title: Posterior reversible encephalopathy syndrome: associated clinical and radiologic findings.
abstract: OBJECTIVE
  To identify and define clinical associations and radiologic findings of posterior reversible encephalopathy syndrome (PRES).
  
  
  METHODS
  Patients prospectively diagnosed as having PRES from October 1, 2005, through April 30, 2009, were pooled with retrospectively identified patients admitted from August 1, 1999, through September 30, 2005. We performed a detailed review of clinical information, including demographics, presenting symptoms, medical history, and risk factors. All patients underwent computed tomography of the brain or magnetic resonance imaging. Findings on magnetic resonance imaging were analyzed independently by 2 neuroradiologists.
  
  
  RESULTS
  We identified 120 cases of PRES in 113 patients (mean age, 48 years). Mean peak systolic blood pressure was 199 mm Hg (minimum-maximum, 160-268 mm Hg), and mean peak diastolic blood pressure was 109 mm Hg (minimum-maximum, 60-144 mm Hg). Etiologies of PRES included hypertension (n=69 [61%]), cytotoxic medications (n=21 [19%]), sepsis (n=8 [7%]), preeclampsia or eclampsia (n=7 [6%]), and multiple organ dysfunction (n=1 [1%]). Autoimmune disease was present in 51 patients (45%). Clinical presentations included seizures (n=84 [74%]), encephalopathy (n=32 [28%]), headache (n=29 [26%]), and visual disturbances (n=23 [20%]). In the 115 cases (109 patients) for which magnetic resonance imaging findings were available, the parieto-occipital regions were the most commonly involved (n=108 [94%]), followed by the frontal lobe (n=88 [77%]), temporal lobe (n=74 [64%]), and cerebellum (n=61 [53%]). Cerebellar involvement was significantly more frequent in patients with a history of autoimmunity (P=.008), and patients with sepsis were more likely to have cortical involvement (P<.001).
  
  
  CONCLUSIONS
  A substantial proportion of patients with PRES have underlying autoimmune conditions that may support endothelial dysfunction as a pathophysiologic mechanism. On brain imaging, the location and severity of vasogenic edema were mostly similar for the different clinical subgroups.
authors.affiliation: Department of Neurology, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA.
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Fugate
authors.forename: Daniel O
authors.initials: DO
authors.lastname: Claassen
authors.forename: Harry J
authors.initials: HJ
authors.lastname: Cloft
authors.forename: David F
authors.initials: DF
authors.lastname: Kallmes
authors.forename: Osman S
authors.initials: OS
authors.lastname: Kozak
authors.forename: Alejandro A
authors.initials: AA
authors.lastname: Rabinstein
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001327:Autoimmune Diseases / Q000150:complications; D001794:Blood Pressure; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D002531:Cerebellum / Q000000981:diagnostic imaging / Q000473:pathology; D002648:Child; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D006973:Hypertension / Q000150:complications; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D054038:Posterior Leukoencephalopathy Syndrome / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology*; D012189:Retrospective Studies; D012307:Risk Factors; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed; D055815:Young Adult