Primitive Trigeminal Artery: A Route for Emboli and Collateral

ABSTRACT

@#INTRODUCTION: Persistent carotid-basilar anastomoses are potentially clinically relevant anomalies of the intracranial vasculature. The trigeminal artery is the largest and persists for the longest embryonic period among the anastomoses. The increasing use of arteriographic procedures has augmented its incidence to 0.1-1%. This is a case of a 39-yearold male who presented with acute occipital lobe infarct after sustaining a traumatic right carotid dissection. CASE PRESENTATION A 39-year-old male was brought in to the emergency room after a 200-kilogram sack fell on his upper back. He landed on his chest with his head rotated to the right and sustained multiple lacerations on his face and chest. There were noted acute bilateral loss of vision, lethargy and unsteady gait. Computed tomography (CT) scan of the brain showed neither infarct nor hemorrhage. However, magnetic resonance imaging (MRI) of the brain revealed an acute occipital lobe infarct. The patient was started on antiplatelet. Further workup revealed a totally occluded right common carotid artery upon carotid duplex. His vision improved to be able to perceive light and hand movement. Further workup was done as an outpatient. A week after hospital discharge, patient’s vision improved to left bilateral hemianopsia. His gait has improved and was able to walk with balance. A cerebral angiogram later revealed a large bilateral persistent primitive trigeminal artery (PPTA). The right PPTA provided collateral flow to the right cerebral hemisphere. This primitive collateral vessel is believed to have served as a route for emboli to be thrown to the posterior circulation in the occipital lobe. CONSLUSION The consideration of a persistent primitive carotid-basilar anastomoses may elucidate the physician when a gap between patient’s manifestation and imaging studies exist. The presence of persistent carotid-basilar anastomoses may herald other vascular anomalies, it may offer as alternative endovascular access, or may serve as access for emboli passage.