Intracranial hemorrhage in posterior reversible encephalopathy syndrome: a systematic review and meta-analysis.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiographic phenomenon characterized by vasogenic edema, predominantly affecting the posterior regions of the brain. The hemorrhagic variant of PRES has been increasingly recognized, complicating the clinical picture and prognosis. METHODS: This meta-analysis was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Observational studies and case reports/series were included. Extracted data included demographics, clinical presentations, imaging findings, and outcomes. A random-effects model to pool the incidence rate of hemorrhagic PRES and heterogeneity was assessed using the I2 statistic. The Joanna Briggs Institute scale for case reports/series and the Newcastle-Ottawa scale for cohort studies were used for quality and risk of bias assessment. RESULTS: A total of 63 individual records and 12 cohort studies were reviewed. Hypertension at arrival was seen in > 90% of cases. Overall, 60.3% of cases occurred in women and the average age was 39.3, with a 12.7% mortality rate. The incidence rate of hemorrhagic PRES was found to be approximately 17%, with significant heterogeneity among the included studies (I2 = 67%). Seizures (31.7%), headaches (33.3%), and altered mental status (30.1%) were the most reported symptoms. Hypertension (31.7%), immunosuppressive therapy (23.8%), and coagulopathy (11.1%) were identified as the most common risk factors. Hemorrhagic findings included intraparenchymal hemorrhage (77.7%), subarachnoid hemorrhage (15.8%), and microhemorrhages (6.3%). CONCLUSIONS: Hemorrhagic PRES is a significant clinical concern, occurring in approximately 17% of PRES cases, and is often associated with poorer outcomes. We highlight the importance of early recognition, aggressive blood pressure control, and careful monitoring in high-risk patients.