Background and purpose: Ischemic stroke in young adults has not fully been studied in Japan. The purpose of this study is to clarify the clinical features and pathogenetic mechanisms of ischemic stroke in young adults.
Methods: From January 1990 to June 2000, 133 (7.1%) of 1,862 consecutive patients with ischemic stroke were aged 16 to 50 years (92 men and 41 women, aged of 42.6 +/- 7.7 years). We divided the patients into three groups according to the age of stroke onset; 16 to 40 (group A, n = 38), 41 to 45 (group B, n = 33), and 46 to 50 years (group C, n = 62). Sex, vascular risk factors including hypertension, diabetes mellitus, hyperlipidemia and smoking, cerebrovascular lesions, potential cardiac sources of emboli (emboligenic cardiac diseases), and clinical categories of stroke were examined. We compared them among the three groups.
Results: Men predominated in the all groups. Patients in the group C had more frequently hypertension (p < .0005) and diabetes mellitus (p < .05) than those in the group A and B. The vertebrobasilar infarcts were often revealed in the group A but not in the group B and C (p < .01). No significant difference was observed about the incidence of emboligenic cardiac diseases among the three groups. Out of 46 emboligenic cardiac diseases, the most frequent one was patent foramen ovale (15 patients), whereas nonvalvular atrial fibrillation was documented only in five. Fourteen of 20 patients with significant atherosclerotic arterial lesions were found in the group C, whereas 13 of 16 patients with nonatherosclerotic vasculopathies in the group A. Ulcerated atheroma in the aortic arch was detected in two patients, both in the group C. Overall, clinical categories of stroke were identified as lacunar (Lac) in 34 patients (26%), atherothrombotic (AT) in 16 (12%), cardioembolic (CE) in 44 (33%), miscellaneous (Misc) in 27 (20%), and undetermined in 12 (9%). The most frequent cause of Misc (nine patients) was arterial dissection, occurring mostly in the vertebrobasilar system (eight of nine patients). Misc was most frequent in the group A (p < .0001), and Lac was so in the group C (p < .001). Seventy-six percent of patients in the group A and 61% of those in the group B were attributed to nonatherosclerotic causes. In contrast, 61% of patients in the group C had atherosclerotic causes.
Conclusions: Incidence of athero- and arteriosclerosis as causes of ischemic stroke was apparently increased beyond 45 years of age. Patients < or = 45 years are likely to have various and unique etiologies for ischemic stroke. A specific diagnostic approach is strongly recommended for young patients with ischemic stroke.