Dual Left-Sided Posterior Inferior Cerebellar Artery Aneurysms Presenting with Subarachnoid Hemorrhage, Intraventricular Hemorrhage and Hydrocephalus: A Rare Case Report and Systematic Review.

Abstract

Aneurysms of the posterior inferior cerebellar artery (PICA) are among the least common intracranial aneurysms, accounting for approximately 0.5% to 3% of cases. Those arising distally are even rarer and are known to rupture at smaller sizes. Their rupture frequently results in subarachnoid hemorrhage, intraventricular hemorrhage (IVH), and hydrocephalus, posing considerable treatment challenges due to the surrounding vital brain structures. A 62-year-old woman presented to the emergency department with a sudden severe headache, nausea, vomiting, and unconsciousness. On examination, her Glasgow Coma Scale score was 3. Brain imaging revealed diffuse subarachnoid hemorrhage, intraventricular hemorrhage (IVH), and obstructive hydrocephalus. Vascular imaging identified 2 aneurysms on the left posterior inferior cerebellar artery (PICA), one proximal, and one distal. The patient underwent suboccipital craniectomy, with successful clipping of both aneurysms and clot evacuation. Postoperatively, she showed neurological improvement, including spontaneous eye opening and reactive pupils. A targeted literature review identified 13 patients from 8 published reports with similar aneurysms. The average age was 45.5 years, with a slight female predominance. IVH was observed in over half the cases. Presentation often included headache, impaired consciousness, and occasionally seizures. Treatment was either surgical or endovascular, with positive outcomes in most reports. Although distal PICA aneurysms are uncommon, prompt diagnosis and individualized surgical intervention can lead to favorable outcomes, especially in cases involving multiple aneurysms and hemorrhagic complications. This paper provides a rare case and presents the first systematic review of distal PICA aneurysms.