Is hypertension predictive of clinical recurrence in posterior reversible encephalopathy syndrome?

Posterior reversible encephalopathy syndrome (PRES) has a distinctive clinical presentation and typical neuroimaging findings. However, data on its clinical course and recurrence are scarce. This study aims to investigate its clinical profile and factors that predict recurrence. We included patients diagnosed with PRES between 2005 and 2010 and collected data on demographics, presenting symptoms, co-morbidities, risk factors, clinical parameters, MRI findings, complications and recurrence. Patients were categorized into two groups: PRES due to primary hypertension and PRES due to secondary causes. Correlation with presenting symptoms, radiological features, and recurrence were analyzed. PRES was identified in 28 patients. Fourteen (50%) had primary hypertension. Secondary causes included immunosuppression-related (39%), preeclampsia/eclampsia (7%), and marijuana-intake-related (4%) causes. Patients presented with altered mental status (79%), headache (75%), seizure (68%), visual disturbance (39%) and hemiparesis (21%). On MRI 93% had the typical parietal-occipital involvement. The frontal lobe was affected in 64%, cerebellum in 29%, brainstem in 21%, and basal ganglia in 11%. About 36% had cortical involvement; 21% had diffusion-restricted lesions. Non-aneurysmal subarachnoid haemorrhage was found in 18% of patients and intracerebral hemorrhage in 14% of patients. No significant difference existed in presenting symptoms and the MRI distribution of vasogenic edema between the primary hypertension group and the secondary causes group. Recurrence occurred in four patients (14.3%, 95% confidence interval 4.2-33.7) and was significantly associated (p=0.05) with primary hypertension as the etiology. Intensive monitoring and treatment of hypertension is recommended for reducing morbidity.