Susac’s syndrome is a triad of retinal artery occlusion, sensorineural hearing loss, and encephalopathy. Neuroimaging findings include white matter lesions, deep gray matter lesions, and leptomeningeal disease. Occasionally however, diagnosis is difficult as patients present with incomplete triads. Treatment of Susac’s syndrome is also challenging, particularly in patients with ongoing disease activity.

49 year old male developed new onset headaches, followed by an acute confusional state. He left the stove on in his apartment and tried to enter his neighbors’ home half-dressed. He was brought to the hospital by police.

MRI Brain revealed foci of T2 hyper-intensities predominantly in the corpus callosum, basal ganglia and cerebellum. Imagining findings were suspicious for Susac Syndrome given classic ‘snowball’ appearance. CSF analysis showed elevated protein. Oligoclonal bands were absent. Patient had no visual symptoms but fluorescein angiography showed arteriolar wall hyperflourescence and Gass plaques in the right eye. Patient reported mild sensorineural hearing loss which was confirmed with auditory testing. A diagnosis of Susac Syndrome was made and treatment started with steroids, IVIG and cyclophosphamide. He had significant clinical improvement, but repeat MRI showed persistent leptomeningeal enhancement. Cyclophosphamide was changed to mycophenolate mofetil. However, follow-up MRI Brain redemonstrated white matter hyper-intensities, nodular leptomeningeal enhancement and worsening cerebral and cerebellar atrophy.

We report the case of a patient with Susac’s syndrome who initially responded well to treatment though subsequent imaging demonstrated progressive brain atrophy. There is no published data to suggest whether ongoing atrophy is a marker of disease progression despite stable clinical symptoms. This emphasizes the need for biomarkers to clearly monitor disease activity. The case also highlights leptomeningeal involvement in some patients with Susac’s and suggests that treatment algorithm may need to be expanded in this subgroup. Additionally, early diagnosis and aggressive therapy is vital in preventing disease progression.