Vasomotor abnormalities as post-polio sequelae: functional and clinical implications

Persons who had poliomyelitis report cold and discolored extremities and decreased muscle strength when exposed to mildly cool ambient temperatures. Bilateral digital cutaneous blood flow, skin temperature and median nerve latencies and amplitudes were measured at 30 degrees C, 25 degrees C and 20 degrees C in five post-polio subjects and age-matched controls. Cutaneous blood flow was lowest on the more affected side in the post-polio subjects but vasoconstriction with decreasing Ta was equal bilaterally in both groups. With decreasing Ta, median motor nerve latencies became clinically abnormal and "giant" sensory nerve potential amplitudes were seen in a majority of the post-polio subjects. It is concluded that an impairment of sympathetic vasoconstrictor outflow in post-polios allows passive dilatation and engorgement of the cutaneous venous capacitance beds. This promotes uncontrolled heat loss and causes cooling of nerve and muscle that is responsible for the impairment of muscle functioning and the abnormal electrophysiological findings.