The commonest form of vascular dementia, in which reduced mental function is caused by multiple strokes causing damage to many areas of the brain.
Alternative names :
What is this?
The third most common cause of dementia in the elderly, after Alzheimer's disease and Lewy body dementia. It affects men more often than women, usually starting after the age of 55, mostly around 65.
What causes this?
Multiple small strokes, caused by small blood clots blocking blood vessels within the brain, and causing the death of small areas of brain tissue and nerve cells.
What are its symptoms?
Memory loss is an early symptom, and difficulty in making decisions. There is increasing difficulty in thinking effectively, loss of judgement and concentration, and there may even be hallucinations and delusions. Personality change may be marked, with mood changes. At times there may be lack of motivation and emotion, and social withdrawal, inability to hold down a job; at other times agitation and excitability. Confusion is often worse at night, and may mainly occur then.
Early in the disorder, the person may be aware that they are losing their mental faculties, and this can be a frightening and frustrating. Mercifully, they usually become apparently unaware of the increasing seriousness of their situation. They may later do the following: start wandering, and get lost even in places that should be familiar to them; have difficulty following instructions or dealing with finances ; and experience loss of bladder and bowel control. The predominant memory problem is with short-term and recent memory, such that while they can remember their schooldays, they may forget what happened this morning.
Later still, they lose independence with an increasing inability to care for themselves, difficulty swallowing, and incontinence. There can be periods of unplanned laughing or crying, not really related to events.
How is it diagnosed?
It may be confused with Alzheimer’s, and both may occur together. The diagnosis depends on a careful history and examination, and on ruling out other causes of dementia. Most importantly, metabolic causes must be ruled out, because several of those can be relieved or reversed. There may be anomalies of reflexes and of co-ordination. A brain scan may show multiple areas of brain damage.
The early, minor strokes may show short-lasting symptoms, including dizziness, temporary weakness in limbs, and slurred speech.
How is it treated?
There is no specific treatment, other than patiently caring for the person, and using medications to control symptoms as needed. There must be caution about using medications which can add to confusion, along with attention to other medical and psychiatric conditions which can worsen the situation and which may be relievable. Medication may be needed to help control agitation and aggression, which can be a risk to the patient and others.
What is the prognosis?
Poor. There is a steady decline in mental functions and inability to care for oneself. Where community and social resources are available to assist in caring for the patient at home, these can be invaluable. Very severe strain can be placed on those family members trying to care for someone with MID, and support for them is essential. The patient may need ultimately to be cared for within an institution.
When to call your doctor.
When there has been a major stroke, or evidence of smaller strokes, and where there are accumulating signs of declining intellectual functioning, it is important for the person to be assessed for the possible onset of dementia.
How can it be prevented?
Risk factors are those for heart and vascular disease and stroke, including high blood pressure, smoking, atrial fibrillation (irregular heart beat) and arteriosclerosis. Efficient treatment of these conditions, and also of diabetes, if present, may reduce the risk.
Where small strokes have been identified, various treatments may be used to reduce the risk of further strokes, including aspirin, dipyridamole, or clopidogrel. Where there are cardiac irregularities such as atrial fibrillation, drugs such as digoxin may be used to help control that, as well as possible use of anticoagulants like warfarin, to reduce the risk of clots forming. Such medications need careful balancing and control, and the involvement of family or other helpers to enable this to be done.