A 70-year-old man developed episodes of rhythmic shaking (approximately
3Hz) of the left arm lasting for up to 2 minutes and preceeded by a brief
period of light-headedness. Occasionally, the left arm shaking was accompanied
by an odd feeling but no shaking in the left leg. Attacks occurred a few
times a week and were almost always triggered by standing up. Consciousness
was never impaired. There was a history of hypertension and type II diabetes
and he was taking metformin and antihypertensive medication.
On examination there was no abnormality except that he was overweight
with an elevated blood pressure of 180/90mm Hg.