Reversible unilateral brain edema presenting with major neurologic deficit after valve repair

Brain edema after cardiac surgery is unusual and often asymptomatic. We encountered a 34-year-old man who had postoperative left flaccid hemiplegia and anosognosia after undergoing composite root replacement and closure of a patent foramen ovale. Computed tomographic and magnetic resonance imaging (MRI) scans showed profound white matter changes indicative of brain edema predominantly in the right hemisphere. His symptoms resolved spontaneously within 3 days with resolution of MRI abnormality. No evidence of cerebral infarction was documented on diffusion-weighted imaging and apparent diffusion coefficient mapping, or on the follow-up MRI obtained 25 days after presentation. The cause for the unilateral brain edema is unknown, but the patient's clinical course and imaging are supportive for a variant of a hyperperfusion syndrome or reversible encephalopathy. The outcome was excellent.