1.6. Chronic Small Vessel Disease
Poorly controlled hypertension and diabetes are associated with small vessel disease both by MRI and neuropathologically. The aging process itself and chronic migraine also are associated with probable microinfarctions. CADASIL, Binswanger's Disease and amyloid angiopathy are well delineated syndromes associated with small vessel disease.
Multiple small vessel infarction is associated with a subcortical dementia characterized by apraxia and slowness of information processing. Pseudobulbar palsy and spasticity are common concomitant features. Congophilic angiopathy is usually differentiated from just small vessel infarction by superficial cortical hemorrhages. Binswanger's Disease frequently is preceded by severe uncontrolled hypertension and is posterior periventricular predominant. Migraine most frequently presents with the T2 weighted lesions rarely associated with neurological deficit. CADASIL is associated with severe migraine and early onset dementia.
- Most patients with lacunar infarction suffer more than one lacune
- Multiple penetrating arteries are involved
- Extensive lacunar infarction
- Cystic lesions of the basal ganglia, thalamus, internal capsule and pons known as "état lacunair".
- Traditional clinical feature of "état lacunaire"
- Pseudobulbar palsy
- Emotional dyscontrol; "laughter without mirth", "crying without tears" inappropriate to the patients environment
- Difficulty with swallowing combined with hyperactive gag reflex
- Subcortical dementia
- Rigidity
- Cautious small stepped gait (Well's dementia gait)
- Bilateral Babinski signs
- Mild focal motor or sensory signs
- Evolving concepts:
- Many patients with multiple lacunes are asymptomatic (common)
- Severe generalized while matter disease:
- Associated with subcortical dementia
- Spasticity
- Ventriculomegaly (ex vacuo)
- New concept:
- Lacunes, white matter gliosis and atrophy exemplified by ventriculomegaly occur concomitantly and constitute a chronic brain micro vasculopathy
Chronic White Matter Changes of Micro Vasculopathy (Binswanger's Disease)
- Occipital lobes and periventricular white matter involvement are predominant location
- Anterior ventricles are affected. The lesions are close to the ependymal surface
- Patchy demyelination that may be confluent
- Cerebellar white matter affected
- Thin corpus callosum
- Cortex is relatively spared
Pathology
- Islands of pallid decreased myelinization surrounded by normal myelin
- Necrosis and cavitation occur in severe cases
- penetrating arteries are thickened and hyalinized
- Usually patent
- Rare amyloid deposition in vessels of hemisphere, cortex and leptomeninges
CADASIL (Cerebral AD Arteriopathy with Subcortical Infarcts and Leukoencephalopathy)
- Pathology of penetrating arteries:
- Fibrous thickening
- Hyaline degeneration of the intima
- Reduplication of the internal elastic lamina
- PAS positive material deposition in the vessel
- Clinical features:
- Onset in the early 40's
- Migraine headaches
- Chromosome 19q 12
- Dementia; abulia; behavioral disturbances
- subcortical > cortical type
- Lacunar strokes
- Pseudobulbar palsy
- Long periods of clinical stability
- MRI evaluation
- Periventricular T2-weighted lesions are prominent
- Patchy areas of myelin abnormality
Amyloid Angiopathy
- Clinical features:
- Subcortical lobar hemorrhages
- Multiple lobes
- Rare TIA during the course of the illness
- Seizures more common than with HCVD
MRI White Matter Lesions from Microangiopathy
- Vascular stripe
- Periventricular internal border zone
- Between arterial penetrating vessel from superficial pial arteries and ascending lenticulostriate arteries
- Ventricular caps of increased T2-weighted lesions
- Anterior and occipital horns of the lateral ventricles
- Periventricular rims
- Gliosis possibly secondary to trans ependymal CSF flow (approximately 30% of all CSF bulk flow)
- Centrum semiovale and corona radiata lesions
- Multiple and discrete
- Rarely syncytial
Epidemiology of Hemorrhagic Vascular Disease
Hypertension is the major cause of intracranial hemorrhage. The age of the patient and underlying medical condition point to the specific etiology of hemorrhagic vascular disease.
Spontaneous intracranial and subarachnoid hemorrhage cause approximately 10% of strokes. In patients less than 40 years of age, vascular malformations, aneurysms, cavernous angioma, illicit drugs and head trauma are the usual causes. In elderly patients, congophilic angiopathy accounts for approximately 10% of hemorrhages. Approximately 10% of patients treated with fibrinolytic agents after myocardial infarction bleed. Approximately 5–10% of patients on warfarin or heparin bleed at some point during their therapy. The rate of ICH on anticoagulation is approximately 0.3% per year. Evidence of prior vascular disease is common as patients with ICH have T2 weighted hyper intensities in cerebral white matter, lacunes and old infarction 68% of the time. There is a correlation of spontaneous ICH with small chronic hemorrhage and ischemic lesions in elderly patients.
|