Majority of Patients with Susac Syndrome Require Long-Term Immunosuppressive Treatment

The majority of patients with Susac syndrome required sustained therapy of multiple immune-suppressive agents, according to a poster presented at the American Academy of Ophthalmology (AAO) 2020 Virtual meeting.

Susac syndrome is an autoimmune condition that affects the very small blood vessels in the brain, retina, and inner ear. “The rare nature of Susac syndrome, combined with its variable systemic manifestations creates a therapeutic challenge for clinicians,” Sruthi Arepalli, MD, of the Department of Rheumatology at the Cleveland Clinic Foundation, and colleagues detailed in their poster.

Dr. Arepalli and colleagues conducted a retrospective review of 22 patients with Susac syndrome with at least 12 months of follow-up performed. Patients had active disease classified as complete (cerebral, retina, and cochlear involvement) or incomplete (cerebral and retinal involvement). Flareups were identified with MRI-confirmed cerebral disease and/or active retinal involvement on fundus exam or fluorescein angiography.

The majority of patients were female (64%). The most common disease type was monocyclic (61%) followed by polycyclic (39%).

At presentation, every patient was started on some form of immunosuppression. Patients with milder manifestations (55%) were treated with a regimen of intravenous immunoglobin (IVIG), an antimetabolite, and corticosteroids. However, almost half of patients (45%) had severe disease burden. These patients were treated with a combination of IVIG, cyclophosphamide, rituximab, an antimetabolite, and corticosteroids.

In all, every patient was treated with corticosteroids; 81% were started on IVIG, 86% on mycophenolate, 50% of rituximab, 14% on cyclophosphamide, and 5% on cyclosporine.

Regardless of the time of treatment they were undergoing, 59% of patients flared during follow-up. Retina flares were more common than central nervous system (CNS) flares (61% vs. 39%). During CNS flares, encephalopathy was more common compared with Corpus Callosum lesions (100% vs. 23%). During retina flares, branch retinal artery occlusion (65%) was the most common sign followed by segmental hyperflourescence (35%).

Only about one-third of patients were able to be tapered off medications. This was more common in the mild and moderate groups.

“There are a spectrum of retinal findings that can point to a flare which should be considered when increasing or tapering immunosuppression,” Dr. Arepalli and colleagues wrote. “In understanding which groups of patients to immunosuppress, we may be able to prevent long-term complications.”

This study was designated a “Best Poster” by AAO 2020 Virtual meeting organizers.