Pathophysiology of Vascular Dementia

       Vascular dementia or vascular cognitive impairment, is the end result of brain damage caused by cerebrovascular disease. The existence of multiple infarcts, lacunar infarction, myocardial single in certain areas of the brain, Binswanger's syndrome, cerebral amyloid angiopathy, hypoperfusion, hemorrhage, and a variety of other mechanisms to the pathogenesis of vascular dementia onset.
1. Multiple Infarcts
         Multi-infarct dementia is the result of multiple and bilateral infarction. There is a history of one or a few times a stroke with focal symptoms such as hemiparesis / hemiplegia, aphasia, hemianopsia. Pseudobulbar palsy are often accompanied by dysarthria, impaired walking (small step gait), forced laughing / crying, Babinski reflex, and incontinence. Computed tomography imaging (CT scan) of the brain showed cortical atrophy with bilateral hypodensity, sometimes accompanied by ventricular dilatation.

2. Lacunar Infarct
          Lacunar infarcts are small, 2-15 mm diameter, caused by abnormalities in the small penetrating arteries in the diencephalon, brain stem and sub-cortical result of hypertension. In one third of cases, is asymptomatic lacunar infarcts. If the cause of symptoms, sensory disturbances may occur, transient ischemic attack hemiparesis or ataxia. When the number of lacunar syndrome increases will arise dementia, often with pseudobulbar palsy. In severe degree occurred lacunar state. CT scan of the brain showed multiple hypodensity small size, it can also appear on a CT scan of the brain due to their small size or located in the brain stem. Magnetic resonance imaging (MRI) of the brain is more accurate investigations to indicate the presence of lacunar especially in the area of the brain stem (pons).

3. Single Strategic Infarct Dementia
         Single strategic infarct dementia is caused by ischemic lesions in cortical or subcortical regions that have important functions. Angular gyrus infarcts cause symptoms of sensory aphasia, alexia, agrafia, memory impairment, disorientation and impaired spatial construction. Infarction of the posterior cerebral artery distribution area cause symptoms of amnesia accompanied by agitation, visual hallucinations, visual disturbances and confusion. Infarction of the anterior cerebral artery distribution area raises abulia, motor aphasia and apraxia. Parietal lobe infarct cause cognitive impairment and behavioral disorders due to spatial perception. Infarction of the paramedian artery distribution area of the thalamus produce thalamicdementia.

4. Binswanger's syndrome
        Binswanger showed progressive dementia syndrome with a history of stroke, hypertension and diabetes mellitus sometimes. Often accompanied by symptoms of pseudobulbar palsy, pyramidal abnormalities, impaired walking (gait) and incontinence. There is a white matter atrophy, ventricular enlargement with normal cerebral cortex. Risk factor is small artery diseases (hypertension, amyloid angiopathy), the failure of autoregulation of blood flow in the brain in the elderly, periventrikel hypoperfusion caused by heart failure, arrhythmias and hypotension.

5. Cerebral Amyloid Angiopathy
      There is accumulation of amyloid in the tunica media and adventisia cerebral arterioles. Incidence increases with age. Sometimes it happens with sudden-onset dementia.

6. Hypoperfusion
        Dementia can occur due to global cerebral ischemia due to cardiac arrest, hypotension, hypoperfusion with / without symptomatic carotid occlusion, arterial cerebral autoregulation failure, and respiratory failure. These conditions cause vascular lesions in the brain, especially in the area of multiple white matter.

7. Bleeding
     Dementia can occur due to bleeding lesions such as subdural hematoma, chronic sequelae of sub-arachnoid hemorrhage and cerebral hematoma. Hematoma multiple cerebral amyloid angiopathy associated with idiopathic or hereditary.

8. Other Mechanisms
   Another mechanism may lead to dementia including vascular abnormalities inflammatory or non-inflammatory (polyarthritis nodosa, limfomatoid granulomatosis, giant-cell arteritis, and etc).

No comments:

Post a Comment

Related Posts Plugin for WordPress, Blogger...