Anterior spinal artery aneurysm presenting with spinal subarachnoid hemorrhage in a case of polyarteritis nodosa

Polyarteritis nodosa is characterized by presence of aneurysms in the renal, hepatic and mesenteric vasculature, and less often by vascular abnormalities in the intracranial compartment. Spinal subarachnoid hemorrhage is a rare phenomenon that can be associated with inflammatory vasculopathies such as polyarteritis nodosa, but the link between aneurysm formation and spinal subarachnoid hemorrhage in polyarteritis nodosa is unclear. We describe a case of a patient with polyarteritis nodosa and spinal subarachnoid hemorrhage following rupture of an aneurysm of the anterior spinal artery. Following operative washout and decompression of the subarachnoid hemorrhage, spinal digital subtraction angiography was performed and revealed intimal contour irregularities, stenotic changes, and multiple small aneurysms in renal, hepatic, and bronchial arteries and some proximal spinal arteries, and, most notably, a pseudoaneurysm of the anterior spinal artery supplied directly by the artery of Adamkiewicz. Polyarteritis nodosa was subsequently diagnosed in light of these findings. Though previous cases have noted spinal subarachnoid hemorrhage in of the context of polyarteritis nodosa, we found no previously documented case of a definitive aneurysm of the anterior spinal artery in a case of polyarteritis nodosa documented on angiography. This case highlights the potential importance of monitoring for aneurysms of the spinal vasculature in cases of polyarteritis nodosa and in screening for vasculitides in cases of spinal subarachnoid hemorrhage. Future studies are needed to describe patterns of the specific anatomic localization and incidence of spinal artery aneurysms in polyarteritis nodosa.