title: Asymmetric papilledema in idiopathic intracranial hypertension.
abstract: BACKGROUND
  Very asymmetric papilledema in idiopathic intracranial hypertension (IIH) is rare, and few studies have dealt with this atypical presentation of IIH. Our aim was to describe the clinical and radiologic features of patients with IIH and very asymmetric papilledema.
  
  
  METHODS
  We identified all adult patients from our IIH database with very asymmetric papilledema defined as a ≥2 modified Frisén grade difference between the 2 eyes. Demographic data and initial symptoms were collected, and all brain imaging studies performed at our institution were reviewed.
  
  
  RESULTS
  Of the 559 adult patients with definite IIH, 20 (3.6%; 95% confidence interval [CI], 2.3-5.6) had very asymmetric papilledema at initial evaluation. They were older (39 vs 30 years; P < 0.001), had lower cerebrospinal opening pressure (35.5 vs 36 cm of water; P = 0.03), and were more likely to be asymptomatic compared with patients with symmetric papilledema (27% vs 3%; P < 0.001). Visual fields were worse on the side of the highest-grade papilledema (P = 0.02). The bony optic canal was smaller on the side of the lowest-grade edema in all 8 patients (100%) in whom the imaging was sufficient for reliable measurements (P = 0.008).
  
  
  CONCLUSIONS
  IIH with very asymmetric papilledema is uncommon. Very asymmetric papilledema may result from differences in size of the bony optic canals, supporting the concept of compartmentation of the perioptic subarachnoid spaces.
authors.affiliation: Departments of Ophthalmology (SB, BBB, NJN, VB) and Neurology (BBB, NJN, VB), Emory University School of Medicine, Atlanta, Georgia; Department of Epidemiology (BBB), Rollins School of Public Health and Laney Graduate School, Atlanta, Georgia; and Departments of Radiology and Imaging Science (AMS) and Neurological Surgery (NJN), Emory University School of Medicine, Atlanta, Georgia.
authors.forename: Samuel
authors.initials: S
authors.lastname: Bidot
authors.forename: Beau B
authors.initials: BB
authors.lastname: Bruce
authors.forename: Amit M
authors.initials: AM
authors.lastname: Saindane
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Newman
authors.forename: Valérie
authors.initials: V
authors.lastname: Biousse
mesh_terms: D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D001921:Brain / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010211:Papilledema / Q000175:diagnosis* / Q000209:etiology*; D011559:Pseudotumor Cerebri / Q000150:complications*; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D015898:Tomography Scanners, X-Ray Computed; D014794:Visual Fields