Multi-infarct dementia
Encyclopedia
Multi-infarct dementia is one type of vascular dementia. Vascular dementia is the second most common form of dementia
after Alzheimer's disease
(AD) in older adults. Multi-infarct dementia (MID) is thought to be an irreversible form of dementia, and its onset is caused by a number of small strokes or sometimes, one large stroke preceded or followed by other smaller strokes. The term refers to a group of syndromes caused by different mechanisms all resulting in vascular lesions in the brain. Early detection and accurate diagnosis are important, as vascular dementia is at least partially preventable.
The main subtypes of this disease are: mild cognitive impairment
, multi-infarct dementia, vascular dementia due to a strategic single infarct (affecting the thalamus
, the anterior cerebral artery, the parietal lobe
s or the cingulate gyrus), vascular dementia due to hemorrhagic lesions, and mixed Alzheimer's and vascular dementia.
Vascular lesions can be the result of diffuse cerebrovascular disease
or focal lesions; usually both. Mixed dementia is diagnosed when patients have evidence of AD and cerebrovascular disease, either clinically or based on neuroimaging evidence of ischemic lesions. In fact vascular dementia and Alzheimer's disease often coexist, especially in older patients with dementia.
In small vessel disease the incidence peaks between the 4th and the 7th decades of life and 80% will have a history of hypertension
. Patients develop progressive cognitive, motor and behavioral signs and symptoms. A significant proportion of them also develop affective
symptoms. These changes occur over a period of 5–10 years. If the frontal lobes are affected, which is often the case, patients may present as apathetic
or abulic. This is often accompanied by problems with attention, orientation and urinary incontinence.
As already stated, small vessel disease and focal lesions often overlap, so these two patterns may be evident in the same individual concurrently.
Rare genetic disorders which result in vascular lesions in the brain have other patterns of presentation. As a rule of thumb they tend to present earlier in life and have a more aggressive course.
, Fourth Edition (DSM-IV) criteria, the International Classification of Diseases, Tenth Edition (ICD-10) criteria, the National Institute of Neurological Disorders and Stroke
- Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS-AIREN) criteria, the Alzheimer's Disease Diagnostic and Treatment Center criteria, and the Hachinski ischemic score.
Lateralizing signs such as hemiparesis
, bradykinesia, hyperreflexia
, extensor plantar reflexes, ataxia
, pseudobulbar palsy
, and gait
and swallowing difficulties may be observed.
In terms of cognitive testing patients have patchy deficits. They tend to have better free recall
and fewer recall intrusions compared with patients with Alzheimer's disease. As small vessel disease often affects the frontal lobes, apathy early in the disease is more suggestive of vascular dementia because it usually occurs in the later stages of Alzheimer's. Consequently patients with vascular dementia perform worse than their Alzheimer's disease counterparts in frontal lobe tasks such as verbal fluency. They also tend to exhibit more perseverative behavior. They may also present with general slowing of processing ability, difficulty shifting sets and impairment in abstract thinking. In the more severe patients, or those patients affected by strategic infarcts in the Wernicke or Broca areas, dysarthria
s, dysphasias and aphasia
s may be present.
The recommended investigations for cognitive impairment should be carried out, including a dementia screening blood test, chest X-Ray, CAT scan and ECG. The screening blood test should typically include full blood count, liver function tests
, thyroid function tests
, lipid profile, erythrocyte sedimentation rate
, C reactive protein, syphilis
serology, calcium serum level, fasting glucose, urea
and electrolytes, vitamin B-12, folate. In selected patients HIV serology and autoantibody testing may be done.
, smoking, hypercholesterolemia
, diabetes mellitus
, and cardiovascular disease
and cerebrovascular disease
.
The general management of dementia includes referral to community services, judgment and decision-making regarding legal and ethical issues (e.g., driving, capacity, advance directives), and consideration of caregiver stress.
Cholinesterase inhibitors such as galantamine
have shown to be helpful in various randomized controlled trials. However their use is not licensed yet for this indication.
