Vascular dementia is the second most common cause of dementia after Alzheimer's disease.
What is vascular dementia?
Vascular dementia is the broad term for dementia associated with problems of circulation of blood to the brain.
Are there different types of vascular dementia?
There are a number of different types of Vascular dementia. Two of the most common are Multi-infarct dementia and Binswanger's disease.
This is probably the most common form of Vascular dementia. Multi-infarct dementia is caused by a number of strokes, often with symptoms that develop progressively over a period of time. The strokes cause damage to the cortex of the brain, the area associated with learning, memory and language. A person with Multiinfarct dementia is likely to have better insight in the early stages than people with Alzheimer's disease, and parts of their personality may remain relatively intact for longer. Symptoms may include severe depression, mood swings and epilepsy.
Binswanger's disease (also known as Subcortical vascular dementia)
This was thought to be rare, but is now being reassessed, and may in fact be relatively common. As with other Vascular dementias, it is associated with stroke-related changes. It is the “white matter” deep within the brain that is affected. It is caused by high blood pressure, thickening of the arteries and inadequate blood flow. Symptoms often include slowness and lethargy, difficulty walking, emotional ups and downs and lack of bladder control early in the course of the disease. Most people with Binswanger's disease have, or have had, high blood pressure.
One single large stroke can sometimes cause Vascular dementia depending on the size and location of the stroke. Risk factors that make strokes more likely to lead to Vascular dementia include:
- Untreated high blood pressure (hypertension)
- Atrial fibrillation
- Other irregular heart rhythms which raise the risk of clots and atherosclerosis (fatty deposits in blood vessels) which causes damage to the arteries of the brain.
How is vascular dementia diagnosed?
Vascular dementia is usually diagnosed through neurological examination and brain scanning techniques such as computerised tomography (CT) or a magnetic resonance imaging (MRI) test. However, as is the case with Alzheimer's disease, a definite diagnosis of Vascular dementia can only be made by examining the brain after death. Vascular dementia can be very difficult to distinguish from other forms of dementia. Some people have both Alzheimer's disease and Vascular dementia.
Who gets vascular dementia?
Anyone can be affected by Vascular dementia, but several factors increase the risk. These include:
- High blood pressure
- High cholesterol
- History of mild warning strokes
- Evidence of disease in arteries elsewhere
- Heart rhythm abnormalities.
Vascular dementia is slightly more common in men than women.
How does vascular dementia progress?
Vascular dementia usually progresses gradually in a step-wise fashion in which a person's abilities deteriorate after a stroke, and then stabilise until the next stroke. If further strokes do not occur, the abilities of people with Vascular dementia may not continue to decline, or in some cases, may improve. However, these improvements may not last. Sometimes the steps are so small that the decline appears gradual. On average though, people with Vascular dementia decline more rapidly than people with Alzheimer's disease. Often they die from a heart attack or major stroke.
Is there treatment available?
While no treatment can reverse damage that has already been done, treatment to prevent additional strokes is very important. To prevent strokes, medicines to control high blood pressure, high cholesterol, heart disease and diabetes can be prescribed. A healthy diet, exercise and avoidance of smoking and excessive alcohol also lessen the risk of further strokes. Sometimes aspirin or other drugs are prescribed to prevent clots from forming in the small blood vessels.
Drugs can also be prescribed to relieve restlessness or depression or to help the person with dementia to sleep better. In some cases surgery known as carotid endarterectomy may be recommended to remove blockage in the carotid artery, the main blood vessel to the brain. Recent research suggests that cholinesterase inhibitor medications such as Donepezil (Aricept) and Galantamine (Reminyl), which are helpful for some people with Alzheimer's disease, may also be of some benefit to some people with Vascular dementia. However, the evidence is not yet as clear or compelling as that for the use of these medications with Alzheimer's disease.
Support is available for the person with Vascular dementia, their families and carers. This support can make a positive difference to managing the condition. Alzheimer's Australia provides support, information, education and counselling for people affected by dementia. Up-to-date information about drug treatments is also available from Alzheimer's Australia.
Research into the cause of Vascular dementia
Vascular dementia is the second most commonly diagnosed type of dementia, and may account for 15 - 20% of all cases. Vascular dementia is caused by chronic reduced blood flow to the brain, usually as a result of a stroke or series of strokes. It can often coexist with Alzheimer's disease.
Stroke, small vessel disease, or a mixture of the two can cause vascular dementia. Most commonly there is a blockage of small blood vessels somewhere in the network of arteries that feeds the brain. Blockages may be caused by plaque build up on the inside of the artery wall, or by blood clots which have broken loose. Clots can form as a result of abnormal heart rhythms, or other heart abnormalities. Also, a weak patch on an artery wall can balloon outward and form an aneurysm, which can burst and deprive brain cells of oxygen.
It is estimated that about 50% of cases of vascular dementia result from high blood pressure, which can lead to a major stroke or a series of strokes and a build up of brain damage over time. Less common causes of vascular dementia are associated with autoimmune inflammatory diseases of the arteries such as lupus and temporal arteritis, which are treatable with drugs that suppress the immune system.
There are a number of different types of vascular dementia, the two most common being Multi-infarct dementia and Binswanger’s disease. Multi-infarct dementia is caused by a number of strokes, often accumulating progressively over a period of time. Binswanger’s disease (also known as subcortical vascular dementia) is associated with damage to the brain’s white matter, or nerve fibres. It is caused by high blood pressure, thickening of the arteries and inadequate blood flow.
An inherited form of vascular dementia known as CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is caused by a mutation on the Notch3 gene. This is a very rare form of dementia and only affects families carrying the Notch3 gene mutation.
Many people with dementia are found to have vascular related brain damage in addition to the plaques and tangles that characterise Alzheimer’s disease. Recent findings concerning the overlap between risk factors for cardiovascular disease and Alzheimer's disease, such as high blood pressure, diabetes and high cholesterol, have indicated that there may be a strong connection between the development of Alzheimer’s disease and vascular conditions. It may be that having Alzheimer’s disease and vascular events increases the risk of dementia more than either one alone, and that there are interactions between the two. These findings may have important implications for preventative strategies, suggesting that reducing vascular risk factors could reduce risk for both Alzheimer’s disease and vascular dementia, in addition to heart disease.
Community support is available for people with Vascular dementia, their families and carers. This support can make a positive difference to managing dementia. Alzheimer's Australia provides support, information and counselling for people affected by dementia.
For information and advice call the National Dementia Helpline on 1800 100 500.
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