SIGNS AND SYMPTOMS
However, the patient may have previously experienced transient episodes of monocular blindness (amaurosis fugax). Rarely, the patient has experienced a transient ischemic attack with hemiparesis, paraesthesia, and/or aphasia. These episodic bouts of amaurosis fugax may be quite frequent, and may last from several seconds to several minutes. Rarely does the patient have any lasting visual deficits.
Frequently, the patient previously experiencing amaurosis fugax will not
exhibit retinal emboli, but may have arteriolar narrowing and sheathing. A Hollenhorst
plaque appears as a bright, glistening, refractile plaque, usually at the bifurcation of a
retinal arteriole. These have the propensity to break up and move, and may not be present
at subsequent visits.
Cholesterol is deposited within the vessel walls and forms an atheroma, narrowing the artery. Turbulent blood flow over the atheroma can lead this plaque to ulcerate, which allows small particles to break off and flow within the blood stream. Eventually, the embolus enters a vessel whose caliber is too small to allow it to flow any further, and it lodges. Ischemia to the tissue occurs if blood flow is significantly impaired distal to the blockage. If the emboli lodges within a retinal vessel, then retinal ischemia with corresponding loss of vision occurs. The result may be a retinal artery occlusion.
In the case of cholesterol emboli, however, the blockage often quickly
dislodges without permanent visual impairment. Instead, the patient experiences a brief
interruption of vision and/or visual field (amaurosis fugax). Multiple bouts of amaurosis
fugax may indicate multiple emboli. In cases where the patient is asymptomatic, yet a
Hollenhorst plaque is visible, there is rarely permanent ischemia. This is because the
cholesterol emboli are malleable and blood flow may be able to get past the emboli.
A retinal embolus indicates significant systemic vascular
disease. Refer the patient to an internist, vascular surgeon, or cardiologist for
hypertension, coronary artery disease, diabetes, and carotid artery disease. A complete
physical, carotid ultrasound, stress echocardiogram, fasting glucose and lipid levels, and
blood chemistry with cardiac enzymes are indicated. Treatment of carotid stenosis, TIAs,
and retinal emboli may include carotid endarterectomy, carotid angioplasty, or aspirin
therapy, depending upon the risks of future ischemic events.
Other reports in this section
Eyelids & Eyelashes | Conjunctiva & Sclera | Cornea
Uvea | Vitreous & Retina | Optic Nerve & Brain | Oculosystemic Disease
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