Multi-infarct dementia

Alternative names
MID

Definition

Multi-infarct dementia, or 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 inadequate blood supply.

Causes, incidence, and risk factors

MID affects approximately 4 out of 10,000 people. It is estimated that 10 to 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 affects of MID vary depending on the location and severity of the infarctions. Memory impairment is often an early symptom of the disorder, followed by judgment impairment. This often progresses in a stepwise manner to delirium, hallucinations, and impaired thinking. Personality and mood changes accompany the deteriorating mental condition. Apathy and lack of motivation are common. Catastrophic reactions, such as withdrawal or extreme agitation, are also common. Confusion that occurs or is worse at night is another common symptom.

Risk factors that make the development of MID likely include a history of Stroke, hypertension, Smoking, and Atherosclerosis. Atherosclerosis is the cause of numerous serious vascular problems, including Heart attacks, cerebrovascular diseases, and peripheral vascular diseases. cerebrovascular disease affects the vessels in the brain and spine, and peripheral vascular disease involves the vessels of the body, especially the limbs. Atherosclerosis may be associated with conditions such as Diabetes mellitus, Obesity, High Cholesterol, and kidney disorders that require Dialysis.

Some research suggests that MID may cause or hasten the progression of Alzheimer’s disease. MID may be misdiagnosed as Alzheimer’s, or may be found in addition to Alzheimer’s disease. Since the difference cannot always be determined without brain biopsy, and since there is little effective treatment for either condition, the distinction is mainly useful to researchers, not patients. However, once better therapies become available, the independent contribution of MID and Alzheimer’s disease to dementia might become more important in tailoring treatments to individuals.

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:       o Difficulties with attention, concentration, judgment, and behavior       o Confusion, disorientation       o Hallucinations (hearing sounds or seeing things which are not there) and delusions       o Uncoordinated or weak movements       o Aphasia (impaired language ability)       o Personality changes       o Progressive decreases in multiple brain functions  
  • Withdrawal from social interaction       o Inability to interact in social or personal situations       o 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 known definitive treatment for MID. Treatment is based on control of symptoms and the correction of the precipitating risk factors (High blood pressure and High Cholesterol, especially). Other treatments may be advised based on the individual condition.

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 underlying causes should be identified and treated as appropriate.

Discontinuing or changing medications that worsen or even cause confusion, or that are not essential to the care of the person, may improve cognitive function. Medications that may cause confusion include anticholinergics (including antidepressants with anticholinergic properties, such as amitriptyline or imipramine), analgesics, cimetidine, central nervous system depressants, lidocaine, and other medications.

Disorders that contribute to confusion should be treated as appropriate. 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. These are usually given in very low doses, with adjustment as required. 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 proven effective in MID.

Sensory function should be evaluated and augmented as needed by hearing aids, glasses, or cataract surgery.

LONG-TERM TREATMENT:
Provision of a safe environment, control of aggressive or agitated behavior, and the ability to meet physiologic needs may require monitoring in the home or in an institutionalized setting. 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 some communities, there may be access to support groups.

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 be helpful for some persons in controlling unacceptable or dangerous behaviors. This 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 is characterized by a downward course with intermittent periods of rapid deterioration. 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  
  • Abuse by an over-stressed caregiver  
  • 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 and should be thought of as a “brain attack” as it may represent the brain equivalent of a Heart attack . If treated early, damage related to larger strokes involved in MID (which produce symptoms and rapid progression) may possibly be reduced. However, this can only be done within three hours of the onset of symptoms.

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 or salt.

Johns Hopkins patient information

Last revised: December 4, 2012
by Amalia K. Gagarina, M.S., R.D.

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