Abnormalities of cutaneous blood flow regulation in patients with reflex sympathetic dystrophy as measured by laser Doppler fluxmetry.

The response of cutaneous blood flow to autonomic stimuli was evaluated in eight patients with clinically staged reflex sympathetic dystrophy and eight healthy control subjects. Blood flow was measured in the affected and contralateral extremities by laser Doppler fluxmetry. Five autonomic stimuli were applied to the contralateral extremity during blood flow measurement in the ipsilateral affected extremity. Affected limbs of patients with reflex sympathetic dystrophy were found to have statistically significantly increased blood flow during the Valsalva maneuver and cold pressor test, while blood flow decreased in normal controls. No significant differences were found in limb temperature or baseline blood flow between patients and controls. Reflex sympathetic dystrophy stage did not affect response to the procedures. Control subjects demonstrated a rhythmic cycling of cutaneous blood flow that was absent in patients with reflex sympathetic dystrophy. These results support a central abnormality of the sympathetic nervous system in reflex sympathetic dystrophy.