Simultaneous bilateral hypertensive putaminal or thalamic hemorrhage: case report and systematic review of the literature.

Simultaneous multiple hypertensive intracranial hemorrhage is rare, and its mechanism is unclear. We report a case of simultaneous hypertensive bilateral thalamic hemorrhage. A 58-year-old man presented with sudden mild right hemiparesis. Computed tomography 1 hour after the onset showed bilateral thalamic hemorrhage. Gradient-echo T2-weighted magnetic resonance imaging showed 17 microbleeds. The patient was treated with medication, discharged home, and achieved a modified Rankin scale of 1 at 3 months from the onset. Additionally, by systematically searching in PubMed, we found 41 cases of simultaneous bilateral hypertensive putaminal or thalamic hemorrhage, including our case: 18 bilateral putaminal, 12 bilateral thalamic, and 11 unilateral putaminal and contralateral thalamic hemorrhage. Symmetric hemorrhage occurred more frequently than expected ratios of hemorrhage occurring randomly in terms of location (p=0.013; Fisher's exact test). These new findings raise the hypothesis that patients may have symmetrically vulnerable vessels. Such conditions would result in coincidence or subsequent rupture of perforating arteries or micro-aneurysms by increased blood pressure and cause symmetric hemorrhages. Studies on the distribution of microbleeds may address these issues.