Albuminocytologic Dissociation in Posterior Reversible Encephalopathy Syndrome

Objectives To describe cerebrospinal fluid (CSF) findings in patients with posterior reversible encephalopathy syndrome (PRES) and to study its association with vasogenic edema. Patients and Methods Retrospective review of 73 consecutive prospectively collected adults diagnosed with PRES from January 1, 2000, through December 31, 2014, who underwent lumbar puncture. Results Seventy-three patients (mean age, 51±17 years), were included in the analysis; of these, 50 (69%) were women. The most common causes for PRES were hypertension (n=61 [84%]) and immunosuppression (n=22 [30%]). Renal failure was present in 42 (58%) patients. The median interval between clinical onset of PRES and CSF analysis was 1 day (interquartile range [IQR], 0-2 days). The median opening pressure was 23 cm H₂O or 17 mm Hg (IQR, 18-28 cm H₂O or 13-21 mm Hg), although it was available in only 27 patients. The median CSF protein level was 58 mg/dL (IQR, 44-81 mg/dL; normal value, <35 mg/dL). The median CSF protein level was higher in patients with more extensive vasogenic edema. The median white blood cell count was 1 cell/μL (IQR, 1-2 cells/μL). Conclusion Elevated CSF protein level without CSF pleocytosis commonly occurs in patients with PRES and is directly associated with the extent and topographical distribution of cerebral edema. Although mild CSF pleocytosis can also occur, it is an uncommon finding and may prompt consideration for further diagnostic testing.