A 28-year-old male was found dead in his bedroom. There were no anomalies in his birth and medical history, and there was no family history of sudden unexpected death (SUD). Autopsy showed subarachnoid hemorrhage (SAH) with basilar top inflammatory pseudoaneurysm rupture accompanied by fibrinoid necrosis in the aneurysm wall. Active and healed arteritides in small- to medium-sized arteries were identified in the brain, heart, and systemic connective tissue, which was consistent with polyarteritis nodosa (PAN). Furthermore, pneumatosis cystoides intestinalis was observed in the ascending colon. Hepatitis B virus infection and antineutrophil nuclear antibodies were negative. Genetic investigation using whole-exome sequencing showed no mutations among autoinflammatory-related genes, including UBA1, MEFV, and ADA2. SAH due to rupture of a pseudoaneurysm formed by PAN was considered as the cause of death in the present case. Although myocardial ischemia linked to coronary arteritis is a recognized trigger for SUD in PAN, our study showed that rupture of inflammatory pseudoaneurysm in the cerebral artery can also cause SUD in younger subjects with PAN, even if prodromal symptoms are not evident before death.

一名 28 岁男性被发现死在他的卧室里。出生及病史无异常，无意外猝死（SUD）家族史。尸检显示蛛网膜下腔出血（SAH），伴有基底顶部炎性假性动脉瘤破裂，伴有动脉瘤壁纤维蛋白样坏死。在大脑、心脏和全身结缔组织中发现了中小动脉活跃和愈合的动脉炎，这与结节性多动脉炎（PAN）一致。此外，在升结肠中观察到肠囊肿积气。乙型肝炎病毒感染和抗中性粒细胞核抗体阴性。使用全外显子组测序进行的基因研究显示，自身炎症相关基因（包括UBA1、MEFV和ADA2）没有突变。PAN 形成的假性动脉瘤破裂导致 SAH 被认为是本病例的死亡原因。尽管与冠状动脉炎相关的心肌缺血是 PAN 中 SUD 的公认诱因，但我们的研究表明，脑动脉炎性假性动脉瘤破裂也可能导致年轻 PAN 受试者中的 SUD，即使死亡前前驱症状并不明显。