Vascular dementia is a common form of dementia caused by cerebrovascular disease.
Dementia describes a clinical syndrome that is characterised by a significant deterioration in mental function that leads to impairment of normal function.
In healthcare, we measure ‘normal function’ by activities of daily living (ADLs). These are a series of routine activities that people should be able to do without assistance. They can be broadly divided into personal tasks and domestic tasks.
Dementia can be caused by several conditions, which all manifest with poor mental performance and impaired normal functioning. The clinical manifestations of dementia can reflect the underlying aetiology.
Vascular dementia (VD) refers to a subtype of dementia that is primarily caused by cerebrovascular disease (CVD). CVD refers to vascular brain injury or dysfunction as a result of conditions that impair cerebral blood flow including chronic small vessel disease, stroke or haemorrhage.
It is the second most common form of dementia in the UK affecting around 150,000 people. It is commonly part of 'mixed dementia' a combination of Alzheimer's disease and vascular dementia.
Dementia is a disease of older adults.
The World Health Organisation (WHO) estimates that almost 50 million people have a diagnosis of dementia worldwide.
VD is the second most common form of dementia with >150,000 people in the UK with the condition. Vascular disease is a contributing factor in up to 50% of cases of dementia.
A significant proportion of patients with dementia remain undiagnosed and up to 54% of patients with dementia require care home placement.
VD is the most severe deficit among a spectrum of vascular cognitive impairment.
Vascular cognitive impairment (VCI) refers to a syndrome of all cognitive disorders which are due to cerebrovascular disease. VD is considered the most severe form of VCI. The main forms of VD are:
Vascular dementia occurs secondary to disorders of the cerebral vasculature.
Any condition that affects the brain parenchyma by impairing cerebral blood flow (i.e. ischaemia) or causing haemorrhage can lead to vascular cognitive impairment, and therefore, VD. Causes include:
This is an autosomal dominant inherited condition termed ‘cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy’. It is due to mutation in the NOTCH3 gene and leads to arterial thickening and occlusion.
CADASIL is characterised by recurrent migraine-type headaches, multiple strokes and progressive dementia. The average age of onset of strokes is the 5th decade of life.
VD is traditionally characterised as ‘stepwise’ cognitive decline.
Dementia can be difficult to identify due to insidious and non-specific symptoms. Many clinical features are attributable to dementia. Some are characteristic of all types of dementia, whereas others are typical of a subtype.
There are two classic presentations of VD include:
It is best to consider the clinical features of all dementias in the following domains: cognitive impairment, behavioural and psychological symptoms of dementia (BPSD), disease-specific features and activities of daily living.
Increasing reliance on others for assistance with personal and domestic activities
A formal mental status examination should be completed using a recognised cognitive assessment tool.
There are multiple cognitive assessment tools, which are designed to test different areas of high cortical functioning.
There are a variety of different cognitive assessment tools that range from basic screening tools, to in-depth assessments of each cognitive domain. Here we summarise some of the main tools.
NOTE: particularly in the hospital setting, dementia needs to be differentiated from delirium, which refers to an acute confusional state. Patients with dementia can develop delirium (i.e. acute on chronic confusion). This can be difficult to distinguish and usually requires further assessment after the acute episode.
It is essential to exclude all reversible causes before making a diagnosis of dementia.
Patients suspected of dementia are usually referred to a memory clinic.
At memory clinic, patients undergo a formal history and examination (including medication review), full complement of baseline investigations including bloods and neuroimaging to exclude an underlying cause, and formal cognitive assessment. During these investigations, the specific type of dementia may become apparent.
There are different criteria that are used to diagnose probable vascular cognitive impairment (VCI).
The Diagnostic and Statistical Manual of Mental Disorders (DSM-V) has a diagnostic criteria for VCI. These assume that criteria are met for a mild or major neurocognitive disorder and the clinical features are consistent with a vascular aetiology. If both are present, a probable diagnosis of VCI can be made.
Criteria for diagnosis of neurocognitive disorder:
Features supportive of vascular aetiology:
Probable diagnosis vascular cognitive impairment:
This describes cognitive deficits in one or more of the major cognitive domains, but the deficit is insufficient to interfere with independence in daily activities.
Mild cognitive impairment is an increasingly important term because it helps identify patients at risk of progressive decline towards dementia. Patients should have regular follow-up and be advised to undertake healthy brain activities (e.g. exercise, socialising).
Dementia is a clinical syndrome that reflects deterioration from an underlying cause. The main differentials to exclude in a patient with features of dementia are the three ‘D’s:
Baseline investigations are essential to exclude an alternative diagnosis.
Typical baseline investigations involve a routine set of blood tests and neuroimaging.
Typically magnetic resonance imaging (MRI) but CT may be used if MRI not available or unsuitable. Important to exclude an alternative diagnosis (e.g. brain tumour) and can be used to help characterised the type of dementia (e.g. small vessel disease in VD).
VD is modifiable and preventable. Management centres on cardiovascular risk factor optimisation.
The management of VD, and dementia as a whole, should involve a full assessment of the biological, psychological and social needs of the patient. With significant deterioration in normal activities of daily living, patients will become dependent on others. This means help from families, organisation of carers, and with more advancing symptoms, need for care home placement.
There are multiple facets to management, which we summarise.
Patients with suspected VD, or cerebrovascular disease, should be screened for cardiovascular risk factors and managed accordingly. If identified, these include anti-hypertensives, diabetic medications or insulin, and anti-lipid therapy.
Medical therapy for the treatment of dementia can only be initiated by a specialist in treating patients with dementia. The two main drugs as acetylcholinesterase inhibitors and N-methyl-D-aspartic acid receptor antagonists. However, there is limited efficacy of using these therapies in VD.
Acetylcholinesterase inhibitors such as donepezil may be used in VD if the cognitive decline cannot solely be attributed to cerebrovascular disease (i.e. could be considered in mixed dementia). This is because a significant proportion of patients with dementia with have mixed AD/VD, which may show a small amount of benefit. In general, evidence does not support use of the N-methyl-D-aspartic acid receptor antagonist memantine in VD.
There is no cure for dementia and it is considered a life-limiting condition.
It is estimated that one in three people over the age of 65 will die with dementia and the estimated median survival after diagnosis is 3-9 years (variable).
Progression of dementia has been estimated by WHO, which is based on each stage of severity. Development of delirium on a background of dementia is associated with more rapid progression.
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