Update on Susac's syndrome

PURPOSE OF VIEW: We review recent developments in the clinical course and imaging modalities for Susac's syndrome, a clinical triad consisting of encephalopathy, branch retinal artery occlusions and sensorineural hearing loss.

Susac's syndrome has variable clinical presentations; recently described presentations include epileptic seizures and transient inverted vision. Advances in neuroradiology suggest that magnetic resonance imaging demonstrates distinctive patterns in the white and grey matter and in the leptomeninges. Reports have verified that Susac's syndrome is under-diagnosed because of its multisystem involvement and confusion with other imitating disorders (such as multiple sclerosis), and because of the fact that neuroradiologists are not acquainted with this syndrome.

The precise aetiology of Susac's syndrome is still unknown and many areas have not yet been explored. Magnetic resonance imaging is the neuroimaging study of choice. Findings include multiple small hyperintense foci on T2-weighted images and contrast enhancement in white and grey matter of both supratentorial and infratentorial structures, corpus callosum and, occasionally, leptomeninges. Callosal lesions typically involve the central fibres and are probably pathognomonic for Susac's syndrome. When assessing patients with unexplained encephalopathy involving white and grey matter, leptomeninges and corpus callosum, the findings of sensorinueral hearing loss or visual disturbances may yield important clues regarding the possibility of Susac's syndrome.