Subarachnoid Hemorrhage Revealing a Fistula Point Venous Aneurysm in a Dural Arteriovenous Fistula at the Craniocervical Junction: A Case Report

Dural arteriovenous fistulas represent approximately 10% of all intracranial vascular malformations, of which 1 to 2% are located at the craniocervical junction. Their location at the craniocervical junction is uncommon but potentially significant, given its proximity to and relationship with vital anatomical structures in this region. The association of a dural arteriovenous fistula with a venous aneurysm is rare. In this report, we present the case of a 49-year-old patient with no particular pathological history who was admitted for acute headaches. The neurological examination revealed a patient with grade I WFNS, intracranial hypertension syndrome. Radiological investigations including CT, CT angio and MRI revealed a fisher IV subarachnoid hemorrhage due to a ruptured venous aneurysm associated to an arteriovenous fistula at the craniocervical junction. He underwent clipping of the veinous aneurysm and microsurgical obliteration of the fistula. The postoperative course was uneventful. The clinical examination at 1-year post-op was unremarkable, and the follow-up MRI at 1-year post-op showed complete obliteration of the malformation. This report showed ruptured dural arteriovenous fistula should be considered in the etiology workup for posterior fossa subarachnoid hemorrhage. Effective and safe obliteration is possible without angiography.