Health Encyclopedia

Multi-infarct dementia

Definition

Multi-infarct dementia (MID) is the most common form of vascular dementia, which is a deterioration in mental function caused by strokes. "Multi-infarct" means that multiple areas in the brain have been injured due to a lack of blood.

Alternative Names

MID

Causes, incidence, and risk factors

MID affects approximately 4 out of 10,000 people. It is estimated that 10 - 20% of all dementias are caused by strokes, making MID the third most common cause of dementia in the elderly, behind Alzheimer's disease and DLBD (dementia of Lewy bodies). MID affects men more often than women. The disorder usually affects people over 55, with the average onset at age 65.

The symptoms of MID vary. Memory loss is often an early symptom of the disorder, followed by trouble making judgments. This often progresses to delirium, hallucinations, and thinking problems. Personality and mood changes can also occur. Lack of emotion and motivation, withdrawal, and extreme excitability (agitation) are common. Confusion that occurs or is worse at night is another common symptom.

Risk factors for MID include a history of stroke, hypertension, smoking, and atherosclerosis.

Some research suggests that MID may cause Alzheimer's disease or make it get worse faster. MID may be misdiagnosed as Alzheimer's, or may be found in addition to Alzheimer's disease.

Symptoms

Awareness of mental deterioration, which may cause frustration, depression, anxiety, stress, and tension
Dementia (slowly progressive memory loss) with lack of awareness of mental deterioration and:
- Difficulties with attention, concentration, judgment, and behavior
- Confusion, disorientation
- Hallucinations (hearing sounds or seeing things which are not there) and delusions
- Uncoordinated or weak movements
- Aphasia (impaired language ability)
- Personality changes
- Progressive decreases in multiple brain functions
Withdrawal from social interaction
- Inability to interact in social or personal situations
- Inability to maintain employment
Decreased ability to function independently
Decreased interest in daily living activities
Lack of spontaneity
Localized numbness or tingling
Swallowing difficulty
Sudden involuntary laughing or crying (emotional instability)
Urinary incontinence

Signs and tests

The disorder is diagnosed based on history, symptoms, signs, and tests, and by ruling out other causes of dementia, including dementia due to metabolic causes. History may include a past stroke or hypertension. History of the dementia often shows stepwise progression of the condition -- periods of abrupt decline alternating with stable periods of minimal decline. Other characteristics that suggest multi-infarct dementia rather than Alzheimer's disease include: abrupt onset, physical complaints, emotional changes, and localized neurologic signs (modified Hachinski ischemia scale).

A neurologic examination shows variable deficits depending on the extent and location of damage. There may be multiple, localized areas with specific loss of function. Weakness or loss of function may occur on one side or only in one area. Abnormal reflexes may be present. There may be signs of cerebellar dysfunction such as loss of coordination.

A head CT scan, and even more likely, MRI of the brain may show changes that suggest multi-infarct dementia because areas of dead tissue may be visible.

Treatment

There is no specific, known treatment for MID. The goal is to control symptoms and correct risk factors such as high blood pressure and high cholesterol. Other treatments may be recommended.

INITIAL DIAGNOSIS AND TREATMENT

The person should be in a pleasant, comfortable, non-threatening, physically safe environment for diagnosis and initial treatment. Hospitalization may be required for a short time. The health care provider will try to identify the cause and treat it.

Stopping or changing medications that worsen or cause confusion may improve cognitive function. Medications that may cause confusion include anticholinergics (including antidepressants with anticholinergic properties such as amitriptyline or imipramine), pain relievers, cimetidine, central nervous system depressants, and lidocaine.

Disorders may contribute to confusion. These may include heart failure, decreased oxygen (hypoxia), thyroid disorders, anemia, nutritional disorders, infections, and psychiatric conditions such as depression. Correction of coexisting medical and psychiatric disorders often greatly improves the mental functioning.

Medications may be required to control aggressive or agitated behaviors or behaviors that are dangerous to the person or to others. The medicines are usually given in very low doses and adjusted as needed. Such medications may include antipsychotics (especially the newer atypical agents, olanzapine and quetiapine), beta-blockers, and serotonin-affecting drugs such as trazodone (which may lower the blood pressure), buspirone, or fluoxetine. Medications used to treat Alzheimer's disease have not been shown to work for MID.

Hearing aids, glasses, or cataract surgery may be needed if the person has sensory problems.

LONG-TERM TREATMENT

The person may need regular monitoring. This may include in-home care, boarding homes, adult day care, or convalescent homes. Family counseling may help in coping with the changes required for home care. Visiting nurses or aides, volunteer services, homemakers, adult protective services and other community resources may be helpful in caring for the person with MID.

In any care setting, there should be familiar objects and people. Leaving lights on at night may reduce disorientation. The schedule of activities should be simple.

Behavior modification may help some persons control unacceptable or dangerous behaviors. This therapy consists of rewarding appropriate or positive behaviors and ignoring inappropriate behaviors (within the bounds of safety). Reality orientation, with repeated reinforcement of environmental and other cues, may help reduce disorientation.

Legal advice may be appropriate early in the course of the disorder. Advance directives, power of attorney, and other legal actions may make it easier to make ethical decisions regarding the care of the person with MID.

Expectations (prognosis)

The disorder gets worse over time.

Death may occur from stroke, heart disease, pneumonia, or other infection.

Complications

Stroke
Atherosclerotic heart disease
Pneumonia
Infection
Reduced life span
Loss of ability to function or care for self
Loss of ability to interact
Increased incidence of infections anywhere in the body
Side effects of medications

Calling your health care provider

Call your health care provider if any symptoms suggestive of vascular dementia appear. Go to the emergency room or call the local emergency number (such as 911) if a sudden change in mental status develops. This is an emergency symptom of stroke.

If treatment is received within 3 hours after symptoms start, damage related to larger strokes involved in MID may possibly be reduced.

Prevention

Control of conditions that increase the risk of atherosclerosis may help in reducing the risk of MID. This may include treatment of related disorders, weight control, control of high blood pressure, and dietary changes to reduce saturated fats and salt.

Review Date:4/28/2006
Reviewed By:Daniel Kantor, M.D., Director of the Comprehensive MS Center, Neuroscience Institute, University of Florida Health Science Center, Jacksonville, FL. Review provided by VeriMed Healthcare Network.

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