Vascular dementia

Vascular dementia is dementia caused by problems in the supply of blood to the brain, typically a series of minor strokes, leading to worsening cognitive decline that occurs step by step. The term refers to a syndrome consisting of a complex interaction of cerebrovascular disease and risk factors that lead to changes in the brain structures due to strokes and lesions, and resulting changes in cognition. The temporal relationship between a stroke and cognitive deficits is needed to make the diagnosis. Vascular dementia is dementia caused by problems in the supply of blood to the brain, typically a series of minor strokes, leading to worsening cognitive decline that occurs step by step. The term refers to a syndrome consisting of a complex interaction of cerebrovascular disease and risk factors that lead to changes in the brain structures due to strokes and lesions, and resulting changes in cognition. The temporal relationship between a stroke and cognitive deficits is needed to make the diagnosis. Differentiating dementia syndromes can be challenging, due to the frequently overlapping clinical features and related underlying pathology. In particular, Alzheimer's dementia often co-occurs with vascular dementia. People with vascular dementia present with progressive cognitive impairment, acutely or subacutely as in mild cognitive impairment, frequently step-wise, after multiple cerebrovascular events (strokes). Some people may appear to improve between events and decline after further silent strokes. A rapidly deteriorating condition may lead to death from a stroke, heart disease, or infection. Signs and symptoms are cognitive, motor, behavioral, and for a significant proportion of patients also affective. These changes typically occur over a period of 5–10 years. Signs are typically the same as in other dementias, but mainly include cognitive decline and memory impairment of sufficient severity as to interfere with activities of daily living, sometimes with presence of focal neurologic signs, and evidence of features consistent with cerebrovascular disease on brain imaging (CT or MRI). The neurologic signs localizing to certain areas of the brain that can be observed are hemiparesis, bradykinesia, hyperreflexia, extensor plantar reflexes, ataxia, pseudobulbar palsy, as well as gait problems and swallowing difficulties. People have patchy deficits in terms of cognitive testing. They tend to have better free recall and fewer recall intrusions when compared with patients with Alzheimer's disease. In the more severely affected patients, or patients affected by infarcts in Wernicke's or Broca's areas, specific problems with speaking called dysarthrias and aphasias may be present. In small vessel disease, the frontal lobes are often affected. Consequently, patients with vascular dementia tend to perform worse than their Alzheimer's disease counterparts in frontal lobe tasks, such as verbal fluency, and may present with frontal lobe problems: apathy, abulia (lack of will or initiative), problems with attention, orientation, and urinary incontinence. They tend to exhibit more perseverative behavior. VaD patients may also present with general slowing of processing ability, difficulty shifting sets, and impairment in abstract thinking. Apathy early in the disease is more suggestive of vascular dementia. Rare genetic disorders that cause vascular lesions in the brain have other presentation patterns. As a rule, they tend to occur earlier in life and have a more aggressive course. In addition, infectious disorders, such as syphilis, can cause arterial damage, strokes, and bacterial inflammation of the brain. Vascular dementia can be caused by ischemic or hemorrhagic infarcts affecting multiple brain areas, including the anterior cerebral artery territory, the parietal lobes, or the cingulate gyrus. On rare occasion, infarcts in the hippocampus or thalamus are the cause of dementia. A history of stroke increases the risk of developing dementia by around 70%, and recent stroke increases the risk by around 120%. Brain vascular lesions can also be the result of diffuse cerebrovascular disease, such as small vessel disease. Risk factors for vascular dementia include age, hypertension, smoking, hypercholesterolemia, diabetes mellitus, cardiovascular disease, and cerebrovascular disease. Other risk factors include geographic origin, genetic predisposition, and prior strokes. Vascular dementia can sometimes be triggered by cerebral amyloid angiopathy, which involves accumulation of beta amyloid plaques in the walls of the cerebral arteries, leading to breakdown and rupture of the vessels. Since amyloid plaques are a characteristic feature of Alzheimer's Disease, vascular dementia may occur as a consequence. Cerebral amyloid angiopathy can, however, appear in people with no prior dementia condition. Amyloid beta accumulation is often present in cognitively normal elderly people.