Behavioral and affective symptoms are particularly important in this patient group and deserve special consideration. These problems, if they develop, tend to be resistant to conventional psychopharmacological treatment and in many cases lead to hospital admission and placement in permanent care.
of the illness is 1.5% in Western countries and approximately 2.2% in Japan. It accounts for 50% of all dementias in Japan, 20% to 40% in Europe and 15% in Latin America. The incidence
of dementia
is 9 times higher in patients who have had a stroke than in controls. 25% of stroke patients develop new-onset dementia within 1 year of their stroke. The relative risk
of incident dementia is 5.5% within 4 years of suffering a stroke.
The prevalence of vascular dementia is higher in men than in women and it increases with age.
Dementia
Dementia is a serious loss of cognitive ability in a previously unimpaired person, beyond what might be expected from normal aging...
after Alzheimer's disease
Alzheimer's disease
Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...
(AD) in older adults. Multi-infarct dementia (MID) is thought to be an irreversible form of dementia, and its onset is caused by a number of small strokes or sometimes, one large stroke preceded or followed by other smaller strokes. The term refers to a group of syndromes caused by different mechanisms all resulting in vascular lesions in the brain. Early detection and accurate diagnosis are important, as vascular dementia is at least partially preventable.
The main subtypes of this disease are: mild cognitive impairment
Mild cognitive impairment
Mild cognitive impairment is a brain-function syndrome involving the onset and evolution of cognitive impairments beyond those expected based on the age and education of the individual, but which are not significant enough to interfere with their daily activities...
, multi-infarct dementia, vascular dementia due to a strategic single infarct (affecting the thalamus
Thalamus
The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...
, the anterior cerebral artery, the parietal lobe
Parietal lobe
The parietal lobe is a part of the Brain positioned above the occipital lobe and behind the frontal lobe.The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the...
s or the cingulate gyrus), vascular dementia due to hemorrhagic lesions, and mixed Alzheimer's and vascular dementia.
Vascular lesions can be the result of diffuse cerebrovascular disease
Cerebrovascular disease
Cerebrovascular disease is a group of brain dysfunctions related to disease of the blood vessels supplying the brain. Hypertension is the most important cause; it damages the blood vessel lining, endothelium, exposing the underlying collagen where platelets aggregate to initiate a repairing process...
or focal lesions; usually both. Mixed dementia is diagnosed when patients have evidence of AD and cerebrovascular disease, either clinically or based on neuroimaging evidence of ischemic lesions. In fact vascular dementia and Alzheimer's disease often coexist, especially in older patients with dementia.
Signs and symptoms
MID and AD, despite the fact that the two organic disorders have different causes, can be almost impossible to tell apart clinically and are often misdiagnosed. Patients suffering from vascular dementia present with cognitive impairment, acutely or subacutely, after an acute cerebrovascular event. After the onset a stepwise progression is typical.In small vessel disease the incidence peaks between the 4th and the 7th decades of life and 80% will have a history of hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
. Patients develop progressive cognitive, motor and behavioral signs and symptoms. A significant proportion of them also develop affective
Affect (psychology)
Affect refers to the experience of feeling or emotion. Affect is a key part of the process of an organism's interaction with stimuli. The word also refers sometimes to affect display, which is "a facial, vocal, or gestural behavior that serves as an indicator of affect" .The affective domain...
symptoms. These changes occur over a period of 5–10 years. If the frontal lobes are affected, which is often the case, patients may present as apathetic
Apathy
Apathy is a state of indifference, or the suppression of emotions such as concern, excitement, motivation and passion. An apathetic individual has an absence of interest in or concern about emotional, social, spiritual, philosophical or physical life.They may lack a sense of purpose or meaning in...
or abulic. This is often accompanied by problems with attention, orientation and urinary incontinence.
As already stated, small vessel disease and focal lesions often overlap, so these two patterns may be evident in the same individual concurrently.
Rare genetic disorders which result in vascular lesions in the brain have other patterns of presentation. As a rule of thumb they tend to present earlier in life and have a more aggressive course.
Diagnosis
Several specific diagnostic criteria can be used to diagnose vascular dementia, including the Diagnostic and Statistical Manual of Mental DisordersDiagnostic and Statistical Manual of Mental Disorders
The Diagnostic and Statistical Manual of Mental Disorders is published by the American Psychiatric Association and provides a common language and standard criteria for the classification of mental disorders...
