Value of lumbar puncture in identifying secondary causes of visual snow syndrome: A case-control study.

AimVisual Snow Syndrome (VSS) typically begins in early life with no significant diagnostic findings in the neurological and ophthalmological workups. Still, secondary forms of VSS have been reported. This study examines the diagnostic value of cerebrospinal fluid (CSF) analysis and the search for autoimmune encephalitis antibodies in patients with VSS.MethodsIn this retrospective case-control study, CSF samples from 36 VSS patients were analyzed and compared to a control group matched for age, sex, and migraine. In addition, serum and CSF antibodies associated with autoimmune encephalitis or paraneoplastic syndromes were analyzed in VSS patients. Cases with CSF abnormalities were further characterized.ResultsNo significant systematic differences in CSF cell count or protein levels were observed between VSS patients (n = 36) and controls (n = 31). CSF abnormalities in the VSS group included elevated cell counts (n = 4), elevated protein level (n = 1) and oligoclonal bands (n = 1). Autoantibodies associated with autoimmune encephalitis or paraneoplastic syndromes were not detected in either serum or CSF of VSS patients.ConclusionThis corresponds to grade 3b evidence (case-control study), suggesting that lumbar puncture and search for autoimmune encephalitis should not be routinely performed in patients presenting with typical VSS without red flags for additional comorbidities.