A CASE OF BILATERAL MEDIAL POSTERIOR INFERIOR CEREBELLAR ARTERY INFARCTION ASSOCIATED WITH SUBCLAVIAN STEAL SYNDROME

Subclavian Steal Syndrome (SSS) is the result of reversed ipsilateral vertebral arterial blood flow caused by proximal subclvian artery steno-occlusive disease. A 78-year-old man with a history of hypertension and smoking presented with sudden dizziness, nausea and vomiting; there was no history of recent trauma and arm claudication. Neurologic examination showed no abnormality except for ataxia of both arms. Diffusion Weighted Image (DWI) indicated acute bilateral medial Posterior Inferior Cerebellar Artery (PICA) infarction. Subsequent brain Magnetic Resonance Angiography (MRA) revealed chronic occlusion at the left proximal subclavian artery with decreased left vertebral artery flow and prominent left (PICA) from vertebral artery. Transcranial Doppler (TCD) ultrasonography showed reversal of flow within the left vertebral artery, and reactive hyperemic cuff test of the left arm showed aggravated reverse flow of left vertebral artery following release of blood pressure cuff inflation, which was suggestive of SSS. Although the etiologies of bilateral PICA infarction might be diverse, we experienced a case of acute bilateral medial PICA infarction, which were presumed as hemodynamic insufficiency due to SSS.