Vascular dementia: diagnosis

Criteria for diagnosis of vascular dementia

A. Development of multiple cognitive defect, manifested simultaneously

1. Memory impairment (a violation of the ability to remember a new one or reproduce previously learned information)
2. One (or several) of the following cognitive disorders:
   • aphasia
   • apraxia (impaired ability to perform actions, despite the preservation of elementary motor functions)
   • agnosia (a violation of the ability to recognize or identify objects, despite the preservation of elementary sensory functions)
   • Disorder of regulatory (executive) functions (planning, organization, phased implementation, abstraction)

B. Each of the cognitive abnormalities specified in criteria A1 and A2 causes significant impairment in social or occupational life and represents a significant reduction in relation to the previous level of functioning

C. Focal neurological symptoms (eg, revitalization of deep tendon reflexes, extensor stop marks, pseudobulbar paralysis, walking disorders, weakness in the limbs) or paraclinic signs of cerebrovascular disease (eg, multiple infarctions involving the cortex and underlying white matter) that can be etiologically related with cognitive impairment

D. The cognitive defect does not arise exclusively during delirium.

Diagnostic criteria for vascular dementia ADDTC

I. Possible vascular dementia

A. - Dementia

• Two (or more) strokes or a single stroke with an apparent temporary connection with the onset of dementia
• At least one infarct outside the cerebellum, documented by the methods of neuroimaging

B. The diagnosis of possible vascular dementia is also confirmed:

• Indications for multiple infarctions in areas whose damage can lead to dementia
• Multiple TIAs in history
• The presence of vascular risk factors (arterial hypertension, heart disease, diabetes mellitus)
• High score on the Khachinsky scale.

C. Clinical signs that are considered manifestations of vascular dementia, but require further study:

• The relatively early occurrence of walking and incontinence disorders
• Changes in periventricular and deep white matter in T2-mode, more pronounced than the corresponding age-related changes.
• Focal changes submitted electrophysiological studies (EEG, VP) or neuroimaging methods.

D. Clinical signs that do not have a strict diagnostic value (neither "for" nor "against" the diagnosis of a possible "vascular dementia:

• Presence of periods of slow progression of symptoms.
• Illusions, psychosis, hallucinations
• Epileptic seizures

E. Clinical signs that make the diagnosis of possible vascular dementia questionable:

• Transortical sensory aphasia in the absence of corresponding focal lesions according to neuroimaging data
• Absence of focal neurological symptoms (in addition to cognitive impairment)

II. Probable vascular dementia.

• Dementia plus one (or more) of the following indications:
  • The presence of anamnestic or clinical data on a single stroke (but not multiple strokes) without a clear connection in time with the onset of dementia.
  • Or Binswanger Syndrome (without multiple strokes), which includes all of the following manifestations: The occurrence of urinary incontinence in the early stages of the disease (which is not associated with urological pathology) or walking disorders (parkinsonian, apraktic, senile) that can not be explained by peripheral causes.
  • Vascular Risk Factors
  • Extensive changes in white matter according to neuroimaging data

III. Reliable vascular dementia

The diagnosis of reliable vascular dementia requires a histopathological examination of the brain, as well as:

• A - the presence of clinical dementia syndrome
• B - morphological confirmation of multiple infarctions, including outside the cerebellum.

With the progression of vascular (and degenerative) dementia, there are signs of brain atrophy in the form of an expansion of the lateral ventricles and convectional subarachnoid space, which reflects the loss of a significant part of the brain volume. The occurrence of any dementia is determined either by the critical volume of the lost brain substance (from 50 to 100 ml) or by the localization of the lesion, which is strategically important for the development of dementia (associative areas of the cortex, anterior parts of the brain, temporal, limbic, thalamic structures, corpus callosum).

The clinical picture of dementia itself with Alzheimer's disease and vascular encephalopathy is almost identical. But since degenerative and vascular dementias constitute the absolute majority among all possible causes of dementia, a differential diagnosis between them acquires paramount importance. In this regard, the Khachinsky scale, which is based on clear clinical signs, is easy to use and has a high diagnostic resolution, has gained wide popularity: in approximately 70% of cases, the diagnosis based on the Khachinsky scale coincides with CT or MRI data. The sudden onset of dementia, its fluctuating course, the presence of arterial hypertension, a history of stroke and focal neurological symptoms speak of the vascular nature of dementia, which is confirmed by high scores (7 points or more) on the Khachinsky scale. The absence of the manifestation gives a total of 4 points or less on this scale, that the evidence in favor of primary degenerative dementia, mainly of disease Alzheimer's or senile dementia of the Alzheimer type.

It is important, however, to take into account that both Aligheimer's disease and vascular dementia are diseases related to age, and therefore are often combined in the same patient. Such mixed degenerative-vascular dementia is difficult to diagnose and occurs quite often (according to some data - about 10% of dementia). Therefore, only about 10% of all dementia cases account for the remaining etiologic forms of dementia ("other" dementia) associated with intoxications, metabolic disorders, tumors, infections, traumatic brain injuries, hydrocephalus, etc. Dementia with HIV infection (the so-called "AIDS dementia complex") is becoming more urgent.

