[A case of transient blindness due to severe stenosis of the internal carotid artery with persistent primitive hypoglossal artery (PPHA)].

We report a patient having transient blindness due to severe stenosis of the internal carotid artery (ICA) with persistent primitive hypoglossal artery (PPHA). This 73 year-old man was admitted because of the transient visual impairment. At first, he had bilateral blindness for a several minutes and after that the right amaurosis continued for an hour. MRI showed an old lacunar infarction of the right caudate nucleus. Carotid duplex ultrasonography and conventional angiography demonstrated severe stenosis of the origin of the right ICA, and PPHA was arising from the right ICA at the level of 2nd cervical spine. The left ICA was normal. Because of the aplasia of the right vertebral artery and hypoplasia of the left vertebral artery, almost all blood flow of the basilar artery was supplied from the right ICA via PPHA. We considered that transient ischemia of both the bilateral posterior cerebral arteries and the right ocular artery occurred due to stenosis of the right ICA which branching PPHA. When ischemic neurological symptoms of multiple vascular territories occurr at the same time, we often think that ischemic mechanism was cardiogenic embolism. But we should recognize that stenosis of the ICA with PPHA cause the complex neurological deficits.