Vascular dementia Dementia is a syndrome of acquired mental retardation. Stroke is an obvious factor in the progression of vascular dementia (Grade A recommendation). After Alzheimer’s disease, vascular dementia is the most common type of dementia. It is noteworthy that a considerable number of family members of patients with vascular dementia have varying degrees of depressive symptoms.
I. Definition
Any dementia related to vascular factors is collectively referred to as cerebrovascular dementia.
Vascular dementia is the result of cerebral infarction caused by vascular disease. The infarct foci are usually small but cumulative. The onset of the disease is often in later life.
II. Diagnosis
Currently, there are no accepted diagnostic criteria for cerebrovascular dementia. According to the classification of mental and behavioral disorders published by the ICD–10, the key points for the diagnosis of vascular dementia (code F01) are as follows: 1) dementia must be definitely present; 2) cerebrovascular disease must be present; and 3) there is a temporal association between the two (e.g., dementia occurs within 3 months of a stroke). The diagnosis presupposes the presence of dementia, the impairment of cognitive function is often uneven, there may be memory loss, signs of intellectual impairment and focal neurological impairment, and self-knowledge and judgment may remain relatively good. Sudden onset or phasic degeneration and focal neurological signs and symptoms make the diagnosis more likely to be established. In some cases, the diagnosis can only be confirmed by CT or eventually by performing a neuropathological examination. The relevant features are hypertension, carotid murmur, emotional instability with transient depressive mood, crying or explosive laughter, transient clouding of consciousness or delirium episodes, often exacerbated by further infarction, and a personality that remains relatively intact, although some patients may present with marked personality changes such as apathy, lack of control, or more prominent pre-existing personality traits such as egocentricity, paranoid attitudes, or irritability.
Differential diagnosis
The differential diagnosis can be very difficult. Although post-stroke dementia may be associated with vascular dementia, it may also be present by a combination of slow progression of dementia under the clinic, as in Alzheimer. both stroke and Alzheimer are common in older adults. The diagnosis often has two tendencies: ischemic white matter injury alone – which may exacerbate dementia – and the increased use of CT or MRI imaging, which increases the misdiagnosis of vascular dementia. On the other hand, the diagnosis of vascular dementia is based only on a history of stroke, which increases the number of missed diagnoses of vascular dementia.
Other disorders that should be identified are Lewy’s microsomal dementia, progressive supranuclear palsy, corticobasal degeneration, Parkinson’s disease dementia, and frontal lobe tumors.
Patients with cognitive impairment should have an informative history from the patient and family, as well as a thorough physical examination. Special attention should be paid to 1) the presence of vascular risk factors, including hypertension, heart disease, and diabetes mellitus; 2) examination of the cardiovascular system for possible embolism (atrial fibrillation, heart failure, heart valve disease, carotid stenosis); and 3) neurological examination for focal neurological deficits, such as pyramidal fasciculus signs, dysarthria, hemianopia, or extra-pyramidal signs. A psychological examination must also be performed.
The examination should also include the exclusion of treatable dementia disorders such as hypothyroidism, neurosyphilis, vitamin B12 deficiency, normal pressure hydrocephalus, frontal lobe tumors, and cerebral vasculitis.CT or MRI is important to exclude these etiologies.
Other tests that should be performed in some patients are; echocardiography, carotid ultrasound in patients who may have carotid stenosis; blood pressure Holter in case of doubt about an incidental blood pressure test; SPECT in patients with atypical stroke.
IV. Cerebrovascular dementia
Clinical types of cerebrovascular dementia are divided into 5 types.
1, multi-infarct dementia: dementia due to multiple cerebral infarcts, often with clinical hypertension, atherosclerosis, recurrent cerebrovascular disease, and more or less neurological and psychiatric symptoms left after each attack, which accumulate and eventually become a comprehensive and severe mental decline.
2.Large cerebral infarct dementia: It is often caused by occlusion of the main trunk of cerebral arteries (such as middle cerebral artery, basilar artery, etc.), resulting in large cerebral infarction, severe cerebral edema, and even cerebral herniation. Most patients may die in the acute phase, and a few surviving patients are left with varying degrees of neuropsychiatric abnormalities, including dementia, and loss of work and life skills.
Subcortical atherosclerotic encephalopathy: With the development of imaging, it has become possible to diagnose it by CT or MRI. Although some authors still doubt whether this type of dementia is an independent type, it has characteristics both clinically and pathologically and should be classified as one of the types of cerebrovascular dementia.
