Posterior reversible encephalopathy syndrome in a patient with a Chiari I malformation

The authors describe a unique case of a patient who developed posterior reversible encephalopathy syndrome (PRES) following postoperative treatment of a Chiari I malformation.A 25-year-old female presented with complaints of left upper and lower extremity paresthesias and gait disturbances. A magnetic resonance imaging (MRI) of the brain and cervical spine showed a Chiari I malformation with tonsillar descent beyond the level of the C1 lamina. She underwent a suboccipital craniectomy and C1 laminectomy with cerebellar tonsillar cauterization and duraplasty. Postoperatively, an MRI showed bilateral acute infarcts of the cerebellar vermis. She was initially treated for cerebellar ischemia with hypertensive therapy with a subsequent decline in her neurologic status and generalized tonic-clonic seizure. Further workup showed evidence of PRES. After weaning pressors, the patient had a significant progressive improvement in her mental status.Although the mechanism of PRES remains controversial given its diverse clinical presentation, several theories implicate hypertension and steroid use as causative agents.