Bilateral subclavian steal syndrome with vertigo.

Subclavian steal syndrome (SSS) is usually caused by unilateral subclavian artery (SA) occlusion, and bilateral SSS is very rare. Takayasu's arteritis (TA) is a chronic granulomatous form of vasculitis that affects the SA, most commonly in women aged 15-40 years. We report a rare case of bilateral SSS due to TA in a 52-year-old woman, who exhibited severe vertigo. Although her blood pressure was within the normal range and did not differ between her arms, Doppler ultrasonography revealed low antegrade blood flow in the right SA and retrograde flow in the left SA. Computed tomography angiography demonstrated complete obstruction of the bilateral SA proximal to the vertebral artery origin. The more marked decrease in the blood flow of the vertebrobasilar artery experienced in bilateral SSS compared with unilateral SSS is considered to have caused the severe rotatory vertigo in the present patient. Since the vascular conditions of TA progressively deteriorate, delayed diagnosis and treatment could result in poor outcomes and unfavorable prognosis. We suggest that SSS with TA might require an early detection and treatment as well as careful follow-up for preventing vertigo and other neurological deficits in the vertebrobasilar arterial region.