, Fourth Edition (DSM-IV) criteria, the International Classification of Diseases, Tenth Edition (ICD-10) criteria, the National Institute of Neurological Disorders and Stroke
National Institute of Neurological Disorders and Stroke
The National Institute of Neurological Disorders and Stroke is a part of the U.S. National Institutes of Health . It conducts and funds research on brain and nervous system disorders and has a budget of just over US$1.5 billion...
- Association Internationale pour la Recherche et l'Enseignement en Neurosciences (NINDS-AIREN) criteria, the Alzheimer's Disease Diagnostic and Treatment Center criteria, and the Hachinski ischemic score.
Lateralizing signs such as hemiparesis
Hemiparesis
Hemiparesis is weakness on one side of the body. It is less severe than hemiplegia - the total paralysis of the arm, leg, and trunk on one side of the body. Thus, the patient can move the impaired side of his body, but with reduced muscular strength....
, bradykinesia, hyperreflexia
Hyperreflexia
Hyperreflexia is defined as overactive or overresponsive reflexes. Examples of this can include twitching or spastic tendencies, which are indicative of upper motor neuron disease as well as the lessening or loss of control ordinarily exerted by higher brain centers of lower neural pathways...
, extensor plantar reflexes, ataxia
Ataxia
Ataxia is a neurological sign and symptom that consists of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum...
, pseudobulbar palsy
Pseudobulbar palsy
Pseudobulbar palsy results from an upper motor neuron lesion to the corticobulbar pathways in the pyramidal tract. Patients have difficulty chewing, swallowing and demonstrate slurred speech...
, and gait
Gait (human)
Human gait is the way locomotion is achieved using human limbs. Different gaits are characterized by differences in limb movement patterns, overall velocity, forces, kinetic and potential energy cycles, and changes in the contact with the surface .- Foot strike :One variable in different gaits is...
and swallowing difficulties may be observed.
In terms of cognitive testing patients have patchy deficits. They tend to have better free recall
Free recall
Free recall is a basic paradigm in the psychological study of memory. In this paradigm, participants study a list of items on each trial, and then are prompted to recall the items in any order...
and fewer recall intrusions compared with patients with Alzheimer's disease. As small vessel disease often affects the frontal lobes, apathy early in the disease is more suggestive of vascular dementia because it usually occurs in the later stages of Alzheimer's. Consequently patients with vascular dementia perform worse than their Alzheimer's disease counterparts in frontal lobe tasks such as verbal fluency. They also tend to exhibit more perseverative behavior. They may also present with general slowing of processing ability, difficulty shifting sets and impairment in abstract thinking. In the more severe patients, or those patients affected by strategic infarcts in the Wernicke or Broca areas, dysarthria
Dysarthria
Dysarthria is a motor speech disorder resulting from neurological injury of the motor component of the motor-speech system and is characterized by poor articulation of phonemes...
s, dysphasias and aphasia
Aphasia
Aphasia is an impairment of language ability. This class of language disorder ranges from having difficulty remembering words to being completely unable to speak, read, or write....
s may be present.
The recommended investigations for cognitive impairment should be carried out, including a dementia screening blood test, chest X-Ray, CAT scan and ECG. The screening blood test should typically include full blood count, liver function tests
Liver function tests
Liver function tests , are groups of clinical biochemistry laboratory blood assays designed to give information about the state of a patient's liver. The parameters measured include PT/INR, aPTT, albumin, billirubin and others...
, thyroid function tests
Thyroid function tests
Thyroid function tests is a collective term for blood tests used to check the function of the thyroid.TFTs may be requested if a patient is thought to suffer from hyperthyroidism or hypothyroidism , or to monitor the effectiveness of either thyroid-suppression or hormone replacement therapy...
, lipid profile, erythrocyte sedimentation rate
Erythrocyte sedimentation rate
The erythrocyte sedimentation rate , also called a sedimentation rate or Biernacki Reaction, is the rate at which red blood cells sediment in a period of 1 hour...
