Multi-infarct Dementia

A deterioration in mental ability due to blood clots in small blood vessels in the brain that cause tissue damage

  • More common over the age of 60
  • More common in males
  • Smoking and a high-fat diet are risk factors
  • Genetics is not a significant factor

Multi-infarct dementia, also known as vascular dementia, occurs when blood flow in the small blood vessels supplying the brain is obstructed by blood clots. Each of these clots prevents oxygen from reaching a small part of the brain, and this causes tissue death (infarcts) in the affected parts. Infarcts occur in a number of distinct episodes. People who have multiple small infarcts are at increased risk of a major stroke, which can be life-threatening.

The risk of multi-infarct dementia is increased by atherosclerosis, in which fatty deposits build up in the artery walls, causing them to become narrowed and increasing the risk of clots forming. The risk of atherosclerosis is increased if a person has high blood pressure (see Hypertension). Lifestyle factors, such as eating a high-fat diet and smoking, can also contribute to the development of atherosclerosis. Multi-infarct dementia is more common in men and is more likely to occur in people over the age of 60.

What are the symptoms?

Symptoms of multi-infarct dementia vary from one individual to another because they depend on the part of the brain affected. Unlike other types of dementia, which progress steadily, multi-infarct dementia gets abruptly worse following each separate episode. Symptoms are similar to those of other forms of dementia and include:

  • Poor memory, particularly when trying to recall recent events.

  • Difficulty in making decisions.

  • Problems with simple, routine tasks, such as getting dressed.

  • Tendency to wander and get lost in familiar surroundings.

It is common for a person with multi-infarct dementia to develop depression and have episodes of agitation. There may be other symptoms, depending on which part of the brain is affected. These may include partial loss of sight; slow, sometimes slurred, speech; and difficulty walking.

What might be done?

Diagnosis of multi-infarct dementia is usually possible from the symptoms, although various tests, such as blood tests, may also be carried out to rule out other types of dementia. The doctor may arrange for CT scanning or MRI of the brain to look for evidence of multiple small infarcts.

Although the dementia itself cannot be cured, treatment can help to prevent further infarcts that would make the condition worse. A person with multi-infarct dementia should eat a low-fat diet and take regular exercise. Smokers should stop smoking immediately. Antihypertensive drugs, which help to control raised blood pressure, and a daily dose of aspirin, which reduces the risk of blood clots, may be prescribed.

Weakness and loss of movement can be treated with physiotherapy, and speech therapy can help to alleviate speech problems. Antidepressants and counselling may be used to treat depression.

What is the prognosis?

Many people with multi-infarct dementia find that their symptoms improve for short periods of time but later become worse again. Early recognition of the condition and treatment of risk factors, such as high blood pressure, may prevent further progression of the disorder and increasing disability and reduce the risk of a future, potentially fatal stroke.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

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