A 28-year-old woman with an intrauterine pregnancy presented to the emergency department with progressive suboccipital neck pain and generalized headache. Medical history included pregestational diabetes mellitus and chronic hepatitis B virus infection. Her blood pressure was 179/102 mm Hg. The patient was given acetaminophen orally and intravenous magnesium sulfate and hydralazine to manage preeclampsia. The patient had a grand mal seizure with postictal residual right upper and lower extremity weakness 4 hours after admission. A computed tomographic image taken after the seizure revealed hypodense areas scattered throughout the brain parenchyma, suggestive of vasogenic edema without evidence of intracranial hemorrhage. A magnetic resonance image showed areas of increased T2 and fluid-attenuated inversion recovery within white matter (Image A, arrows), consistent with posterior leukoencephalopathy syndrome (PRES). The patient was given nifedipine to manage her blood pressure and underwent physical therapy to strengthen right-sided weakness. She was discharged on hospital day 7. Repeated magnetic resonance imaging at a 6-week follow-up showed improvement of edematous brain parenchyma (Image B).