Revealing the unique clinical characteristics of subarachnoid hemorrhage in young adults.

Subarachnoid hemorrhage (SAH) is a severe condition with high morbidity and mortality rates. While SAH is well-documented in the general population, its characteristics in young adults remain unclear. This study aimed to investigate the specific features of young adults with SAH and to identify predictors of clinical outcomes following SAH in young adults. This retrospective study included 894 patients with aneurysmal SAH who underwent surgical clipping or endovascular treatment between 2012 and 2024. Patients were divided into two groups: the young adult group (< 40 years) and the older adult group (≥ 40 years). Clinical characteristics, aneurysm features, and clinical outcomes were compared between the groups. Among the 894 patients, 42 (4.7%) were classified as young adults. Compared to older adults, young adults had a higher proportion of males (57.1% vs. 30.6%, p < 0.01) and a lower prevalence of hypertension (38.1% vs. 64.2%, p < 0.01). Young adults also had significantly smaller aneurysms than older adults (median: 4.0 mm vs. 5.0 mm, p < 0.01). Both the WFNS (World Federation of Neurosurgical Societies) grade on admission (p < 0.01) and hydrocephalus requiring shunt surgery (p = 0.01) were associated with worse clinical outcomes in the young adult group. Young adults with SAH exhibit distinct clinical characteristics, including male predominance, lower hypertension rates, and smaller aneurysm size. Even in the absence of well-known risk factors, close follow-up and proactive therapeutic interventions are essential for managing intracranial aneurysms in this population.