The same endothelial cell swelling, loss of tight-junctions, "leakage," and partial/complete occlusion that is going on in the tiny blood vessels of the retina (see "Eye" section) can go on in the microvasculature of the brain and explains the brain disturbances and the typical MRI brain abnormalities of SS.

• Abnormalities in the Corpus Callosum
• "Snowballs"
• Linear defects ("Spokes")
• "Holes"

Autoimmune Endotheliopathy In The Retinal Vasculature

Patients with Susac's Syndrome typically notice "dark spots" in one or both of their visual fields. This "dark spot" obstructs their vision in that particular portion of their visual field, so that they "can't see anything" in that particular spot. The patient might say, "When I look at your face, I can't see part of it." Some patients describe this as a "black spot," a "pink spot," or a "shadow." Sometimes, instead, patients complain of "flashing lights" appearing somewhere in their visual field.

The third component of the Susac's Syndrome clinical triad is inner ear involvement---involvement of the cochlea and the vestibular apparatus. Again, it is an autoimmune endotheliopathy in the microvascular of the inner ear that is the problem. This endotheliopathy leads to narrowing of the channel within the tiny blood vessels that feed the cochlea and vestibular apparatus, and the resultant decreased blood flow and decreased delivery of oxygen and nutrients causes ischemic injury to these tissues.