The clinical characteristics of posterior reversible encephalopathy syndrome in patients with chronic renal failure.

Few studies have investigated posterior reversible encephalopathy syndrome (PRES) in patients with chronic renal failure (CRF). The present study analyzed the clinical manifestations, laboratory examinations and imaging features of PRES in patients with CRF. A total of 42 patients with CRF with or without PRES were recruited in the current retrospective case-control study. Patient data taken prior to the onset of PRES in patients with CRF and PRES (n=21) were collected and analyzed. At the same time, data from patients with CRF but without PRES (n=21) were also analyzed. Brain magnetic resonance imaging (MRI) scans were collected from patients in the PRES group. The mean blood pressure of patients in the PRES group was significantly higher than that of the control group (systolic blood pressure: 172±15 mmHg vs. 135±14 mmHg, P<0.01; diastolic blood pressure: 95±16 mmHg vs. 64±13 mmHg, P<0.01). Furthermore, compared with the control group, mean serum albumin (Alb) and hemoglobin (Hb) concentrations in the PRES group were significantly lower (Alb: 29.1±5.3 g/l vs. 34.6±6.1 g/l, P=0.001; Hb: 74±16 g/l vs. 89±28 g/l, P=0.037). By contrast, mean LDH concentration was significantly higher in the PRES group (LDH: 336±141 U/l vs. 235±89 U/l, P=0.004). In the PRES group, 24 h urine volume was significantly lower in the PRES group than in the control group (24 h urine volume: 651±520 ml vs. 982±518 ml, P=0.046). No significant differences in levels of serum potassium (4.5±0.6 mmol/l vs. 4.4±0.5 mmol/l, P=0.377), sodium (138.3±4.9 mmol/l vs. 139.0±6.8 mmol/l, P=0.325), calcium (2.0±0.24 mmol/l vs. 1.9±0.24 mmol/l, P=0.673), alanine aminotransferase; (24±14 U/l vs. 18±8 U/l, P=0.975); aspartate aminotransferase (29±11 U/l vs. 24±9 U/l, P=0.619) and uric acid (448±148 µmol/l vs. 378±116 µmol/l, P=0.599) were found between the two groups. PRES is a relatively common nervous system complication arising in patients with CRF. Certain biochemical markers, including Hb and Alb, may be associated with PRES. Diagnosing PRES is difficult as computed tomography (CT) brain scans may be normal and MRI scans, which are more sensitive than CT scans at diagnosing PRES, are not always performed in patients with CRF. Thus, brain MRI scans should be taken first in such patients when PRES is suspected.