Recurrent horner syndrome and persistent trigeminal artery

INTRODUCTION:: A persistent primitive trigeminal artery (PTA) is the most common type of fetal carotid-basilar anastomosis in adulthood; however, its prevalence is low and estimated between 0.1% and 0.7% in angiographic studies. PTA is usually diagnosed incidentally during an angiographic examination, though some symptomatic cases associated with cranial nerve dysfunction have been described. We describe the unusual association between PTA and ipsilateral Horner syndrome triggered by hypertensive crisis. CASE REPORT:: A 40-year-old man presented to medical attention for recurrent episodes, over the last 3 years, characterized by hypertensive crisis (up to 220/150 mm Hg), dizziness, tachycardia, flushing of the forehead on the left side, ptosis, miosis, and conjunctival injection of the left eye without pain. Imaging revealed a left PTA originating from the carotid siphon with moderate ectasia of the proximal tract. We speculate that the recurrent Horner syndrome observed in our patient could be due to the disruption of the postganglionic peripheral fibers in the pericarotid plexus. Adequate antihypertensive therapy led to resolution of signs and symptoms. CONCLUSIONS:: To our knowledge, we present the first case of persistent PTA and ipsilateral Horner syndrome during hypertensive crisis. Adequate antihypertensive therapy can be useful in patients bearing trigeminal artery variants.