Posterior Spinal Artery Aneurysm Presenting with Leukocytoclastic Vasculitis

Abstract

Rupture of isolated posterior spinal artery (PSA) aneurysms is a rare cause of subarachnoid hemorrhage (SAH) that presents unique diagnostic challenges owing to a nuanced clinical presentation. Here, we report on the diagnosis and management of the first known case of an isolated PSA aneurysm in the context of leukocytoclastic vasculitis. A 53-year-old male presented to an outside institution with acute bilateral lower extremity paralysis 9 days after admission for recurrent cellulitis. Early magnetic resonance imaging was read as negative and repeat imaging 15 days after presentation revealed SAH and a compressive spinal subdural hematoma. Angiography identified a PSA aneurysm at T9, as well as other areas suspicious for inflammatory or post-hemorrhagic reactive changes. The patient underwent a multilevel laminectomy for clot evacuation and aneurysm resection to prevent future hemorrhage and to establish a diagnosis. The postoperative course was complicated by medical issues and led to the diagnosis of leukocytoclastic vasculitis that may have predisposed the patient to aneurysm development. Literature review reveals greater mortality for cervical lesions than thoracolumbar lesions and that the presence of meningitic symptoms portents better functional outcome than symptoms of cord compression. The outcome obtained in this case is consistent with outcomes reported in the literature.

Keywords: Aneurysm; Hypersensitivity vasculitis; Leukocytoclastic vasculitis; Posterior spinal artery syndrome; Spinal cord vascular diseases; Subarachnoid hemorrhage.

Fig. 1. Diagnostic imaging, 15 days (MR) and 16 days (Angiography) post-presentation. (A) Sagittal T1 MR with compressive hyper-intense ventral lesion at T2-level (open arrowhead) and axial extension from C7-T8. (B) Masked angiogram of the T9 radiculopial artery with 1.5mm ectasia (open arrowhead). (C) Masked angiogram of the T5 radiculopial artery with lesion suspicious for vascular pathology (open arrowhead).

Fig. 2. Intraoperative images and photomicrographs stained with hematoxylin and eosin. (A) Intraoperative image of the aneurysm in situ with the T9 nerve root retracted. (B) Adjacent segments of the parent vessel wall appear normal (filled arrowhead) compared to the aneurysm wall (open arrowhead; 100 ×). (C) Myxoid degeneration (open arrowhead) and medial necrosis with fibrin deposition (filled arrowhead), both typical features of an aneurysm, were present in the aneurysm wall (400 ×).

Fig. 3. Literature review on posterior spinal artery (PSA) aneurysm presentation, management and outcomes. (A) Age of presentation for cervical and thoracolumbar PSA aneurysms. (B) Outcomes observed in cases of cervical and thoracolumbar PSA aneurysms. Outcomes observed were not significantly different between cervical and thoracolumbar lesions (p > 0.5, Fisher's Exact test). (C) Cases that presented with pain or meningitic symptoms ("SAH") had significantly better outcomes after intervention than those that presented with symptoms of cord compression (p < 0.05, Fisher's Exact test). SAH = subarachnoid hemorrhage.