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. Our report reveals that patients with life-threatening PAN may present acutely with unexpected historical, physical examination and laboratory features not commensurate with the gravity of the clinical findings. We also highlight that long-term survival lasting greater than 11 years can occur when the correct diagnosis and appropriate treatment are introduced early in the course of the illness.