Vision Loss in Subacute Sclerosing Panencephalitis: A Systematic Review of Case Reports and Case Series.

Vision loss is a presenting complaint in many patients with subacute sclerosing panencephalitis (SSPE). Data related to vision loss in SSPE is available only in the form of case reports. In this systematic review, we evaluated characteristics of vision loss, affected anatomic site, and patient course and outcome. We extracted data from four databases: PubMed, Embase, Scopus, and Google Scholar. The last search was done on October 26, 2022. We adhered to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The protocol was registered with PROSPERO (CRD42022362652). Dyken's criteria were used for the diagnosis of SSPE. The data were recorded in an Excel sheet. The Joanna Briggs Institute Critical Appraisal tool was used to assess the quality of data. The mean age of patients with SSPE was 17.9 years. Males outnumbered females (60:34). In 73 patients (76%), duration of illness/onset of vision loss was less than 6 months. In 76% patients (n = 73), visual manifestations appeared before encephalopathy. Involvement of the retina (58 of 96, 60.4%), optic nerve (9 of 96, 9.3%), or cerebral cortex (29 of 96, 30.2%) was responsible for vision loss. T2/fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) parieto-occipital hyperintensities were the most frequent (71.4%) neuroimaging abnormality. Retinal biopsy revealed similar findings revealed by brain histopathology. All patients died and became akinetic mute during the follow-up period, which ranged from a few weeks to a few years. In conclusion, retinal involvement was the most common cause of vision loss. Vision loss often precedes encephalopathy. Cortical vision loss was associated invariably with T2/FLAIR MRI hyperintensities in the parieto-occipital region.