[Orthostatic hypotension with repeated bilateral limb shaking and metamorphopsia. A case of hemodynamic transient ischemic attacks].

A 78-year-old right-handed man with idiopathic orthostatic hypotension and a history of Hashimoto's thyroiditis presented over 2 years with recurrent, stereotyped attacks of bilateral limb shaking and metamorphopsia, which were precipitated by standing more than 3 or 4 minutes, or walking a few meters. These symptoms would resolve upon squatting or lying down and did not occur spontaneously at rest. He did not lose consciousness during the attacks. Speech, power, and sensation were preserved during these attacks. He had no history of seizures or habit of smoking. On examination, his supine blood pressure was 110/60 mmHg, and 62/27 mmHg on standing, with the pulse rate being 61/min and 66/min, respectively. Although he showed orthostatic hypotension, he did not complain of fainting or lightheadedness on standing alone. Magnetic resonance imaging of the brain revealed mild periventricular white matter changes and multiple small ischemic lesions bilaterally in the cerebral deep white matter. An electroencephalogram (EEG) showed mild, generalized slowing of nonspecific feature. EEG monitoring during a limb shaking episode showed no epileptiform abnormalities. Cerebral angiogram revealed a moderate degree of stenosis of the left internal carotid and a mild degree of stenosis of the right internal carotid, the right vertebral arteries and the left vertebral arteries. A single-photon emission computed tomography (SPECT) showed a moderate compromise of perfusion of the left internal carotid territory. After managing both hypotension and orthostatic hypotension with antihypotensive medication and levothyroxine sodium, his symptoms dramatically disappeared. Thus, we diagnosed that transient hemodynamic insufficiency due to combination of vascular stenosis and hypotension was the cause of these symptoms. Limb shaking is a well-described presentation of carotid artery occlusive disease and is usually unilateral. Bilateral limb shaking is rare and only 2 cases have been reported. Metamorphopsia is also a rare symptom of vertebrobasilar ischemia. We suggest that bilateral limb shaking correlates with hypoperfusion in the anterior border zones and metamorphopsia with that in the posterior border zones of both hemispheres. Hemodynamic TIA should be considered as a cause of movement disorders affecting four limbs.