Characteristics and management of Susac syndrome in an emergent country: a multi-center case series from Brazil

Background: Susac syndrome (SS) is a rare endotheliopathy with an estimated prevalence of 0.14-0.024 per 100,000. It is an important differential diagnosis in demyelinating disorders. There are few case series and no large randomized controlled trials, and most reports come from developed countries. We report six cases of SS in three centers in Brazil and discuss management challenges in emergent countries.

Methods: This is a retrospective case series of patients diagnosed with SS in three medical centers in Brazil between April 2018 and July 2021. The European Susac consortium (EuSaC) criteria were used for diagnosis of SS. Demographic data and clinical interventions were described and outcomes were assessed subjectively and by applying the modified Rankin Scale (mRS) on last follow-up.

Results: Six patients were diagnosed with SS (3 males, 3 females). Mean age at presentation was 36 years (range 17 to 54). The most common initial symptom was confusion, followed by visual impairment and hearing loss. Characteristic snowball lesions on magnetic resonance imaging (MRI) were present in four patients (66%). Retinal artery abnormalities were present in half (3/6) of patients, and sensorineural hearing loss was present in four patients (66%). Outcome was favorable (mRS ≤ 2) in five patients (86%). Patients treated early had a more favorable outcome.

Conclusion: Emergent countries face challenges in the diagnosis and management of patients with SS, such as access to advanced tests (fluorescein angiography, serial MRI) and treatment drugs (rituximab, mycophenolate). Further research should consider particularities of patients with SS in emergent countries.