Acute Retroperitoneal Hemorrhage Due to Multi-Vessel Aneurysmal Bleeding As the Initial Manifestation of Polyarteritis Nodosa in a Previously Healthy Female.

Polyarteritis nodosa (PAN) is a heterogeneous disease characterized by constitutional symptoms, multi-organ dysfunction, and a subacute to chronic mode of onset. We describe a rarely encountered manifestation of PAN in a previously healthy 64-year-old woman who developed acute intra-abdominal bleeding due to multi-vessel, vasculitis-induced retroperitoneal aneurysmal ruptures, followed by the spontaneous cessation of abdominal pain and intra-abdominal bleeding within 24 hours after hospitalization, in the absence of immunosuppressive treatment. Aneurysms regressed and eventually normalized coincident with a moderate-term course of oral corticosteroids and six months of monthly intravenous cyclophosphamide.