Spontaneous intracerebral hemorrhage: epidemiology and clinical presentation.

The advent of widespread CT availability has dramatically changed our understanding of the incidence and risk factors regarding intracerebral hemorrhage (ICH). In the pre-CT era, many patients with a small ICH were misclassified having had ischemic strokes and patients with massive ICH or subarachnoid hemorrhage (SAH) were often difficult to classify correctly. The fact that the precise mechanism of spontaneous ICH is often difficult to ascertain without pathologic evidence continues to hamper epidemiologic studies. This article reviews the incidence rates, natural history, epidemiology, and clinical presentations of nontraumatic ICH.