The reflex sympathetic dystrophy syndrome. An experimental study of sympathetic reflex control of subcutaneous blood flow in the hand.

Adrenergic sympathetic vasoconstrictor activity in subcutaneous tissue on the back of the hand was studied in 13 patients suffering from reflex sympathetic dystrophy syndrome. Subcutaneous blood flow was measured by the local 133Xe wash-out technique with simultaneous measurements on the healthy side as a control. The results indicated an increased subcutaneous blood flow in the affected hand compared with the control side. Proximal nervous blockade caused only a slight, 35% increase in subcutaneous blood flow on the affected side, whereas an increase of 122% was registered on the control side. Augmented sympathetic vasoconstrictor activity elicited by the local veno-arteriolar axon reflex mechanism or centrally elicited by head-up tilt caused an equal degree of arteriolar vasoconstriction in both hands. The results suggest that sympathetic vasomotor tone during resting conditions is reduced in the affected hand in patients with the reflex sympathetic dystrophy syndrome.