Sympathetic nervous system involvement in the syndrome of painful legs and moving toes

The objective of this study is to investigate sympathetic nervous system involvement in 2 patients with painful legs and moving toes. The first case was studied several years after the initiating trauma produced a peripheral nerve lesion and demonstrated the characteristic sequence of progression of pain and moving toes from the injured leg to the contralateral leg. The second case was initially studied within 3 months of an injury that did not produce definitive signs of a peripheral nerve lesion. Pain increased when the patients were startled and subsided temporarily after sympathetic blockade. In the first patient, toe movements and allodynia to light tactile stimulation persisted during sympathetic blockade, and pain sometimes returned before the vascular effects of blockade disappeared. In the second patient, pain and toe movements could be provoked reproducibly by light tactile stimulation of the affected foot and by sympathetic arousal. These symptoms and signs disappeared after lumbar sympathectomy, and re-emerged when signs of sympathetic reinnervation were detected. We concluded that sympathetic neuronal discharge may provoke pain by activating an impulse generator in the affected limb. Sympathetic involvement in the painful legs and moving toes syndrome appeared to be greater in the second case than the first, presumably due to differences in the initial injury or stage of the condition