Postsympathectomy limb pain, postsympathectomy parotid pain, and Raeder's
paratrigeminal syndrome are pain states associated with the loss of sympathetic fibres
and in particular with postganglionic sympathetic lesions. There is a characteristic interval
of about 10 days between surgical sympathectomy and onset of pain. It is proposed that
this pain in man is correlated with the delayed rise in sensory neuropeptides seen in
rodents after sympathectomy. These chemical changes probably reflect the sprouting of
sensory fibres and may result from the greater availability of nerve growth factor after
sympathectomy. The balance between the sensory and sympathetic innervations of a
peripheral organ may be determined by competition for a limited supply of nerve growth
factor.
Lancet. 1985 Nov 23;2(8465):1158-60.