Review of Susac syndrome

The quest to better understand Susac syndrome has led to advancements in different aspects of the disease. The present article reviews the current literature on the clinical presentation, diagnostic modalities and trends in the management of Susac syndrome.

The pathogenesis of Susac syndrome still remains unclear. Fluorescein angiography demonstrates arterial wall hyperfluorescence of the arterioles at various locations along the course of the vessels suggesting a primary endotheliopathy. Multifocal electroretinogram (mfERG) provides evidence of focal retinal dysfunction related to branch retinal artery occlusion (BRAO). Diffusion tensor imaging demonstrates widespread disruption in the normal appearing white matter with damage to the genu of the corpus callosum considered relatively specific for Susac syndrome. Single photon emission computerized tomography imaging failed to identify perfusion abnormalities with 99mTc-ethyl cysteinate dimer in a patient with Susac syndrome.

Susac syndrome is a multisystemic microvascular occlusive endotheliopathy with suspected immune-mediated pathogenesis. The incidence may be more common than previously thought. Diagnosing Susac syndrome can be challenging, especially in patients presenting without all features of the clinical triad of encephalopathy, BRAO and hearing loss. Awareness of the condition, a high index of suspicion in any patient with unexplained encephalopathy, a dilated fundus examination, audiogram and typical MRI findings aid in the prompt diagnosis of the condition. Successful treatment has been documented with various immunosuppressive treatment regimens.