored, its involvement, as in the surgical patients mentioned above, is worthy of another analysis. This paper will discuss the topics introduced above and suggest diagnostic and therapeutic options available for this condition.
Wilsey
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B
Department of Anesthesiology and Pain Medicine University of California, USA.
Teicheira
D
D
Caneris
O A
OA
Fishman
S M
SM