Vascular dementia

Vascular dementia
Name	Vascular dementia
Synonyms	Multi-infarct dementia, vascular cognitive impairment
Field	Neurology, Psychiatry, Geriatrics
Risks	Hypertension, Diabetes mellitus, Atrial fibrillation
Differential	Alzheimer's disease, Lewy body dementia

Vascular dementia is a broad term describing impairments in cognitive function resulting from cerebrovascular disease. It is considered the second most common cause of dementia after Alzheimer's disease, often co-occurring with it in a mixed pathology. The clinical presentation is highly variable, depending on the location and extent of the underlying brain injury, and typically involves a stepwise or gradual decline in cognitive abilities.

Signs and symptoms

Core features often include pronounced difficulties with executive function, such as planning, judgment, and problem-solving, alongside slowed processing speed. Memory impairment may be less prominent initially compared to Alzheimer's disease. Focal neurological signs like hemiparesis, bradykinesia, gait apraxia, or urinary incontinence are common. Mood and personality changes, including apathy, emotional lability, and depression, are frequently observed. Symptoms may present abruptly following a major stroke or emerge insidiously from cumulative small vessel disease.

Causes and risk factors

The primary cause is impaired blood flow to the brain, stemming from cerebrovascular disease. Major etiologies include cerebral infarction (both large vessel and lacunar stroke), cerebral hemorrhage, and cerebral hypoperfusion. Key modifiable risk factors are hypertension, diabetes mellitus, hyperlipidemia, atrial fibrillation, coronary artery disease, and smoking. Non-modifiable risks include advanced age, genetic predisposition such as in Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), and a history of transient ischemic attack or myocardial infarction.

Pathophysiology

The pathophysiology involves ischemic or hemorrhagic damage to brain parenchyma, disrupting critical neural networks. Common substrates include multi-infarct dementia from large vessel occlusions, subcortical ischemic vascular dementia from small vessel disease affecting white matter (leukoaraiosis) and basal ganglia, and strategic infarct dementia from localized damage in areas like the thalamus or angular gyrus. Chronic cerebral hypoperfusion leads to blood-brain barrier dysfunction, neuroinflammation, and white matter lesions, contributing to progressive cognitive decline.

Diagnosis

Diagnosis is clinical, based on history, cognitive assessment demonstrating impairment, and evidence of relevant cerebrovascular disease on neuroimaging such as MRI or CT scan. The National Institute of Neurological Disorders and Stroke and the Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS-AIREN) criteria are commonly used. Neuroimaging typically reveals evidence of prior stroke, lacunes, or extensive white matter hyperintensities. Differential diagnosis from other dementias is crucial and may involve tools like the Hachinski Ischemic Score and assessments for Alzheimer's disease biomarkers.

Prevention and management

Prevention focuses on aggressive management of vascular risk factors through antihypertensive drugs, statins, anticoagulation for atrial fibrillation (e.g., warfarin, dabigatran), and antiplatelet therapy like aspirin or clopidogrel. Lifestyle interventions include smoking cessation, Mediterranean diet, and regular physical exercise. There are no medications approved specifically for treatment; management involves symptomatic support, cognitive rehabilitation, and treating comorbid depression or agitation. Caregiver education and support through organizations like the Alzheimer's Association are essential components.

Prognosis

Prognosis is variable but generally poorer than for Alzheimer's disease, with reduced life expectancy. The course is often stepwise, with periods of stability followed by sudden declines, frequently correlated with new cerebrovascular events. Rate of progression depends on the underlying vascular pathology, adequacy of risk factor control, and presence of comorbid conditions. Mortality is often due to complications such as pneumonia, subsequent major stroke, or cardiovascular disease.

Epidemiology

It is estimated to account for 15-20% of dementia cases in North America and Europe, with higher prevalence in populations with high rates of vascular disease, such as in some Asian countries like Japan. Incidence increases dramatically with age. The prevalence of mixed dementia, combining vascular pathology and Alzheimer's disease, is very common in older populations. Studies such as the Framingham Heart Study and the Rotterdam Study have been instrumental in elucidating its epidemiological links to vascular risk factors.

Category:Dementia Category:Cerebrovascular diseases Category:Neurological disorders