2020–2021 BCSC Basic and Clinical Science Course™
9 Uveitis and Ocular Inflammation
Chapter 9: Posterior Uveitis and Panuveitis
Susac syndrome (also known as SICRET syndrome, for small infarctions of cochlear, retinal, and encephalic tissue) is a rare entity, initially reported in 1979 by Susac and colleagues. The clinically observed triad consists of encephalopathy, hearing loss, and branch retinal artery occlusions (BRAO). The syndrome occurs mostly in young women but has been noted in patients aged 16–58 years.
The differential diagnosis at presentation includes multiple sclerosis, herpetic encephalitis, acute disseminated encephalomyelitis, and Behçet disease; however, ocular findings are highly specific and may aid in diagnosis. Ophthalmoscopy shows diffuse or localized narrowing of retinal arteries with a “boxcar” segmentation of the blood column at the level of peripheral retinal arteries (Fig 9-6A). Vitreous haze or cells are absent. Angiography demonstrates focal nonperfused retinal arterioles with hyperfluorescent walls (Fig 9-6B). There is usually no evidence of embolic material or inflammatory reactions around the vessels. Magnetic resonance imaging (MRI) is another useful diagnostic tool and shows multifocal supratentorial white matter lesions; the corpus callosum may be involved. Audiometry should be performed in any patient being evaluated for this entity; sensorineural hearing loss is a common finding.
Figure 9-6 Susac syndrome. A, Color fundus photograph revealing an area of intraretinal whitening corresponding to a superotemporal branch artery occlusion in the left eye. B, Fluorescein angiogram showing a superotemporal branch artery occlusion with multiple areas of segmental staining well away from sites of bifurcation.
(Courtesy of Albert T. Vitale, MD.)
Dörr J, Krautwald S, Wildemann B, et al. Characteristics of Susac syndrome: a review of all reported cases. Nat Rev Neurol. 2013;9(6):307–316.
Treatment Treatment remains controversial and includes high-dose intravenous corticosteroids, anticoagulants, and IMT, such as intravenous immunoglobulin and mycophenolate mofetil. The course of Susac syndrome is not always self-limiting, and isolated retinal arteriolar involvement may occur as a very late manifestation.
Excerpted from BCSC 2020-2021 series: Section 9 - Uveitis and Ocular Inflammation. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.