An important achievement of neurology in recent years is the development of the concept of so-called reversible and irreversible forms of dementia. Reversible dementia occurs in many diseases, such as intoxications, infections, nutritional disorders (nutritional dementia), metabolic and vascular disorders, volumetric intracranial processes, normotensive hydrocephalus.

It is useful to remember that intoxication can be the result of the use of medications, whether intentionally or accidentally. It is necessary to register each of the drugs taken, including seemingly the most banal. The list of medicines that can cause dementia is gradually expanding. This includes opiate analgesics, corticosteroids, anticholinergics, antihypertensives, digitalis and its derivatives. Finally, combinations of drugs can have such a destructive effect in the end. In addition, virtually all chemicals used as drugs from heroin to glue are capable of causing dementia. The same final effect can be produced by other chemicals: carbon monoxide, lead, mercury, manganese.

Any infection that can affect the brain can lead to reversible dementia: bacterial, fungal or viral encephalitis. Among nutritional disorders, as a possible cause of reversible dementia, such states as vitamin B1 deficiency are described; persistent vomiting during pregnancy; pernicious anemia; insufficiency of folic acid; pellagra.

Metabolic disorders as a cause of reversible dementia include diseases of the thyroid and parathyroid glands, adrenal glands and the pituitary gland. Diseases of the lung can cause reversible dementia due to hypoxia or hypercapnia. The prognosis and course of encephalopathy and dementia in renal or hepatic insufficiency depend on the underlying cause.

Surgery of shunting with normotensive hydrocephalus often has a dramatic effect, causing the reverse development of dementia.

Irreversible dementias are characteristic of such progressive degenerative diseases of the nervous system as Alzheimer's disease, Pick's disease, Parkinson's disease, Huntington's chorea, multisystem atrophy, some forms of amyotrophic lateral sclerosis, progressive supranuclear palsy, cortico-basal degeneration, Levy diffuse bodies disease, Creutzfeldt-Jakob disease . Almost all of these diseases are recognized by the characteristic neurological manifestations that accompany dementia. Among the latter, parkinsonism is more common than others.

For the diagnosis of vascular dementia, the ischemic scale of the Khachinsky is traditionally used. However, if this scale is used in isolation from other data, then, as clinico-pathomorphological comparisons show, its accuracy, sensitivity and specificity are rather low. The Khachinsky scale differentiates patients with clinically manifested middle and large heart attacks and patients with other very heterogeneous changes: lacunar infarctions, subclinical infarctions, chronic ischemic white matter damage, Binswanger's disease, a combination of vascular dementia and Alzheimer's disease - that is, variants of vascular dementia, excellent from multi-infarct dementia.

Vascular dementia is a heterogeneous group of conditions common to which is the presence of dementia, a degree of disruption of the blood supply to the brain, and the presence of cause-effect relationships between them. The diagnosis is confirmed by carefully collected history, examination data and neuropsychological examination.

Among the frequently used criteria are the criteria for vascular dementia developed by the international working group NINDS-AIREN (National Institute of Neurological Disorders and Stroke - Association Internationale pour la Recherche et l'Enseignement en Neurosciences). According to the criteria of NINDS-AIREN, the diagnosis of vascular dementia is confirmed by the acute development of cognitive impairment, the presence of walking disorders or frequent falls, frequent urination or incontinence, focal neurologic symptoms (hemiparesis, weakness of the facial muscles of the lower half of the face, sensitivity disorders, visual field defects, pseudobulbar syndrome , extrapyramidal manifestations), depression, affective lability, and other mental changes. According to the NINDS-AIREN criteria, dementia is defined as a memory impairment combined with a deficit in the other two cognitive domains (orientation, attention, speech, visual and spatial and regulatory functions, motor control and praxis). Cognitive impairments should interfere with a patient's daily activities, regardless of the effect of a physical defect associated with a stroke. Cases with impaired consciousness, delirium, sensorimotor disorders, severe aphasia and psychosis should be excluded if they interfere with a full neuropsychological study. In accordance with the criteria of NINDS-AIREN, neurological examination should reveal focal symptoms that are characteristic of a stroke. Several types of ischemic brain damage have been identified in the criteria, which can lead to vascular dementia, including: extensive infarctions associated with lesions of large cerebral arteries, single heart attacks in strategic zones (with a cognitive defect corresponding to their localization), lacunar infarctions in the inferior parts white and gray matter, extensive ischemic damage to white matter, or a combination of these changes. Dementia should be manifested within 3 months after a documented stroke or characterized by the presence of episodes of sudden deterioration of cognitive functions or a fluctuating course with a step-like progression of the cognitive defect.

The differential diagnosis of vascular dementia and Alzheimer's disease is important, as the approaches to treating these conditions differ; In the case of vascular dementia, effective primary and secondary preventive therapy is possible. According to the criteria of Alzheimer's disease, developed by NINCDS-ADRDA, for diagnosis of dementia, cognitive defect detection is sufficient only in two areas, including outside the mnestic sphere.