, C reactive protein, syphilis
Syphilis
Syphilis is a sexually transmitted infection caused by the spirochete bacterium Treponema pallidum subspecies pallidum. The primary route of transmission is through sexual contact; however, it may also be transmitted from mother to fetus during pregnancy or at birth, resulting in congenital syphilis...
serology, calcium serum level, fasting glucose, urea
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....
and electrolytes, vitamin B-12, folate. In selected patients HIV serology and autoantibody testing may be done.
Cause
Risk factors for vascular dementia include hypertensionHypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
, smoking, hypercholesterolemia
Hypercholesterolemia
Hypercholesterolemia is the presence of high levels of cholesterol in the blood. It is not a disease but a metabolic derangement that can be caused by many diseases, notably cardiovascular disease...
, diabetes mellitus
Diabetes mellitus
Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced...
, and cardiovascular disease
Cardiovascular disease
Heart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...
and cerebrovascular disease
Cerebrovascular disease
Cerebrovascular disease is a group of brain dysfunctions related to disease of the blood vessels supplying the brain. Hypertension is the most important cause; it damages the blood vessel lining, endothelium, exposing the underlying collagen where platelets aggregate to initiate a repairing process...
.
Treatment
The aim of the management is the prevention of further cerebrovascular lesions. This includes administering antiplatelet drugs and controlling major vascular risk factors (hypertension, hypercholesterolemia, smoking and diabetes mellitus to mention a few).The general management of dementia includes referral to community services, judgment and decision-making regarding legal and ethical issues (e.g., driving, capacity, advance directives), and consideration of caregiver stress.
Cholinesterase inhibitors such as galantamine
Galantamine
Galantamine is used for the treatment of mild to moderate Alzheimer’s disease and various other memory impairments, in particular those of vascular origin...
have shown to be helpful in various randomized controlled trials. However their use is not licensed yet for this indication.
Behavioral and affective symptoms are particularly important in this patient group and deserve special consideration. These problems, if they develop, tend to be resistant to conventional psychopharmacological treatment and in many cases lead to hospital admission and placement in permanent care.
Prognosis
The 5-year survival rate is 39% for patients with vascular dementia compared with 75% for age-matched controls. Vascular dementia is associated with a higher mortality than "Alzheimer's", presumably because of the excess in cardiovascular risk factors.Epidemiology
Vascular dementia is the second most common cause of dementia in the United States and Europe in the elderly, but it is the most common form in some parts of Asia. The prevalencePrevalence
In epidemiology, the prevalence of a health-related state in a statistical population is defined as the total number of cases of the risk factor in the population at a given time, or the total number of cases in the population, divided by the number of individuals in the population...
of the illness is 1.5% in Western countries and approximately 2.2% in Japan. It accounts for 50% of all dementias in Japan, 20% to 40% in Europe and 15% in Latin America. The incidence
Incidence (epidemiology)
Incidence is a measure of the risk of developing some new condition within a specified period of time. Although sometimes loosely expressed simply as the number of new cases during some time period, it is better expressed as a proportion or a rate with a denominator.Incidence proportion is the...
of dementia
Dementia
Dementia is a serious loss of cognitive ability in a previously unimpaired person, beyond what might be expected from normal aging...
is 9 times higher in patients who have had a stroke than in controls. 25% of stroke patients develop new-onset dementia within 1 year of their stroke. The relative risk
Relative risk
In statistics and mathematical epidemiology, relative risk is the risk of an event relative to exposure. Relative risk is a ratio of the probability of the event occurring in the exposed group versus a non-exposed group....
of incident dementia is 5.5% within 4 years of suffering a stroke.
The prevalence of vascular dementia is higher in men than in women and it increases with age.
External links
- Helpguide article on vascular dementia
- J Bowler & V Hachinsky, Vascular Cognitive Impairment: Preventable Dementia, Oxford University Press 2003, ISBN 0-19-263267-1.
- Multi-Infarct Dementia Fact Sheet at ninds.nih.gov
- Multi-Infarct Dementia at nmha.org
- Vascular Dementia: Symptoms, Prognosis, and Support at helpguide.org
- American Academy of Neurology (2007, December 21). Walking And Moderate Exercise Help Prevent Dementia. ScienceDaily. Retrieved December 21, 2007, from http://www.sciencedaily.com/releases/2007/12/071219202948.htm
- What is vascular dementia? Alzheimer's Society fact sheet