Vascular dementia

Abstract

The epidemic growth of dementia causes great concern for the society. It is customary to consider Alzheimer's disease (AD) as the most common cause of dementia, followed by vascular dementia (VaD). This dichotomous view of a neurodegenerative disease as opposed to brain damage caused by extrinsic factors led to separate lines of research in these two entities. Indeed, accumulated data suggest that the two disorders have additive effects and probably interact; however it is still unknown to what degree. Furthermore, epidemiological studies have shown "vascular" risk factors to be associated with AD. Therefore, a clear distinction between AD and VaD cannot be made in most cases, and is furthermore unhelpful. In the absence of efficacious treatment for the neurodegenerative process, special attention must be given to the vascular component, even in patients with presumed mixed pathology. Symptomatic treatment of VaD and AD is similar, although the former is less effective. For prevention of dementia it is important to treat all factors aggressively, even in stroke survivors who do not show evidence of cognitive decline. In this review, we will give a clinical and pathological picture of the processes leading to VaD and discuss its interaction with AD.

Figure 1

Major pathological findings underlying vascular dementia

Figure 2

Some of the major pathological changes underlying vascular dementia. A) Ischemic infarct. Note the wedge-shape border of the infarct (arrows). Both white and gray matter are involved. Nissl staining. B) Lacunar infarct characterized by an irregular cavity and a central blood vessel surrounded by a rim of gliotic, rarefied brain tissue (arrow). Hematoxylin and Eosin stain (H&E). C) Histopathological counterpart of a white matter lesion detected by MRI in a 62 years-old male. Note the regions of myelin pallor (**) and an enlarged perivascular space (arrow). Kluever-Barrera stain. D) Cerebral amyloid angiopathy (CAA). The Aβ-deposition in the wall of a cortical artery is colored in brown (arrow). In this case, there is a microbleed around this artery (note the anuclear red blood cells). Immunostain with an antibody against Ab17-24 (4G8; Covance). E) Small vessel disease. Two white matter arteries exhibit fibrosis and hyalinization of wall (arrows). These lesions are also referred to as arteriolosclerosis, arteriohyalinosis or lipohyalinosis (arrow). H&E. The calibration bars correspond to:100 μm.