Cerebrovascular Disease, Occlusive

Key Features

Essentials of Diagnosis

• Sudden onset

  • Weakness and numbness of an extremity

  • Aphasia

  • Dysarthria

  • Unilateral blindness (amaurosis fugax)

• Bruit heard loudest in the mid neck

General Considerations

• Unlike the other vascular territories, symptoms of occlusive cerebrovascular disease are predominantly due to emboli

• The ischemia is reversible (transient ischemic attacks [TIAs]) when collateral flow reestablishes perfusion but is a sign that the risk of additional emboli and stroke is high

• Most ischemic strokes are due to emboli from the heart

• One-quarter of all ischemic strokes may be due to emboli from an arterial source; approximately 90% of these emboli originate from the proximal internal carotid artery

• Intracranial atherosclerotic lesions are less uncommon in western populations but are the most common location of cerebrovascular disease in Asian populations

Clinical Findings

Symptoms and Signs

• Ischemic symptoms of TIAs

  • Generally last only a few seconds to minutes

  • May continue for up to 24 hours

• Most common lesions associated with carotid disease are in the cortex with both motor and sensory involvement

• Emboli to the retinal artery cause unilateral blindness which, when transient, is called amaurosis fugax

• Posterior circulation symptoms referable to the brainstem, cerebellum, and visual regions of the brain are

  • Due to atherosclerosis of the vertebral basilar systems

  • Much less common than carotid disease

• Carotid artery bruits

  • Correlation between the degree of stenosis and the presence of the bruit is poor

  • Absence of a bruit does not exclude the possibility of carotid stenosis

• Nonfocal symptoms, such as dizziness and unsteadiness, seldom are related to cerebrovascular atherosclerosis

Differential Diagnosis

• Transient ischemic attack

• Ischemic stroke

• Intracerebral hemorrhage

• Subdural or epidural hematoma

• Space-occupying lesion, eg, brain tumor

• Seizure (Todd paralysis)

• Migraine

• Peripheral causes of vertigo, eg, Ménière disease

• Hypoglycemia

• Guillain-Barré syndrome

• Multiple sclerosis

• Aortic dissection

Diagnosis

Imaging Studies

• Duplex ultrasonography

  • Imaging modality of choice

  • Has high specificity and sensitivity for detecting and grading degree of stenosis at the carotid bifurcation

  • Prospective screening valuable in timing intervention in asymptomatic patients since about 10% will have evidence of plaque progression in a given year

• Magnetic resonance angiography or CT angiography

  • Provides excellent depiction of full anatomy of the cerebrovascular circulation from aortic arch to cranium

  • Each of these modalities may have false-positive or false-negative findings

• Use at least two modalities to confirm degree of stenosis

• Cerebral angiography is reserved for cases that cannot be resolved by magnetic resonance or CT angiography

Treatment

Asymptomatic patients

• Carotid intervention is likely beneficial in those

  • With no neurologic symptoms but with carotid stenosis on imaging

  • Who are considered to be ...