SUSAC SYNDROME: CASE SERIES FROM ADULT & PEDIATRIC TERTIARY ACADEMIC MEDICAL CENTERS
Authors: Couette N et al.
Susac Syndrome (SS) is a rare autoimmune endotheliopathy that affects the brain, retina, and inner ear, characterized by a clinical triad of encephalopathy, retinal artery occlusion, and sensorineural hearing loss.
In this retrospective case study the clinical features and therapeutic strategies in adult and pediatric patients with Susac Syndrome was described.
The authors found 9 patients (seven adult- patients and two pediatric-onset patients). All of them were females, and the majority (78%) were Caucasian. The age at presentation ranged from 10 to 45 years old with a mean age of 38 years. The time to diagnosis ranged from 3 to 17 months with a mean of 7.8 months. The most common symptoms at onset included dizziness, hearing loss, and visual change. ESR was elevated in 50% with a range of 23 to 52 mm/hr. CRP was elevated in 22% of patients with a range of 11 to 22 mg/dl. Low to medium titer ANA was positive in 30%. Seven out of 9 patients had unilateral or bilateral retinal artery occlusion. Sensorineural hearing loss was confirmed on audiogram testing in 7 of 9 patients, and 4 patients had bilateral hearing loss. 88% of the patient population had evidence of corpus callosal involvement («snowball lesions») in the brain MRI. CSF study was done in 5 patients. 4/5 had elevated CSF protein at 77 mg/dL (range 15-45 mg/dL) and the mean cell count was <3 (normal), without any oligoclonal bands.
The most common initial treatment was high-dose steroids. Oral immunosuppressive therapy with mycophenolate mofetil (MMF) was initiated in 78% and was maintained in 56% of patients, who remained stable. Intravenous immunoglobulin (IVIG) was initially used in 56% of patients. Two patients transitioned from MMF to azathioprine due to pregnancy. Due to the severity of the disease, one patient transitioned from MMF to tacrolimus and Rituximab. 20% had a disease flare after the initial therapy requiring additional immunosuppression.
Although the Susac Sndrome is a rare, neurological disease, we rheumatologists should know about this syndrome. This clinical picture belongs to the spectrum of vasculitis. In patients with visual and hearing disorders and possible elevated inflammation markers, this syndrome should be considered.
Treatment depends on the severity of the presentation and involves the use of high-dose corticosteroids along with immunosuppression including mycophenolate, IVIG, tacrolimus, rituximab, and cyclophosphamide.