Serial angiographic appearance of segmental arterial mediolysis manifesting as vertebral, internal mammary and intra-abdominal visceral artery aneurysms in a patient presenting with subarachnoid hemorrhage and review of the literature.

Segmental arterial mediolysis (SAM) is a rare, non-inflammatory, non-atherosclerotic vasculopathy typically affecting the abdominal arteries although it may also affect the great vessels and cerebral vasculature. Diseased vessels manifest with aneurysms and/or dissections, often presenting clinically with catastrophic thromboembolic injury and less frequently with subarachnoid hemorrhage (SAH). The etiology of SAM remains indeterminate although there is evidence it may be an endogenous pathological response to vasospasm. The SAM literature is reviewed and a case of SAH related to a ruptured dissecting-type vertebral artery aneurysm is described. In addition to furthering awareness of SAM, this unique case offers insight into the acute phase of the disease and the potential role of vasospastic induction.