Susac syndrome: an imaging-led approach to differential diagnosis and management, with an illustrative postpartum case

Abstract Susac syndrome is a rare immune-mediated endotheliopathy affecting the microvasculature of the brain, retina, and inner ear. Diagnosis is frequently delayed because the complete triad of encephalopathy, branch retinal artery occlusions, and sensorineural hearing loss is often absent at presentation and several inflammatory, vascular, infectious, neoplastic, and genetic disorders may produce overlapping findings. This focused narrative review provides an imaging-led framework for recognizing Susac syndrome, organizing its differential diagnosis, and linking radiologic findings to multidisciplinary management. A targeted literature search was performed in PubMed and Google Scholar using terms related to Susac syndrome, magnetic resonance imaging, retinal angiography, audiovestibular involvement, differential diagnosis, treatment, and pregnancy. Characteristic magnetic resonance imaging findings include small central corpus callosal “snowball” lesions, later “punched-out” callosal defects, multifocal acute microinfarcts with diffusion restriction, and leptomeningeal enhancement. These findings should prompt fluorescein angiography, optical coherence tomography, audiometry, and vestibular testing even when ocular or auditory symptoms are absent. The differential diagnosis is structured around demyelinating disorders, immune-mediated brain-eye-ear syndromes, primary or secondary vasculopathies, infections, malignancies, and inherited small-vessel diseases; representative images of selected high-yield mimics complement the mechanism-based comparison. A postpartum illustrative case demonstrates how multimodal imaging can resolve an initially nonspecific presentation. Treatment remains based on expert guidance and observational evidence; rapid, severity-adapted immunosuppression and organ-specific monitoring are emphasized because neurological, retinal, and cochlear injury may become irreversible. This practical approach aims to improve early recognition, reduce misclassification as multiple sclerosis or vasculitis, and support timely multidisciplinary care.