Myoclonus with burning sensation in legs that remits with sympathetic blockade

Two patients with hitherto unrecognized spells of involuntary movements in legs are described. They occurred on dropping off to sleep, were preceded by a burning sensation and resembled myoclonus. Subcutaneous injection of epinephrine reproduced the spells. Neurogenic bladder of uninhibited type was noted on cystometry. Epidural or sympathetic nerve block of the lumbar region relieved all the symptoms including the neurogenic bladder. A few minutes before the spells, a rise in blood pressure and pulse rate was observed in one of the cases. Pathophysiological resemblance to painful legs and moving toes was pointed out, but more widespread involvement of the spinal cord was suspected.