4. Thalamic dementia: dementia caused by focal infarction or lesion of bilateral thalamus (occasionally one side of the thalamus), which is rare clinically. Thalamic dementia refers to dementia caused by focal lesions in the thalamus alone, excluding the thalamic lesions present in multiple cerebral infarcts.
5.Watershed infarct dementia: Also known as limbic dementia, it refers to severe ischemia or even infarction due to long-term hypoperfusion at the junction of the anterior, middle and posterior cerebral artery distribution areas, resulting in brain dysfunction. Dementia may appear clinically and can be diagnosed by imaging during life, which is less common.
V. Treatment
(I) Recommendations.
1. Antiplatelet therapy, such as low-dose aspirin (75 mg ) can reduce the occurrence of further vascular events in patients with early dementia. (Grade B recommendation)
2. Patients with carotid artery stenosis should undergo surgery. Those caused by hypoperfusion should have increased cerebral perfusion and antihypertensive therapy should be disabled. In addition to these modifiable patient risk factors, other specific treatments are also available.
3. Anticoagulation with Warfarin is only appropriate for a small subset of patients. Vasodilators have no sustained efficacy. Some pro-intellectual drugs may be used.
(II) Methods
1, active treatment of the original disease, control the risk factors. 2, the intellectual drugs intellectual drugs at home and abroad research is quite active, new drugs continue to emerge, but the effectiveness and specificity of the drug is not strong, and more side effects, clinical application is limited, many are still in the experimental research stage, cholinergic drugs are still a very promising class of drugs. Cholinergic drugs are still a promising class of drugs.
(1) cholinergic drugs in the brain cholinergic system and human learning, memory function is closely related. Therefore, drugs that promote cholinergic nerve function have been developed to increase the acetylcholine content at synaptic sites. Their research has mainly focused on cholinergic esterase inhibitors and muscarinic M receptor agonists.
① Cholinesterase inhibitors: They are the most used and longest-standing class of drugs in the treatment of dementia. Such as stigmasterol, miramicolin, and anterolimus. However, cholinergic replacement therapy can only improve pre-existing symptoms and cannot lead to complete recovery of the impaired patient, much less prevent the development of the disease. At the current level of knowledge, tetrahydroaminomyridine (tacrine) is not recommended for the treatment of dementia. (Grade A recommendation)
② r-aminobutyric acid (GABA) receptor modulators: GABA receptors have a down-regulatory effect on memory consolidation. Another GABA receptor antagonist, CGP-35348, reverses scopolamine-induced memory loss.
(iii) Drugs acting on N C methyl-D-monate (NMDA) receptors: Piracetam-like pro-intellectual drugs are positive modulators of AMPA-sensitive glutamate receptors in neurons and can improve human remembrance processes by enhancing induced calcium inward flow. It also improves glucose utilization and energy reserves in the brain, promotes phospholipid uptake, and RNA and brain protein synthesis, and also acts directly on the cerebral cortex with activating, protective and repairing effects on nerve cells. Amantadine has shown significant improvement in behavioral and psychiatric symptoms in patients with mild to moderate dementia syndrome in clinical double-blind trials, and the drug is well tolerated.
④ Calcium channel blockers: Indirectly affect learning memory, mainly by acting on L-type calcium channels. For example, nimodipine.
⑤ Antioxidant drugs: Vitamin E has antioxidant properties and can prevent the peroxidation of unsaturated fatty acids in the plasma membrane.
(6) Chinese herbal medicines: ginsenosides, gibberellins, ginkgo biloba preparations, ginkgo biloba, Chuanxiong, Astragalus, etc., have different degrees of protective effects on memory impairment in experimental animals, and can exert pro-intellectual effects in different ways, thus improving patients’ learning memory.
(7) Other classes: e.g. Xidezhen is a brain metabolism enhancer. It treats Alzheimer’s disease by improving the function of neurotransmitter system, enhancing neuronal metabolism and neurotransmitter capacity, and improving the effect of dopamine and norepinephrine on the peripheral nervous system through activation of postsynaptic dopamine and 5-hydroxytryptamine receptors. Xidrozine has shown improvement in some patients, but it is not routinely recommended because it is not possible to determine in advance whether patients are sensitive to such drugs. (Grade A recommendation) ⑧ Olanzapine is a cholinergic puzzler that acts on the central nervous reticular formation.
(2) In addition to drug therapy, rehabilitation is very important, including psychotherapy, speech training, and physical function training, all of which should be carried out in a planned and gradual manner.