A 48-year-old female with uncontrolled hypertension, chronic kidney disease, and polysubstance use disorder presented to the emergency department with abdominal pain and emesis of unknown duration. Shortly after admission she had her first lifetime seizure. After initial treatment, EEG was without definitive lateralizing or epileptiform findings. MRI revealed vasogenic edema, extensive in the brainstem and only mild in the parietal and occipital lobes. Without other laboratory or imaging explanations, the etiology was felt to be PRES, likely triggered by uncontrolled hypertension related to cocaine use and opiate withdrawal. Ultimately, with aggressive blood pressure management, the patient had complete resolution of symptoms and imaging findings.

This case demonstrates a classic clinical presentation of PRES, but with atypical radiographic findings. PRES is an acute onset neurological disorder that commonly presents with headache, altered mental status, visual deficits, and seizure. Typical imaging findings of PRES include vasogenic edema in the parietal and occipital lobes, which is present in 98% of patients. Edema can also occur in the frontal lobes (68%), temporal lobes (40%), and cerebellar hemispheres (30%), basal ganglia (14%), and brain stem (13%). This patient’s imaging was particularly striking as there was such extensive brainstem involvement, yet only minimal parietal and occipital involvement.

As described in this case, if diagnosed and treated rapidly, PRES generally has a good prognosis. The unique radiographic findings in this case add to the current body of evidence that PRES can instead present predominantly with extensive brainstem involvement. As a result, it is important to keep PRES on the differential in cases of brainstem edema.