Posterior Reversible Encephalopathy Syndrome (PRES) and the related term Reversible Posterior Leukoencephalopathy Syndrome (RPLS) denote a constellation of clinical symptoms paired with key radiological findings. These symptoms may include headache, altered mental status, visual changes, and seizures. PRES is a rare condition and remains a challenging diagnosis to make in the emergency department. Data on risk factors and clinical presentation are limited, and there is no recent literature-supported diagnostic criteria. Our primary objective was to identify initial symptoms, clinical presentation, and risk factors that should guide the emergency clinician to consider a diagnosis of PRES. A secondary objective was to identify associations between risk factors and the outcomes of mortality and ICU admissions.

This was a retrospective, observational study that evaluated patients seen in the Emergency Department (ED) in an urban tertiary care center with the diagnosis of PRES or RPLS from 1/1/2008 to 1/1/2018. The Health System’s Electronic Medical Record was used to collect data. Search criteria included any patient diagnosed with Posterior Reversible Encephalopathy Syndrome (PRES) or Reversible Posterior Leukoencephalopathy Syndrome (RPLS), and excluded patients under 18 years of age, transfer patients, or patients that were not evaluated in our emergency department.

We identified 98 patients based on our initial search criteria. After a chart review, 27 patients met our predefined eligibility criteria. In patients with confirmed diagnosis of PRES, the majority were female (70%) and 37% were either on an immunomodulator or undergoing chemotherapy at the time of presentation. 67% of patients presented with altered mental status, 41% had a focal neurologic deficit, and 37% had a witnessed seizure prior to diagnosis. Headache (48%), nausea (33%), and vision changes (30%) were the next most common reported symptoms. The majority of patients were hypertensive at time of presentation (82%) and many had a past medical history of hypertension (78%); twelve were given anti-hypertensive medications. 33% of the patients were admitted to the ICU and 26% died. There were no statistical associations found between documented ED interventions and the outcome of mortality.

PRES is difficult to identify and diagnose in the emergency department. Significant risk factors such as female gender, hypertension, and those currently undergoing active immunotherapy/chemotherapy are associated with PRES. Common presenting complaints and exam findings include headache, altered mental status, and neurologic deficits. Emergency providers should consider PRES in patients presenting with altered mental status with significant risk factors, especially with neurologic deficits for which stroke has been ruled out.