When Stroke Strikes Early: Unusual Causes of Intracerebral Hemorrhage in Young Adults

Background/Objectives: Intracerebral hemorrhage (ICH) is primarily a disease of older adults, commonly linked to chronic hypertension and cerebral amyloid angiopathy. In young adults, however, ICH is rare and often driven by distinct structural, hematologic, or vascular causes. Methods: Using the National Inpatient Sample (2016–2022), we identified hospitalizations with a primary diagnosis of ICH (ICD-10-CM: I61. x). Patients younger than 18 years were excluded. Patients were stratified into 18–39 vs. ≥40 years. Comorbidities were defined using validated ICD-10 codes (E08–E13 for diabetes mellitus, I10–I15 for hypertension), excluding transient hyperglycemia (R73. x). Weighted analyses using NIS discharge weights compared demographics, comorbidities, rare etiologies, and outcomes, including in-hospital mortality, length of stay (LOS), and total hospital charges. Survey-weighted multivariable logistic regression identified independent predictors of mortality. Results: Among 76, 264 ICH hospitalizations, 4012 (5. 3%) occurred in patients < 40 years. Compared with older adults, younger patients had lower prevalence of hypertension (47. 8% vs. 84. 1%) and diabetes (10. 2% vs. 60. 4%) but higher rates of substance use (27. 7% vs. 15. 6%). Rare etiologies were more frequent, including arteriovenous malformation/aneurysm (14. 0% vs. 3. 6%), Moyamoya disease (1. 4% vs. 0. 2%), sickle cell disease (1. 1% vs. 0. 1%), and pregnancy-related ICH (0. 05%). In-hospital mortality was lower among young adults (15. 7% vs. 21. 7%, p < 0. 001), though LOS was longer (12. 1 vs. 8. 7 days, p < 0. 001), and mean hospital charges were higher (228, 000 vs. 125, 000, p < 0. 001). Conclusions: Young-adult ICH is uncommon but etiologically distinct, often associated with vascular malformations, hemoglobinopathies, and substance use. Despite lower mortality, these patients experience longer and more resource-intensive hospitalizations, underscoring a substantial clinical and economic burden.