Nodular Polyarteritis With Superior Mesenteric Artery Involvement: A Report of a Complex Case.

Polyarteritis nodosa (PAN) is a chronic autoimmune vasculitis characterized by inflammation and structural damage to medium-sized blood vessels throughout the body. Its clinical presentation is heterogenous and often complex, with potential progression to disability. In this study, we report a case of a 73-year-old male with PAN who presented with acute abdominal pain. Computed tomography angiography (CTA) revealed a retroperitoneal hematoma and multiple aneurysms of the intestinal arteries. Emergency digital subtraction angiography (DSA) showed multiple aneurysms, stenoses, and dissections of the superior mesenteric artery (SMA). The diagnosis of PAN was confirmed. The patient experienced recurrent hemorrhage, which was managed by multiple arterial embolization procedures to achieve hemostasis. Subsequently, administration of methylprednisolone led to favorable clinical outcomes. This case underscores the importance of considering PAN in patients with acute abdominal pain and highlights the efficacy of staged endovascular and immunosuppressive therapy.