Vascular cognitive impairment and dementia is acute or chronic cognitive deterioration due to diffuse or focal cerebral infarction that is most often related to cerebrovascular disease.
(See also Overview of Delirium and Dementia andDementia.)
Dementia is chronic, global, usually irreversible deterioration of cognition.
Vascular cognitive impairment and dementia is the 2nd most common cause of dementia among older people. It is more common among men and usually begins after age 70. It occurs more often in people who have vascular risk factors (eg, hypertension, diabetes mellitus, hyperlipidemia, smoking) and in those who have had several strokes. Many people have both vascular dementia and Alzheimer disease.
Dementia should not be confused with delirium, although cognition is disordered in both. The following helps distinguish them:
Dementia affects mainly memory, is typically caused by anatomic changes in the brain, has slower onset, and is generally irreversible.
Delirium affects mainly attention, is typically caused by acute illness or drug toxicity (sometimes life threatening), and is often reversible.
Other specific characteristics also help distinguish the 2 disorders (see table Differences Between Delirium and Dementia).
Etiology of Vascular Cognitive Impairment and Dementia
Vascular cognitive impairment and dementia typically results from multiple cerebral infarcts (or sometimes hemorrhages). Although each infarct may be only minimally symptomatic in itself, the combination of multiple infarcts can cause enough neuronal or axonal loss to impair brain function.
There are four major types of vascular cognitive impairment and dementias (1):
Subcortical ischemic vascular cognitive impairment and dementia
Multi-infarct dementia
Poststroke dementia
Mixed dementia
Subcortical ischemic vascular cognitive impairment and dementia is caused mainly by small vessel disease. Subcortical lacunar lesions may develop, as may white matter lesions, which are mainly subcortical. Subcortical ischemic vascular cognitive impairment and dementia may include
Multiple lacunar infarction: Multiple lacunar infarcts occur deep within hemispheric white and gray matter.
Binswanger dementia: This variant is associated with severe, poorly controlled hypertension and systemic vascular disease. It causes diffuse and irregular loss of axons and myelin with widespread gliosis, tissue death due to an infarction, or loss of blood supply to the white matter of the brain.
Multi-infarct dementia affects medium-sized blood vessels, leading to large cortical infarcts.
Post-stroke dementia is immediate and/or delayed irreversible cognitive decline that begins within 6 months after stroke.
Mixed dementia is characterized by both vascular cognitive impairment, dementia, and other coexisting pathology (eg Alzheimer disease, dementia with Lewy bodies).
Uncommon types of vascular cognitive impairment and dementia include the following:
Strategic single-infarct dementia: A single infarct occurs in a crucial area of the brain (eg, angular gyrus, thalamus).
Cerebral amyloid angiopathy: Clinical history includes slowly progressive cognitive decline, episodic transient focal neurologic episodes (so-called amyloid spells), and sudden-onset focal neurologic deficits secondary to cortical lobar intracerebral hemorrhages.
Hereditary vascular dementia: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a cerebral small vessel disease caused by mutations in the NOTCH3 (NOTCH receptor 3) gene, which codes for a transmembrane receptor located on vascular smooth muscle cells. Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is also a small vessel disease; it is caused by mutations in the HTRA1 gene.
Cerebral amyloid angiopathy (CAA) is the accumulation of beta-amyloid in cerebral blood vessel walls, which results in a high risk of intracerebral hemorrhages. CAA occurs in several types of hereditary disorders but usually occurs sporadically. Cognition can be normal; however, prevalence of CAA is much higher in patients with Alzheimer's disease than in the general population.
Etiology reference
1. Skrobot OA, O’Brien J, Black S, et al: The Vascular Impairment of Cognition Classification Consensus Study. Alzheimers Dement Jun;13 (6):624–633, 2017. doi: 10.1016/j.jalz.2016.10.007
Symptoms and Signs of Vascular Cognitive Impairment and Dementia
Symptoms and signs of vascular cognitive impairment and dementia are similar to those of other dementias (eg, memory loss, impaired executive function, difficulty initiating actions or tasks, slowed thinking, personality and mood changes, language deficits). However, compared with Alzheimer disease, vascular cognitive impairment and dementia tends to cause memory loss later and to affect executive function earlier. Also, symptoms can vary depending on where the infarcts occur.
Unlike other dementias, multiple-infarct dementia tends to progress in discrete steps; each episode is accompanied by intellectual decline, sometimes followed by modest recovery. Subcortical vascular cognitive impairment and dementia caused by small-vessel ischemic damage (which includes multiple lacunar infarction and Binswanger dementia) tends to cause small, incremental deficits; thus, the decline appears to be gradual.
As the disease progresses, focal neurologic deficits often develop:
Exaggeration of deep tendon reflexes
Extensor plantar response
Gait abnormalities
Weakness of an extremity
Hemiplegias
Pseudobulbar palsy with pathologic laughing and crying
Other signs of extrapyramidal dysfunction
Aphasias
Cognitive loss may be focal. For example, short-term memory may be less affected than in other dementias. Because loss may be focal, patients may retain more aspects of mental function. Thus, they may be more aware of their deficits, and depression may be more common than in other dementias.
