Background: Posterior reversible encephalopathy syndrome (PRES) is a complication that occurs during treatment of various diseases. Imaging examination is the gold standard for diagnosis. PRES occurrence in patients with hematological malignancies results in poorer prognosis and higher mortality. We aim to establish a practical and operable scale for early prediction, assessment of the severity of the Posterior Reversible Encephalopathy Syndrome, and timely intervention for better prognosis.

Methods: The scale was designed by reviewing the literature and by referring to clinical practice. We assessed the reliability and validity of the scale. Scale-based assessment of children undergoing chemotherapy for acute lymphoblastic leukemia was conducted as early warning and intervention for those who may have PRES.

Results: Establishment of Posterior Reversible Encephalopathy Syndrome early warning scoring (PEWS) scale included three parts, as follows: (1) risk factors, including underlying disease, hypertension, Infection, and drug toxicity; (2) clinical features, including high cranial pressure, visual symptoms, seizure, and disturbance of consciousness; and (3) EEG features, including slow wave and epileptiform discharges. Utility assessment of PEWS scale showed that in 57 patients with acute lymphoblastic leukemia, 54 scored less than 10 and none of them were detected as PRES. The other two had scores of 12 and 13 and were both diagnosed with PRES by brain MRI scan.

Conclusions: PEWS scale can predict PRES early. PRES was highly suspected when the score was 10 points or more. Thus, prophylactic intervention can be given to improve the prognosis of PRES.