A 27-year-old man noted imbalance and staggering when walking. Vertigo, nausea, vomiting, and mild fever developed. This was presumed to be due to an inner ear infection, and antibiotics were prescribed. He began experiencing intermittent left face and arm numbness, bilateral hearing loss and tinnitus. Audiography indicated low-frequency hearing loss in both ears, left worse than right. He reported headaches and neck stiffness, and his family noticed that he was moody, easily aggravated, and confused, with slow mentation. Magnetic resonance imaging showed patchy, nodular, leptomeningeal enhancement involving both cerebral hemispheres and the posterior fossa, with scattered hyperintense T2 signal changes of the internal capsule and prominent abnormal signal changes in the corpus callosum. Cerebrospinal fluid analysis was remarkable for a markedly increased protein concentration and white blood cells. Eye examination showed 20/20 vision in both eyes with a superior visual field defect in the right eye. Retinal whitening was noted in the vascular distribution of the inferotemporal arcade. Intravenous fluorescein angiography showed delayed filling in this region consistent with a branch retinal artery occlusion and scattered areas of arteriolar wall hyperfluorescence. A diagnosis of Susac syndrome was made on the basis of the branch retinal artery occlusion, magnetic resonance imaging findings, and hearing deficit. Intravenous methylprednisolone was given, followed oral prednisone, which resulted in substantial improvement in headaches and cognition. Cyclophosphamide was also started at the same time as intravenous methylprednisolone. A new visual field defect developed due to a branch retinal artery occlusion in the left eye, which prompted initiation of intravenous immunoglobulin and transition from cyclophosphamide to rituximab. He had no recurrent branch retinal artery occlusions or other relapses of his underlying Susac syndrome on this treatment regimen. Susac syndrome was initially described as a microangiopathy of the brain and retina. It is an idiopathic autoimmune disorder that primarily affects the brain, eye, and inner ear.
In vivo identification of alteration of inner neurosensory layers in branch retinal artery occlusion
