Objective:

To describe a potential novel association between adenovirus infection and the onset of Susac Syndrome (SuS).

Background:

SuS is a rare autoimmune endotheliopathy of the brain, retina, and inner ear which classically presents with encephalopathy, branch retinal artery occlusion (BRAO), and sensorineural hearing loss. Its pathophysiology is presumed immune-mediated, and infectious triggers have been proposed. Adenovirus has not previously been described as an infectious trigger for SuS.

Design/Methods:

Case report.

Results:

A 24-year-old woman presented with two weeks of progressive headaches, fevers, nausea, and cognitive decline. Examination revealed lethargy, disorientation, and left-sided arm/leg weakness. Given the presence of headaches, fevers, and nausea/vomiting, a broad infectious workup was obtained and notable for a positive adenovirus PCR on a respiratory viral panel. MRI brain demonstrated diffusion-restricting lesions in the corpus callosum, deep white matter, and pons. CSF studies showed lymphocytic pleocytosis (WBC 8; 92% lymphocytes, 8% monocytes) and elevated protein (201 mg/dl). Serum and CSF evaluations for infectious, autoimmune, and neoplastic/paraneoplastic etiologies were otherwise unrevealing. Fluorescein angiography revealed left eye periarterial vasculitis and right eye focal BRAO, consistent with SuS. Audiology evaluation was normal. The patient received IV steroids (1000mg methylprednisolone for 7 days) and a course of IV immunoglobulin (IVIg, 2000 mg/kg total over 3 days) for probable SuS. She had marked improvement in symptoms and was continued on maintenance rituximab, IVIg, and a prednisone taper in the outpatient setting.

Conclusions:

This case highlights a possible link between adenovirus and SuS, suggesting that infection may act as a trigger in susceptible individuals. Infectious triggers have been proposed in SuS, however, an association with adenovirus infection has not yet been reported. SuS often presents with nonspecific clinical features such as encephalopathy, making diagnosis challenging. Recognizing parainfectious presentations may aid in early detection and potentially improve understanding of pathophysiology.