Patients with CADASIL commonly present with cognitive impairment, migraine headaches, and/or stroke. CARASIL can cause alopecia and spondylosis. Age at onset varies.
Diagnosis of Vascular Cognitive Impairment and Dementia
Generally similar to diagnosis of other dementias
Neuroimaging
Diagnosis of vascular cognitive impairment and dementia is similar to the diagnosis of other dementias. A general diagnosis of dementia requires all of the following:
Cognitive or behavioral (neuropsychiatric) symptoms interfere with the ability to function at work or do usual daily activities.
These symptoms represent a decline from previous levels of functioning.
These symptoms are not explained by delirium or a major psychiatric disorder.
Evaluation of cognitive function involves taking a history from the patient and from someone who knows the patient plus doing a bedside mental status examination or, if bedside testing is inconclusive, formal neuropsychologic testing.
Differentiation of vascular cognitive impairment and dementia from other dementias is based on clinical judgment. Factors that suggest vascular cognitive impairment and dementia (or Alzheimer disease with cerebrovascular disease) include the following:
Imaging evidence of brain infarcts and other vascular brain damage
Clinical features characteristic of vascular cognitive impairment and dementia (eg, prominent executive dysfunction, mild or absent memory loss)
High Modified Hachinski Ischemic Score (if brain imaging is not available)
Confirmation of vascular cognitive impairment and dementia requires a history of stroke or evidence of a vascular cause for dementia detected by neuroimaging. If focal neurologic signs or evidence of cerebrovascular disease is present, a thorough evaluation for stroke should be done.
CT and MRI may show
Bilateral multiple infarcts in the dominant hemisphere and limbic structures
Multiple lacunar strokes
Periventricular white-matter lesions extending into the deep white matter
In Binswanger dementia, leukoencephalopathy in the cerebrum semiovale adjacent to the cortex, often with multiple lacunae affecting structures deep in the gray matter (eg, basal ganglia, thalamic nuclei)
In CADASIL and CARASIL, diffuse white matter hyperintensities with ischemic lesions in subcortical regions, including characteristic involvement of the anterior temporal lobe
In cerebral amyloid angiopathy, lobar hemorrhage, multiple cortical microhemorrhage or superficial siderosis
Key features can help distinguish Alzheimer disease from vascular cognitive impairment and dementia (see table Differences Between Vascular Cognitive Impairment and Dementia and Alzheimer Disease). The Hachinski Ischemic Score is sometimes used to help distinguish vascular cognitive impairment and dementia (mainly multi-infarct dementia) from Alzheimer disease when no brain imaging is available (1).
The diagnosis of CADASIL and CARASIL can be confirmed by genetic tests, which identify characteristic mutations of the NOTCH3 gene for CADASIL and HTRA1 gene for CARASIL. Sometimes a skin biopsy can be done instead to confirm the diagnosis of CADASIL.
Diagnosis reference
1. Hachinski VC, Iliff LD, Zilhka E, et al: Cerebral blood flow in dementia, Arch Neurol 32 (9):632–637, 1975. doi: 10.1001/archneur.1975.00490510088009
Treatment of Vascular Cognitive Impairment and Dementia
Safety and supportive measures
Management of vascular risk factors, including smoking cessation
Safety and supportive measures for vascular cognitive impairment and dementia are similar to those of other dementias. For example, the environment should be bright, cheerful, and familiar, and it should be designed to reinforce orientation (eg, placement of large clocks and calendars in the room). Measures to ensure patient safety (eg, signal monitoring systems for patients who wander) should be implemented.
Troublesome symptoms can be treated.
Managing vascular risk factors (eg, hypertension, diabetes, hyperlipidemia) may slow the progression of vascular cognitive impairment and dementia and help prevent future strokes, which could cause more cognitive impairment. Management includes the following:
Blood pressure control
Cholesterol-lowering therapy
Regulation of plasma glucose (90 to 150 mg/dL)
Smoking cessation
Medications, such as cholinesterase inhibitorsN-methyl-d-aspartate) antagonist, may help slow the loss of cognitive function in patients with moderate to severe dementia and may be synergistic when used with a cholinesterase inhibitor.
Prognosis for Vascular Cognitive Impairment and Dementia
The 5-year mortality rate for patients with vascular dementia is about 60%, which is higher than that for most forms of dementia, presumably because other atherosclerotic disorders coexist.
End-of-life issues
Because insight and judgment deteriorate in patients with dementia, appointment of a family member, guardian, or lawyer to oversee finances may be necessary. Early in dementia, before the patient is incapacitated, the patient’s wishes about care should be clarified, and financial and legal arrangements (eg, durable power of attorney, durable power of attorney for health care) should be made. When these documents are signed, the patient’s capacity should be evaluated, and evaluation results recorded. Decisions about artificial feeding and treatment of acute disorders are best made before the need develops.
In advanced dementia, palliative measures may be more appropriate than highly aggressive interventions or hospital care.
Key Points
Vascular cognitive impairment and dementia can occur as a series of discrete episodes (which may seem like a gradual decline) or in a single episode.
Focal neurologic signs may help differentiate vascular cognitive impairment and dementia from other dementias.
Confirm that dementia is vascular based on a history of stroke or neuroimaging findings that suggest a vascular cause.
