Original Article
Blood Pressure Fluctuations in Posterior Reversible Encephalopathy Syndrome

https://doi.org/10.1016/j.jstrokecerebrovasdis.2011.03.011Get rights and content

Background

Posterior reversible encephalopathy syndrome (PRES) can be a consequence of hypertensive crisis and is often associated with rapid fluctuations in blood pressure (BP). However, the role of these BP changes in the pathogenesis of PRES has not been formally studied. Our objective was to analyze the relationship between BP fluctuations and the occurrence of PRES.

Methods

We identified consecutive patients who developed PRES in the hospital and compared them with randomly selected controls matched for age, gender, and history of hypertension (HTN). Systolic BP (SBP) and diastolic BP (DBP) were collected at 2-hour intervals over a 48-hour window before the onset of PRES symptoms. A profile of changes in the values of SBP, DBP, mean arterial pressure (MAP), and pulse pressure (PP) over the 48-hour window was summarized for each individual by calculating a single number (M value) using the approach by Service et al. Comparisons of these summary numbers between the 2 groups (cases and controls) were made with the Wilcoxon signed rank test because of the smaller sample size and paired nature of the data. All tests were 2-sided, and P < .05 was considered statistically significant.

Results

We analyzed the BP profiles in 25 cases of PRES and 25 controls. The median age of PRES patients was 54 years (range 31-72). Fourteen of them (56%) had a history of HTN. Hypertensive encephalopathy was considered the underlying cause of PRES in 13 patients (52%). At the time of the first symptoms of PRES, the mean SBP was 182 ± 20 mm Hg (range 218-145), DBP 95 ± 16 mm Hg (range 134-62), MAP 124 ± 15 (range 152-93), and PP 87 ± 18 (range 123-46). While BP was higher in PRES cases, the severity of HTN was variable and BP fluctuations were not significantly more common than in controls (P = .38 for SBP, .79 for DBP, .25 for MAP, and .73 for PP, respectively).

Conclusions

Although acute HTN is frequent in patients with PRES, BP fluctuations do not appear to be more common in hospitalized patients who develop PRES compared with controls matched for age and history of HTN. Other predisposing factors must therefore contribute to the development of PRES.

Section snippets

Methods

We identified consecutive cases of PRES from the medical registries and radiology logs of 2 medical centers: Saint Marys Hospital (Mayo Clinic, Rochester, MN) and the University of Minnesota Medical Center (Minneapolis, MN). The study period extended from October 2005 until June 2006. The study protocol was approved by the institutional review boards of both academic centers.

The inclusion criteria for cases to be entered into this study were: 1) a confirmed diagnosis of PRES, defined by the

Results

We identified 25 cases of PRES in hospitalized patients (for reasons other than PRES), 25 controls matched for age and gender, and 25 controls matched for age, gender, and history of HTN. The median age among PRES cases was 54 years (range 31-76) and among controls 54 years (range 32-73). There were 16 women in each of the groups. History of HTN was present in 14 patients (56%) in the PRES group and control group 2. PRES was primarily ascribed to acute HTN in 13 cases (52%). Other predisposing

Discussion

Our findings indicate that hospitalized patients who develop PRES have higher BP than hospitalized controls matched for age, gender, and history of HTN. However, the severity of HTN in PRES cases is variable and not extreme. Furthermore, BP fluctuations before PRES onset are not more common than in other patients with history of HTN.

The pathophysiology of PRES remains incompletely understood. The most commonly held theory postulates that acute HTN exceeding the autoregulatory capacity of the

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