Vascular dementia typically presents in elderly patients, often with a history of stroke or cardiovascular disease, with stepwise decline in cognitive function. Radiologically, it is characterised by cerebral atrophy and white matter hyperintensities on T2-weighted MRI, especially in periventricular regions.
Description
Vascular dementia is the second most common cause of dementia after Alzheimer’s disease, resulting from reduced blood flow to the brain. It is characterised by cognitive impairment that typically follows a stepwise progression, often associated with neurological deficits. The condition is caused by various cerebrovascular pathologies, including small vessel disease, stroke, and chronic hypoperfusion.
Pathogenesis
Vascular dementia results from brain damage due to impaired blood flow, leading to neuronal death. Contributing factors include large or small vessel disease, strokes, and chronic cerebral hypoperfusion. Hypertension, atherosclerosis, and diabetes mellitus are significant contributors to the disease’s pathogenesis by causing vascular changes.
Subtypes
- Post-stroke dementia: Occurs after a major stroke.
- Subcortical vascular dementia: Associated with small vessel disease.
- Multi-infarct dementia: Caused by multiple small strokes.
- Mixed dementia: Combination of Alzheimer’s disease and vascular dementia features.
Epidemiology, Risk Factors & Associations
- More common in older adults, particularly over the age of 65.
- Risk factors include hypertension, diabetes, smoking, atrial fibrillation, and hyperlipidemia.
- Frequently associated with cardiovascular diseases.
Clinical Features
- Stepwise decline in cognitive functions.
- Memory loss, confusion, and difficulty concentrating.
- Neurological signs such as weakness, numbness, or problems with coordination and balance.
Complications
- Increased risk of recurrent strokes.
- Progressive worsening of cognitive and physical functions.
- Risk of depression and other psychiatric symptoms.
Pathological Features
Histopathology
- Macroscopic: Evidence of cerebral infarcts, small vessel disease, and brain atrophy.
- Microscopic: Ischemic changes, arteriosclerosis, and lacunar infarcts in the brain.
Serology
- Not specific for vascular dementia.
Biochemistry
- Markers of cardiovascular risk (e.g., lipid profile) may be elevated.
Radiological Features
General Features
- White matter hyperintensities on T2-weighted MRI.
- Evidence of cerebral infarcts and brain atrophy.
CT
- Generalised atrophy with focal cortical infarcts typical
- Hypodensity in periventricular white matter
MRI
- T1: Shows areas of cerebral atrophy. Hypointense basal ganglia lacunar infarcts.
- T2: Punctate or confluence white matter hyperintensities, especially periventricular. Central pontine infarcts. Large areas of volume loss with widened sulci.
- FLAIR: Hyperintense foci within basal ganglia. Multifocal diffuse and confluent white matter hyperintensity.
- SWI/GRE/T2*: Microbleeds in cortex and along pial surface.
Grading and Staging
No universally accepted grading or staging system for vascular dementia, but cognitive impairment is commonly assessed using scales like the Mini-Mental State Examination (MMSE).
Diagnosis
Diagnosis is based on clinical criteria, including a history of stroke or cerebrovascular disease, stepwise progression of symptoms, and imaging findings. Neuropsychological testing is important for assessing cognitive function.
Differential Diagnosis
- Alzheimer’s disease: Gradual onset, predominant memory loss. Hippocampal and amygdala atrophy.
- Frontotemporal dementia: Changes in personality and behavior, less pronounced memory loss. Frontotemporal atrophy causing knife-like gyri.
- Lewy body dementia: Visual hallucinations, Parkinsonism features.
- CADASIL: Earlier age of onset. Imaging mimics small vessel disease.
Management
Management focuses on controlling vascular risk factors, cognitive rehabilitation, and symptomatic treatment. Antihypertensive, antidiabetic, and lipid-lowering medications are used to manage underlying conditions. Supportive therapies include occupational and speech therapy.